Problem of modeling impact

[confidentyou]

Hi everyone!
I used Impact Material to model pounding and I found that the parameter such as Keff, δy, K1 and K2 are all depend on the δm (the maximum penetration during the pounding event). But I don't know how to determine the value of δm. Could you please tell me how to get the value of δm?

[fmk]

that's model dependent .. is it impacting some infinitely rigid medium or something as soft as air .. as the answer is somewhere in between it is up to you to use some engineering judgement for coming up with the properties needed .. you should probably do some sensitivity study to see range of responses you might obtain.

[confidentyou]

thanks very much!