Shell template for nonlinear dynamic analysis

[nonlinfeap]

hi all,

is there a shell element template for 3 node triangle for nonlinear dynamic analysis like elmtxx.f for linear analysis.

interested in developing shell element (eg cst + dkt). not clear on how to set it up in nonlinear case including how to call urotxx.f

i'm on feap 8.4

many thanks

[Prof. S. Govindjee]

There are these two (old) examples for thin plates:  DKQ (rectangle) http://projects.ce.berkeley.edu/feap/elmt06.f  and DKT http://projects.ce.berkeley.edu/feap/elmt07.f

Can you be more specific as to what your question is in regards to to UROTxx.F?

[nonlinfeap]

hi professor,

i'm studing nonlinear fem in school. i got dkt (http://projects.ce.berkeley.edu/feap/elmt07.f) working for linear. now i want to add large deflection nonlinear terms using cst element for inplane. this is test for understanding.

the program manual talks about large rotations and using urotxx.f. this is the part i'm asking about. is there a template like elmtxx.f explaining what to insert in elmtxx.f to use large deflections/rotations. this would help code a nonlinear plate/shell element

many thanks

[Prof. S. Govindjee]

Have a look at the program/protXX.f files these are the built-in ones for FEAP.  They get called if your element declares rotyp to be a negative number under isw.eq.1.  The urotXX.f files get called if you declare rotyp to be positive.  See the frame elements for the rotyp declaration and how the rotations can be extracted for use in the elements.

[nonlinfeap]

hi professor,

many thanks for suggestions. i will study the frame element.