Recoving Composite Ply Stress After a DDAM Analysis

[kth42]

Hello. I am trying to recover composite ply stresses after a DDAM run. DDAM does not support (or at least I don't think it does)laminate property cards, so my results are outputed as Shell stress. Does anyone know of a way that I can convert these shell stresses back to laminate stresses so I can get ply stresses in my composite.
Thanks in advance.

 

[Onda]

You can try to load on your model the deformation obtained from DDAM analysis and make a linear solution for imposed displacement.
remember to keep one knot free (without imposed displacement) to obtain a solution else the solver do not have degree of freedom to solve.
Check the consistence of the system for a non layered model first, as I've never applied this method to a DDAM analysis.
regards
Onda

 

[SWComposites]

Convert the shell stresses into load and moment resultants (Nx, Ny, etc) (or just output the load and moment resultant directly), and input the them into a laminate analysis code to get ply stresses, strains.

 

[kth42]

Thank you for the responses. Outputing the loads on the shell elements and running them into a laminate code is what I am doing. This is a bit labor intensive, and therefore I am only verifying the highest stressed elements.

This seems like it would be perfect for a FEMAP API, since FEMAP has all the data available to it (shell loads, composite material properties etc) but I do not know how to take advantage of these things and create a program to automate the failure index calculations. If anyone can help in this area I would greatly appreciate it.

Thanks again.