A tri-particle model of sandwich panels

A multiparticle model (referred to as M4; multi-particle model of multilayered materials) (Naciri T, Ehrlacher A, Chabot A. Interlaminar stress analysis with a new multiparticle model. Composites Science and Technology 1998;58:337–343) has been used to describe the behavior of sandwich panels in monotonic bending. The main purpose of this study is the analysis of global response and shear stresses in sandwich panels. The equilibrium equations, boundary conditions and generalized constitutive law of the M4 model are given and applied to sandwich panels, which are assumed to be made up of three layers (two skins and a core). This sandwich multi-particle model is called a tri-particle model. The accuracy of this model is then assessed for bending problems the solutions of which can be derived analytically or computed. The example of sandwich panels in cylindrical bending is first investigated by taking Pagano’s solutions as reference. A second example is proposed for the estimation of the accuracy of the tri-particle model with classical finite elements used in sandwich design. A refined SAMCEF 3-D mesh served as the calculation reference. The tri-particle model was found to be more accurate than the classical sandwich theory based on the Reissner cinematic hypotheses in the first example and more precise than the SAMCEF finite-element plate models in the second example.