In this lecture prof. C. Kassapoglou talks about calculation methods for failure modes of sandwich panels.

The first segment covers symmetric and antisymmetric wrinkling respectively, followed by a comparison of the results to finite element calculations. Because of inherent imperfections in real structures due to the production processes the results can’t be compared to test data without expecting a significant decrepancy.

The effect of waviness on the difference between analytical and real results is then explained, as wel as examined why it is relatively difficult to use this to make better predictions. Finally the last two wrinkling modes are explained, shear wrinkling and wrinkling under combined loads.

The last section of the lecture covers shear crimping, similar to asymetric wrinkling, but with zero wavelength, folowed by design considerations for the rampdown of sandwich structures back to monolithic material. Finally an example of a sandwich structure under compression is discussed.