prop loading

[Shuai Wang]

Dear FEAPers,

Right now I meet with a problem with prop loading.

I build a model which coupled mechanical and electrical properties of a 2-D solid. I want to give a time-dependent electric field  loading in the 2nd direction (eprop1) and a time-invarent mechanical force loading(eforce). the input is shown below.

However, the simulation results shows that the mechanical force loading is also time dependent which is not what I expected. Can anyone help me out of this problem. Thanks.

Code: [Select]

ebound
2 0 0 0 1 0 0
2 b 0 0 1 0 1
1 0 0 0 0 1 0

eforce
1 a 0 0 0 -1  0
2 b 0 0 0  0 -1

edisp
2,0  0 0 f 0 0

eprop
2,0  0 0 1 0 0

end

batch
  prop,,1
end
2 6
0.0,0.0   0.25,1.0  0.75,-1.0  1.25,1.0  1.75,-1.0  2.0,0.0

[Prof. R.L. Taylor]

In ver8.4 you can control this using load groups (see FEAP User Manual) in the specification of the boundary conditions.  This allows you to specify which proportional load is to be applied to the various parts.  If it is from an element body force loading the same thing can be done using the GROU material command option, which also requires specific proportional loads.

Older versions are more difficult to control.  You can use FPRO mesh commands to associate specific proportional loads to forces and displacements.

[FEAP_Admin]

You should define 2 proportional loads.  One that is constant and the other that is changing.
The assign the mechanical dofs to the proportional load that is not changing and the electrical dofs to the one that is changing.

[Shuai Wang]

Thanks for your reply. It works fine for me right now.