Welcome to the LS-DYNA Product Space

<p>Hello everyone.<br>I have two cylinders nested inside each other. The inner cylinder (red) is 300 mm in diameter, and the outer (black) is 2 mm thick.<br>Both cylinders are made of SPH particles.<br>How can I configure the outer cylinder to have a single layer of the specified size, for example, a 2 mm thick cylinder? The system won't let me build particles on the outer cylinder larger than 0.05 mm, resulting in a total particle count of over 3 million.<br>Thank you.</p><p> </p><p></p>

<p>Hello everyone.<br>I'm simulating a calculation with rubber and cord inside.<br>Everything was working fine before, but now the calculation stops with an error and terminates.<br>I'm using a 20-core MPP.<br>I have a fairly powerful processor and 512 GB of DDR.<br>Why is this happening and how can I fix it? Thank you.</p><p></p><p></p>

<p>Hello everyone.<br>I'm simulating rubber inflation under pressure. I'm also using mass scale.<br>In my calculations, I see that the mesh on the rubber end is severely distorted. Why? How can I fix this? There's no pressure on the end.</p><p></p><p></p>

<p>Hello,</p><p>I have created a bumper and a guard-rail. (I have used similar KEYWORDS like in the Yaris test case.)</p><p>In the time step, where the bumper hits the rail. Big, fast growing cells are produced at the bumper (see red circle).</p><p>Is it weak convergence? What can I do?</p><p>My best wishes & Thank you!</p><p>Frank</p><p></p>

<p>Hello,</p><p>I am trying a simple model of beams, and a damping effect is appearing although no visable card including damping is used. The beam is modelled wiht MAT_SPOTWELD.</p><p></p><p></p><p>This are the forces in the SPC at the start of the beam:</p><p> </p><p></p><p>How is the force reduced? Is due to artificial damping due to numerical reasons?</p>

<p>Hello everyone, I have a model made of beams, it's a steel frame. I selected the required points in the FORCE REACTION tracker. But when I run the calculation, I see the following warnings:</p><p>*** Warning 50135 (MPP+135)<br>Tracked node is not constrained<br>since it is not found on a segment.<br>tied interface # = 725<br>tracked node # = 86264</p><p>And there are no results. Why?</p>

<p class="MsoNormal">I am simulating one part with a top and bottom die. I want to extract the volume reduction and density change after pressing. For Volume change, I usually go to the Element tool->measure->Volume. I will plot the volume change to get a density plot.</p><p class="MsoNormal">I know that LS Prepost won’t output Density by default. Is there any way to Fringe the density in LS PrePost directly or indirectly? For my application, I would like to get a contour plot for the density gradient and the density change. Any user-defined procedure or something?</p><p class="MsoNormal">Let me know if you have any suggestions or recommendations for this.</p>

<p>We have a reference for the column from previous study, and we want to try and simulate it using the parameters they've given us, it consist of Concrete, Reinforcements, and a TNT for blast explosion. However we cannot get the same or predicted result because we didnt really know how to use the software and out time is limited. Can some of the experts help us in understanding how the blasting works in Ansys mechanical. Note that, We know how to make it (Geometry and Engineering data maybe), but we're not sure if its right because the results we get are not the same. Thank you if someone notices this.</p>

<p>In LS-DYNA, when defining multiple *CONSTRAINED_GENERALIZED_WELD_SPOT constraints, if the node sets of two constraints contain the same node, the following error is reported:</p><p></p><p>Does LS-DYNA have another type of constraint or tie that allows two constraints to have node sets sharing the same node?</p>

<p>I recently noticed something I didn't understand with the EM_CONTROL_MAGNET keyword. On page 385 of the keyword manual (https://lsdyna.ansys.com/wp-content/uploads/2025/04/LS-DYNA_Manual_Vol_III_R16.pdf) it mentions there are two inputs, both mcomp to turn on the keyword, and ncycm to set the number of cycles. So it would be written like this:<br>*EM_CONTROL_MAGNET<br>$# mcomp ncycm<br>1 100<br>However, when I use lsprepost to make a keyword file and include the EM_CONTROL_MAGNET keyword, there is no ncycm command, only the mcomp, and it is automatically written as:<br>*EM_CONTROL_MAGNET<br>$# mcomp<br>1</p><p> </p><p>Moreover, with the syntax written by LSPP, the simulation will crash stating "forrtl: severe (164): Program Exception - integer divide by zero" after assembling Fem-Bem matricies, and building P mat, Q mat, and W mat through 100 percent.  This may be a problem with the syntax, or maybe the rebuilding of magnetic vector of a deforming magnet happens too often and there is a threshold somewhere between NCYCM being undefined and 100 that allows the simulation to complete.  If it helps, here is the EM chunk of my .k file<br><br>*EM_PERMANENT_MAGNET<br>$#      id       pid     mtype     north     south        hc<br>         1         1         1         2         1     21033<br>*EM_CONTROL<br>$#   emsol     numls         -   dimtype    nperio         -   ncylfem   ncylbem<br>         1       100                   0         0                   1         1<br>*EM_CONTROL_MAGNET<br>$#   mcomp<br>         1<br>*EM_CONTROL_TIMESTEP<br>$#  tstype    dtcons      lcid    factor     tsmin     tsmas     rlcsf    mecats<br>         3       0.0         0       1.0    1.0E-4      0.25        25         0<br>*EM_CONTROL_COUPLING<br>$#   thcpl     smcpl    thlcid    smlcid   thcplfl   smcplfl<br>         1         2         0         0         0         0<br>*EM_SOLVER_FEMBEM_MONOLITHIC<br>$#   mtype     stype    abstol    reltol     maxit<br>         0         1    1.0E-6    1.0E-4       100<br>*EM_MAT_002<br>$#     mid     mtype     sigma     eosid     murel     eosmu    deatht<br>         1         4       0.0         0       1.1         0    1.0E28<br>*EM_EXTERNAL_FIELD<br>$# fieldid     ftype      fdef     lcidx     lcidy     lcidz<br>         1         1         1         4         2         4</p>