Analytical and Numerical Models of Sandwich Panel taking into Account Wrinkling Phenomenon

The problem of local instability of the compressed facing of a sandwich panel is discussed in this paper. Proper estimation of wrinkling stress has become a challenging issue because of a strong tendency to optimize technical parameters and costs. The aim of the study is numerical and analytical analysis of bending of three-layer panels. Linear constitutive equations and identical elasticity modules in tension and compression are assumed. In practice, wrinkling stress depends on many factors, usually neglected in analytical solutions, though observed in experiments. In this paper we use numerical methods and hence we can allow for the loss of face adhesion or anisotropy of the core. Created models are validated and calibrated by experimental results. The analyses are carried out for various mechanical and geometrical parameters of the sandwich panel. The influence of these parameters on structural response is studied. The range of applicability of classical theoretical models is discussed basing on numerical examples. The study presented in the paper was inspired by sandwich panels producers, with the aim to increase safety and economy.