An analytical modelling of the symmetrical wrinkling is proposed : from original assumptions on displacements within the core, and from an energy minimisation method, it is possible to predict critical loads and buckling modes better than traditional models do, and to distinguish the influence of each structure component. Compression tests were carried out on sandwich structures to validate the model. Little curved structures were also tested to estimate the influence of skin curvature on rupture and buckling mode. A finite elements analysis has been achieved in parallel : a fine modelling allows to find results close to experimental ones