FEAP User Forum

FEAP => Input File Issues => Topic started by: Colin McAuliffe on April 09, 2013, 02:33:09 PM

Title: Time dependent bc's
Post by: Colin McAuliffe on April 09, 2013, 02:33:09 PM

Dear all,

Is it possible to specify an edge with a time dependent bc which has a specified displacement for a certain time range, and traction free bc's thereafter? One option is to do a restarted analysis but I would prefer to avoid that if possible.

Thanks
Colin

Title: Re: Time dependent bc's
Post by: Prof. R.L. Taylor on April 10, 2013, 08:05:21 AM

In a serial run you can change boundary conditions during a single execution.  So it is possible to do what you describe.

In a parallel solution you probably cannot do it since the equation structure is determined when you partition.

Title: Re: Time dependent bc's
Post by: Colin McAuliffe on April 10, 2013, 08:20:06 AM

Ok thanks. I am using parallel so I think I'll try to make a function that alters the eq. structure manually. Could you point me to the subroutine that sets up the eq. structure?

Title: Re: Time dependent bc's
Post by: Prof. S. Govindjee on April 10, 2013, 09:45:47 PM

It may be possible if the equations are blocked.  In that case all the equations are in the matrix allocation.  However, if you change the fill of the matrix mid computation, it will be important to kill and then reallocate the memory for the matrix since petsc memorizes the non-zero pattern on the first assembly.