FEAP User Forum

FEAP => Programming => Topic started by: jbruss on November 20, 2017, 07:06:23 AM

Title: Components of Solution Array, U
Post by: jbruss on November 20, 2017, 07:06:23 AM

Hello -

In the programmer's manual it states that the "U" solution array has the following components:
   dim1  dim2  dim3
U ndf   numnp    3

Why is there a third dimension to this array? Are the previous 2 time steps also stored? Perhaps they are the increments?

The solution rate array has a similar explanation.
       dim1   dim2   dim3
VEL  ndf    numnp    nt

The programmers manual shows that nt is the number of text inputs. What is in this array other than the solution rate in the first ndf*numnp locations? Are the accelerations also stored here?

Thank you very much for your help!
Jonathan

Title: Re: Components of Solution Array, U
Post by: FEAP_Admin on November 20, 2017, 07:29:59 AM

Yes, U stores the current t_n+1 in slot 1, slot 2 contains the current t_n+1 minus the previous t_n solution, and slot 3 has iterative increment for the global Newton-Raphson solution procedure.

The velocity and acceleration vectors have extra slots too and vary depending on the time integrator chosen.  See the program/dynaXX.f files.

Title: Re: Components of Solution Array, U
Post by: jbruss on November 20, 2017, 08:02:36 AM

Great! Thank you very much!