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Hi. It is possible to define heat transfer coefficient as functions of temperature and pressure in LS-Dyna? Or tabelar dependency ? 

We received the segmentation error at various timesteps for the same model just increasing the speed linearly as shown below. I tried to solve implementing various solver parameters like double-precision, medium priority hardware sources and so on. It is interesting that the error occurs inconsistently. Therefore, it is not easy to diagnosis from my point of view. All the models run on a cluster using single-precision Dyna solver with ncpu=48 & 16GB as shown below.Can you please let me know about your comments to find out the source of the problem? Partially the slurm file shared below.-----------------------------------------------------------------------30kph     node  number 362930 deleted at time  4.5900E-03forrtl: severe (174): SIGSEGV, segmentation fault occurred 60kph      node  number 387621 deleted at time  3.7800E-03forrtl: severe (174): SIGSEGV, segmentation fault occurred 90kph     solid element 330148  failed at time  2.9691E-03forrtl: severe (174): SIGSEGV, segmentation fault occurred 120kph     shell element 584554  failed at time  1.1339E-02forrtl: severe (174): SIGSEGV, segmentation fault occurred------------------------------------------------------------------------------#SBATCH --ntasks=48#SBATCH --partition=k2-hipri#SBATCH --nodes=1#SBATCH --mem-per-cpu=16G

Hi,I believe I have made a post on here before. I am trying to use ANSYS LS-DYNA's simulation capabilities to simulate concussions and other brain injuries. At this stage, the model can be quite crude. I just want to gain a basis level of understanding to build off of that allows me to see how the brain might move in the skull based on a given impact. I believe the brin has a high coeffcient of restitution, so even a little change in the angle or amount of force applied can affect the ways the brain moves or makes contact with the skull. These slight changes can create huge chnages in terms of patient symptoms of injury. I can use average brain sizes/volumes and average skull sizes/volumes to do this; I am not concerned about the effects of the neck at this time. Essentially, I want to see how a smaller spheroid with a very soft gelatin-like texture/strcuture material moves inside a larger spheroid that is far more rigid. The gap between these two surrogate spheroids is known anatomically as the sub-arachnoid space, and is about 1/4 inches. I was hoping to apply the force somewhat simply, using arrows or some type of vector, in a drag-and-pull sort of way. A good example of what I mean can be found here: https://phet.colorado.edu/sims/html/collision-lab/latest/collision-lab_all.html I like this simulation, but it doesn't allow me to reflect 3D-motion or put the objects inside one another. But the method of applying force is quite simple and is analogous to what I'm looking for. Now onto the ANSYS relevance... I have downloaded the own LS-DYNA package and the ANSYS Workbench which contains an LS DYNA mechanical module??? I am just really confused and overwhelmed by the capabilities of ANSYS and its intracacies. I see there's an ANSYS Mechanical LS-DYNA as a part of the workbench, and a separate Pre-Post LS DYNA package along with a powershell. It's just a lot. Could anyone help guide me on how to proceed in creating my model of the brain and skull-- which can and should be crude in their geometrical design, though the consistency of the materials can hopefully be quite accurate-- and how to simply apply force to this model. Also, I see that LS DYNA, the individual package NOT the mechanical module as a part of the workbench, has a head impact positioning feature. But it seems you may need to upload a model from somewhere else. I created two sphereoid objects in Pre-Post, but don't know how to upload these into the head impact positioning feature, or if I even can/should do that. Just really confused on how to proceed, I'm only 16. If anyone knows of any other simpler software that may be better for my purposes, I'm open to that. I just heard that LS DYNA has the ability to reflect biological tissues, like brain and bone, and the way the respond to force stimuli. 

Hi, I need manual for LSTC.H3_50TH.DETAILED.190217_BETA.k Dummy Model, can someone give me it?

Hi ,im trying to solve a model in Mechanical with LSDYNA application, but when i try to solve, im getting the next error from the solver: initialization completed            error from spvec_initsparse(spvObject)  -2 E r r o r   t e r m i n a t i o n          can someone help me? Thanlks.

Hello,I have ran the Shock Bubble Interaction (+FSI) (+3D) case here from the dynaexamples.com website here (https://www.dynaexamples.com/cese/dualcese/shockbubblefsi) How do I best visualize this? I see the animated gifs, but not sure how those were obtained. Thanks,Peter

Hello LSDYNA communityDo structures in the fluid domain have to be coupled to ICFD? I recently made a DEM-ICFD coupled model. There is a baffle structure for DEM particles in the fluid domain. Because of this structure I want to couple with DEM, but I don't want the structure to disturb the fluid motion. I would like to let the fluid pass freely through the structure, is it possible to realize it?

Hello everyone,I would like to know, if there is any list with a detailed information about supported materials (MAT_) in LS Dyna when using the smoothed particle Galerkin (SPG) method. I am especially interested in anisotropic materials that can simulate carbon fiber reinforced polymers (CFRP).Thanks a lot in advance for your answer!Best Regards,Fritz. 

I have downloaded the both student softwares "Ansys Student and Ansys LS-Dyna student" and then extracted the files and installed the softwares as in shown in this link https://www.youtube.com/watch?v=BxZKZHbsdVA&t=3sBut I am getting the general errors while using LS Dyna - "the demanded solver was not found in the specified path" and “An error occurred inside the SOLVER module: general error.” and I tried to uninstall and install everything completely but still the errors exist as shown below,I need to know how to download the solver along with the install package.

Hello! I am interested in studying SPR3 element. This element works fine with shells (shell - spr3 - shell). According to LS-Dyna R13 manual beams also could be connected with SPR3 (elform1 - spr3 - elform1). But trying to use spr3 with beams results in memmory error:expanding   memory to       94283 d     3849095 constrained spr 1 expanding   memory to************ d     3849095 constrained spr 2  *** Error 70021 (OTH+21)     Memory is set 4429334070282377342 words short     memory size 325000000     Increase the memory size by one of the following     where #### is the number of words requested:       1) On the command line set - memory=####       2) In the input file define memory with *KEYWORD       i.e., *KEYWORD #### or *KEYWORD memory=####Any ideas how can I solve the problem? 

Hello, I am new at LS-Dyna and I wanted to perform a simulation with the Particle Blast Method (PBM). My questions are: Has someone experience with this method? Could you share a tutorial or a simple example (keyword-file) for the particle blast method?How could I postprocess these simulations? I wanted to extract the pressure development at specific positions in the air. Thanks and kind regards,

Is it possible to use peridynamic theory to predict the crack propagation of concrete at temperature in the R13 version of LS-DYNA?

Hello,I have tried to simulate the crash behavior of crash boxes under different temperatures.I am using the material model MAT_015. Unfortunately, the simulation does not show any significant differences between the different temperatures (in contrast to previous tests).For the thermal analysis I use- INITIAL TEMPERATURE- CONTROL_THERMAL_SOLVER- CONTROL_SOLUTION- CONTROL_THERMAL_TIMESTEP- T01_THERMAL_ISOTROPICKEYWORDS*CONTROL_SOLUTION$#    soln       nlq     isnan     lcint     lcacc     ncdcf     nocop              2         0         0       100         0         1         0*CONTROL_THERMAL_SOLVER$#   atype     ptype    solver         -       gpt    eqheat     fwork       sbc         1         0        11                   8       1.0       1.0       0.0*CONTROL_THERMAL_TIMESTEP$#      ts       tip       its      tmin      tmax     dtemp      tscp      lcts         0       0.5     0.001       0.0       0.0       1.0       0.5         0*MAT_THERMAL_ISOTROPIC$#    tmid        ro     tgrlc    tgmult      tlat      hlat             1       0.0       0.0       0.0       0.0       0.0$#      hc        tc  5.000000E8    0.0162*INITIAL_TEMPERATURE_SET$#    nsid      temp       loc            1     260.0         0Why does it show no differences when I change the INITIAL_TEMPERATURE?Am I using the wrong solver? Or the wrong T01 model?RegardsNoah

Hello,I have two solid PARTs, I defined both of them in CESE_PART. Hence Section ID and Material ID need not be defined. But still I am getting following error.Error 10125 (KEY+125)     Checking PART and SECTION definition input.     PART ID 1 with     SECTION ID 0 does not exist.     This is PART 1 in the order of input.Can you please help on this?Regards,Atish

Hello, I am currently trying to perform a Full Restart on a model. So far everything works but there is one problem: I remove some parts from the original model and add new parts in the restarted simulation. The contacts assigned to the removed parts are killed during the original simulation via birth/death. When I try to run the restart with these killed contact cards removed or new contact cards introduced the calculation is not started and no error message is printed. The modelcheck (.mchekout file) stops after the line "initialization completed" not reaching the "normal termination" line. Currently a workaround is possible: I use the ID´s of the contact cards from the original model (contcats already killed during original simulation) and just assign new master and slave IDs from the new included parts to them. This only works if all contact ID´s present in the original simulation are also prensent in the restarted simulation. That seems wrong to me as those are entirely new contacts with new parts. I would think that it should be possible to remove contatc ID´s from contacts no longer used and introduce new contatcs with new ID´s? At least that is what LS-Dyna 12.0 documentation suggests: "Pre-existing contacts, in general, carry forward seamlessly using data from the d3dump (or d3full if MPP) database. It is important that the contact ID(s) in the full restart input deck match the contact ID(s) in the original input deck if the intent is for the contacts to be initialized using data from the d3dump/d3fulldatabase."My intent is to remove contacts and add new contacts just initializing those that are present in both simulations. I am happy for any suggestions as the workaround will fail once I am working with models that will have an unequal number of removed and added contacts or situations where no contacts are added at all but parts are removed. Kind regards, Vince

I am trying to create a spring element in LSDYNA for a mass spring system. I have done this using a discrete element but I was wondering if there is a way to create the spring without using a discrete element. The reason being I am doing a study on stiffness damping (*DAMPING_PART_STIFFNESS) on a 1DOF system but this card cannot be applied to a discrete element. 

Dear LS-DYNA Community, I am currently developing a 3D model using the DEM coupled with ICFD functionality in LS-DYNA. In my model, DEM particles are bonded into a large rectangular structure, resembling a train, approximately 100 meters in length. This is achieved through the De_bond command. ICFD is utilized to simulate the natural air surrounding this structure. For the air domain, which extends several kilometers and is rectangular, I've set 'free slip' boundary conditions on all six sides. The primary focus is on modeling the high-speed airflow that results from the structure's movement through the surrounding air. Having previously worked with EDEM coupled with FLUENT, I was accustomed to detailed air pressure data outputs, including dynamic, absolute, relative, static, and total pressure, all reported separately. However, in the ICFD results post-processing in LS-DYNA, it appears that only fluid pressure is available, lacking the detailed division found in FLUENT's results.My questions are as follows:Can LS-DYNA's ICFD post-processing differentiate and display various types of air pressures such as dynamic, absolute, relative, static, and total pressure?Does ICFD in LS-DYNA account for atmospheric pressure in its simulations? If my goal is to simulate a natural air domain, is setting 'free slip' as the boundary condition on all six sides of the air domain the optimal choice?Are there specific boundary conditions within LS-DYNA that can incorporate atmospheric pressure, or should I maintain the boundary pressure at a constant zero (as observed in some official website examples)? Your insights and recommendations on these aspects of ICFD modeling in LS-DYNA would be invaluable to me. Thank you for your guidance and support.

Hello LS-DYNA Community,I am currently engaged in simulating rock-like materials using the De_Bond feature in LS-DYNA and have encountered a specific challenge that I hope to get guidance on.In my simulations, the rocks are characterized by planar fractures. These fractures are present in two orientations: depth-wise and longitudinally. Notably, the longitudinal cracks exhibit zero cementation strength. My objective is to accurately replicate the behavior of these fractures. To do this, I intend to assign a zero cementation strength to the particles situated along the longitudinal planar fractures at varying depths, while maintaining normal cementation for the remaining particles.My queries are as follows:Does LS-DYNA offer a feature that allows for the importation of planar surfaces? If so, can this feature be used to automatically adjust the bond strength of particles situated along these surfaces?Is it possible within LS-DYNA to track and quantify specific parameters related to the bond, such as the bond energy and the count of damaged bonds during simulations?I believe these functionalities would greatly enhance the accuracy of my simulations. Any insights, suggestions, or guidance on how to approach this within LS-DYNA would be greatly appreciated.Thank you in advance for your assistance.

Is it possible to do convergence test in ANSYS LS-DYNA? How is it done? I'm facing a problem where I can't solve and there is a question mark next to the solution. Help me, please

I am attempting to evaluate the modal response of a pressurized membrane-like structure.I have created a simple example consisting of a square membrane, simply supported along the edges, and subjected to uniform pressure. Here are some additional details:I am utilizing a fully integrated Belytschko-Tsay membrane (ELFORM=9) that is designed to be hourglass-free.I am using a linear elastic material (*MAT_ELASTIC).The pressure load is applied using the *LOAD_SHELL_SET_ID keyword.Currently, I have opted for the explicit solver, applying the pressure linearly.I am constraining the translational degrees of freedom (DOF) of the edges only.I am using version R13.1.1-13-g5480eca294 mpp_dp for Windows.Upon running the simulation, I immediately observe what I thin kto be significant hourglassing in the membrane deformation and am unsure about the cause (please see the attached picture).How can I suppress this behavior? What is causing it? Best regards,Rocco   

According to LS-DYNA Material Manual, *MAT_058 can be fed with stress strain curves for tensile/compression and in-plane shear. Is there a way to include these curves directly in the engineering data in Workbench without the need of modifying the LS-DYNA input files generated by Mechanical/LS-DYNA to include it before analysis ?Regards,

Hello everyone,We are currently working to prescribe some earthquake motions in LS-Dyna (V14.0.0) with LS-PrePost (V4.10.5-23Jun23) and have come across an interesting issue. I'm hoping you can help us with this.In our simulations model, which involve 6721 nodes and 6244 elements, we prescribed all three components of the ground motions as accelerations. However, when we checked the displacement response of a node from the prescribed motion nodeset from d3plot, there was an unexpected drift at the end of the displacement time-history. Interestingly, this drift doesn't occur if we derive the displacement by integrating the acceleration using alternative methods. This problem happens regardless of the specifics of the input acceleration data, or the target node I choose to compare the integrated acceleration output with the output displacement.In the figure below, I've plotted the displacement response, integrated from acceleration, alongside the actual displacement response of node 28289 in the x direction with help of the History tool. This is a random node on the surface of the rigid body system subjected to the motion. As you can see, there is a clear difference between the displacement derived by LS-Dyna and the displacement integrated from LS-Dyna's acceleration in LS-PrePost -Interestingly though, when we approach the problem in reverse – starting with output displacements and then performing differentiation twice to obtain the accelerations of a node – the results align much more closely with the output response acclerations -I'm trying to understand why this issue happens and if there is something we are doing wrong.Another question I have is about prescribing ground motions: should we use displacement or acceleration? And how does the internal algorithm of LS-Dyna originally handles this? Any insights would be greatly appreciated. Thanks in advance for your help! With Regards,Tonmoy.

Hello, I have been using Johnson Cook models in my impact analyses, and I wanted to try some other constitutive models. I am running into an error where the material models are not recognized, including the models that come built-in with ANSYS Workbench (STEEL V250 for example, with Steinberg-Guinan strength model and Mie-Gruneisen EOS). How can I implement these models in LS-DYNA for ANSYS Workbench? Here is the error code from the Solver output below. It looks like it simply is not detecting the material model at all. I am currently using it with an SPH mesh, but I get the same error with other mesh methods too.  Beginning of keyword reader                                   11/17/23 17:55:35  *** Error 10157 (KEY+157)     MAT 2 is not found  *** Error 10304 (KEY+304)     CHECKING MATERIAL INPUT Part ID= 2     PART ID 2 with     SECTION ID 2 and     MATERIAL ID 2 does not exist.     This is PART 2 in the order of input.  *** Error 10133 (KEY+133)     input data failed with: 4 errors E r r o r   t e r m i n a t i o n                             11/17/23 17:55:36 

Hello,I am trying to simulate the sudden gas expansion of compressed H2 gas in open atmosphere using CESE solver in LS Dyna.How can I insert CHEMKIN file as input to CESE solver? Is it possible to include real gas properties in LS Dyna using NIST database?Regards,Atish

Hi everyone, I am using Ls-Dyna Workbench. The simulation consists of a first step in which a wire is deformed, and a second step (added with a full restart) in which the deformed wire is deployed inside a hollow body. I would insert multiple wires inside the same body (from ten to twenty wires) so i need to repeat these simulations many times. Do you have any suggestions for how perform it?Thank you in advance, Camilla