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<p>When running an impact analysis of termination time 0.25s, after the failure of a single shell element at 0.191s the job immediately terminates. The lsrun.out file records the following error message: </p><p class="MsoNormal">forrtl: severe (157): Program Exception - access violation</p><p class="MsoNormal">The version of LS-DYNA I am using is 2024, and the contact algorithm I am using for impact is *CONTACT_AUTOMATIC_NODES_TO_SURFACE. </p><p class="MsoNormal">Is it the way I have set up my contact or is there an internal LS-DYNA bug/issue with the 2024 version?</p>

<p>Hello gentlemen，</p><p>I want to write some program to extract some data from the d3plot and d3htd file, but I can't found any information about the script form the documentaion, also nothing from the ansys website. </p><p>Are there any help documention I can found to reference? </p><p>Thank you</p>

<p>Hello gentlemen，</p><p>I want to do a shock vibration with lsdyna explicit, shock condition: 18G, 6ms, half sine wave,Y direction</p><p>Question 1: I use the keyword *BOUNDARY_PRESCRIBED_MOTION_RIGID to apply the acceleration, but I found I have to release the freedom of Y on the base fix points so that the acceleration can be normal (18G). Unlike the random vibration and response spectrum analysis, I can fully fixed the base and apply the acceleration at the same time. Can you help me to explain it?</p><p>Question 2: When I was apply the acceleration, Do I need to apply a initial velocity on the oppsite direction of the acceleration? This question really confused me. I did not find a similar example from the dynaexample.</p><p>If any one have a K file model with similar condition, It will be really thanksful to share with me. Thank you!</p><div> </div><p> </p>

<p data-path-to-node="4">Hi everyone,</p><p data-path-to-node="5">I’m running a 2D plane-strain site response analysis of a soil basin. To handle the side boundaries, I meshed 1D columns (local periodic boundaries) on the far left and right edges, and connected them to the main basin using dashpots.</p><p data-path-to-node="5">During gravity initialization (Dynamic Relaxation), I use a <code data-path-to-node="7" data-index-in-node="73">*BOUNDARY_SPC_SET_BIRTH_DEATH to lock the basin edges horizontally so a gap doesn't form. DR converges perfectly, and the mesh sits completely flush.</p><p data-path-to-node="5">I am also applying <span class="math-inline" data-math="\sigma_{xx}" data-index-in-node="21">sigma_xx </span>and <span class="math-inline" data-math="\tau_{zx}" data-index-in-node="37">tau_zx  form elout to the inner sides of main model which are on the boundary between far side columns and main domain. <br><br>I am still not capturing uniform free field response on the surface. </span></p><p data-path-to-node="5"><span class="math-inline" data-math="\tau_{zx}" data-index-in-node="37">How can I mimic the free field case just like a 1D site response analysis? (I cant want to use *CONSTRAINED_NODE_SET as I will non-flat non-uniform geometry affects in future) </span></p><p data-path-to-node="5"><span class="math-inline" data-math="\tau_{zx}" data-index-in-node="37">Best,</span></p><p data-path-to-node="5"><span class="math-inline" data-math="\tau_{zx}" data-index-in-node="37">Muhsin</span></p><p data-path-to-node="5"> </p>

<p>Hi everyone,</p><p>I’m a student currently learning about LS-DYNA.<br>I would like to use simulation to analyze soft and flexible materials, I'm using thin structures so I would like to use shell (2D) elements.<br>Does anyone have suggestions for suitable material cards for this type of material?</p><p>Also, I currently only have tensile test data for the material and do not have compression test data.<br>Can tensile stress–strain data still be used as the Curve ID input even if the simulation involves compression behavior?</p><p>Thanks in advance!!!</p>

<p>Dear Sir/Madam,</p><p>I hope you are doing well.</p><p>I am currently working on a Notched Semicircle Bend test simulation project in ANSYS LS-DYNA and would greatly appreciate your guidance regarding crack propagation modeling.</p><p>In my model, I am using MAT_ELASTIC along with MAT_COHESIVE_MIXED_MODE and MAT_ADD_EROSION to simulate crack initiation and material failure under three point loading. However, despite implementing these material models, the crack is not propagating as expected during the analysis. (the specimen material is Sandstone)</p><p>I suspect the issue may be related to the erosion parameters, cohesive zone calibration, mesh dependency, or contact/timestep settings. Since I am relatively new to this type of coupled damage modeling, I would be very grateful for any suggestions or best practices you could share.</p><p>Specifically, I would like to seek guidance on:.<br>Appropriate failure criteria for realistic crack initiation and propagation.<br>Proper setup of MAT_COHESIVE_MIXED_MODE parameters.<br>Recommended element types and mesh strategies for crack tracking.<br>Possible reasons why cohesive cracks fail to propagate .<br>Common mistakes or numerical stability issues to avoid in LS-DYNA.</p><p>Thank you very much for your time and support. I look forward to learning from your experience and insights.</p><p>Best regards,</p><p>Shreeya Julme</p>

<p>Hello,</p><p data-pm-slice="1 1 []">I want to run a simulation using MAT_063 (Crushable Foam), with Model 1 selected in the material card. I have read the documentation for this material model, and as far as I understand, the material requires the yield stress as a function of volumetric strain. My first question is whether I should provide only the plastic part of the stress–strain curve obtained from experiments, or if the material requires the entire stress–strain curve. Also, is it possible to use stress–strain data obtained from a uniaxial compression test?</p><p data-pm-slice="1 1 []">The other question concerns a warning I receive in Keyword Manager → Model Check → Keyword Check for the defined material (MAT_63). The warning message states: "MAT_CRUSHABLE_FOAM (ID: 1): curve 1 does not monotonically increase." The experimental stress–strain curve contains drops in stress, as shown in the figure below as an example. What should I do in this case to be able to use this material model and resolve the warning?</p><p data-pm-slice="1 1 []">Does anyone have any ideas about these questions?</p><p><span style="font-size: 14pt;"></span></p>

<p>Hello everyone,</p><p>I am working on a space debris capture simulation using a kevlar net. The following are all the parameters I am using for the simulation, either the net disappears or stays in the same place upon running, I have been trying to fix it for a couple of weeks now, I dont know what the issue is. If anyone can help me to see what inputs i might be missing or identify the problem and direct me into a right direction, that would really help me. I am using Altair Hypermesh 2025 for the pre-processing. </p><p>Net: 10cm x 10cm in size, thread diameter = 1.1mm, made with 2D tria shell elements. The net needs to move towards the debris and wrap around it. Material model: MAT_58_LAMINATED_COMPOSITE_FABRIC. Section shell card: ELFORM = 16 (Fully Integrated Shell Element)</p><p>Debris: 4cm diameter sphere, made with 3D tetra elements as it is a rigid body and is fixed. Material model: MAT_20_RIGID. Section solid card: ELFORM = 1 (constant stress solid)</p><p>Velocity: Initial velocity generation at 4.5m/s</p><p>Contact parameters: CONTACT_AUTOMATIC_SURFACE_TO_SURFACE</p><p>Then i have CONTROL_TERMINATION, CONTROL_TIMESTEP, CONTROL_ENERGY, DATABASE_BINARY_D3PLOT cards too. </p><p>If you can help me, I can email you my key file. Thank you</p><p>This is how both the mock debris and the net look in the software. </p><p></p>

<p><span data-olk-copy-source="MessageBody">Hi,<br><br>I have Ansys LS-DYNA 2025 R2 installed on a Windows workstation. </span></p><div class="x_elementToProof" data-olk-copy-source="MessageBody">Currently, I am developing a custom phase-field fracture model in LS-DYNA, instead of using any inbuilt material models. Could anyone please help me with how to get (or whom to reach out at Ansys to get) the compatible/matching LS-DYNA 2025 R2 / v252 Windows x64 user-defined material and user-defined element object/static-linking package, including:</div><ul data-spread="false">dyn21.F / dyn21.f for user-defined materialsdyn21b.F / dyn21b.f for user-defined elementsinclude filesobject/static librariesMakefile or Windows build scriptsexample UMAT and user-element source filesexample keyword decks for user-defined elementsrecommended compiler and linker instructions<div class="x_elementToProof">Also, my current installation is using the SMP single-precision executable, but the phase-field fracture problems may become computationally heavy. Please also advise whether I should request or use:</div><ul data-spread="false">SMP single precision, SMP double precision, or MPP double precisionWindows MPP support, if availableMS-MPI or another MPI packageIntel oneAPI Fortran / Intel Fortran compiler versionMicrosoft Visual Studio / MSVC versionIntel MKL / BLAS / LAPACK support, if needed for solving the equations<div class="x_elementToProof">Please let me know which exact package is compatible with my LS-DYNA 2025 R2 / v252 installation and what additional software I need to install before compiling a custom executable.</div><div class="x_elementToProof">Also, if Ansys has any tutorials, documentation, examples, training material, or technical notes on using the LS-DYNA user-defined material and user-defined element packages, especially for compiling custom executables on Windows, I would appreciate it if you could share them.<br><br></div><div class="x_elementToProof">Thank you.</div><div class="x_elementToProof">Sincerely,<br><br>Umar<br>PhD student @GeorgiaTech</div>

<p>Hello,</p><p>Acoording to different Ansys recommendations sources, in case of using Hexa and Tetras for a solid mesh, it is recommended to use ESORT = 1. LSDYNA Recommendations for structural impact</p><p>This tranforms tetras to type 10 formulation, which adds a lot of stiffness according to Microsoft PowerPoint - solid_elements.pptx. </p><p>Why not ESORT = 11 to change to TET13, which is more accurate with a not that different rsimulation time? <br><br>Is there some reasons that I might not be seeing?<br><br>Best regards,</p><p>Roberto</p>