T. Cloake, C. Bastien (Coventry University), J. Hardwicke (University Hospitals Coventry and Warwickshire), D. Venetsanos (Coventry University), C. Neal-Sturgess (University of Birmingham)
The Total Human Model for Safety (THUMS) is widely used for biomechanics research and validated at the component and full-body levels. Nonetheless, some authors have reported differences in predictions between the model and real-life injuries, particularly in the lower limbs. This study aims to perform an extensive critique of the THUMS lower limb and identify areas for improvement. The THUMS model was assessed across quasi-static and dynamic validation tests to understand geometry, material properties and response to impact. The study has highlighted that the THUMS’ geometry is comparable to published cadaveric data for bones and ligaments, but soft tissues (muscle, adipose and skin) and fascia have significant simplifications.
C. Liebold (DYNAmore), D. Zerbst (German Aerospace Center), T. Gereke (TU Dresden), S. Clauß (Mercedes Benz)
Automotive interior components in upper-class vehicles are often made of wood veneer sheets that are subject to a forming process . Due to the anisotropy and inhomogeneity of the material caused by the development of annual rings during the growth of the tree, establishing a stable production process based on trial-and-error forming tests is time-consuming and costly . Hence, numerical methods for simulating the forming process are in high demand to support the development of feasible trim part geometries. The key for reliable process simulations of wood-based materials is the consideration of the variability of material properties.
H. Zheng, K. Upadhyay, F. Litwa (Mercedes-Benz), K. Paetzold (University of the German Federal Armed Forces Munich)
The virtual process chain is an essential step for the sustainable digital transformation in the manufacturing industry. For the Body-In-White (BIW) sheet metal parts, the manufacturing joining simulation based on finite element method is used to simulate the joining processes in the body shop. The target is to predict the dimensional accuracy of assemblies after using different types of joining technologies. However, the assembly deviation is not only affected by the joining operations, but also by the initial part deviations. Therefore, an integration of geometrical variations in the joining simulation model is necessary to improve the prediction accuracy.
H. Granum (Enodo), D. Morin, T. Børvik, O. Sture Hopperstad (NTNU)
This paper presents a study on AA6016 plates in temper T4 subjected to blast loading. Four different crack-like defects have been introduced in the plates to facilitate crack propagation as the dominating failure mode. Uniaxial tensile specimens extracted from a plate are used in the calibration of the *MAT_258 material model available in LS-DYNA. This material model contains a non-quadratic yield surface, isotropic work hardening and a failure model where the onset of failure is dependent on the element size as well as its bending-to-membrane loading ratio. Four different element sizes are investigated to assess the ability of the model to predict the onset of failure and subsequent crack propagation in blast-loaded plates by comparison to experiments conducted in a shock tube facility.
L. Kappis, P. Froitzheim, Prof. W. Flügge (Fraunhofer IGP)
Roll bending is a manufacturing process in which sheet metal is continuously formed into a round shape with the help of typically three or four rotating rolls. It is used in particular for the production of thick-walled pipes and shells with large volumes, which are used in the maritime sector, in pipeline construction and in the field of renewable energies. In these areas, at the current state of the art, the process is mainly controlled manually. However, the control of the process is of great importance for its efficiency. For example, over-controlling the machine leads to over-bending of the plate and thus often to material waste, whereas under-bending requires additional rolling passes and leads to an increase in production time. To reduce the human influence on the economic efficiency of the process and to objectify the process, research is currently being carried out on the development of automation solutions for roll bending
P. Daniel (Btechc), J. Främby (DYNAmore Nordic), M. Fagerström (Chalmers University), P. Maimí (University of Girona)
The accurate modelling of delaminations is necessary to capture the correct behavior of composite structures subjected to demanding loads. While the use of cohesive elements is valid when the discretization is smaller than the failure process zone , for many composite materials it implies using a fine mesh, typically smaller than 1.0 mm, leading to excessive computational cost for large structures. On the contrary, the Virtual Crack Closure Technique (VCCT) allows the prediction of delamination growth in larger elements  but lacks of an energy dissipation mechanism. Therefore, it leads to excessive vibrations when the delamination propagates in dynamic analyses. The present work aims to combine the best of both methods in order to develop a viable solution for large structures, allowing for coarser meshes than what is possible to use today. To do so, the VCCT is used as a failure criterion to predict damage initiation while a cohesive-like model is added to dissipate the released energy. The model has been implemented in LS-DYNA in the frame of an adaptive user element recently published [3,4]. The model has been validated with Double Cantilever Beam, End-Notched Flexure and Mixed-Mode Bending tests. It demonstrates the ability of the method to accurately model delamination with larger elements and higher stable time step.
M. Schlicht, T. Nehls, P. Froitzheim, Prof. W. Flügge (Fraunhofer IGP)
Increasing resource efficiency, for example through the consistent application and further development of lightweight construction concepts, plays an important role in the development of the mobility sector. This requires a steadily increasing use of high-strength aluminum alloys in primary vehicle structures. A suitable and efficient process for joining high-strength aluminum alloys is solid self-piercing riveting (SSPR). A major advantage of this process is the elimination of time-consuming preparatory work such as pre-drilling, deburring and positioning of the components to be joined, as the rivet punches through these during the installation process. Due to the high stresses on the rivet during the installation process and the lack of knowledge on the use of ultra-high-strength aluminum alloys as the rivet material, solid self-piercing rivets (SSP-rivets) made of steel are generally used. However, against the background of recyclability, thermal expansion and corrosion protection, the use of aluminum SSP-rivets would be desirable.
M. Okamura, H. Oda (JSOL)
In recent years, CAE has been used extensively in vehicle development, and parameter study of sheet metal thickness for design exploration and optimization is one of the major applications. Response surface method is commonly used for this application among various analysis tools. The concept is to connect input variables such as sheet metal thickness and output variables such as firewall intrusion with non-linear functions such as radial base, kriging, and neural network.
K. Bayram, M. Pfeiffer, C. Alter, Prof. S. Kolling (THM)
As the automotive industry and its companies start to look for sustainability, materials made of natural fibers receive a growing interest. In the present work, the mechanical properties of a vulcanized fiber material were investigated to understand the orthotropic and rate-dependent material behavior and make it more predictable and thus practicable. *MAT_PAPER was used to represent the anisotropic elastic-plastic behavior of the material for crash and impact simulations. To confirm numerical results from explicit FEM calculations, a user material subroutine comparable to *MAT_PAPER was utilized. Therefore, it was possible to perform implicit calculations of the conducted validation experiments which were performed at low strain rates.
T. Usta, C. Liebold (DYNAmore), M. Vinot (DLR)
This work focuses on an integrated modeling scheme of a sensor embedded woven composite structure which is created for the joint project “Digitaler Fingerabdruck” (DFA) or in English: “Digital Fingerprint” within the research campus ARENA2036 . The process chain includes a draping simulation of a woven fabric and a trimming simulation using LS-DYNA®, optimization of a tailored-fiber placement process on top of this woven fabric structure using Optistruct®, fiber direction mapping from weaving simulation results using beam elements to shell element target meshes and handling of reinforcing patches using the mapping tool Envyo® . The final goal is to establish an integrated process chain with parametrized variables using LS-OPT® for robustness analysis. A new feature of *MAT_REINFORCED_THERMOPLASTIC (*MAT_249) is also demonstrated to introduce fiber directions as an integration point history variable in global coordinate system to the subsequent simulations .
Z. El Khatib, U. Reuter (TU Dresden), M. Thiele (SCALE)
Numerical simulations are often characterized by long computational times, especially as the size of the model grows larger. In many cases, this necessitates the use of a high-performance computer in order to speed up the simulation and obtain results faster. Nevertheless, computational times can still be large, such as in the automotive and aerospace industries. The automotive industry is highly dependent on numerical modelling. Companies perform numerical simulations for crash analysis in the preliminary phases of design, because it eliminates the need to perform expensive physical crash tests of prototypes. Optimization, another time-consuming process, is also often performed during the different stages of a project and is only possible using virtual testing. However, optimization adds to the scale of computational time needed in the automotive industry for virtual product development. The longer it takes to perform such numerical processes, the longer the time-to-market of a certain vehicle model and eventually, the higher the cost.
Len Schwer Schwer Engineering & Consulting Services
Data and simulation results presented by Teland et al. (2018) for incident and reflected pressure histories indicated the simulation results time of arrival and pressure magnitude did not agree well with the data for the reflected shock. They posited three possibilities for the differences: (1) Charge load (explosive mass per chamber volume), (2) Afterburning and (3) Variable Gamma for the gas mixture.
V. Alvarez (Lightness by Design), H. Wendelrup (Hövding), K. Brolin (Lightness by Design)
For the past 20 years, single-bicycle accidents have been the most common cycling accidents in Sweden (more than 70% of all injuries) [1-4] and in other countries where many people use bikes as means of transportation [5-6]. Vehicles were involved in a majority of the lethal bicycle accidents. Neck injuries were a small portion of all cycling injuries, but they were associate with a large risk of permanent medical impairment. Therefore, it is interesting to explore if head protective safety devices can provide safety benefits for the neck as well. Hövding is a head protective device that is worn as a scarf around the neck, with sensors that trigger inflation of an airbag in case of an accident. Theoretically, the portion of the airbag that surrounds the neck could protect from neck injuries (see Fig. 1).
M. Duhovic (TU Kaiserslautern), I. Caldichoury, P. L’Eplattenier, T. Nguyen (Ansys/LST), J. Hausmann (TU Kaiserslautern), L. Kielhorn, T. Rüberg, J. Zechner (Tailsit)
Previous implementations of LS-DYNA’s EM module have relied on an explicit scheme, requiring very small time-step sizes and therefore long simulation times. Recently, a new magnetostatic solver/ AMS preconditioner has been developed in LS-DYNA®. Unlike the current implementation, the new solver is unconditionally stable with respect to the time-step size and allows for the handling of materials with high permeability and low electrical conductivity. In this paper, the capabilities of the new solver is tested on the use-case of carbon fiber reinforced thermoplastic composite (CFRTPC) laminate induction heating using magnetic flux concentrators/field formers. In the current work, induction heating characterization experiments were performed on carbon fiber poly(ether ether ketone) (CF/PEEK) laminates using two different coil geometries.
A. Kaloudis (BETA CAE Systems)
The level of complexity of the full-vehicle digital crash models varies between car manufacturers. Undoubtedly, however, it is very high and the trend is to become higher and higher, due to the fact that the development teams want their models to include even more details. During all these years a standard technique, that has become of common use, is the fragmentation of the full-vehicle model into *INCLUDE files. Each one contains a distinct physical subassembly of the vehicle, which we shall subsequently name module. This technique offers various advantages, but definitely sets a challenging task. That of connecting the modules to each other and assembling them into a full-vehicle model. Using the embedded capabilities of ANSA we have created processes and tools that enable : i) fast and robust intermodular connections represented by various element types, ii) efficient and reliable integrity check of these connections, iii) the assembly of multi-variant modules, iv) inspection of the connection areas in a lightweight view, v) an error-free update of modules’ versions, vi) the overview of the modules participating in the full-vehicle models with aid of graphs, vii) the reusability of already existing models, as the basis for the creation of new ones.
The substitution of classical constitutive material models with data-driven models supported by machine learning techniques could provide a leap in the modelling of materials. The most notable benefits are a faster description of new materials without a tedious manual parameter identification procedure, lower computational time for simulations due to efficient computation within the material model and a more efficient selection of the correct material model for the use-case. The base for any data-driven model is adequate amount and quality of training data. Based on this, machine learning techniques can be used to train neural networks such that they learn the relationship between given input and output. The mapping in the machine learning based material model will be the strain measures to the stresses, similar to classical models.
S. Hoque (AIT), A. Rauscher (University of Applied Sciences Upper Austria)
The crushing performance of aluminum-CFRP (Carbon Fiber-Reinforced Plastics) hybrid generic crash components under axial compression load is experimentally investigated. Aluminum crash components, having similar geometry, are also crushed and compared with the hybrid components. The performance of the hybrid components is found to be twice as much as that of the aluminum components in terms of peak force and specific energy absorption (SEA). Finite element simulations of the crush tests are carried out in LS-DYNA®. The extended 3-parameter Barlat model (MAT36E) is used to characterize the anisotropic elasto-plastic behavior of aluminum sheet. The CFRP laminate is characterized by an orthotropic linear elastic material model (MAT54) with a progressive failure criterion (Chang and Chang). The aluminum-CFRP interface is modeled using tied contact with cohesive mixed mode failure criterion to capture the delamination behavior. Good agreement is found between experiment and simulation in terms of Specific Energy Absorption (SEA) as well as deformation pattern.
Slides of the presentation from S. Rybak (EDAG)
C. Woll (GNS Systems)
A decision in favor of the cloud and the associated organizational changes are of central strategic importance for automotive OEMs and their suppliers. In advance, it is important to clarify whether existing organizational structures and processes can actually be optimized with the help of the cloud. To this end, we regularly carry out benchmarks for well-known customers as a decision-making aid. In the presentation, we will present a benchmark with real productive jobs based on existing data in the customer’s specific environment. Mapping the workflow with selected CAE applications in the cloud provided a realistic basis for evaluation of their benefits and costs. In addition to comparing runtimes and results of selected benchmark jobs, our experts tested the quality of remote work in a workstation scenario for selected finite element analyses (FEA), Computational Fluid Dynamics analyses (CFD) and iterative analyses.
L. Paris, M. Duchateau (Gexcon France), P. GLAY (DYNAmore France)
There is a need for transitioning to an energy system with less greenhouse gas emissions and more sustainable energy production and consumption. A long-term structural change in energy systems is needed. Germany and France, among other countries, have decided to scale up the green hydrogen sector, with fundings of 9 billion and 7 billion euros respectively in the next 10 years
J. Holmen, J. Johnsen (Enodo), D. Morin, M. Langseth (NTNU)
*MAT_258 (*MAT_NON_QUADRATIC_FAILURE) is a through-thickness failure regularization model for shells in LS-DYNA. In this model the failure indicator is computed as a function of both the size of the element and its bending-to-membrane loading ratio. The constitutive behavior and fracture surface in *MAT_258 are represented by well-known analytical expressions which simplify calibration. We present the calibration process for *MAT_258 with a three-parameter Extended Cockcroft-Latham fracture surface for the high strength steel Docol 1500M. The material card is applied in shell element simulations of three-point bend tests.
R. Nasouri (University of Texas), H. Rokhy (Amir Kabir University), A. Matamoros, A Montaya (University of Texas), R. Backzadeh (Urmia University)
Recently, several constitutive material models have been developed and added to the LS-DYNA library to predict concrete geomaterial behavior. These developments were established merely from using concrete compressive strength, which limits the level of robustness in capturing actual concrete behavior. This study focuses on developing a simplified approach to calibrate six constitutive material models including Soil and Foam, Pseudo Tensor, Geological Cap Model, Concrete Damage Model Rel-3, Johnson Holmquist, and Continues Surface Cap Model against Triaxial and Hydrostatic Compression Tests (TXC and HCT) data. Comparisons between individual numerical results were performed to evaluate whether accuracy can be offered through a corresponding constitutive material model. The presented calibration method can also be applied to different geomaterials such as rock and soil.
P. L’Eplattenier, I. Caldichoury, K. El Houari (Ansys/LST)
Heart disease is among the leading causes of death in the Western world; hence, a deeper understanding of cardiac functioning will provide important insights for engineers and clinicians in treating cardiac pathologies. However, the heart also offers a significant set of unique challenges due to its extraordinary complexity. In this respect, some recent efforts have been made to be able to model the multiphysics of the heart using LS-DYNA.
B. Hirschmann, Y. Nakagawa, N. Matsuura (Honda), H. Pothukuchi, M. Schwab (4a engineering)
Computer simulation is used in many fields of automobile development to shorten the development term and reduce tests. Large plastic parts such as instrument panels and bumper fascia take a lot of time to make a die, so it is necessary to determine the part shape quickly to shorten the term. Therefore, performance verification by simulation is important. However, due to issues such as material property and complicated part shapes, reproduction of phenomena such as deformation and failure are sometimes not sufficiently accurate in simulations of plastic parts. Creating a die, testing part, and evaluating its performance in such a situation may raise the possibility of inadequate performance. In that case, it is necessary to modify the die, which requires extra cost and time. Therefore, high simulation accuracy is necessary to avoid such risks.
M. Herr (AC2T research), M. Varga, L. Widder (AC2T), J. Mermagen, S. Rodinger, W. Harwick (Fraunhofer EMI)
Transport of raw materials in industrial applications usually involves highly abrasive processes and requires wear protection for a reliable, long operation period. At transfer points such as between conveyer belts additional impact loads can limit the lifetime. For such conditions rubber-ceramic hybrid materials can extend the lifetime multifold by combining the wear resistance of ceramics with the impact resistance of rubbers.
S. Maier (University of Stuttgart), M. Helbig (DYNAmore), H. Hertneck (SAS-TEC), J. Fehr (University of Stuttgart)
A study on traffic fatalities  shows that the most frequent causes of motorcyclists’ deaths in accidents are multiple skeletal and visceral injuries. Brain and skull injuries are the second leading cause. An injury frequency and pattern data analysis of discharged riders of powered two-wheelers from hospitals  show that the most common injuries of non-fatal accidents are injuries of the lower extremities followed by upper extremity and traumatic brain injuries. With this data of fatal and non-fatal accidents it can be said that besides head protection, the protection of a two-wheeler rider’s whole body with lower and upper extremities is of major importance.
T. Legaud, V. Lapoujade (DynaS+)
A substantial number of debris coming from human production gravitates around the Earth. Their size, nature, orbit and velocity can extremely vary, but all these debris represent an increasing collision risk and a threat for the current and future spatial activity. The spatial researchers are looking for solutions to limit this risk, by better controlling the launched objects number and by improving the protection of their structures.
A. Jonsson, T. Borrvall, F. Bengzon (DYNAmore Nordic)
Recently, many enhancements have been made to LS-DYNA’s implicit solver with regard to improved robustness and general functionality. New material models, element formulations, and features for convenient load history management all contribute to making the implicit solver more versatile and user friendly. The new features are of course relevant to general analyses, but here a case-study of a combustion engine analysis is presented to illustrate and promote these new features. Focus will be on thermal and mechanical analyses, to evaluate deformation, stress, plastic strain, gasket pressure etc. The built-in fatigue analysis capabilities of LS-DYNA will also be demonstrated since fatigue life is often the design target in structural analyses of combustion engines.
S. Tokura (Tokura Simulation Research Corporation)
Core materials such as honeycomb core panels are used in various industrial products as lightweight and high stiffness materials. As one of the characteristics of the core panel, the sound absorption effect due to the core structure is expected. By using a large core panel for a soundproof wall such as a highway, the possibility of producing a soundproof wall that is lighter than the conventional soundproof wall and has a high sound insulation/absorption effect is being studied. In addition, with the electrification of automobiles, further quietness in the passenger compartment is required, and the use of core panels is being considered for improving the quietness of various transportation machines such as automobiles. Therefore, in this research, we assume several types of core shapes and compare the sound absorption effect of the core panel by modeling the interaction between the core panel and the sound in the air using ALE-based FEM in LS-DYNA®.
E. Svenning (DYNAmore Nordic), K. Mroz (Autoliv), T. Johansen (DYNAmore Nordic), N. Lubbe (Autoliv), J. Iraeus (Chalmers University)
The VIVA+ 50F average female Human Body Model (HBM), currently in early beta status, was compared to the SAFER average male HBM Version 9 with the aim of investigating differences between females and males in terms of kinematics and injury assessment in frontal impacts. The VIVA+ HBM is under development within the research project VIRTUAL and will be released as open source during the summer 2022.
A. Soni, S. Schilling, H.Hinrichs, C. Verheyen, M. Grikschat, B. Eickhoff, A. Lucht, A. Cirstea (Autoliv)
Forward leaning postures have been observed for current car passengers  and are expected to occur even more frequently in future autonomous vehicles . For existing restrain systems a strategy to provide optimized protection is to deploy mechatronic belt pre-pretensioner (MBPPT) before the crash targeting to maintain or better prevent possible forward leaning postures, mostly induced through pre-crash vehicle maneuvers [3 – 5]. Where for future restraint systems in highly automated vehicles [6 – 9] an additional load case for MBPPT might become important. Here the airbag restraint system is mounted into the seat, enclosing the upright occupant during deployment. If the occupant is out-of-position, the enclosure of the restrain system might not function optimally. Hence, a pre-triggered MBPPT can be used to bring the occupant back to the upright position before the crash.
C. Kaulich, L. Benito Cia (GNS)
The current transformations in the automotive industry are forcing all car manufacturers to check their processes constantly and repeatedly for economic efficiency. Regarding the areas of body development, vehicle safety and occupant as well as pedestrian protection, economic efficiency can only be achieved through a high degree of automation in virtual product development. Such a degree of automation is only feasible, if the software used and the integrated models are well coordinated. In this presentation it will be shown how a high precision barrier model and several dummy models can be combined and positioned for any vehicle model within the pre-processor Generator4 with ease. Both direct positioning tools and simulation driven ones can be fully automated in a simple way. Information on positioning and kinematic relationships can be taken directly from the input files. This simplifies the following processes and reduces the error rate due to less manual data input. Generator4 is then able to directly start the simulation with LS-Dyna or other solvers.
A. Kaloudis, A. Poulias (BETA CAE Systems)
The use of topology optimization gives us the capability to create an optimal design for a product, taking into consideration a set of predefined constraints, under certain load cases to which it is subjected. However, its results exhibiting jagged and/or no well-defined boundaries, lead into difficulties, regarding the interpretation of these results into proper CAD geometry, which subsequently could be used downstream in the CAD based product development process or could be parametrized and further optimized. Moreover, the manufacturing process, that will be followed to build the parts or the structure, adds an extra variable and increases the degree of difficulty to the task of creating adequate CAD geometry.
S. Jagtap, D. Thorat, D. Chhetri, S. Vishwakarma (Whirlpool of India), M. Fiori (Whirlpool Technical Center)
The efficient staging and storing of home appliances in warehouses are critical to avoid human injuries and huge losses to the company. After manufacturing the packaged product needs to be stored for a particular duration in the warehouse before it’s shipped out to suppliers. For optimum space management, those products are stacked one over the other. So it is important to have a robust packaging design to ensure even distribution of stacked product loads maintains their stability. Considering the constant loading over a longer period there is a high possibility of creep effects in packaging material, and it becomes even more crucial when packaging material is Expanded Polystyrene (EPS). So it’s imperative to study material creep behavior in designing product packaging. In this study creep behavior of EPS material is evaluated with standard test setup, where precise measurement is done to get creep curves. The results were obtained for long-term constant compressive loading at different stress levels for multiple material densities, at ambient temperature 23°C.
T. Willmann (University of Stuttgart), A. Wessel (Fraunhofer IWM), T. Beier (thyssenkrupp), A. Butz (Fraunhofer IWM), M. Bischoff (University of Stuttgart)
For most sheet metal forming simulations, shell elements that consider a reduced stress state, in particular, assuming a zero transverse normal stress 𝜎33 and neglecting the shear stress components 𝜎13 and 𝜎23 in the yield function, are used. Moreover, certain kinematic assumptions, like cross-sectional material fibers being assumed to remain straight during deformation, are typically applied. However, for some applications, like bending with small radii and thick sheets, this approach is not a workable solution to obtain accurate and reliable results, since the prerequisites that justify the aforementioned kinematic assumptions are not met anymore.
F. Andrieux, C. Frie , D. Sun (Fraunhofer IWM)
Aluminum die casting components are widely used in vehicle constructions because of their good compromise between weight reduction and improvement of mechanical properties. The complex geometries of these components with inhomogeneous defect distribution are a relevant issue, as material with higher defect content shows lower fracture strain. It makes the analysis of the damage behavior for crash simulation more challenging. An extensive experimental investigation is required to quantify the scatter as well as the development of a suitable material model to describe it.
Road traffic accidents and falls are catastrophic events leading to serious injury and in some cases fatality. The dichotomy is that traumatic injuries are assessed using the Abbreviated Injury Scale (AIS), which is a measurement of the probability of death, whilst the engineering tools available to support the understanding of injury causation rely on engineering measurements of stress and strain. Further to this, the problem of ageing is not adequately dealt with using existing engineering tools. The research proposes the development of a generic mathematical injury severity model, based on Peak Virtual Power (PVP) , to establish relationships between AIS, ageing and collision speed. This method, newly implemented JSOL THUMS injury post-processor web-based estimator, has the ability to calculate all AIS levels from the white and grey matter and is defined as a polynomial function. This paper explains the underpinning of the Peak Virtual Power theory, as well as provide the coefficients to calculate brain injury severity under blunt trauma impact.
A. Polla, E. Cestino, G. Frulla, P. Piana (Politecnico di Torino)
Define numerical analysis capable of predicting the behaviors of laminates composites is a research challenge for engineers and scientists from the first implementation of laminated model for shell elements in 1984 . In these last 35 years all aspects of composite materials behavior have been evaluated such as for example, the impact response, crack propagation, crushing resistance. All contributions, for example from Abrate , Farley et al. , Botkin et al.  to actuals individuated a lot of ways to study numerically all aspects associated to related topic, as descripted and clearly resumed in the following picture.
Amritha U, Kottresh Kurudimath, Subhransu Mohapatra SABIC Research & Technology Center, Bangalore, India.
Material models for high-performance thermoplastic polymers need to capture highly complex material characteristics accurately to enable lightweight and sustainable designs. ULTEMTM 1000 Polyetherimide Resin from SABIC’s Specialties business display different behavior under impact loading under multi-axial loading compared to uniaxial tensile testing.
M. Ross, D. Pope (Dstl)
A thermomechanical modelling technique was developed using LS-DYNA for simulating the heating and subsequent erosion of metallic elements by a continuous wave laser beam. Accurate representation of the laser-material interaction requires inclusion of several physical phenomena.
S. Mattern (DYNAmore), M. Koch (Porsche), R. Bitsche (SCALE)
LS-DYNA models for industrial applications are often composed from several smaller sub-models. For example, in the automotive industry the different components of a car are usually modelled separately. These “include files” may be built-up in different departments of the same company or even developed by external suppliers. Due to the huge variety of features and functionalities in LS-DYNA, it is a good idea to set up general rules for the sub-models to achieve robust and efficient simulation models for production. Also, the successful assembly of models can be assured by defining generalized modeling guidelines, especially for the interaction of the different include files.
T. Pierrot, A. Guilpin, T. Legaud, V. Lapoujade (DynaS+), J.-E. Chambe, M. Charlotte, Y. Gourinat (Université de Toulouse), M. Delorme (ATECA)
The ecological transition necessity makes the use of cryogenic fluids more and more relevant. However, experimental tests and associated modelling of those liquids dynamic vibratory behaviour remain extremely challenging. Indeed, security, control and conditioning are critical issues due to the intrinsic fluid instabilities. Among those critical fluids, liquid hydrogen and supercritical xenon are both highly used in the spatial propulsion domain. Because of their hazardous behaviour, only few experimental dynamic tests have been performed to improve the knowledge of their behaviour inside a vibrating tank.
S. Pethe (FCA US), M. Channegowda (Altair), S. Patil, A. Sheshadri, K. Jaboo (FCA)
Current challenges in the auto industry are compelling virtual simulations to predict strength and rupture of MIG welded joints. Rupture prediction of such joints enhances the design and development process. In body-on-frame vehicles most metal parts are joined using MIG welds and strength evaluation of such joints are crucial to vehicle crash and safety performance. Virtual simulation capabilities with these predictions help in enormous ways to reduce cost and time involved in proto-type testing of vehicles in the product development cycles.
C. Liebold, T. Usta (DYNAmore)
From 2017 until mid’ 2020, DYNAmore collaborated with various partners from the manufacturing industry, universities, independent research institutions, and software vendors to develop a software neutral storage format for finite element data. The goal was to define a new standard which allows for the flawless exchange of all the required information, enabling the industrial partners to easily establish closed simulation process chains for production processes, where various software tools with non-consistent data formats have been a barrier in the past. During the project, an interface between the mapping tool Envyo® and the established VMAP standard has been realized and validated with test cases.
M. Styrnik (BMW Group), T. Erhart (DYNAmore)
It is known that the simulation of fastening elements can be carried out by using different approaches. One common way is the use a force-displacement based approach for single-point-connections. While enabling LS-DYNA to calculate crash simulations in our crash simulation tool chain it was necessary to make several adjustments to the standard *CONSTRAINED_INTERPOLATION_SPOTWELD keyword to ensure that the currently available data can be used almost completely.
E. Dagdilelis, T. Fokylidis, T. Lioras (BETA CAE Systems)
With safety protocols and regulations becoming increasingly enhanced, safety analysts try to keep up replicating all possible crash event scenarios in laboratories using specifications that frequently change. In this pursuit, it is crucial for analysts to have at their disposal accurate and robust digital models that enable the tune and study of any real crash event parameter. Through the ANSA pre-processor, BETA CAE Systems offers an extensive crash and safety portfolio of automated tools for simulation modelling, to create a complete “virtual crash and safety laboratory”. Such tools include this of the seat and the dummy guide, from the identification of HPOINT of the seat to the positioning of the coupled restrained seat-dummy system according to a regulation or a test data position, available not only for standard crash dummies but also for human body models. Pedestrian and Interior tools ensure the proper marking of the exterior and interior of the vehicle but also the accurate positioning of the headform to the desired targets. The Impactor tool enables the positioning of barriers/impactors according to all available regulations. Moreover, the Knee Mapping plugin helps the analyst avoid knee modifier, while Airbag stitching and folding tools set up the pre-crash simulations required for the proper treatment of the airbags. The current paper presents all the afore mentioned tools and more handy features that crash and safety analysts need to set up detailed and accurate models for different regulations fast, and with the minimum human interaction.
J. Johnsen (Enodo), L. Dæhli, T. Børvik, O. Sture Hopperstad (NTNU)
During plastic deformation of a metal, a part of the plastic work is stored in the material due to local distortion of the crystal lattice, while the remainder is dissipated as heat. The part of the plastic work dissipated as heat can be observed on a macroscopic scale through thermal measurements in high strain rate experiments. Typically, this fraction of plastic work converted into heat is assumed to be constant and around 90%. In this study, we have performed tension tests at a constant crosshead velocity of 0.6 mm/s on flat notched specimens from a DP600 steel material. Digital image correlation (DIC) was used to apply virtual extensometers spanning the length of the notched area. Furthermore, an infrared camera was used to measure the temperature increase over the same area as monitored by DIC, enabling correlation between temperature and displacement. These temperature-displacement curves were used as the target curves in thermomechanical simulations to obtain the Taylor-Quinney coefficient as a function of the equivalent plastic strain. It was found that the Taylor-Quinney coefficient exhibits quite large variations during the experiment, ranging from a minimum of about 0.5 in the beginning of the test, to about 0.95 at the end of test.
J. Jung, W. Rimkus, S. Mouchtar, J. Schlosser, M. Schmiedt (Hochschule Aalen)
Forming simulation models and the associated material characterisation are important factors when representing the increasingly complex deep drawing operations. Especially in context of automotive components, the finite element analysis ensures producibility prior to pilot series and minimises the risk of wasting resources by predicting the material behaviour as accurately as possible, such as plastic, thermal and anisotropic behaviour. For the representation of the plastic material deformation during forming, material models like Barlat or Hill, representing the real material behaviour as precisely as possible, must be implemented in the simulation. For this purpose, the model needs to describe occurring effects of the material such as anisotropy or further effects.
S. Cassola, M. Duhovic, L. Münch, D. Schommer, J. Weber, J. Schlimbach, J. Hausmann (TU Kaiserslautern)
The strive for high energy efficiency through lightweight design, especially for medium- and long haul aircrafts, has significantly increased the use of carbon fiber-reinforced plastics (CFRP) in the aviation industry in recent years . High specific strength, corrosion resistance and improved fatigue life are only a few advantages that qualify CFRPs as structural parts in aircrafts. However, high material, manufacturing and assembly costs are still restricting their use . Highly automated manufacturing processes, which provide a high degree of mounting part integration are needed to lower the part and assembly costs. Structural frames in aircraft fuselages currently make use of a differential design and consist either of aluminum, which provides insufficient specific strength or carbon fiber-reinforced thermosets, which involve long processing times. To overcome these drawbacks, a carbon fiber-reinforced, thermoplastic frame with integrated mounting parts has been developed in order to reduce the complexity of the assembly process. The frame is manufactured in an one-shot process involving tape preform production by automated tape laying (ATL) and a subsequent thermoforming step. ATL allows near-net-shape manufacturing of preforms, which reduces scrap rates to a minimum . The subsequent thermoforming step enables the production of complex 3D-parts with low cycle time .
M. Triebus, A. Reitz, O. Grydin (Paderborn University), J. Grenz, A. Schneidt, R. Erhardt (BENTELER), T. Tröster, M. Schaper (Paderborn University)
Hot forming of metal parts is characterized by forming over recrystallisation temperature . For steel, press hardening is a popular production technology for creating hardened parts under hot forming conditions. In the conventional press hardening process, the blank is heated above austenitizing temperature and then transferred to the forming tool. The tools are water cooled and therefore ensure a martensitic transformation of the steel material. The most popular alloy is the boron steel 22MnB5, where a tensile strength of around 1500 MPa is reached through press hardening processes. The latest body-in-white concepts show a broad range of press hardened parts. The underlying forming methods are aiming to create purpose build components through variations of the press hardening process like tailored property processes, the use of tailor-welded or tailor-rolled blanks . In the tailored property process, tailoring of the material properties is realized through the decrease of the cooling rate in a designated area of the part e.g., with a heated tool region. Due to the lower cooling rate, a softer and more ductile state is created in this area with microstructures of ferrite, pearlite and bainite. As a result, from the multiphase microstructure of tailored property parts, shape distortion is more pronounced then in conventional press hardening parts with a fully martensitic microstructure. Increased shape distortion can lead to additional rework cycles in the tool manufacturing.
K. El Houari, P. L’Eplattenier, C. Shao, I. Caldichoury, M. Rochette (Ansys/LST)
Sudden cardiac death commonly occurs due to heart rhythm disorders called arrhythmia. Although recognized as the most efficient treatment options, Cardioverter Defibrillator implantation and tissue ablation are still not used to their full potential. Recently, advances in computational modeling and the increasing use of imaging tools have proven that patients’ digital twins can play a role in addressing these limitations. This paper presents such an approach using the industrial software ADAS-3D and LS-DYNA. The workflow starts from Late Gadolinium Enhanced-Magnetic Resonance Imaging (LGE-MRI) data from a patient with structural heart disease. The left ventricle and fibrotic substrate were analyzed using ADAS-3D software, which enables to distinguish between tissue that is healthy, scarred, and intermediate, and to extract topological information. This segmentation and tissue classification are used to build, using LS-DYNA, a detailed electrophysiology model containing the relevant features for simulating arrythmia. Using LS-DYNA, this model is then used to simulate a normal heartbeat and a clinical pacing protocol for inducing arrhythmia.
H. Schmidt (Bertrandt), Prof. A. Matzenmiller, M. Nahrmann (University of Kassel)
Finite element (FE) simulations with constitutive models for softening materials, such as in the case of standard continuum damage mechanics based approaches, suffer from pathological mesh sensitivity as a result of strain localisation into a single element row. To overcome this major drawback, the local damage has to be enhanced towards nonlocal damage evolution. A suitable method for this purpose is the integral nonlocal formulation, available in LS-DYNA® by the keyword *MAT_NONLOCAL. However, its costly underlying search algorithm can result in a strong increase of the simulation time, leading to an impractical application for engineering problems.
A. Iliev, M. Miloshev (Mott Macdonald)
Failure of rotating machinery in nuclear power stations may result in ejection of fragments with high kinetic energy. Pieces of the disk or blades of a damaged turbine may cause failure of surrounding systems, structures, and components. The current paper presents study of effect of turbine disk fragment ejected as hard missile on the capacity of the protective walls of safety-related nuclear building. The investigation is performed by the missile-target interaction method, i.e. impact simulation of the model of the missile (i.e. the disk fragment) into the model of the protective barrier. Detailed model of the target is generated utilising non-linear material models for rebar steel and concrete. Different scenarios are investigated to define the most unfavourable impact with respect to the protective capacity of the safety barrier. The acceptance criteria are adopted form the relevant international regulatory documents. Special emphasis is given to the hourglass reduction. Various options are studied such as the hourglass control keywords, mesh refinement and different element formulation. The outcome in terms of CPU time and fulfilment of the structural acceptance criteria is compared and conclusions are drawn.
G. Mohamed, G. Newlands (Arup)
Human body models (HBMs) are detailed bio-fidelic finite element models of the human body and are primarily used to simulate human body kinematics and injury responses and risks in a variety of simulated impact scenarios. The current generation of HBMs, such as the industry leading THUMS and GHBMC family of models, encompass different genders, ages, and physiques, including detailed skeletal structures, internal organs (including the brain) and other soft tissues like skin, flesh and ligaments. Some HBM model variants also include muscle-activation features to simulate changes in occupant posture, taking into account changes in musculature activity, prior to a vehicle collision. Thus, combined emergency manoeuvres and crash events, or other long duration crash events, can be simulated.
L. Leidinger, S. Hartmann (DYNAmore), D. Benson, A. Nagy (ANSYS/LST) L. Rorris, I. Chalkidis (BETA CAE Systems), F. Bauer (BMW Group)
Isogeometric Analysis (IGA)  is a rather new approach to Finite Element Analysis (FEA), using spline basis functions known from Computer Aided Design (CAD) for describing both the geometry and the solution field. The main motivation for IGA is the integration of design and analysis. Achieving such a full integration requires a holistic approach with a fundamentally different modeling strategy and development process to exploit the full potential of IGA. Such changes certainly take time and cannot be achieved overnight. Fortunately, IGA with its higher-order and higher-continuity elements also offers several additional advantages such as an accurate geometry description, superior analysis qualities, a larger explicit time step size or smart modeling techniques. Thus, users may benefit from IGA immediately, even without a full paradigm shift.
E. Yreux, I. Caldichoury (Ansys/LST)
Cooling jet flows are commonly encountered in many industrial applications where fast and strong heat dissipation is required such as in pistons, gears, electrical engines and so forth. With the rapid growth and acceptance of simulation as a companion tool intervening directly in the design process, there is a need to provide fast and robust numerical solutions that can provide information on flow patterns and cooling efficiency
M. Parab, J. Sholingar, E. Stahmer, A. B. Sheshadri (FCA)
CAE tools are one of the best techniques in the auto industry to drive design and help product development with minimal physical tests. Physical tests are very time consuming and expensive which is driving the Auto industry towards virtual simulations to replace physical tests. CAE has become an integral part of product development to accurately predict physical testing and drive design direction. For CAE to accurately predict the physical test, it depends on details captured in the full vehicle model. In the small overlap load case it’s necessary to capture as much detail as possible for components engaged during the impact event. However, capturing too much detail leads to prohibitively large models with excessive computational time. So it is important to understand the load path to decide the critical vehicle components which play a vital role in the crash event. This includes the sheet steel/aluminum stamped parts, aluminum extrusion and also the fasteners and welds. In this paper an attempt is made to revisit the modeling of these critical vehicle components and later confirm the performance with respect to the physical test. The sheet steel/aluminum stamped parts and also the aluminum extrusions are finely meshed and GISSMO material models are implemented to define their rupture. The fasteners (bolts) are modeled using solid elements. Spot welds are modeled as solid nuggets with damage material model MAT_SPOTWELD_DIAMLERCHRYSLER and a simple elegant technique is used to define the aluminum MIG welds. The MIG welds are joining thick Aluminum parts in the cradle. MIG welds are represented by discrete beams with MAT119 material model. The stiffness, loads and rupture displacement parameters are adjusted to component tests and an envelope of rupture is created. This is carried on to the full vehicle as a predictive model and the designs are iterated. All of the above modeling methods and techniques helped to accurately predict velocities, intrusion, wheel kinematics and a good correlation to the physical test was achieved.
I. Catalina, K. Manzanera (ITP Aero)
Motivated by the necessity of validating new materials for future turbines, a set of Blade Crush Tests have been performed with Inconel 713 blades, TiAl blades, Inconel 718 casing material and steel plates. The objective of these tests is to study separately the deformation of a blade during a containment event (configuration 1 tests), and the damage of the casing caused by the impact of different blades (configuration 2 tests). The results of these tests are validated with LS-Dyna analysis, providing a reliable tool for predicting the containment capability of the casings and the out of balance progression in a blade off event. This will allow to assess the containment capability of future designs without the need of large and very costly test campaigns or service experience.
J. Kronsteiner, S. Hovden, S. Jäger (LKR), E. Kabliman (TUM)
Conventional metal deformation simulations which include microstructure evolution would not consider any initial spatial variations but assume a uniform microstructure. In metal manufacturing, the liquid phase during casting and its subsequent solidification play major roles in characterizing the material properties (both micro- and macroscopic). Physics-based material models allow to simulate microstructural effects based on measurable microstructural properties. However, some parameters such as the grain size vary considerably within the manufactured part geometry depending on the processing conditions. Since the grain size distribution influences the microstructure evolution during subsequent heat treatment (HT) and metal forming operations, considering a more realistic initial distribution can be beneficial for subsequent simulations.
L. Juhasz, A. Wüst, S. Glaser, S. Ebli, T. Hensel, (BASF), G. Summ, M. Herok, G. Jäger (Daimler)
Energy management in passenger cars has traditionally been dominated by metal structures due to high energy demand and structural integrity. Due to changing legislation and increasing requirements, the trend in vehicle development is towards spatially distributed energy management concepts, leading to more and new load paths. Euro NCAP to frontal MPDB test is to be mentioned here. To serve these new load paths, new absorbers would actually be needed.
D. Lyu, W.Hu, X. Pan, C. T. Wu (Ansys/LST)
Solder joints have become the main mechanical and electrical connections in modern microelectronics packaging for most consumer electronics products and they are typically observed to be the weakest links in terms for structural strength in the drop shock event. A drop shock simulation involves modeling the shock wave effect on mesoscale solder joints and macroscale chip packages concurrently, which is a typical multi-scale problem. Conventional finite element approaches using beam elements for the representation of the solders and the one-way sub-modeling technique cannot offer a high-fidelity solution. In addition, the shape of the solder ball is a very important contributory factor in determining the local stress levels and it is impractical to obtain all solder ball geometries by experimental measurement. Therefore, an effective simulation tool for the prediction of solder ball shape in the solder joint design as well as for the drop shock analysis is required in electronics industry.
S. Hartmann, L. Leidinger (DYNAmore), D. Benson, A. Nagy, M. Pigazzini, L. Li, L. Nguyen (Ansys/LST)
Hughes et al.  introduced the term isogeometric analysis (IGA) in the framework of finite element analysis (FEA). Its main idea is to use the same mathematical description for the geometry as well during the design process in a computer aided design (CAD) environment as in the later analysis phase using FEA. Numerous research papers devoted to IGA have demonstrated beneficial and superior analysis properties, using higher order and higher continuity basis functions compared to standard, low order finite elements. As B-splines and non-uniform rational B-splines (NURBS) are the most widely used geometry descriptions in CAD, NURBS-based finite elements have been developed and implemented into LS-DYNA over the last few years.
M. Messmer (TUM), L. Leidinger, S. Hartmann (DYNAmore), R. Wüchner, Prof. F. Duddeck, K.-U. Bletzinger (TUM), F. Bauer (BMW Group)
Engineering workflows are habitually split into a modelling phase and a consecutive analysis phase, which is primarily driven by the finite element method (FEM). However, bridging the gap between design and analysis remains a sophisticated problem and may consume a vast amount of computational as well as manual operations, especially in highly iterative development processes. To avoid this major bottleneck, Isogeometric Analysis (IGA)  and later Isogeometric B-Rep Analysis  were developed. They rely on the mathematical descriptions of Computer Aided Design (CAD), such as NURBS- and B-Spline-based boundary representation (B-Rep) models. However, classical B-Rep formulations describe a solid only by its boundary faces and do neither provide any physical nor geometrical description of the interior. Therefore, the IGA concept cannot be applied to three-dimensional structures in a straightforward manner.
S. Hayashi, S. Dougherty, S. Hiroi, S. Wang, Y. Atsushi (JSOL)
Composite materials like fiber reinforced plastics (FRP) are becoming more widely used in the automotive industry and have been found very effective in reducing vehicle weight. Recently, discontinuous long carbon fiber reinforced plastics are increasingly used for lightweight structural parts with high stiffness, strength and energy absorption performance. Compression molding is considered one of the most efficient manufacturing processes to mass produce FRP parts for automotive applications. Compression molding can form discontinuous long fiber reinforced plastics into complex shapes with relatively low manufacturing cost and short process time. LST and JSOL developed new compression molding simulation techniques for discontinuous long fiber reinforced plastics using a beam-in-adaptive EFG coupling function in LS-DYNAⓇ. Then JSOL developed a modelling tool called J-CompositesⓇ/Compression Molding to generate an input deck for this new compression molding simulation. In this paper, new functions of J-Composites/Compression Molding Version 2.0 are introduced and two compression molding simulations using hybrid lay-up composites are presented.
C. Michel, V. Lapoujade, T. Maillot, J. Grassy (DynaS+)
Massively used in aeronautical structures, composites are nowadays essential in the search for a more ecological and successful industry. Their low density enables weight reduction and then decreases airplanes consumption. However, the current composites assembly process represents a limitation in their use. In fact, we do not have any reliable, industrialized and non-destructive technology to control the adhesive quality. Then composites are also riveted which adds weight and drilling process during which fibres can be locally damaged. For about 10 years, the LASAT (Laser adhesion test) technology appears to be a promising alternative. The laser impact creates a plasma that induces shock waves propagation in the structure. The LASAT technology can also be used to generate damage anywhere in the assembly thickness. The experimental technology is mature but is lacking a numerical tool so to calibrate the input laser parameters depending on the targeted results.
L. Rorris, I. Chalkidis (BETA CAE Systems)
During the last two years, ANSA, the leading preprocessor for crash analysis, has been heavily involved supporting the IGA community, helping create IGA models and Hybrid FE-IGA full vehicle crash models. In doing so we a set a dual target. First, advance and explore all needed technologies which are mainly new and mostly in academic research phase. Second, bring in, industry expertise in making these technologies robust and well suited for production, both in terms of stability and performance, but also in terms of data interoperability and adaptation to the highly automated process flows that characterize current automotive crash procedures. The cooperation with the ANSYS LST team has been very fruitful and rewarding. These latest developments in the pre-processor side are presented in this presentation.
C. Kleessen, C. Shah (Humanetics)
P. Krishnaswamy, U. Mallikarjunaiah (Xitadel), Y. Nakagawa (Honda)
There is rapid convergence of multiple technologies that are creating unprecedented capabilities in every field of technology. The incorporation of new technologies like Artificial Intelligence/Machine Learning (AI/ML) in the CAE process has been quite gradual. Xitadel’s XIPA technology is a pioneering effort to leverage the power of ML to transform the CAE model build process and bring this to production level. CAE modeling is a critical path in the overall CAE process. CAE modeling however is very time consuming, particularly because plastic subsystems typically contain multiple complex features and variable thicknesses.
N. Stander, A. Basudhar (Ansys/LST)
LS-OPT Version 7.0 was released in November 2020 with several new features which are briefly summarized here:
T. Nguyen, I. Caldichoury, P. L’Eplattenier (Ansys/LST), L. Kielhorn, T. Rüberg, J. Zechner (Tailsit)
The LS-DYNA® Electromagnetic solver (EM) has recently integrated a new monolithic FEM (Finite Element Method) – BEM (Boundary Element Method) solver along with an AMS (Auxiliary Maxwell Space) preconditioner. Eddy-Current and Magnetostatic – including linear or non-linear magnetic materials – analysis can be done thanks to these new implementations . On top of this, the capability to have permanent magnets has been introduced. We will start by showing a benchmark between LS-DYNA® and ANSYS Maxwell on the force calculation between two magnets in different conditions. The first model consists of two-cylinder magnets at a distance d. The magnet is a Neodymium Iron Boron magnet with a magnetic coercivity of -900 kA/m. In the first comparison, a linear magnetic characteristic of the magnet is considered. Then a non-linear BH curve is introduced in the next comparison. The insulator is a linear material with no conductivity. In the second model, we added a steel plate with high permeability between the 2 magnets to see its influence on the force on each magnet. The benchmark gives a good agreement between Ansys-Maxwell and LS-DYNA® in terms of results and computational cost in both linear and nonlinear case.
A. Cherniaev (University of Windsor)
In a typical satellite bus, most impact-sensitive equipment is situated in the enclosure of the structural sandwich panels. Being the most commonly used elements of satellite structures, these panels form the satellite’s shape and are primarily designed to resist launching loads and provide attachment points for satellite subsystems . With low additional weight penalties, their intrinsic ballistic performance can often be upgraded to the level required for orbital debris protection [ 2]. Consequently, assessing the orbital debris impact survivability of satellites requires the availability of predictive techniques and hypervelocity impact (HVI) simulation models for sandwich panels, which are capable of accounting for various impact conditions and design parameters.
M. Morak (Polymer Competence Center Leoben), R. Steinberger, I. Sladan, S. Seichter (Hirtenberger), W. Hahn, M. Göttlinger (Hilti), P. Reithofer, M. Schwab, H. Pothukuchi (4a engineering)
Viscoelasticity respectively the time-dependent and the recovery behavior plays an essential role, especially for polymers. Nowadays, it is becoming increasingly important to be able to make service life predictions and forecasts regarding the long-term behavior of components using simulation models. In this context, constant or cyclic loads are usually the decisive mechanisms for deformation. Moreover, the short-term behavior of plastics is also strongly characterized by viscoelastic phenomena. Even in the case of very short-time high loads on polymer components, the corresponding recovery behavior is of great importance and must be correctly represented in the simulation. Material and simulation models must take this long-term but also the short-term behavior into account for a realistic prediction of the deformation behavior in order to be able to make corresponding estimates of the service life of components, which is often designed for years. For this purpose, this behavior must be characterized in the application-specific framework and considered accordingly in the modeling. This article will present and compare some of the currently available material models that can account for the viscoelastic or time-dependent behavior of polymers, as well as the possibilities and effort required to obtain the material data needed for simulation.
P. Bähr (Fraunhofer IWM)
The increasing application of press-hardened steel in combination with aluminum sheets in the construction of car bodies results in the use of mechanical joining techniques such as self-piercing riveting and thermo-mechanical joining techniques such as resistance element welding. These joints generally represent a notch within the component. The cause of the notch effect is different for the investigated joining techniques and can be distinguished in a geometrical notch and a metallurgical notch. Riveted joints result in a pierced hole with high plastic strains at the edge and thus represent a geometrical notch. Thermo-mechanical joints in press-hardened steel result in a softened heat affected zone (SHAZ) around the weld due to the applied heat during the joining process
A. Cherniaev , R. Aslebagh (University of Windsor)
In a typical satellite bus, most impact-sensitive equipment is situated in the enclosure of the structural sandwich panels, often – panels with a honeycomb core (honeycomb-core sandwich panels, HCSPs). As commonly used elements in satellite structures, these panels form the satellite’s shape and are primarily designed to resist launching loads and provide attachment p oints for satellite subsystems . With low additional weight penalties, their intrinsic ballistic performance can often be upgraded to the level required for orbital debris protection .
B. Schaufelberger, A. Altes, P. Matura (Fraunhofer EMI)
Short-circuits caused by external forces, as they occur in crash situations, may lead to uncontrolled discharge of battery cells. As a consequence, the battery heats up locally, which, if it comes to the worst, results in an explosive reaction of the cell. However, the detection of critical deformations, for example in car crash simulations is very challenging: On the one hand, local indentations in the range of a few millimeters often result in a breakup of the inner structure and consequently in a short circuit. On the other hand, battery cells can also withstand surprisingly large deformations with the internal structure remaining intact. Thus, a reliable battery cell model has to capture a variety of different deformation modes.
R. Færgestad, J. K. Holmen, T. Berstad (NTNU) T. Cardone (ESA), K. A. Ford (NASA), T. Børvik (NTNU)
Orbital debris is an increasing threat to current and future missions in low Earth orbit (LEO), and spacecraft shielding is vital for future space exploration efforts. Experimental hypervelocity impacts (HVI) are expensive and can only be performed at a few laboratories worldwide, making numerical simulations an essential tool in the development and design of debris shields. A debris shield is a sacrificial plate that shatters an impactor into a cloud of particles, distributing the momentum of the impactor over a large area, thus preventing it from perforating the spacecraft. In this study, HVI were modelled in LS-DYNA using a coupled finite element-discrete particle method (FEM/DES), through the *DEFINE_ADAPTIVE_SOLID_TO_DES keyword. The results were compared to experimental data from the literature as well as to simulations applying the smoothed particle hydrodynamics (SPH) method. First, impacts by projectiles with diameter below 1 cm and impact velocities up to 6.7 km/s were simulated to study the debris cloud after perforation of a single plate. Here, aluminium alloy AA6061-T6 was used as both the target and the projectile material. The FEM/DES method was able to predict the shape of the debris cloud as a function of impactor shape, impactor velocity and shield thickness. Then, the FEM/DES method was applied to a dual-wall Whipple shield configuration and was able to accurately describe the damage from the debris cloud on the rear wall.
M. Tatarsky, D. Aggromito, J. Farley, J. Klimenko, W. Wholey, L. Pascoe (Arup)
In the event of an explosion in a populated urban area, fragmentation from glass is a significant contributor to human injury. The mitigation of glass fragmentation hazards is well-established through the use of laminated glass featuring a polymer interlayer, such as DuPont Sentry Glass Plus (SGP) or polyvinyl butyral (PVB). These interlayers work by exploiting the inherent viscoelastic and adhesive properties of the polymer, providing a mechanism to dissipate the energy of the blast through work done in deformation of the interlayer while retaining fragments of broken glass. This behaviour is fundamental to limit the projection of fragments of otherwise brittle glass, thereby reducing or eliminating highly hazardous secondary fragmentation associated with glazing
R. Sturt, C. Cengiz, Y. Huang, S. Bandara, A. Pillai, J.Go (Arup)
Saturated sandy soils can be prone to liquefaction during earthquakes: the soil loses strength and stiffness due to cyclic shear loading, becoming more like a liquid or quicksand. When liquefaction occurs, structures founded on such soils may experience severe damage or large settlement, or may even overturn. Designers of structures in seismically-active regions where liquefiable soils are present need to assess the likelihood of liquefaction occurring under design-level earthquakes and, if required, provide mitigating measures in the design. Three-dimensional nonlinear finite element analysis can be used to understand the effects of liquefaction on a structure and, if sufficient validation of the soil properties has been carried out under a range of stress conditions, can potentially predict the extent of liquefaction that will occur as a result of a given earthquake time-history. However, this requires a soil material model capable of reproducing the phenomena relevant to liquefaction.
K. Osnes (NTNU), S. Kreissl, J. D’Haen (BMW Group), T. Børvik (NTNU)
More than half of all road fatalities involve vulnerable road users, such as pedestrians and cyclists . When involved in crashes with cars, the head is particularly susceptible to injuries, and especially if the road user hits the windshield of the car . Impact tests are often performed to estimate the risk of head injury during such an event. A pedestrian head strike test normally involves a spherical headform, in which the likelihood of head injury is described by the head injury criterion (HIC) .
A. Journaux, T. Legaud, V. Lapoujade (DynaS+)
Flow drilling is an alternative drilling solution for metal plates up to several centimeters. Using a conical tool, the process combines high rotation speed and high pressure to initiate friction and heat up the plate material locally in contact with the tool. As a consequence, the heated material has its mechanical characteristics reduced and is subjected to a very large plastic deformation. The surplus of matter is not wasted but is shaped into a collar above the metal plate and a socket below. These bulges induce a local additional thickness enabling a direct threading without added parts (bolt…)
H. Wei,C. T. Wu, D. Lyu, W. Hu, F. Rouet, K. Zhang, P. Ho (Ansys/LST), H. Oura, M. Nishi (JSOL), T. Naito (Honda), L. Shen (CoreTech System)
Injection-molded short-fiber-reinforced composites (SFRC) have been widely used for structural applications in automotive and electronics industries. Due to the heterogeneous microstructures across different length scales, the nonlinear anisotropic behaviors of SFRC are very challenging to model. Therefore, an effective multiscale approach that links the local microscopic properties (e.g., fiber orientation, fiber volume fraction) to the global behaviors is required. To this end, multiscale analysis functions are recently developed in the engineering simulation software LS-DYNA to enable high-fidelity micromechanical finite element analysis, mechanistic machine learning-based reduced-order modeling, and accelerated concurrent multiscale simulation of SFRC composite structures.
V. André, D. Morin, M. Costas, M. Langseth (NTNU)
This paper presents an artificial neural network (NN) modeling approach for representing mechanical fasteners in large-scale finite element crash simulations for explicit analysis using LS-DYNA version R9.3.1. The NN-model is established to describe the local force-deformation response of point-connectors in automotive applications like self-piercing-rivets and flow-drill-screws. The behaviour from initial loading until failure or unloading is covered. Various architectures and complexities of feedforward NNs were evaluated and trained based on synthetic experiments generated from the constraint model proposed by Hanssen et al. . The constraint model is available as *CONSTRAINED_SPR2 but was used in form of a cohesive element (8-noded, 4-point cohesive element with offsets for use with shells).
P. Huang, F. Del Pin, I. Çaldichoury, R. R. Paz (Ansys/LST)
There is a great interest in the fluid-structure interactions (FSI) of flow mechanics around valves in the heart or in mechanical parts. The capability to allow flow blockage due to the valve closure is very important.
F. Del Pin, R. R. Paz, P. Huang, I. Çaldichoury (Ansys/LST)
This paper will discuss some of the new additions that will be part in the R13.0 release for the Incompressible CFD (ICFD) solver in LS-DYNA. The paper will also cover some of the highlights of R12. In the past year there has been an increased interest in the model of problems that involve the simulation of free surfaces, Fluid Structure Interaction (FSI) and porous media flow. These topics will be discussed, and the new features/improvements will be presented. The road map is a collection of feature requests from LS-DYNA distributors, Ansys ACE organization, academic collaborators and customers. Based on this a brief discussion the top topics will be presented including immersed interface techniques, gap closure models, multi-species transport and tighter integration with Ansys tools.
P. Cruz, E. Martin-Santos, L. Martorell (Applus IDIADA) M. Lobdell, H. Lobo (Applus Datapointlabs)
A deep understanding of advanced material plasticity and fracture is one of the cornerstones of mechanical engineering to overcome present and future challenges in the automotive industry with respect to lightweight multi-material body solutions. The von Mises plasticity model is well-known and efficiently implemented in the various CAE solvers conventionally used in the automotive industry. One of the principal characteristics of the von Mises model is the assumption of isochoric plasticity (i.e. no change of volume is caused by yielding). The literature and experiments show that some materials, like extruded aluminium or polymers, exhibit non-isochoric plastic behaviour. Since this effect cannot be captured by the von Mises plasticity model, an optimal design for lightweight structural solutions is compromised.
C. Heckötter, J. Sievers (GRS)
Impact loading is a safety relevant loading case for reinforced concrete structures used to protect vital parts of nuclear facilities. Numerical methods used for the assessment are validated on the basis of impact tests. Even though normal impacts are the most common item of analysis, special issues are related to inclined impact. Effects of inclined impact include slipping and rotation of the missile, motion of the impact point and effects of tangential forces. Recently, an experimental program dealing with bending failure of reinforced concrete slabs subjected to inclined soft missile impact was carried out at Technical Research Centre of Finland (VTT) in the frame of phase IV of the international research project IMPACT. This paper reports on simulation results on these tests using LS-DYNA
F. Biondo, A. Sordi, G. Magnabosco (Marcopolo)
The behavior of mechanical structures, when subjected to impact load, is a matter of great relevance and its applications in terms of vehicle collision. When we analyze the superstructure of a bus, those vehicles must be tested according to prerequisites established in standards such as UNECE ECE 29 (European standard) or CONTRAN 629/2016 (Brazilian standard). The standards prescribe to use a pendular system to evaluate the frontal structure of the vehicle. In this regulation is defined the height and the mass that will collide with the structural modulus. However, the procedures described in these standards do not represent the real collisions involving these types of vehicles. This can be seen when comparing the energy imposed on the test module, detailed in CONTRAN 629/2016, where the energy imposed on the vehicle is approximately 20 kJ on each side of the test module, this corresponds to a collision of a 5 tons vehicle at 10 km/h or a 20 tons bus at 5 km/h.
In this work, the flow behavior of sandwich foldcores and their influence on the fluidic parameters such as pressure drop are investigated. The subjects of the investigation are three different foldcore geometries, which are analyzed with the ICFD solver from LSDyna. The results are then examined with results from numerical simulations using OpenFoam as well as experiments in the water channel.
P. Kabala (TU Braunschweig), I. Karb (Compositence), D. Trudel-Boucher (National Research Council Canada), T. Ossowski, K. Dröder, A. Hürkamp (TU Braunschweig)
The automotive industry is facing stronger requirements for crash safety and environmental friendliness of passenger cars from legislators, society and customers. This is reflected in legal requirements that regulate CO2 fleet emissions over the next few years as well as the relevance of CO2 emissions and vehicle safety as purchase criteria for vehicles [1, 2]. Fiber-reinforced plastics (FRP) offer a great potential to meet these requirements due to their high specific strength and stiffness as well as energy absorption capacity . In particular, fiber-reinforced thermoplastics (FRTP) are suitable for large-scale production owing to their good recyclability and short cycle times .
F. Hekmat (GM), P. Du Bois (Consultant)
The increased use of castings, forgings and thick extrusions in vehicle structures has led to the need for modeling certain parts with solid elements in crash simulations. Since the geometries of the considered parts are typically highly complex, using tetrahedral elements seems to be the practical solution. In the LS-DYNA simulation software, a multitude of different tetra element formulations are available however there is some uncertainty whether these elements can be used with confidence in a simulation for accurate fracture prediction based on a stress state dependent failure model.
D. Grimmeisen, M. Schneider (CASCATE)
Violation of nominal operating conditions in Li-ion batteries can lead to internal damage and failure of the cells. This usually triggers chemical reactions that produce a large volume of hot gas. As a safety feature, 18650 battery cells are equipped with a safety vent. Once an internal pressure threshold is exceeded, the vent opens, and the gas escapes the cell at a high velocity to prevent uncontrolled structural failure. Within a battery pack, the hot gas needs to be guided to exit the pack while at the same time keeping neighbouring battery cells cool enough to stay within the safe temperature range. CFD simulation offers the capabilities to explore the mechanism of battery cell venting and flow guidance. This paper describes how such a simulation can be set up and run. Several steps are necessary to achieve this. First, Simcenter Battery Design Studio is used to model the 18650 battery cells. However, it is also described how this step can be avoided if certain prior knowledge about the process is available. Simcenter STAR-CCM+ is used for that and all subsequent steps. The cells are then assembled to a battery module and placed within a simplified battery pack housing.
R. Nasouri (University of Texas), H. Rokhy (Amir Kabir University), A. Matamoros, A. Montaya (University of Texas) R. Backzadeh (Urmia University)
Accurate estimation of acting forces on the disk cutter is very important in the design of Tunnel Boring Machines (TBM) operations factors such as propulsion (driving) force and torque. To do this, first the forces applied to a single disk cutter, as well as its performance for a particular rock, are determined by performing a linear cutting machine (LCM) test. The results are then generalized for design of TBM on the same rock. In the present numerical study, the linear cutting machine test for a fixed cross-sectional cutter was simulated using LS-DYNA software, and the results of the numerical model were compared with the laboratory results. The results show that the use of the Lagrangian solution method is not appropriate due to the strong dependence of the accuracy of the results on the failure criterion defined to remove the elements, and the use of the SPG solution method will be a more appropriate option instead. Also, using the RHT material model instead of the JHC model will have a much better estimate of the width of the damaged area in the rock. The accuracy of the results shows that in the next step, this solution method can be used to simulate the rotational cutting machine (RCM) test
S. Kumaraswamy (Volvo), A. Dutta (KTH), M. Landervik, A. Bernhardsson (DYNAmore Nordic), M. Åkermo (KTH)
The usage of composite materials in automotive body structures has the potential of reducing weight and thereby improving energy efficiency of the vehicles. Two key factors that limit their usage are long cure time for the material and the lack of simulation support. The recent development of snap-cure or rapid-cure prepregs can address the former problem. For the latter, LS-DYNA simulations can support the design of composite parts and production process which can improve both their structural properties and manufacturability, avoiding the economic and environmental costs of trial and error used today to obtain defect free parts. This paper concerns the simulation of the forming of parts using unidirectional (UD) carbon fiber prepreg.
G. Newlands, B. Crone (Arup)
The Oasys LS-DYNA Environment provides a comprehensive solution across the whole LS-DYNA workflow. One aspect of that workflow in automotive engineering is pedestrian protection. Pedestrian protection is important to the design and development of the front end of vehicles. The various protocols, impactors and methods relating to pedestrian protection mean that the CAE process can be complex and time consuming. The Oasys tools aid in this process. These tools are available for both head and leg impact analyses and have been used successfully on past and current vehicle design projects within Arup and in OEM’s to accelerate the workflow. This paper gives an overview of the tools, with a focus on the latest features introduced to the recent releases of the Oasys LS-DYNA Environment – The HIC Area Calculator and the Pedestrian Run Builder.
Seat belt is one of the main load bearing parts for restraining an occupant in a vehicle crash. Thus, accurate modelling of seat belt is important to achieve realistic interaction between belt to Anthropometric Test Devices dummy model in passive safety crash simulation. The belt modelling in the lap area is even more challenging because it also bears out-of-plane load during interaction with the pelvis, causing bending in webbing. Inadequate modelling of the bending response often results in rope-like effect in the lap belt during passive safety crash simulations, causing loss of contact area and eventually incorrect pelvis coupling. Such a behavior of belt is often observed with the application of THOR dummy in crash simulations, leading to an argument that simulations are not able to correctly predict submarining (slippage of belt over the pelvis to load the abdomen) and eventually incorrect estimation of the pelvis iliac forces and moments on the dummy . Therefore, concerns are growing for improving the belt modelling. Besides other modelling aspects (e.g., mesh size, contact modelling, directional dependency of friction etc.), it is believed that including appropriate bending stiffness could improve dummy-to-belt interaction. There are several options available in LS-DYNA to model bending in webbing but the inevitable use of 2D slipring for its robustness and efficiency in the system models poses limitations.
C. Keisser (DYNAmore France), M. Hübner, T. Graf (DYNAmore), A. Basudhar, N. Stander (Ansys/LST)
When performing an optimization, it is important to avoid introducing unnecessary variables that do not impact the design objectives and constraints. Such variables increase the design space size and lead to unnecessary sample evaluations, which can significantly increase the overall computation time or cost. A sensitivity analysis can be performed to quantify the significance of the variables; only the important variables are then used in the sampling and optimization, thus reducing the computational cost.
B. Pockszevnicki, V. Carvalho Rosa, R. Rajagopalan (Stellantis)
This study aims to present a proposal for finite element modeling for electrical cables of a PDC to improve the response of the virtual analysis during design phase, establishing a good interation of electrical cables during crash tests. The objective of this study is to present types of elements and contact pairs that are capable of predicting the response of electrical cables.
D. Salin (CADLM), W. Wei, N. Bailly (Aix Marseille Univ)
Skiing and snowboarding are very popular sports, associated with a high risk of injury (2.35/1000 skiing days in 2019 in France ). Among those injuries, the leading cause of death is the head injury which accounts for 5-10% of all injuries. Several studies have shown that helmet was effective in reducing the risk of head injury ,  but the effect of the helmet in reducing certain types of brain injuries such as concussion is still unclear , . To better evaluate and design effective helmets, it is critical to understand the head impact condition during the crash as well as the injury mechanism.
S. Wang, R. Troain, L. Khalij (INSA)
At present, the Finite Element Analysis (FEA) method is indispensable in the field of simulation technology, as this kind of numerical analysis method can assist engineers to predict results, which are often difficult to obtain from experimental tests. However, there exist some problems in terms of finite element mesh generation time and geometric representation. In this studying, we adopted a new numerical analysis method, Isogeometric Analysis (IGA) to develop static and dynamic analyses on two models, a notched plate and a wind turbine tower model in Ls Dyna software. From the static convergence analysis result, it is shown that IGA is more time-efficient compared with FEA. In terms of fatigue analysis results, IGA can predict the fatigue life corresponding very well to the fatigue life computed by FEA. It can be concluded that IGA is appropriate for the numerical analysis
M. Bernardi, F. Kanavaris, R. Sturt (Arup)
The cement hydration reaction has long been recognized as an important contributor to defects throughout the service life of concrete structures. As the hydration reaction is highly exothermic, and the thermal conductivity of concrete is relatively low, high temperatures and temperature gradients have special relevance in massive concrete structures. Massive concrete structures can endure significant cracking when temperature induced deformations are restrained. Uncontrolled cracking may compromise the structure durability and reliability, e.g. in massive concrete slabs for rail infrastructures or marine structures or the structure functionality, e.g. watertightness in liquid retaining structures or may even represent an aesthetically unacceptable defect for a concrete structure with demanding architectural finishing requirements. The heat generation and the consequent temperature rise in concrete structures is also a problem for the damaging effects on the concrete mechanical properties following deleterious chemical reactions such as Delayed Ettringite Formation (DEF). This chemical reaction is known to be associated with thermal fields in early-age concrete usually of the order 65°C to 75°C
A. Alfoqaha, K. O’Connell, E. Campbell, M. Hamid (IBM)
At IBM systems robust and reliable designs of servers and supercomputers are one of the main objectives. Predicting mechanical performance of servers, such as IBM Cognitive Systems’ Power9 portfolio can be more challenging considering shorter development cycles, increasingly dense product design as well as advanced design features. The 2U version includes DDR4 RDIMM’s, Power9 hybrid land grid array (HLGA) processor modules, PCIe Gen3 and Gen4 slots, blowers, hard drives, and internal storage controller slots.
L. Rorris, A. Lioras (BETA CAE Systems)
The use of Human Body Models, for safety simulations, in the automotive industry, has not been widespread for various reasons. One was that the specific models had not reached expected sophistication levels as they are mainly used in the research phase and not in production. Nevertheless, from their first introduction in late nineties until now, a lot of development and research effort has been invested. The parallel growth in computational power during the same period resulted in much more complex and realistic models that can cover the needs of the occupant safety engineering community.
Y. Huang, T. Littlewood, Z. Cui, U. Basu (Ansys/LST), S. Hartmann (DYNAmore), D. Benson (Ansys/LST)
As one of the mainstream software packages widely used in automotive industry, LS-DYNA provides not only strong nonlinear capabilities for crashworthiness simulation, but also a suite of solvers for NVH and fatigue (durability) analysis. For NVH analysis, a series of vibration and acoustic solvers have been implemented to meet the need from CAE analysis of automotive of different levels and phases. They include FRF (Frequency Response Function), SSD (Steady State Dynamics), random vibration, response spectrum analysis, and acoustic analysis based on BEM (Boundary Element Method), FEM (Finite Element Method) and SEM (Spectral Element Method). The fatigue analysis features include fatigue damage solvers in both time domain and frequency domain (based on random vibration and steady state vibration).
L. Kielhorn, T. Rüberg, J. Zechner (TAILSIT)
Since 2017 TAILSIT has maintained a close collaboration with Ansys/LST, formerly LSTC. Our partnership focuses mainly on the enhancement of LS-DYNA’s electromagnetic (EM) solver module which is based on a coupling between Finite Elements (FEM) and Boundary Element Methods (BEM). This approach makes the EM solver highly suited for multiphysics problems. Prominent examples are, e.g., the simulation of parts moved by electromagnetic forces as well as processes like metal forming, welding, and induction heating
K. Shepherd (Brigham Young University), X. D. Gu (Stony Brook University), T. J. R. Hughes (University of Texas)
The traditional engineering design-through-analysis process is inadequate for modern needs. In it, an engineering designer will create a model in a computer-aided design (CAD) software, after which an analyst takes this smooth CAD model, defeatures it, cleans up the model, and ultimately approximates the intended shape as a faceted, semi-structured mesh for subsequent engineering analysis. Analysis, thus, no longer operates on the intended object, but instead evaluates physics on a faceted approximation, which may lead to compromised results . Furthermore, while design and analysis are the primary objects of interest in the design-through-analysis process, the intermediary steps of geometry cleanup and meshing consume over 70% of the time spent in the design-through-analysis process [2, 3]. Naturally, this leads to increased associated costs .>
P. Glay (DYNAmore France), S. Hartmann (DYNAmore)
Roll forming is a continuous bending operation of a long strip of metal sheet. The sheet is gradually formed through pairs of rotating rolls (called stands) until the desired cross-sectional configuration is obtained (see Fig. 1). Although roll forming is a classical method to produce constant cross-sectional profiles, it remains a complex process. Finite element analysis (FEA) can assist the designer to improve this process
A. Ulbertus, M. Schöttelndreyer (thyssenkrupp Marine Systems), S. Ehlers (Hamburg University)
The launching process of ships is always a critical event during its construction. Especially a sideways launching process can be challenging. Besides high loads on the ship’s hull structure at the impact with the water surface, the stability has to be checked carefully to prevent capsizing of the ship. The resulting maximum heeling angle is one of the most critical parameters during such a launching process. If the maximum heeling angle gets too high, the ship can capsize or higher openings (e.g. ventilations) can come in contact with the water resulting in flooding of compartments. Therefore, the movement of the ship and the loads at impact with the water surface have to be assessed as accurately as possible during the design of a ship, if a sideways launching process is planned.
A. Trondl, D.-Z. Sun, S. Sommer (Fraunhofer IWM)
Due to increasing requirement on the reduction of CO2-Emissions, the meaning of E-Mobility becomes more and more important. The related development of efficient Li-ions with high charge densities has also a direct impact on the automotive industry. This applies in particular to the crash safety of Li-ion-battery-powered vehicles. The structure of Li-ion batteries is in principle a repetitive layered system.
M. Duhovic, T. Hoffmann, S. Becker, P. Mitschang (TU Kaiserslautern)
The objective of this work is to create an FEM-based model for the inductive heating of carbon fiber reinforced thermoplastic composite (CFRTPC) laminates. A macroscale simulation model was created using the multi-physics capabilities of LS-DYNA®. Material model parameters were largely determined by micromechanical considerations. In order to further increase the accuracy of the FEM model, dynamic differential calorimetry (DSC) measurements were also carried out to determine the temperature dependence of the heat capacity of the laminates investigated. The model was then validated for laminates reinforced by non-crimped fabrics (NCF) with fiber volume contents (FVC) of 32%, 47% and 60% via induction heating tests. In general, the heating experiments could be approximated well both qualitatively and quantitatively. Furthermore, analyses were carried out in order to investigate the influence of individual ply orientations in the laminate on one another as well as the influence of the layer thickness on the resulting heating behavior.
M. Schill, J. Karlsson (DYNAmore Nordic), H. Magnusson, F. Huyan (Swerim), N. Safara Nosar, Jonas Lagergren, T. Narström (SSAB)
Creating a virtual model of a hot plate rolling process involves many challenges. In an attempt to address these, a research project called FINBEAM (“Full Scale Integrated Workability Modelling”) was initiated by Jernkontoret and the Swedish steel industry, financed by the Swedish innovation agency, VINNOVA. The purpose was to bring research institutes, industry and software developers together to reach a common modeling ground for simulation based design of hot working processes for the steel industry in Sweden.
M. Gustavsson, D. Aspenberg (DYNAmore Nordic), B. Stoltz (IKEA)
Accurate representation of materials is an essential part of the quest for realistic and predictive simulation, not least for anisotropic materials such as short fiber reinforced plastic (SFRP). Still, it is common to neglect the anisotropic properties of SFRP components when evaluating the structural performance of the design in FE simulation, thereby often failing to predict a realistic mechanical behavior. Neglecting the anisotropic features of SFRP, especially at an early stage in the design development, may lead to a design that is not viable for the component in question.
M. Vinot, D. Schlie, T. Behling, M. Holzapfel (DLR)
Railway transportation represents an environmentally friendly alternative to automotive transportation for long distance travel. In the project Next Generation Train of the DLR, new railway solutions are developed for passenger and freight transportation for a broad range of applications (intercity, cargo, long distance). Specifically, the high-speed train NGT HST aims at reducing travel times and specific energy consumption with new technologies. At the maximal operating speed of 400 km/h, the coupling of mechanical and aerodynamical forces leads to increasing risks of ballast stone impact on the train structures (in particular underbody structures), thus threatening primary components underneath . Through the repetition of stone impacts during the entire lifetime of a structure, critical damage can occur and reparation or replacement concepts are required. The present work aims at investigating an impact-resistant underbody structure made out thermoplastic composite materials for the HST train on numerical and experimental basis. By considering multiple impact scenario in the structure sizing process, the project intends to reduce the interval at which the structure has to be replaced.
B. Näser (BMW Group), D. Friedemann, J. Rademann (HTW Berlin)
To ensure today’s development cycles for products and components, the main part of the development process has to be supported by numerical simulations. For complex parts, many simulation disciplines have to be considered to meet all the requirements. This results in a usage of different simulation tools with different input file languages. Moreover, a typical simulation engineer has to be an expert for numerical simulation (in most cases for a specific solver), and also an experienced engineer (for a specific development discipline).
Y. Li, N. Zhang, R. Fuentes (RWTH Aachen)
Granular column collapse is a commonly studied granular flow problem, where an initially cylindrical column of dry granular materials collapses onto a flat surface under gravity. In this study, the meshless method Smoothed Particle Hydrodynamics (SPH) is used to model this phenomenon examining in particular the effect of aspect ratio, defined as the ratio of the initial height h0 and radius r0 of granular column. The numerical results are consistent with experimental results in terms of three aspects: (1) description of flow shapes; (2) runout distance and (3) final deposit height. Further observations and measurements are obtained to explore the collapse.
T. Littlewood, Y. Huang, Z. Cui (Ansys/LST)
Increasingly there is an emphasis in the engineering simulation community on ultrasonic devices. They are seen in medical imaging, structural health monitoring, and of course, in the rapidly emerging world of autonomous/semi-autonomous vehicles. These devices operate at frequencies of 50KHz and above, sometimes well above. Wavelengths at those frequencies are measured in millimeters, sometimes even micrometers. The simulation of the propagation of such short waves over any substantial distance is a very demanding endeavor. This is especially true if tri-linear/quadratic iso-parametric finite elements are used. Newer, higher-order finite element methods exist . Among those methods is the spectral element method (SEM). Many SEM references are available in the literature, a sampling being [1-6.] Spectral elements are appealing because they are highly accurate and can be efficiently incorporated in an explicit solver like LS-DYNA. In a massively parallel setting, they allow for the solution of models with billions of degrees-of-freedom in a reasonable amount of time.
A. Antoniou, M. Kristoffersen, T. Børvik (NTNU)
This study briefly presents four concrete models used for ballistic impact simulations. The models are the RHT model (*MAT_272 or *MAT_RHT), the CSCM model (*MAT_159 or *MAT_CSCM), the K&C model (*MAT_072R3 or *MAT_CONCRETE_DAMAGE_REL3) and a modified Holmquist-Jonson-Cook model (MHJC). The first three are available as standard models in LS-DYNA with the option to automatically generate their constitutive parameters. The MHJC model has been implemented as a user subroutine. In the present study, we calibrated the MHJC model parameters for C75 high-strength concrete by using laboratory material experiments and data from the literature. Ballistic simulations of C75 concrete slabs impacted by ogival projectiles validated the accuracy of the calibrated parameters. We evaluated the default parameter generation of the former three models compared to the latter.
S. Alameddin, F. Fritzen (University of Stuttgart)
This work presents a multiscale simulation framework that will be used for the simulation and experimental validation of eigenstresses in composite materials generated via laser-dispersion. These materials are obtained by adding tungsten carbide particles into the melt pool of a base metal to generate surface coatings. Such coatings are used to boost wear-resistance, more precisely to protect metallic surfaces against abrasion, erosion or corrosion. The coating significantly extends the part’s lifetime due to the outstanding material characteristics of the locally produced metal matrix composite (MMC). Eigenstresses, which are the residual stresses left in the MMC material after the coating process, shall be investigated and predicted within the framework of this project and their effect on the lifetime shall be estimated.
W. Roux, I. Gandikota, W. Roux, G. Yi (Ansys/LST)
To reduce the head impact injuries in case of traffic accidents, the design of an automotive hood must consider many design requirements including impact of the head against the hood at different locations, be lightweight but with enough stiffness to resist various loads imposed on the hood, and have NVH characteristics such as the fundamental frequency. Methodologies to solve this type of design optimization problem that integrates multiple design criteria are rare to non-existent in the automotive design field. This paper shows how to conduct the worst-case design of the hood for multiple head impact locations, which is required by the pedestrian safety code. In addition, a topology optimization problem of the hood that combines statics, impact, and eigen frequency load cases is solved by using LS-TaSC to provide the optimal lightweight hood structure satisfying the design constraints. This is possibly the first demonstration of both the worst-case design and multi-disciplinary design optimization considering both impact and frequency load cases on an industrial problem
A. Nair, I. Caldichoury (Ansys/LST)
A Clutch is a mechanical link used to transmit torque from engine to transmission and typically rotates at very high RPMs. The clutches continuously engage with friction pads to transmit power for motion and only disengage when a gear ratio change is required. During this process of engaging and disengaging the clutch goes from stationary to moving instantaneously. A combination of friction pads and disks are used to transmit the power. There is a significant increase in temperature due to friction between the pads and plate at transition and during rotation. This temperature increase leads to thermal expansion of parts and can cause uneven shape changes. The deformation leads to increase in frictional energy and eventual rise in heat generation. Friction and temperature along with pressure applied during the high rpm rotation leads to high probability of failure at the leading edge of the pads. Uneven distribution of heat can cause failure in the friction pads. To alleviate the effect of temperature, lubricating oil is injected via channels in the friction pad.
I. Fernández (Gompute), D. Dorribo (Gompute)
Industries worldwide are going through a Digitalization process towards industry 4.0 where cloud resources play a key role, forcing a transition for CAE engineers from traditional, in-house HPC to more flexible solutions in the cloud. On the digital maturity journey there are different dimensions to consider when transitioning a CAE team to the cloud as a permanent solution, being the needs and requirements of the different industries not always covered with a single solution, what requires an analysis of the different layers involved (IT/Network, Licensing, Security, Engineering).
H. Dong, J. P. Leiva, B. Watson (OmniQuest), W. Gao, F. Pan (ShareFEA Engineering Technology)
This paper demonstrates how to efficiently perform optimization for vehicle structures, taking into account nonlinear responses from LS-DYNA crash simulation, as well as responses from linear loading conditions such as NVH and Static. The optimization process is based on the Equivalent Static Load (ESL) method and uses an iterative process which utilizes the non-linear structural analysis results from LS-DYNA and the linear structural analysis and optimization capabilities of GENESIS. With this integration, the combined multidiscipline problem can be solved with only a few LS-DYNA simulations (5 to 10). In addition, large-scale optimization techniques, such as topology, topometry, topography and freeform, can easily be employed. The optimization process and results will be demonstrated using two examples: topology optimization of a beam cross-section under impact and static loading and topometry design of a truck frame under crash, normal modes, and static loading conditions simultaneously.
A. Schmid (TU Graz), A. Schmid (TU Graz)
For the simulation of the mechanical behaviour of pouch cells, there are varieties of modelling approaches, which differ greatly in the level of detail. In macroscopic models the single plies constituting the cell are not discretized separately, but are homogenized in thickness (pouch cell) or in radial direction (cylindrical cell), respectively. The main advantage of macroscopic models lies in their computational efficiency. However, these models fail in predicting short-circuit on a component-based level. Determination of the component behaviour is only possible to a very limited extent, which means that a component-based short-circuit criterion is also not an option.
M. Styrnik (BMW Group), T. Erhart (DYNAmore)
In crashworthiness simulation the definition of material properties is one of the key aspects to obtain reasonable results. However, a lot of materials come with properties that either change locally or are generally of stochastic nature. Additionally, production processes (e.g., welding) might change the behavior of certain materials. To overcome the necessity of defining an individual part for each region where material properties differ a new approach was developed. With the new keyword *DEFINE_TABLE_COMPACT it is now possible to define material properties by means of a multi-dimensional table with arbitrary variables controlling for example the plastic flow curve or the damage behavior. Secondly, the keyword *INITIAL_HISTORY_NODE enables the user to set these variables individually on each node in the model. This presentation shows possible applications of this approach and the benefits on parametric modelling and simulation.
R. Taylor (Arup), S. Hayashi, M. Murase (JSOL)
JFOLD is a software tool for simulation-based airbag folding in LS-DYNA®. This paper presents how JFOLD and LS-DYNA can be used effectively to research how slight changes in automotive passenger airbag folding can lead to significant changes in occupant injury prediction. The demands placed on today’s occupant safety teams continue to increase, driving up the need for airbag complexity and simulation accuracy whist driving down the time to deliver. Accurate airbag simulation is critical to improve occupant safety in an increasing number of crash scenarios and out-of-position cases, including passengers of autonomous vehicles. In addition, airbag simulation is now being used to assess the performance of interior trim components during early break-out and deployment.
T. Borrvall, F. Bengzon, A. Jonsson (DYNAmore Nordic), M. Lindvall (IKEA)
Thermoplastics are widely used in many industries today. Products such as packaging solutions, consumer goods, medical devices, furniture, electronic devices and vehicles are constantly demanding more and more sophisticated polymer components. In addition, sustainability agendas at many companies today means a necessity to transition from high spec petroleum-based polymers to recycled and biobased alternatives . This creates a pressure on the CAE departments to assess candidate resins at a high pace and make fact-based judgements on their predicted life cycle performance. In a competitive market, there are good reasons to adopt best practice for predicting the life cycle performance of these polymers already during the design phase with the use of realistic simulation.
R. Nasouri (University of Texas), H. Rokhy (Amir Kabir University), A. Montaya, A. Matamoros (University of Texas), R. Backzadeh (Urmia University)
The CHEMISTRY solver has been added to the LS-DYNA software, enabling users to model and predict accidental gas explosions in refinery plants, pipelines, and coal mines. Although this new solver has shown theoretical potential in chemical, oil and gas refineries, there are limited studies implementing the capabilities provided by the CHEMISTRY solver. In this study, a series of fundamental chemistry problems were simulated, to compare the numerical results with existing experimental data. This study finds excellent agreement between solver results and experimental data, proving a high level of precision obtained through the CHEMISTRY solver.
C. Woll (GNS Systems)
While the traditional development cycle of “design-build-test” often lasted several years, today it is imperative to bring innovations to market readiness with simulation-driven design and digital twin in shorter time spans. Virtual tests on vehicles make a significant impact in effectively reducing development times and costs. Companies must master two fundamental challenges for their efficient use: on the one hand, complex and time-intensive engineering tasks have to be mastered quickly. On the other hand, solutions are increasingly required that organise the complex product development across organizational units. The Digital Engineering Center, an engineering workplace in the cloud, meets these challenges.
S. Heiland, L. Penter, S. Ihlenfeldt (TU Dresden), L. Klingel, F. Jaensch, A.Verl (University of Stuttgart), C. Schenke (Fraunhofer IWU)
The commissioning of forming tools includes the mechanical spotting of the active surfaces and the identification of suitable actuator set values. It represents a time-consuming and expensive step in the tool development process. A major cause for the necessity of this manual die spotting is the elastic compliance of press and die that results in geometric deviations between predicted and produced part geometry as well as the control characteristics and the resulting accuracy of the drives. The interactions between the machine and the forming process can be computed numerically. An integration of simulation models that includes the machine behavior into the tool development process offers potential for time and cost savings for die manufacturers and machine operators
K. Wolf, P. Gulati (Fraunhofer SCAI) G. Duffett (NAFEMS)
With the progress in CAE simulation leading to more complicated and integrated workflows, data control and transfer becomes essential. This is extremely important in the manufacturing industry where complicated simulation workflows are necessary in tracking material changes throughout the manufacturing proclete software interoperability.
F. Knieps, I. Moldovan, B. Liebscher, M. Köhl (thyssenkrupp), M. Merklein (IMT)
In packaging steel forming processes, conditions in-between plane strain and biaxial tension are mostly relevant as they lead to failure in deep drawing applications and characterize e.g. the process of the rivet forming in easy-open end applications. To receive precise simulation results in finite element analysis, it is important to consider an accurate modelling of the yield locus in this area. Complex anisotropic yield functions like e.g. Yld2000-2d which was proposed by Barlat and is implemented in LS-DYNA using keyword *MAT_133 do not consider the characterization of this area and maintain an uncertain variable by the yield locus exponent.