# Drop test against a protection to see if it's effective

Question asked by Federico Bassi on Aug 25, 2020
Latest reply on Aug 26, 2020 by Federico Bassi

Hi everyone,

I am trying to simulate a drop test to see whether a shield protection is effective or not with solidworks simulation professional.

I have a disk that is travelling at 40 m/s hitting a static steel protection structure bolted at ground (see fig below).

I know that with SW sim professional I can't simulate the effective impact between the two bodies but I would like to know if there is a way to do that "approximately" anyway.

I thought this alternative:

1) evaluate the normal and tangential distributed stiffness of the protection through a static simulation where I apply a unit distributed pressure P = 1 (N/m^2) on one direction and then evalute the displacement u (m) of the structure in the same direction. Then the distributed stiffness is = P / u [(N/m^2)/m]. (NOTE: with this option I get very low stiffness values compared to the drop tests tutorials)

2) run a drop test sim of the disk, setting the target to be flexible with the same stiffness values of point 1). (NOTE: what thickness should I apply to the target considered that the protection is a mix of UPN beams for frame and sheet metal as cover)

3) check the max. stress of the simulation at point 2) and then apply it with a static simulation to the steel protection structure to see whether the protection is effective or not.

What is your opinion? Any other strategies (especially to calculate the effective stiffness)?

I have already started simulating this way but, as mentioned, I am obtaining very low stiffness values (2.9E9 (N/m^2)/m)...

Thank you very much for your help