TAGGED: heat, lsdyna, sph, strainenergy


April 9, 2024 at 12:55 pmRong JinSubscriber
Hello,
I'm using the SPH method in LSDYNA to simulate the ballistic highvelocity impact problem. I find that the strain energy plot is not consistent with temperature change and pressure plots.
Specifically, the material I used for the projectile and target plate are both defined by *MAT_015 (*MAT_JOHNSON_COOK). In the postprocessing, the strain energy plot for the very first time frame is shown:
It is wired that the maximum strain energy starts at the middle of the target plate when the projectile first contacts it. There is almost no deformation and stress change; the shock wave has just begun. So, there is no reason that the strain energy in the middle becomes the maximum at first.
But for the temperature change plot (history variable #5 for *MAT_015_JOHNSON_COOK) and pressure plot, it can be easily seen that the maximum points in the first time frame starts at the contact point.
All the results above are calculated by using the R 13.0 solver.Â
Besides, I try to use the latest solver to test the result but for the same job in the R 14.0 solver, the job will be stuck at some point and cannot be fully calculated. So,Â I changed different mesh sizes and solver with the same setup for other conditions (initial velocity, material properties, etc.), and the result of the strain energy plot has the same problem:
The result above is calculated by the R 14.0 solver with coarse mesh.
Coincidentally, the maximum point starts at the 16th layer of the SPH plate. I don't know if this error comes from numerical methods or comes from visualization errors. Could help to explain or tell me how to find the correct strain energy distribution in the whole plate?
Â
Best,
Rong

April 10, 2024 at 1:07 pmAniketForum Moderator
Unfortunately, Ansys employees can not answer this question on a public forum, so hopefully other members can chime in!
Aniket

April 10, 2024 at 7:11 pmRong JinSubscriber
Hi Aniket,
Could you tell me if there are any other places to report the problem? I'm not sure whether the problem occurs due to the solver itself or due to the visualization of the results.
Best,
Rong

April 12, 2024 at 5:11 amAniketForum Moderator
Hello Rong, Please reach out to your Ansys account manager in university, and they can try to help you here.
Aniket



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