Learning Forum

[LeslieQuiroz]

Hi everyone, 

I´m running a bouncing ball simulation and I want to analize the plastic deformation at the ball after impact. I´m usingTotal Deformation applied to the ball body however what it shows me is the height instead. Is there any other tool that I could use or am I missing steps?

Another result that I can´t analize is the energy distribution at the plate during the impact (attached files). Why is this happening if both bodies are flexible? 

Thank you and regards,

Leslie.

[Ram Gopisetti]

Hi @LeslieQuiroz, can you able to show us the Material definition used in the is model.
Scope the deformation to Y-direction and see the curve the difference in it shows the distance travelled. (initiated at 0)
For energy, use the trackers from the solution before you hit the solve. You can get (kinetic, internal , hourglass and eroded internal energy etc and scope to the plate)
Cheers, Ram

[Chris Quan]

If you want to plot plastic strain (user-defined results -> EPS), make sure the material model of the ball and the plate accounts for plasticity. The material parameters should include yield stress and plastic hardening. Also, make sure the simulation has run enough long time so the materials have undergone sufficiently large deformation before plastic deformation occurs.
The time history of kinetic energy, internal energy, and hourglass energy can be plotted under Solution Information for all bodies (default) or selected body or bodies. See attached picture below:

[LeslieQuiroz]

and Thank you for your answers. Here are the material definition:
Ball (A35)
PLATE (AR500)
Please if you see something irregular feel free to tell me because I am not getting realistic results. The first bounce height must be around 100 mm but I got 3 meters on the simulation and I don┬┤t know what I am doing wrong :(
In the case i want to know how many milimeters had been deformed what should I do? Is there a tool on workbench LS-Dyna? Because EPS-STRAIN shows me (mm/mm).
Thank you again for your help :)

[Ram Gopisetti]

Have you checked the initial velocity or the drop height configuration ?.
is your End time correct ?
Deformation is measured using the deformation result contours and scope to the ball in the geometry selection. Use the trackers (deformation plot tracker) to get better resolution in the graph.
Cheers, Ram

[LeslieQuiroz]

Yes, the initial velocity is correct and the drop height too. Actually, I tried each to check if there is any difference but I got the same results.
My end time is about 0.2. The idea is to track the maximun height the ball gets using UY (displacement in axis Y ). Maybe I┬┤m not using the correct tool.
Thanks a lot Leslie

[Ram Gopisetti]

Hi @LeslieQuiroz, is the end time is 0.2s or 0.2ms ?
UY scoped to ball is correct method.
perhaps you need to control the ICOR (coeff of restitution)in the contact definition (0 for plastic and 100 for elastic) and tune the VDC parameter via snippets (LSDYNA wb ONLY)
Cheers, Ram

[LeslieQuiroz]

The end time is 0.2 s
About the UY, the max. height that is shown in the graphic is measured between wich points? I mean, in the picture below which lenght is taking into acount? H1,H2 or H3?
I send the images of the contact configuration, i couldn┬┤t find the restitution coeff control in there.

And finally the VDC snippet is incorporated to the geometry or the contact??
Thanks :)
Leslie