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JM Desrosiers

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Posts posted by JM Desrosiers


  1. Hi,

     

    I'm using Law 38 for a model using a foam specimen (see image1), an impactor and a anvil. I try to model the unloading of that foam block. I tried 2 methods following Altair helps:

     

    1- I use a single unloading curve (see image2). It's working but, the calculation time is very high compared to the model without a unloading curve

    2- I use the same unloading curve but I use it like a quasistatic curve using strain rate at 0 and the next curve at 0.0001 (see image3). I also put K_R parameter to 1. Calculation time is almost infinite, so not an option.

     

    What I'm a doing wrong, or what should I do to make it work. Here's the attached model too.

     

    Thanks!

     

    JM

     

     

    Image1.png

    Image2.png

    Image3.png

    EPP33_A7_30_iso25_0000.rad EPP33_A7_30_iso25_0001.rad


  2. Hi,

     

    I was wondering why Rigid bodies are all regrouped together when passing from Hypercrash to Hypermesh. For exemple, my model in Hypermesh has multiple Rigid bodies. But, when I export it in Hypercrash and import it back to Hypermesh, all Rigid Bodies are identifies as one component in the model browser (in the Rbody Manager, they are kept separated of course).

     

    I like to work with both softwares, but I would like to keep the Rigid bodies separated all the time. Is there a way? Or is there something I'm doing wrong?

     

    Thanks!

     

    JM


  3. 14 hours ago, Prakash Pagadala said:

    We had an issue with one of the patches of 14.0,

     

    If you can share the model, we will try at our end to confirm if it has something to with version or not.

    I shared the files in the secured folder. The problem is kind of solved, since I can now export it with Hypermesh if I import and export with Hypercrash before.


  4. I'm using Hypermesh version 14.0.130, and the model is supposed to have been created in version 12.0.224. It's the Hybrid III 50e percentile version 8.0.5 model made by Altair. I don't think that I can share it here, but maybe in a secured folder. And yes, my user profile is define as Radioss (Block 140).

     

    Can somebody help?

     

    JM


  5. Hi George,

     

    Thanks for the fast response! I did download the model and it helped me understand a couple of things. I was just wondering, if the model is the exact same that the one in the case study that you provided (http://altairatc.com/europe/presentations/session10/session10_ford_schilling.pdf). In fact, the geometry looks different, but if everything else is the same, it's perfect for me. More precisely, if the model has the same material, the EPP, it's even better.

     

    Also, I have an additional question. I was wondering if in law 70, there were parameters to change the shear behavior of the foam. I ''played'' with some of them, but I don't have what I expected. In fact, in pure compression the model behaves like the experimental tests that are obviously in pure compression. However, when I run combined or oblique loading simulations (pure compression and shear), the forces are not the same.

     

    If you want more precision on my problem, I'll share it to you. So, if you know some parameters that I can play with to get more of what i want or another tabulated law like 38 maybe, let me know! 

     

    Thanks!

     

    JM


  6. Hi, 

     

    I got a problem with radioss recently. At the end of the simulation, it is not written "job completed" at usual. And in Hyperworks Solver Run manager, it is still written "running 1 job". So, when the 1st simulation is completed, the 2nd one does not start because of this.

     

    Can someone help me please!?

     

    Thanks

     

    JM


  7. Hi Vikas,

     

    I thought using this option, but I really need to lauch my hammer at a certain velocity (initial velocity). Therefore, I don't want to impose a displacement to the hammer. I only want to stop it by using a coil spring. But, maybe I can define a component which would be a coil spring and add a interface between the 1D coil spring and my 3D impactor? The coil spring would be at a certain distance from the initial position of the hammer. So the hammer will impact my dummy and be stopped after the impact at a certain distance.

     

    I don't know if I'm clear or not, but thanks for your response!

     

    JM

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