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<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>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>
<p>Hi everyone, I'm striking a rigid wall. LS-Dyna Workbench.<br>The impact is on the bolts. The bolt and nut have bonded contact. But when the impact occurs, the bolt slips through the nut.</p><p></p><p>I'm also getting penetration messages:</p><div id="paraDiv" class="text-color-primary" style="display: inline;"><p id="paragraphData" class="paragraphText text-color-primary" style="font-size: 12px; display: inline;">23098 initial penetrations were found for interface 763<br> 57 initial penetrations were found for interface 646<br> 70 initial penetrations were found for interface 649<br> 78 initial penetrations were found for interface 652<br> 32 initial penetrations were found for interface 655<br> 62 initial penetrations were found for interface 847<br> 27 initial penetrations were found for interface 658<br> 14564 initial penetrations were found for interface 712<br> 60 initial penetrations were found for interface 850<br> 50 initial penetrations were found for interface 865<br> 60 initial penetrations were found for interface 880<br> 11442 initial penetrations were found for interface 730<br> 60 initial penetrations were found for interface 841<br> 14557 initial penetrations were found for interface 718<br> 60 initial penetrations were found for interface 844<br> 48 initial penetrations were found for interface 859<br> 14514 initial penetrations were found for interface 724<br> 48 initial penetrations were found for interface 862<br> 14504 initial penetrations were found for interface 706<br> 122 initial penetrations were found for interface 673<br> 741 initial penetrations were found for interface 823<br> 107 initial penetrations were found for interface 676<br> 551 initial penetrations were found for interface 838</p></div><p>Help please.</p>
<p><p><p>I have read the user manual on user defined materials but it doens't address the following use case so I thought I would post here. </p><p>Is it possible define a user material that calls a predefined LS-DYNA material model? If so what would the syntax look like to accomplish this? </p><p>For example let's say I want to introduce a topology optimization variable as part of a user defined material model and I want to use a predefined elastoplatic model which already exists in LS-DYNA in combination with said TO variable. I am trying to take advantage of the material model that already exists rather than reimplementing it myself. </p><p>Any help or insight would be greatly appreciated. Thanks in advance. </p></p></p><p>Update 6/6/26:</p><p><p><p> A small update. I remembered being able to view the signatures of object files .o or .a files with command line tools like nm or objdump. So as a small first step I can at least view the function names available in precompiled object files. Which I believe correspond to the material subroutine names. However, this is not the complete function definition with variable names in the correct order but it is a start. It is also probably reasonable to assume that the variable ordering in the card definitions in the user manual are the same order as the variables in the function call. Although it will probably get a little tricky with cards that can be repeated and other such options. But it is a start...</p></p></p><p>Update 6/10/26:</p><p>After downloading and reviewing the object version of LS-DYNA and the accompanying Fortran files for defining the user defined materials I actually think the calls to the existing material models will look more like what is found in those Fortran files, e.g.,</p><p> call umat41 (cm(mx+1),eps,sig,epsp,hsv,dt1,capa,eltype,tt,<br> . temper,failel,crv,nnpcrv,a(lcma),qmats,elsiz,idele,reject)</p><p>Of course instead of calling umat41 it would be the material model you want to use. But now I'm having a hard time finding the function names of the existing material functions in the object files as suggested above. I wonder if it as simple as "matxxx"....?</p>
<p>Hello, I am getting an error as shown below when trying to use sensor_define_element_set. in the below parameter, if I set comp = PRIN1, below error shows up. if I set it to XX, YY, ZZ, it doesn't</p><p>I have database_elout, database_history_solid and control_output all properly set. If anyone can think of anything causing this, I would realy appreciate it. </p><p> </p><p></p>
<p>Hello all, I'm hoping to find some help here. Hopefully I am just misunderstanding the physics of what i going on.</p><p>So i set up an Explicit Dynamics sim of a rotating shaft coupling impacting a guard. The axis of the coupling is angled 45deg off the YZ plane and 30deg off the XY plane. Coupling is set to rotate around the coupling center axis at 2000rpm and translate 2000in/sec in the global Y direction. Or so i think. But the solution is showing the coupling rotating as expected, but translational movement is mostly in the X global direction with some translation in the intended Y global direction. </p><p>Attached are some pictures of the setup. I'm sure there will be questions and more information i have not thought to answer and provide, so please ask.</p><p>My question is why is the coupling translating mostly in X instead of Y as intended? Is it because i am misunderstanding the effects of angular momentum?</p><p></p><p></p><p></p><p></p><p> </p>
<p>I am modeling a rigid/inclined PDC cutter cutting into a rock block in LS-DYNA using an RHT-type rock material, MAT_ADD_EROSION, and CONTACT_ERODING_SURFACE_TO_SURFACE. The cutter motion is prescribed only in the positive x-direction, while the rock is constrained at the base and, in some trials, subjected to lateral confining pressure of 40 MPa. The model initializes without fatal errors in many runs, but it stalls very early or shortly after contact/erosion starts; CPU usage drops significantly, the time step becomes very small, and failed rock elements are either not visibly deleted or only a few elements erode before the simulation stops progressing.</p><p>I have tried changing erosion/contact parameters such as CON1/CON2, ISYM, EROSOP, IADJ, commenting out the confining pressure, and running in double precision, but the same stalling behavior persists. I suspect the issue may be related to the eroding contact definition, contact update after element deletion, conflicting contact/control keywords, or inappropriate RHT/erosion parameters. I would appreciate advice on the required/typical keyword setup for rock cutting with CONTACT_ERODING_SURFACE_TO_SURFACE, especially regarding contact cards, CONTROL_CONTACT, erosion deletion/update settings, and stable parameter ranges.</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>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>
<p>Hi everyone, I'm striking a rigid wall. LS-Dyna Workbench.<br>The impact is on the bolts. The bolt and nut have bonded contact. But when the impact occurs, the bolt slips through the nut.</p><p></p><p>I'm also getting penetration messages:</p><div id="paraDiv" class="text-color-primary" style="display: inline;"><p id="paragraphData" class="paragraphText text-color-primary" style="font-size: 12px; display: inline;">23098 initial penetrations were found for interface 763<br> 57 initial penetrations were found for interface 646<br> 70 initial penetrations were found for interface 649<br> 78 initial penetrations were found for interface 652<br> 32 initial penetrations were found for interface 655<br> 62 initial penetrations were found for interface 847<br> 27 initial penetrations were found for interface 658<br> 14564 initial penetrations were found for interface 712<br> 60 initial penetrations were found for interface 850<br> 50 initial penetrations were found for interface 865<br> 60 initial penetrations were found for interface 880<br> 11442 initial penetrations were found for interface 730<br> 60 initial penetrations were found for interface 841<br> 14557 initial penetrations were found for interface 718<br> 60 initial penetrations were found for interface 844<br> 48 initial penetrations were found for interface 859<br> 14514 initial penetrations were found for interface 724<br> 48 initial penetrations were found for interface 862<br> 14504 initial penetrations were found for interface 706<br> 122 initial penetrations were found for interface 673<br> 741 initial penetrations were found for interface 823<br> 107 initial penetrations were found for interface 676<br> 551 initial penetrations were found for interface 838</p></div><p>Help please.</p>
<p><p><p>I have read the user manual on user defined materials but it doens't address the following use case so I thought I would post here. </p><p>Is it possible define a user material that calls a predefined LS-DYNA material model? If so what would the syntax look like to accomplish this? </p><p>For example let's say I want to introduce a topology optimization variable as part of a user defined material model and I want to use a predefined elastoplatic model which already exists in LS-DYNA in combination with said TO variable. I am trying to take advantage of the material model that already exists rather than reimplementing it myself. </p><p>Any help or insight would be greatly appreciated. Thanks in advance. </p></p></p><p>Update 6/6/26:</p><p><p><p> A small update. I remembered being able to view the signatures of object files .o or .a files with command line tools like nm or objdump. So as a small first step I can at least view the function names available in precompiled object files. Which I believe correspond to the material subroutine names. However, this is not the complete function definition with variable names in the correct order but it is a start. It is also probably reasonable to assume that the variable ordering in the card definitions in the user manual are the same order as the variables in the function call. Although it will probably get a little tricky with cards that can be repeated and other such options. But it is a start...</p></p></p><p>Update 6/10/26:</p><p>After downloading and reviewing the object version of LS-DYNA and the accompanying Fortran files for defining the user defined materials I actually think the calls to the existing material models will look more like what is found in those Fortran files, e.g.,</p><p> call umat41 (cm(mx+1),eps,sig,epsp,hsv,dt1,capa,eltype,tt,<br> . temper,failel,crv,nnpcrv,a(lcma),qmats,elsiz,idele,reject)</p><p>Of course instead of calling umat41 it would be the material model you want to use. But now I'm having a hard time finding the function names of the existing material functions in the object files as suggested above. I wonder if it as simple as "matxxx"....?</p>
<p>Hello, I am getting an error as shown below when trying to use sensor_define_element_set. in the below parameter, if I set comp = PRIN1, below error shows up. if I set it to XX, YY, ZZ, it doesn't</p><p>I have database_elout, database_history_solid and control_output all properly set. If anyone can think of anything causing this, I would realy appreciate it. </p><p> </p><p></p>
<p>Hello all, I'm hoping to find some help here. Hopefully I am just misunderstanding the physics of what i going on.</p><p>So i set up an Explicit Dynamics sim of a rotating shaft coupling impacting a guard. The axis of the coupling is angled 45deg off the YZ plane and 30deg off the XY plane. Coupling is set to rotate around the coupling center axis at 2000rpm and translate 2000in/sec in the global Y direction. Or so i think. But the solution is showing the coupling rotating as expected, but translational movement is mostly in the X global direction with some translation in the intended Y global direction. </p><p>Attached are some pictures of the setup. I'm sure there will be questions and more information i have not thought to answer and provide, so please ask.</p><p>My question is why is the coupling translating mostly in X instead of Y as intended? Is it because i am misunderstanding the effects of angular momentum?</p><p></p><p></p><p></p><p></p><p> </p>
<p>I am modeling a rigid/inclined PDC cutter cutting into a rock block in LS-DYNA using an RHT-type rock material, MAT_ADD_EROSION, and CONTACT_ERODING_SURFACE_TO_SURFACE. The cutter motion is prescribed only in the positive x-direction, while the rock is constrained at the base and, in some trials, subjected to lateral confining pressure of 40 MPa. The model initializes without fatal errors in many runs, but it stalls very early or shortly after contact/erosion starts; CPU usage drops significantly, the time step becomes very small, and failed rock elements are either not visibly deleted or only a few elements erode before the simulation stops progressing.</p><p>I have tried changing erosion/contact parameters such as CON1/CON2, ISYM, EROSOP, IADJ, commenting out the confining pressure, and running in double precision, but the same stalling behavior persists. I suspect the issue may be related to the eroding contact definition, contact update after element deletion, conflicting contact/control keywords, or inappropriate RHT/erosion parameters. I would appreciate advice on the required/typical keyword setup for rock cutting with CONTACT_ERODING_SURFACE_TO_SURFACE, especially regarding contact cards, CONTROL_CONTACT, erosion deletion/update settings, and stable parameter ranges.</p>
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