Need Opinion on Stress Analysis Procedure for Interior Monument Honeycomb Laminates

[VN1981]

Hello,
In some of my previous aircraft interior monuments analysis which are constructed from Nomex or similar Honeycomb Laminates, I've modeled the laminates using smeared or equivalent PSHELL formulation (Ref: FEMCI NASA document). So Nastran will spit out stress values for the entire laminate instead of each individual layer if I had defined laminate using PCOMP/PSHELL formulation. I've used Panel long beam bending allowables obtained from long bending test to check against the Von Mises output from FE for the laminate. Similarly, one can extract the shear running forces from Nastran and convert them to shear stresses and compare against short beam shear allowables which are for core shear failures. Is the procedure is accurate? If no, can a more accurate method of check be suggested i..e how to use panel allowables from long beam & short beam test against FE results? Thanks

 

[aerostress82]

I understand why you are trying to model everything as shell elements including the core+laminates. Why wouldn't you consider modeling your core as hex elements? And at locations where your core is ending and you are left only with laminates, use wedge elements for these transition region cores?

Perfect 3-4 rows of hex elements between laminates to model the core structure. And then you can use the hex stresses to evaluate your core failure as you would define the material orientation with respect to a local coordinate system.

Just another approach to your case if the latter got too complicated on its way.

Spaceship!!
Aerospace Engineer, M.Sc. / Aircraft Stress Engineer