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<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>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> 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>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>
I wish to use the MAT_ADD_EROSION model in LS-DYNA to capture material failure and erosion effectively. Are there any resources to help me get started?
Thanks!
Is it possible to simulate a pre-strained material directly without any pre-simulation? We have conducted uniaxial prestraining on a material and would now like to run another simulation.
The major and minor strains from our previous operation are available to us.
Thanks!
<p> Dear LS-DYNA Support Team, I hope you are doing well.</p><p>I would like to ask whether the yield locus model **YLD2004-18p** can be applied to **shell elements** in LS-DYNA.</p><p>Could you please let me know if this material model is supported for shell formulations, and if there are any specific limitations or requirements that need to be considered?</p><p>Thank you very much for your support.</p><p> Best regards,</p><p> Philipp</p>
<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>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> 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>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>
I wish to use the MAT_ADD_EROSION model in LS-DYNA to capture material failure and erosion effectively. Are there any resources to help me get started?
Thanks!
Is it possible to simulate a pre-strained material directly without any pre-simulation? We have conducted uniaxial prestraining on a material and would now like to run another simulation.
The major and minor strains from our previous operation are available to us.
Thanks!
<p> Dear LS-DYNA Support Team, I hope you are doing well.</p><p>I would like to ask whether the yield locus model **YLD2004-18p** can be applied to **shell elements** in LS-DYNA.</p><p>Could you please let me know if this material model is supported for shell formulations, and if there are any specific limitations or requirements that need to be considered?</p><p>Thank you very much for your support.</p><p> Best regards,</p><p> Philipp</p>
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