strain rate calculation in GOM software

[[He...]]

Hello,

Is there any formula to calculate the strain rate in GOM software? 

I can find the mechanism and formulation of the "strain" calculation at GOM software in the manual, but I cannot find the strain rate calculation mechanism.

I'm trying to figure out the strain rate calculation mechanism of the GOM by applying the finite difference method to the formula; change (d(epsilon)/dt) to ((epsilon(i+1)-epsilon(i))/(t(i+1)-t(i))) but the result are not same with the strain rate calculated by GOM software even though I change the time step at each stage.

Thanks.

Edited March 17, 2022

[[Th...]]

I am not sure if there is some documentation about it somewhere, but as much as I know all "rate" calculations (speed and acceleration, too) are computed:

((eps(i+1)-eps(i-1))/(t(i+1)-t(i-1))

So it is close to what you suggested but taking one stage ahead and back into account to get an somehow averaged value for the current state.