Appying body-force like loads in a 2d user element

[shenrilin]

Dear Feap team,

    I'm now writing my own element considering distributed loads in the plane, just like body force. I have some possible method, but I'm not sure which one can work.
    (1) using commands body force, b1, b2, b3 in MATE part
    (2) applying node forces on all nodes, that is translate  the body force to node force manually in advance.
    (3) in user element, when isw=3 or 6, adding the body force contributions into residual vector.
    (4) using command load,,q option in MATE part.

    Could anybody tell me the feasibility of these method? I appreciate any help.

Best,

[Prof. R.L. Taylor]

The commands in MATE are mostly for the standard FEAP elements included with the program.  Thus using:

(1) body force b1 b2 b3 would not be recognized by your element unless you were using the inmate.f routine to input all your properties into the d(*) array in your user element.

(2)  this is too tedious for any problem with  many elements unless you wrote your own umesh*.f routine to perform the volume integrals (area in 2-d usually).

(3) is what we usually recommend.  If you want to have proportional load multipliers look at the routine sbodyf.f in the elements/solid2d directory.  Here d(11:13) are constant b1, b2, b3 values and d(74:76) are proportional load numbers, and d(71:73) are load multipliers

(4) is like (1).