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<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 class="ds-markdown-paragraph"><span class="">Solver Version:</span></p><p class="ds-markdown-paragraph"><span class="">Version : smp s R14                           <br>Revision: R14.1.1-8-g2ef819c24f <br>AnLicVer: 2025 R1 (20241030+dl-67-g73b144a) </span></p><p class="ds-markdown-paragraph"><span class="">Description:</span></p><p class="ds-markdown-paragraph"><span class="">I've encountered an issue where hyperelastic materials develop strange initial stresses (solver: SMP single precision, double precison solver will crash the simulation immediately) when a part is switched from rigid to deformable using </span>*DEFORMABLE_TO_RIGID_AUTOMATIC<span class="">. The same setup works perfectly with elastic materials.</span></p><p class="ds-markdown-paragraph"><span class="">Summary of behavior:</span></p><p class="ds-markdown-paragraph"><span class="">A part with hyperelastic material is initially rigid, then automatically switched to deformable at t=10.0</span></p><p class="ds-markdown-paragraph"><span class="">Immediately after the switch, the part shows spurious stresses</span></p><p class="ds-markdown-paragraph"><span class="">If I replace the hyperelastic material with an elastic material, the problem disappears</span></p><p class="ds-markdown-paragraph"><span class="">The same issue occurs whether using full restart with </span>*STRESS_INITIALIZATION<span class=""> to add a new hyperelastic part, or within a single continuous simulation using </span>*DEFORMABLE_TO_RIGID_AUTOMATIC</p><p class="ds-markdown-paragraph"><span class="">Attached test case:</span><br><span class="">A minimal working example demonstrating the issue. One single element uses </span>*DEFORMABLE_TO_RIGID_AUTOMATIC<span class=""> to switch from rigid to deformable at t=10.0 with hyperelastic rubber material. Simply swap the material to elastic (</span>*MAT_ELASTIC<span class="">) to see the problem disappear.</span></p><p class="ds-markdown-paragraph"><span class="">Questions:</span></p><p class="ds-markdown-paragraph"><span class="">Is this a known limitation/bug in R14?</span></p><p class="ds-markdown-paragraph"><span class="">Any insights would be greatly appreciated.</span></p><p class="ds-markdown-paragraph"><span class=""></span></p><p class="ds-markdown-paragraph"><span class="">Key file to reproduce:</span></p><div><div><span style="font-size: 12pt;">*KEYWORD</span></div><div><span style="font-size: 12pt;">*TITLE</span></div><div><span style="font-size: 12pt;">Hyperelastic part - deformable/rigid automatic switch</span></div><div><span style="font-size: 12pt;">$</span></div><div><span style="font-size: 12pt;">$</span></div><div><span style="font-size: 12pt;">$  Units: mm, kg, ms, kN, GPa, kN-mm</span></div><div><span style="font-size: 12pt;">$</span></div><div><span style="font-size: 12pt;">$</span></div><div><span style="font-size: 12pt;">*CONTROL_TERMINATION</span></div><div><span style="font-size: 12pt;">$   endtim    endcyc     dtmin    endeng    endmas</span></div><div><span style="font-size: 12pt;">      13.0         0       0.0       0.0       0.0</span></div><div><span style="font-size: 12pt;">$</span></div><div><span style="font-size: 12pt;">*DEFINE_CURVE</span></div><div><span style="font-size: 12pt;">$ LCID    SIDR    SFA     SFO     OFFA    OFFO    DATTYP  LCINT</span></div><div><span style="font-size: 12pt;">      1005         0       1.0       1.0       0.0       0.0         0         0</span></div><div><span style="font-size: 12pt;">$ time    timestep</span></div><div><span style="font-size: 12pt;">                 0.0                1e-2</span></div><div><span style="font-size: 12pt;">                 10.0               1e-2</span></div><div><span style="font-size: 12pt;">*CONTROL_TIMESTEP</span></div><div><span style="font-size: 12pt;">$#  dtinit    tssfac      isdo    tslimt     dt2ms      lctm     erode     ms1st</span></div><div><span style="font-size: 12pt;">      1e-2       1.0         0       0.0         0      1005         0         0</span></div><div><span style="font-size: 12pt;">*CONTROL_ENERGY</span></div><div><span style="font-size: 12pt;">$     hgen      rwen    slnten     rylen</span></div><div><span style="font-size: 12pt;">         2         2</span></div><div><span style="font-size: 12pt;">*CONTROL_OUTPUT</span></div><div><span style="font-size: 12pt;">$    npopt    neecho    nrefup    iaccop     opifs    ipnint    ikedit</span></div><div><span style="font-size: 12pt;">         1         3</span></div><div><span style="font-size: 12pt;">*CONTROL_SHELL</span></div><div><span style="font-size: 12pt;">$   wrpang    itrist     irnxx    istupd    theory       bwc     miter</span></div><div><span style="font-size: 12pt;">                                       1         2</span></div><div><span style="font-size: 12pt;">*DATABASE_BINARY_D3PLOT</span></div><div><span style="font-size: 12pt;">$       dt      lcdt</span></div><div><span style="font-size: 12pt;">      1.00</span></div><div><span style="font-size: 12pt;">*DATABASE_EXTENT_BINARY</span></div><div><span style="font-size: 12pt;">$    neiph     neips    maxint    strflg    sigflg    epsflg    rltflg    engflg</span></div><br><div><span style="font-size: 12pt;">$   cmpflg    ieverp    beamip</span></div><div><span style="font-size: 12pt;">                   1</span></div><div><span style="font-size: 12pt;">*DATABASE_BINARY_D3THDT</span></div><div><span style="font-size: 12pt;">$       dt      lcdt</span></div><div><span style="font-size: 12pt;">    999999</span></div><div><span style="font-size: 12pt;">*DATABASE_GLSTAT</span></div><div><span style="font-size: 12pt;">$       dt</span></div><div><span style="font-size: 12pt;">      0.10</span></div><div><span style="font-size: 12pt;">*DATABASE_MATSUM</span></div><div><span style="font-size: 12pt;">$       dt</span></div><div><span style="font-size: 12pt;">      0.10</span></div><div><span style="font-size: 12pt;">*DATABASE_NODOUT</span></div><div><span style="font-size: 12pt;">$       dt</span></div><div><span style="font-size: 12pt;">      0.10</span></div><div><span style="font-size: 12pt;">*DATABASE_RBDOUT</span></div><div><span style="font-size: 12pt;">$       dt</span></div><div><span style="font-size: 12pt;">      0.10</span></div><div><span style="font-size: 12pt;">*PART</span></div><div><span style="font-size: 12pt;">$      pid       sid       mid     eosid      hgid    adpopt</span></div><div><span style="font-size: 12pt;">part1</span></div><div><span style="font-size: 12pt;">         1         2         2</span></div><div><span style="font-size: 12pt;">$</span></div><div><span style="font-size: 12pt;">$  Aluminum</span></div><div><span style="font-size: 12pt;">$</span></div><div><span style="font-size: 12pt;">*MAT_PLASTIC_KINEMATIC</span></div><div><span style="font-size: 12pt;">$      mid        ro         e        pr      sigy      etan      beta</span></div><div><span style="font-size: 12pt;">         1   2.70e-6      68.9     0.330     0.286   0.00689</span></div><div><span style="font-size: 12pt;">$      src       srp        fs</span></div><br><div><span style="font-size: 12pt;">*SECTION_SHELL</span></div><div><span style="font-size: 12pt;">$</span></div><div><span style="font-size: 12pt;">$      sid    elform      shrf       nip     propt   qr/irid     icomp</span></div><div><span style="font-size: 12pt;">         1         2</span></div><div><span style="font-size: 12pt;">$       t1        t2        t3        t4      nloc</span></div><div><span style="font-size: 12pt;">       1.0       1.0       1.0       1.0</span></div><div><span style="font-size: 12pt;">*SECTION_SHELL</span></div><div><span style="font-size: 12pt;">$       ID    elform      shrf       nip     propt        qr     icomp     setyp</span></div><div><span style="font-size: 12pt;">         2         2  0.833333         3         0         0         0         0</span></div><div><span style="font-size: 12pt;">$       t1        t2        t3        t4      nloc     marea              unused</span></div><div><span style="font-size: 12pt;">       0.1       0.1       0.1       0.1         0         0                    </span></div><div><span style="font-size: 12pt;">*MAT_HYPERELASTIC_RUBBER</span></div><div><span style="font-size: 12pt;">$       ID        ro        pr         N        Nv         G      sigf       Ref</span></div><div><span style="font-size: 12pt;">         2 8.699E-07 0.4999172         0         0         0         0         0</span></div><div><span style="font-size: 12pt;">$      C10       C01       C11       C20       C02       C30             unused1</span></div><div><span style="font-size: 12pt;">   0.11e-3  0.028e-3         0         0         0         0                    </span></div><div><span style="font-size: 12pt;">*NODE</span></div><div><span style="font-size: 12pt;">$   node               x               y               z      tc      rc</span></div><div><span style="font-size: 12pt;">       1             0.0             0.0             0.0</span></div><div><span style="font-size: 12pt;">       2             1.0             0.0             0.0</span></div><div><span style="font-size: 12pt;">       3             1.0             1.0             0.0</span></div><div><span style="font-size: 12pt;">       4             0.0             1.0             0.0</span></div><div><span style="font-size: 12pt;">$$$$  Define Elements</span></div><div><span style="font-size: 12pt;">*ELEMENT_SHELL</span></div><div><span style="font-size: 12pt;">$    eid     pid      n1      n2      n3      n4</span></div><div><span style="font-size: 12pt;">       1       1       1       2       3       4</span></div><div><span style="font-size: 12pt;">*DEFORMABLE_TO_RIGID</span></div><div><span style="font-size: 12pt;">         1</span></div><div><span style="font-size: 12pt;">*DEFORMABLE_TO_RIGID_AUTOMATIC</span></div><div><span style="font-size: 12pt;">$#   SWSET      CODE     TIME1     TIME2     TIME3     ENTNO     RELSW    PAIRED</span></div><div><span style="font-size: 12pt;">         1         0      10.0      1.0e20     0.0         0         0         0</span></div><div><span style="font-size: 12pt;">$#    NRBF      NCSF       RWF     DTMAX       D2R       R2D    OFFSET</span></div><div><span style="font-size: 12pt;">         0         0         0       0.0         0         1       0.0</span></div><div><span style="font-size: 12pt;">$# Rigid to deformable card: one card because R2D = 1</span></div><div><span style="font-size: 12pt;">$#     PID     PTYPE</span></div><div><span style="font-size: 12pt;">         1      PART</span></div><div><span style="font-size: 12pt;">*END</span></div></div>

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>Hello everyone.<br>I'm simulating a blast calculation in the explicit module.<br>I have three solid bodies: a cylinder, a TNT charge (a sphere), and air (a cube surrounding everything).<br>The TNT charge and air are Eulerian solids, while the cylinder is a Lagrange solid. Furthermore, it's a rigid body, so it won't collapse. I'll be looking at the pressure around it.<br>I got the pressure result, but why is the rigid body also colored? I only want the pressure to be colored nicely for the Eulerian solids. Because the cylinder body is also colored, the animation is terrible. If I display the result not in an animation but simply as a picture at the last second, it will display correctly: Why? How can I fix this?<br>Thanks!</p>

<p data-start="61" data-end="177">I am trying to simulate the attachment between a rubber suction cup and a rigid/plastic part due to vacuum pressure</p><h3 data-section-id="1k4ofxk" data-start="179" data-end="196">Current setup</h3><ul data-start="197" data-end="362"><li data-section-id="jlzsy9" data-start="197" data-end="239">Hyperelastic suction cup (Mooney-Rivlin)<li data-section-id="1sx8pp3" data-start="240" data-end="281">Frictional contact between cup and part<li data-section-id="1vhzoul" data-start="282" data-end="334">Negative pressure applied on internal cup surfaces<h3 data-section-id="ydusx9" data-start="364" data-end="375">Problem</h3><p data-start="376" data-end="579">The vacuum pressure deforms the cup, but the part separates instead of remaining attached. It seems the pressure only acts on the cup and does not generate the expected suction holding force on the part.</p><h3 data-section-id="197y263" data-start="581" data-end="594">Questions</h3><li data-section-id="1eszei1" data-start="595" data-end="654">What is the correct way to model vacuum suction contact?<li data-section-id="1hvl2ni" data-start="655" data-end="705">Is internal negative pressure alone sufficient?<li data-section-id="u82b10" data-start="706" data-end="775">How should the pressure transfer to the contacted part be modeled?<li data-section-id="1tfkvrt" data-start="918" data-end="1072">Is there a recommended method in <span class="whitespace-normal">LS-DYNA</span> or <span class="whitespace-normal">ANSYS Mechanical</span> for suction cup attachment simulations?<p data-start="1074" data-end="1129" data-is-last-node="" data-is-only-node="">Any guidance or example workflows would be appreciated</p><p data-start="1074" data-end="1129" data-is-last-node="" data-is-only-node=""></p><p data-start="1074" data-end="1129" data-is-last-node="" data-is-only-node=""></p><p data-start="1074" data-end="1129" data-is-last-node="" data-is-only-node=""></p>

<p>Hello everyone.<br>Could you please tell me if it's possible to adjust the transparency of the results? For example, for pressure?</p><p></p><p>I'd like to set the transparency to 50% so that other bodies can be seen through the result.</p>