Is it possible to use shell elements for thin target plate during high velocity impact (penetration) loading? Solid elements was used for the thin target plate in many literatures. However, I don't know why solid element was used for the thin plate instead of using shell element. Can anybody explain this? Since the timestep will so small when solid is used.
Another question is what's the difference between the shell and solid element? How to choose them in a simulation with thin shell plate? Why more than 3 elements are needed when using solid elements for thin shell plate?
Dear Majid Moeinifard,
Thank you for your reply.
Many literatures modeled the thin homogeneous metal plate with solid elements. For example,
I don't know why they don't use shell element, do you have an answer to it? Does the thin shell element in LS-DYNA consider normal and shear stress through thickness? Is it possible to use shell elements for thin target plate during high velocity impact (penetration) loading?
http://www.sciencedirect.com/science/article/pii/S0734743X1400253X
Hello, actually I think you can use shell elements in penetration applications. But with solid elements you can have more realistic result. The contact and friction are really important phenomena in penetration events. Due to that, generally solid elements are used in modelling studies. In shell elements you only have mid-section (or upper/lower section) of your plate and friction as in real event cannot be accurately modeled. As I said shell elements can be used but even I think accuracy would be less due to the contact and friction issues. Here you have to find a balance between computational cost and accuracy. Sincerely.
Dear Ali Kara,
The friction can be ignored due to small thickness (thin plate), many papers had mentioned this. So I think this is not a problem.
Can the normal and shear stress be considered with shell element? And do you think this two things are important in a high velocity penetration problem?
Dear Majid Moeinifard,
What you said is a basic method. However, there are some problems when doing this.
1. Does the shell element and solid element use the same material model and parameters, especially the failure parameters? Because perforation will happen in a high velocity impact.
2. The element size has an influence on the result. But when the mesh is refined, how to deal with the failure parameter?
Dear Majid Moeinifard,
1. My concern is if it is correct to use the same material model (including failure parameters -- for example the failure strain) for the shell and solid element when simulating the same problem. I think the shell and solid may calculate the strain in a different way.
2. I don't know how to choose failure parameters by using a special element size in a numerical simulation. Because I think the failure strain is depend on the mesh size.
Shell elements can be used with the same material and failure models (if the material and failure model supports the element formulation, some shell elements cannot be used with some material models). But JC is OK for shell elements also. And failure model contains material parameters obtained from tests. Those are mesh independent. But simulation can be mesh dependent, then you can conduct mesh sensitivity analysis. Sincerely.
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