A General approach to the wrinkling instability of sandwich plates

Sandwich plates are widely used in lightweight design due to their high strength and stiffnessto weight ratio. Due to the heterogeneous structure of sandwich plates, they can exhibit local instabilities(wrinkling), which lead to a sudden loss of stiffness in the structure. This paper presents an analyticalsolution to the wrinkling problem of sandwich plates. The solution is based on the Rayleigh-Ritz method,by assuming an appropriate deformation field. In contrast to the other approaches up to now, this modeltakes arbitrary and different orthotropic face layers, finite core thickness and orthotropic core material intoaccount. This approach is the first to cover the wrinkling of unsymmetric sandwiches and sandwichescomposed of orthotropic FRP face layers, which are most common in advanced lightweight design. Despitethe generality of the solution, the computational effort is kept within bounds. The results have beenverified using other analytical solutions and unit cell 3D FE calculations.