Reply To: How to apply displacement derivative dependent force on bunch of nodes in apdl?

[Mehdi Baghaee]

 

Thanks dlooman and mjmiddle. 

In my problem the load is both proportional to the derivative of displacement with respect to time and coordinate x, concurrently (F=dW(x,y,z,t)/dx+dW(x,y,z,t)/dt),where W(x,y,z,t) is the displacement of nodes in z direction in current time t.

It seems to me that COMBIN14 can be used for second term of my force (dW(x,y,z,t)/dt), but since in the first term the derivative is done with respect to coodinate x, using the chain rule :

dW/dx=(dW/dt)*(dt/dx)=dw/dt*(1/v)

which v is the velocity calculated in the previous substep. So I need to define the damping coefficient given by 1/v.

Is it true?