Sandwich panel stress analysis

[arsehole]

I'm trying to figure out the yield stress of a plywood core (0.72", 7 ply douglas fir), SST faced (0.015&quot, plymetal panel subject to bending. I am assuming that the stress strain relation is nonlinear elastic, theoretically placing the yield stress at a strain of 0.005. However, upon performing destructive testing of a sample with strain gages on the outer faces, can I assume that the strain readings are representitive of the strain for the entire panel, or just for the outer SST skins?
Should I just assume that the panel's mechanical properties are similar to that of the plywood, or does adding the skins increase the strength of the panel enough to warrant the testing?
I'm somewhat new to the sandwich panel design world, so any input would be greatly appreciated.

 

[arsehole]

I found information from the Engineered Wood Association on design and fabrication of plywood sandwich panels. It gives stress analyisis formulas for plywood faced, foam/balsa/honeycomb core panels. Could these formulas be applied to stainless steel faced, plywood core panels, or are they specific to plywood faced panels?

http://www.gp.com/panels/pdf/apa/u814.pdf