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<p>if I artificially scale the mass of an entire component, like every single element on it, and matsum check after solve still show KE is nearly non-existent (like 1% of IE or less), can I make the claim that my result is, for the most part, just as accurate as if I had solved the same problem implicitly in a static structural sense. basically, I am looking for a reason why literally 100x my density value (or selectively mass scale one part by a lot) on my mat card for that one component would invalidate my result in a quasi-static analysis. I can't think of one but can anyone help me think of one?</p>

<p>Hello, I would greatly appreciate some help regarding my code. I am taking an official LS-DYNA example, Underwater F (https://lsdyna.ansys.com/underwater-f/), and modifying it to create an S-ALE mesh without the cutout.</p><p>I am generating a square field. I fill the entire region with water and there is a smaller square region in the bottom left corner, in which I place an explosive material. I detonate the bottom left corner, the origin, at time 0.</p><p>However, the detonation front created by this explosion is not propagating smoothly into the water. It looks like there is a boundary at the box region, even though I have not defined a boundary. Might this be due to a discontinuity in the interface between the two materials or is there something I am missing in my code? How would I fix this? Thank you very much in advance.<br><br>Here is the input file:</p><div>*KEYWORD</div><div>*NODE</div><div>       1 0.000000000E+00 0.000000000E+00 0.000000000E+00</div><div>       2 0.000000000E+00 0.000000000E+00 0.000000000E+00</div><div>       3 0.100000000E+00 0.000000000E+00 0.000000000E+00</div><div>       4 0.000000000E+00 0.100000000E+00 0.000000000E+00</div><div>*ALE_STRUCTURED_MESH_CONTROL_POINTS</div><div>      1001</div><div>                   1       0.0</div><div>                  51       8.0</div><div>                 201      32.0</div><div>*ALE_STRUCTURED_MESH_CONTROL_POINTS</div><div>      1002</div><div>                   1       0.0</div><div>                  51       8.0</div><div>                 201      32.0</div><div>*ALE_STRUCTURED_MESH_CONTROL_POINTS</div><div>      1003</div><div>                   1       0.0</div><div>                   2       1.0</div><div>*DEFINE_COORDINATE_NODES</div><div>       234         2         3         4</div><div>*ALE_STRUCTURED_MESH</div><div>         7      5000     10000     10000</div><div>      1001      1002      1003         1       234     </div><div>*DEFINE_BOX</div><div>         9       0.0       8.0       0.0       8.0       0.0       1.0</div><div>*PART</div><div> </div><div>         1         1         1         1</div><div>*PART</div><div> </div><div>         2         2         2         2</div><div>*MAT_NULL</div><div>         1       1.0</div><div>*MAT_HIGH_EXPLOSIVE_BURN</div><div>         2      1.63     0.784     0.260 0.000E+00</div><div>*EOS_GRUNEISEN</div><div>         1       1.5</div><div> </div><div>*EOS_JWL</div><div>         2      3.71 3.230E-02      4.15     0.950     0.300 4.300E-02      1.00</div><div>*ALE_STRUCTURED_MULTI-MATERIAL_GROUP</div><div>     water         1         1</div><div>      expl         2         2</div><div>*ALE_STRUCTURED_MESH_VOLUME_FILLING</div><div>         7               water</div><div>       ALL</div><div>*ALE_STRUCTURED_MESH_VOLUME_FILLING</div><div>         7                expl</div><div>    BOXCOR         0         9</div><div>*CONTROL_ALE</div><div>         0         1         2      -1.0</div><div> </div><div>*CONTROL_ENERGY</div><div>         2         1         2         2</div><div>*INITIAL_DETONATION</div><div>      5000 0.000E+00 0.000E+00 0.000E+00 0.000E+00</div><div>*CONTROL_TERMINATION</div><div>     100.0</div><div>*DATABASE_BINARY_D3PLOT</div><div>       1.0</div><div>*DATABASE_GLSTAT</div><div>       0.1</div><div>*END</div><div> </div><div>Here are screenshots of the relevant time steps:</div><div></div><div></div><div></div><div></div>

<p><p><p>Hi fellows,</p><p>I have an issue with 2025R1.03 which was okay with 2024R2.04</p><p>When openning the keyword file to check in LS-Prepost, I get this error for many of the elements of the 'Layered Sections' of the model:</p><p>                   Invalid entity ID!  ** Prog Error:<br>                   Warning -Part Id of element is zero</p><p>When I suppress the 'Layered Section', the error goes away.</p><p>Has anyone faced this issue and any idea how to resolve it? </p><p>Cheers,</p></p></p>

<p>Hi everyone,</p><p> </p><p>I'm running an explicit thermomechanical analysis in LS-DYNA and I'm trying to speed up the simulation using time scaling, by applying an appropriate TSF (Thermal Speedup Factor).</p><p> </p><p>To evaluate the impact, I ran two simulations:</p><p> </p><p>1. One with time scaling, using a TSF to modify thermal properties accordingly.</p><p> </p><p> </p><p>2. One without time scaling, i.e., standard time and no TSF applied.</p><p> </p><p> </p><p> </p><p>Surprisingly, the simulation with TSF results in higher temperatures compared to the one without time scaling. I was expecting both simulations to show the same thermal behavior (just occurring over different time scales), but it seems that the temperature evolution is affected in a nontrivial way.</p><p> </p><p>Has anyone encountered this issue before? I'm trying to understand:</p><p> </p><p>Is this temperature increase a known side effect of using TSF?</p><p> </p><p>Are there specific best practices or precautions when using TSF (e.g., adjusting boundary conditions, time step, or coupling settings)?</p><p> </p><p>Could the discrepancy be related to how I’m scaling the thermal material properties or defining the thermomechanical coupling?</p><p> </p><p> </p><p>Any guidance or shared experience would be greatly appreciated. Thanks in advance!</p>

<p>I would like to ask the community or Ansys employees if it's a reasonable approach to use mat_184 as just springs with some stiffness I arbitrarily define and a failure traction value that I made up as well basd on the cohesive element size I am using. </p><p>Basically, is there any meaningful way to actually calibrate a CZM model like mat_184 or was this mat card created just as a very rough simplification.    It would be good to understand why this card was created originally for what purposes. </p>

<p>After lateral impact, I encountered some issues when resetting the keywords in the restart K file and adding displacement loads. I need help and am willing to offer a small reward.</p>

<p>Could anyone tell me what might be the reason for the penetration of the rigid sphere (*MAT_020) when compressing the compressible foam material (*MAT_063) (as shown in first Figure)? The contact settings are depicted in the second figure, and self-contact has also been set.</p><p></p>

<p><div class="html-div xdj266r x14z9mp xat24cr x1lziwak xexx8yu xyri2b x18d9i69 x1c1uobl" data-ad-rendering-role="story_message"><div id="_r_12s_" class="x1iorvi4 xjkvuk6 x1g0dm76 xpdmqnj" data-ad-comet-preview="message" data-ad-preview="message"><div class="x78zum5 xdt5ytf xz62fqu x16ldp7u"><div class="xu06os2 x1ok221b"><div class="html-div xdj266r x14z9mp xat24cr x1lziwak xexx8yu xyri2b x18d9i69 x1c1uobl"><div class="xdj266r x14z9mp xat24cr x1lziwak x1vvkbs x126k92a"><div dir="auto">Hi everyone,</div><div dir="auto"> </div></div><div class="x14z9mp xat24cr x1lziwak x1vvkbs xtlvy1s x126k92a"><div dir="auto">I'm beginner.</div><div dir="auto">Please! Could someone guide me on how to calculate or export the average pressure on a surface?</div><div dir="auto"> </div></div><div class="x14z9mp xat24cr x1lziwak x1vvkbs xtlvy1s x126k92a"><div dir="auto">Thank you very much!</div></div></div></div></div></div></div></p>

<p>As shown in those figures, after I imported the dynain file resulting from one impact into the original k file, the CNRB settings in the dynain file have become very disordered. Could someone please tell me how to solve this problem?</p><p></p>

<p><span style="">Dear all, I am currently attempting to reproduce a certain paper.<br><br>I conducted a high-speed compression on a crashable foam material ( *MAT_CRASHABLE_FOAM, with a constant rate of 10 m/s, set at a relatively high level to improve computational efficiency). The paper provided the material's Young's modulus, Poisson's ratio, tensile cutoff value, and constitutive equation (the input data as shown in the two previous photos).<br><br>However, the force-strain curve I obtained is inconsistent with that in the paper (As shown in the third photo). Could you please help me understand what might be the reason for this discrepancy?<br><br>Additionally, I don't understand why the results always exhibit a HOURGLASS phenomenon (As shown in the last photo). I would greatly appreciate any answers. Thank you!</span></p><p><span style=""></span></p><p><span style=""></span></p><p><span style=""></span></p>