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<p><p class="font-claude-response-body break-words whitespace-normal">Hi,<br>I'm working with THUMS (v6) positioned in a vehicle seat in LS-DYNA. My vehicle model (2014 Honda Accord from NHTSA) already includes a seatbelt model.</p><p class="font-claude-response-body break-words whitespace-normal">After completing the positioning simulation, I'd like to fit this existing seatbelt onto the THUMS mannequin, but I'm not sure about the correct workflow in LS-PrePost.</p><p class="font-claude-response-body break-words whitespace-normal">Could anyone explain how to properly adapt and fit the existing seatbelt to the repositioned THUMS?</p><p class="font-claude-response-body break-words whitespace-normal">Thanks</p></p>

<p class="MsoNormal" style="text-indent: 21.0pt;"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">I am trying to use the SALE method to simulate the penetration of a spherical high-pressure gas cylinder by a projectile. However, I encountered the following error:</span></p><p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">“forrtl:severe (157): program exception-access violation”</span></p><p class="MsoNormal" style="text-indent: 21.0pt;"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">The simulation behaves normally when the projectile enters the cylinder, and no leakage occurs at that stage. However, when the projectile exits from inside the cylinder, the calculation crashes with the above exception as soon as the projectile just touches, or is about to touch, the inner surface of the cylinder on the exit side</span><span style="font-family: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-bidi-font-family: 'Times New Roman';">。</span></p><p class="MsoNormal" style="text-indent: 21.0pt;"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">The model details are as follows:The model is a 1/4 symmetric model, using the mm-ton-N-s unit system. The projectile consists of an aluminum core and a copper jacket. The cylinder body has two layers. The meshes of the two cylinder parts share common nodes at the interface. Both cylinder layers are made of titanium alloy.</span></p><p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">All solid parts are modeled with solid elements and use *MAT_JOHNSON_COOK together with *EOS_GRUNEISEN. The solid mesh size is 0.5 mm.The gas is modeled using *MAT_NULL with*EOS_LINEAR_POLYNOMIAL.</span></p><p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">I used *ALE_STRUCTURED_MESH_VOLUME_FILLING to initialize the entire S-ALE background mesh as “airout”,with:RO=1.225e-12,C4=0.4,E0=0.25 which corresponds to a pressure of about 0.1 MPa.The region inside the cylinder, bounded by the inner surface of the cylinder, was initialized as “airin”, with:RO=1.225e-10,C4=0.4, E0=25 which corresponds to a pressure of about 10 MPa.</span></p><p class="MsoNormal" style="text-indent: 21.0pt;"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">I used three *ALE_STRUCTURED_FSI definitions:</span></p><p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">1. coupling between “airin”. and the outer cylinder layer;</span></p><p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">2. coupling between “airin”. and the inner cylinder layer;</span></p><p class="MsoNormal"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">3. coupling between the projectile and “airin”.</span></p><p class="MsoNormal" style="text-indent: 21.0pt;"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">For the first two FSI definitions, the “PFAC” value is defined through a user-defined curve for leakage control. For the projectile–airin coupling, “PFAC” is kept as the default value of 0.1.</span></p><p class="MsoNormal" style="text-indent: 21.0pt;"><span lang="EN-US" style="mso-bidi-font-family: 'Times New Roman';">I also tried a penetration-only case without the fluid domain, and that model could reach normal termination.</span></p><p class="MsoNormal"><span lang="EN-US"></span></p>

<p>Hi all,</p><p>I am running a windshield impactor simulation in LS-DYNA, and I would like to obtain the internal energy output for a specific set of shell elements.</p><p>I tried using ELOUT and DATABASE_HISTORY_SHELL, but so far I have not been able to find the internal energy output for the shell element set.</p><p>Is there a way to directly output the internal energy of a selected set of shell elements in LS-DYNA?</p><p>If this output is not available directly, what would be the recommended way to extract or calculate this data? For example, are there any post-processing scripts, LS-PrePost options, or other methods that could be used?</p><p>Thank you.</p>

Hi <p>I am using LS-DYNA to perform a drop simulation of a ball impacting the ground. The questions are:<br>(1)The total time is 1.5 ms. During the ball's rebound, the internal energy continues to change. To accelerate the stabilization of the internal energy, I set global damping. <br>Could someone review whether this is correct?<br><br>(2) By the end time of simulation, does the strain represent the plastic strain?<br>Thank you in advance.</p>

<p>Hello,</p><p>How does LS-DYNA compute the consistent mass matrix (before diagonalizing) for a 4-noded plane stress element? Reduced or full integration of the consistent mass matrix?</p><p>Thanks.</p>

<p class="isSelectedEnd">I have a simulation that involves shell elements and SPH particles. According to the documentation, setting SHLTHK=0 under CONTROL_CONTACT means that the shell thickness is not considered in contact calculations. I used the same setting and ran the simulation. However, the messag file indicates that many SPH particles have initial contact.I do not understand how initial contact can occur if the shell thickness is ignored. I should mention that the coordinates used for geometry/mesh generation were defined such that there was no penetration before starting the simulation. Could someone help me understand why these initial contacts are being detected and how to resolve this issue when the shell thickness is ignored in the contact definition?</p><p>Thank you in advance.</p>

<p>Hello everyone,</p><p>I encountered a possible inconsistency when setting the concentration boundary condition for species transport in LS-DYNA.</p><p>The keyword *ICFD_BOUNDARY_PRESCRIBED_<wbr>SPTRANSP_CONC appears differently in the LS-PrePost keyword interface and in the LS-DYNA manual.</p><p>In LS-PrePost, the keyword is shown as a two-line structure:</p><p>the first line defines the PID</p><p>the second line contains the LCID values</p><p></p><p>However, in the LS-DYNA manual, the keyword is documented in a single-line format where PID, LCID and CONC fields appear together.</p><p></p><p> </p><p>Because of this difference, I observed the following behaviour:</p><p>If I follow the format shown in LS-PrePost, the solver produces an error:</p><div><div><div><div><div><div><div><div> </div><div><div><div id="m_2277478720517859887gmail-code-block-viewer" dir="ltr"><div><div>input conversion error<br>forrtl: severe (64) </div><div></div></div></div></div></div></div></div></div></div><div><div> </div></div></div></div></div><p>and the simulation cannot start.</p><p></p><p> </p><p>Even if I instead follow the manual format and remove the second line, the simulation runs but the concentration boundary condition does not seem to be applied. In this case:</p><p>the inlet concentration remains zero</p><p>residuals for the scalar transport equation are not computed<br></p><p><br></p><p>I also noticed a similar mismatch for another keyword related to species transport:</p><div><div><div><div><div><div><div><div> </div><div><div><div id="m_2277478720517859887gmail-code-block-viewer" dir="ltr"><div><div>*ICFD_MODEL_SPECIES_TRANSPORT</div></div></div></div></div></div></div></div></div><div><div> </div></div></div></div></div><p>where the format in the LS-PrePost interface does not fully match the manual description.</p><p>Because of this inconsistency I am currently unable to run simulations that require inlet concentration boundary conditions for species transport.</p><p>Could anyone clarify:</p><p>The correct keyword format  *ICFD_BOUNDARY_<wbr>PRESCRIBED_SPTRANSP_CONC</p><p>whether this difference between LS-PrePost and the manual is expected</p><p>or if this might be a bug?</p><div>My LS-DYNA version: R16 SMP and LS-PrePost version: 4.12.6</div><p>Thank you so so so much for any guidance! </p>

<p>Hello everyone,</p><p>I encountered a possible inconsistency when setting the concentration boundary condition for species transport in LS-DYNA.</p><p>The keyword *ICFD_BOUNDARY_PRESCRIBED_<wbr>SPTRANSP_CONC appears differently in the LS-PrePost keyword interface and in the LS-DYNA manual.</p><p>In LS-PrePost, the keyword is shown as a two-line structure:</p><p>the first line defines the PID</p><p>the second line contains the LCID values</p><p></p><p>However, in the LS-DYNA manual, the keyword is documented in a single-line format where PID, LCID and CONC fields appear together.</p><p></p><p> </p><p>Because of this difference, I observed the following behaviour:</p><p>If I follow the format shown in LS-PrePost, the solver produces an error:</p><div><div><div><div><div><div><div><div> </div><div><div><div id="m_8717735918342925683gmail-code-block-viewer" dir="ltr"><div><div>input conversion error<br>forrtl: severe (64) </div></div></div></div></div></div></div></div></div><div><div> </div></div></div></div></div><p>and the simulation cannot start.</p><p></p><p> </p><p>Even if I instead follow the manual format and remove the second line, the simulation runs but the concentration boundary condition does not seem to be applied. In this case:</p><p>the inlet concentration remains zero</p><p>residuals for the scalar transport equation are not computed<br></p><p> </p><p>I also noticed a similar mismatch for another keyword related to species transport:</p><div><div><div><div><div><div><div><div> </div><div><div><div id="m_8717735918342925683gmail-code-block-viewer" dir="ltr"><div><div>*ICFD_MODEL_SPECIES_TRANSPORT</div></div></div></div></div></div></div></div></div><div><div> </div></div></div></div></div><p>where the format in the LS-PrePost interface does not fully match the manual description.</p><p>Because of this inconsistency I am currently unable to run simulations that require inlet concentration boundary conditions for species transport.</p><p>Could anyone clarify:</p><p>The correct keyword format  *ICFD_BOUNDARY_<wbr>PRESCRIBED_SPTRANSP_CONC</p><p>whether this difference between LS-PrePost and the manual is expected</p><p>or if this might be a bug?</p><div>My LS-DYNA version: R16 SMP and LS-PrePost version: 4.12.6</div><p>Thank you so so so much for any guidance! </p>

<p>Hello,</p><p>Is a quadratic 3 noded bar element available in LS-DYNA?</p><p>Thanks.</p>

<p>Received new license file recently and tried to update it on a previously working server. Got the following error message:<br><br></p><div>******************************<wbr>******************************<wbr>*********</div><div>LSTC license server version 77918 started at Wed Jun 3 10:21:30 2026</div><div>******************************<wbr>******************************<wbr>*********</div><div>Using configuration file /opt/lstc/server_data</div><div>ERROR: the host id(s) of this machine ( 50327FA0 )</div><div>not found in the license file /opt/lstc/server_data</div><div> </div><div>It's confirmed the 50327FA0 id is in the server_data file. I would really appreciate suggestions on how to debug/solve this.</div>