Welcome to the LS-DYNA Product Space

<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>

<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, the cylinder is a Lagrange solid.<br>But the sphere doesn't explode. Furthermore, all the results show that there's no explosion at all:</p><p> </p><p>For air, all these parameters are present.</p><p>Why? How can I fix this?<br>Thanks!</p>

<p>I am a Third year engineering student working on an aluminium honeycomb Impact Attenuator for my FS/FSAE team.</p><p>For my project within Prepost/Dyna I followed this video: https://youtu.be/tmLD_urs3z8?si=tv_cjp77mjVnGBDF </p><p>I've done everything up to the point where I need to run my simulations but it gives me an error termination and I don't know what to do.</p><p>Attached is my proof & my project</p>

<p>Hello everyone.<br>I'm simulating an urban blast calculation in the explicit module, but first I put together a small test problem.<br>I need help with some settings.<br>1. 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, and the cylinder is a Lagrange solid.</p><p><br>The mesh has 70,000 elements.</p><p><br>2. I set the calculation time to 0.001 since the model is small. For a large model, the calculation time is 1-15 ms because it includes a large building.</p><p><br>3. I also adjusted the SPH speed time and the number of cells for my model, and I increased the number of result records to 200 (see images).<br>4. The calculation time is 10 minutes. I also configured the solver to Autodyn.</p><p><br>5. I display the results: Total Deformation (for the body around the charge), Pressure (expression), ALPHAALL (expression).<br>These are the results I see:</p><p></p><p></p><p></p><p>6. Now I want to see how the explosion waves propagate and make a nice animation, like this:</p><p></p><p>How do I do this?<br>Thanks!</p>

<p>Hello all,</p><p>I am trying to use a compiled solver from the usermat version of LS-DYNA. Initially I had some issues compiling the solver with the Makefile, but after adding some lines to the LIBS variable in the Makefile, I was able to compile something. However, when trying to use the file made with the Makefile, with LSrun, I get a license error.</p><p></p><p>I tried some of the suggested solutions from previous posts, such as:</p><p>export ANSYSLMD_LICENSE_FILE=127.0.0.1</p><p>env ANSYSLMD_LICENSE_FILE=1055@127.0.0.1</p><p>In the lsout file, it says "license option:check ansys licenses only" at the top. I am using the usermat version of R13.1 mpp double precision. I also saw an "ansyscl" file was mentioned. If this is needed, where would it be located when downloading the compressed folder? Is it supposed to be inside the compressed folder? I am unable to find file. Also looking in the license tab of LSrun shows licences are active and are waiting to be used.</p><p>Best,</p><p>K</p>

<p>I am running a Hypervelocity Impact simulation of a projectile impacting an assembly built with Constrained nodal rigid bodies and Beam elements to represent the bolts.</p><p>When I run the model without setting a Control_termination endtime (so just initialise the model with a velocity applied to the impactor) it will initalise normally and terminate normally. But when I include the Control_termination endtime keyword and run the model, it will initialise but then all the solid elements which are connected to my CNRB fail on the first timestep.</p><p>Could someone help explain why this might be the case please?</p><p>For context, the model is built from entirely solid meshes (quad and tet for different parts), and the elements which are failing are those connected to a second order solid tetrahedral mesh (the mesh was generated in hypermesh and imported to LS DYNA) - for this part I am using a Solid Section with ELFORM 16 following literature I found online. </p><p> </p><p>Thank you!</p>

<p class="isSelectedEnd">Hi everyone,</p><p class="isSelectedEnd">I am running a windshield impactor test in LS-DYNA using <code dir="ltr">*MAT_ELASTIC glass shell elements with <code dir="ltr">*MAT_ADD_EROSION.</p><p class="isSelectedEnd">The erosion card includes a critical stress, critical strain energy, and critical radius. My understanding is that when a glass element reaches the critical stress, LS-DYNA evaluates the accumulated strain energy within the specified radius around that element. If this accumulated strain energy exceeds the critical energy, the related elements are eroded.</p><p class="isSelectedEnd">For my study, I want to keep the critical energy very high so that erosion does not occur, and I want to post-process the time history of this  accumulated strain energy during the windshield impact.</p><p class="isSelectedEnd">However, I cannot find this quantity in the output. I can only see part-level <code dir="ltr">internal_energy from <code dir="ltr">MATSUM, but this is not the local  strain energy I need.</p><p class="isSelectedEnd">How can I get this strain energy output in LS-DYNA?</p><p class="isSelectedEnd">Thank you</p><p class="isSelectedEnd">Ali</p>

<p>Hello, I've created a model to calculate the pressure on a hull during a water entry.</p><p>I've used S-ALE method and on my PC it works, I get pressure measures using DATABASE_FSI keyword and then exporting the csv files.</p><p>I have to get a bigger analysis of a complete structure impacting water and I use a MPP.</p><p>I've just tryed to run the same analysis (the one which works on my pc) on the MPP but I can't get the dbfsi file I need.</p><p>The plot I get in post processing are just many plots all with the same values which are not correct, they are all equal to the results of the first sensor I've placed on the bottom of the shell element. The dbfsi doesn't appear in the ASCII files and so I have to select the BINOUT option and import the "results".</p><p>I don't understand what I'm doing wrong, the run files are the same but the results I need don't appear</p><p> </p><p></p>