The paper considers sandwich panels, which consist of two thin facings and a shear-deformable core. Such elements are commonly used in civil engineering, but also in the space, aviation and automotive industries. One of the basic problems of such structures is the local instability of thin facing. The facing is stabilized by the core, but at a certain compressive stress, the facing wrinkles. In the classic case of uniform stress and strain states, the wrinkling stress for is known. However, the problem becomes much more difficult when, at the location of the greatest compression of the facing, the core deforms in the direction perpendicular to the facing. Such a situation is common in practical applications of sandwich panels, e.g. at the location of supports or concentrated forces. This paper presents the influence of core deformation on the value of the wrinkling stress. The theoretical energy approach will be used to solve the problem, and appropriate numerical simulations will be performed. The obtained results will allow to determine the influence of parameters of the applied models on the value of stress causing instability of the facing.

Acknowledgement: The scientific activity of the Institute of Mathematics, Poznan University of Technology was funded under grant no. 0213/SBAD/0122.