huangyhg

sandwich design of composite panels
does anyone know of a method to calculate the stresses and deflections for a sandwich type panel with edge loading in a beam type problem?
normally, the panels have fiberglass facings top and bottom with a honeycomb core, and the loading is normal to the facing, similar to a floor panel.
in the case that i am looking at, the loading is parallel to the facing.
the foam core panel formulas i've seen are for isotropic (sp?) cores ie cores that have the same properties in all directions. they basically calc bearing resistance and buckling.
you will need to also check the shear value for the honeycomb to panel bonding in case is is lower than the shear strength of the honeycomb.
see the text 鈥淐ellular solids: structure and properties鈥?by gibson and ashby for these type of equations. there is a nice coverage of the mechanics of honeycomb and foam structures as well as the sandwich structures in this text.
i don鈥檛 have the text with me right now, but i could dig up my copy of the book and post eqns if you don鈥檛 get any other responses.
spike,
hexcel company has a design manual for composite sandwich structures with relevant equations for beam type loading and edge wise loading conditions with failure modes and such. it is pretty good and below is the url where you can find it.

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