## General

#### How to change the contact normal stiffness factor between the load steps in Workbench Mechanical?

• FAQ
Participant

One can use a simple command snippet to do this. Here is a sample code for changing the contact siffness factor from 0.1 to 0.2 during load step 1 and back to 0.1 during load step 2. Note that the change in the stiffness factor is linearly ramped over the load step. If one wishes to change the load step in a nonlinear fashion, they may do so as piecewise linear table by introducing more points in the table definition. Also, please note that keeping the change in stiffness more gradual ensures a robust convergence behavior.

*DIM,fkn,table,3,1,,TIME ! Define a new table variable â€˜fknâ€™ as a function of time

fkn(1,0) = 0.0 ! Define the row 1 (time) of the table
fkn(2,0) = 1.0
fkn(3,0) = 2.0

fkn(1,1) = 0.1 ! Define row 2(stiffness factor) of the table
fkn(2,1) = 0.2
fkn(3,1) = 0.1

RMODIF,cid,3,%fkn% ! Modify the real constant 3 of the contact elements â€˜cidâ€™