Effective finite element model to calculate the indentation of sandwich panel

Computationally effective finite element model of composite material was developed to predict the strength and energy absorption at lowvelocity impact. Object of research - a sandwich panel, consisting of two layers of randomly-reinforced fiberglass plastic and cellularcore Divinycell ™ P100. Mechanical characteristics of fiberglass skin for the numerical model have been determined from experiments on tension, bending and shear. Porous core was considered as a solid nonlinear hyperelastic material model Ogden Foam (first order). The constants of the model were determined from the corresponding curves under uniaxial and biaxial tension/compression, pure shear, and triaxial tension/compression for evaluating volume change. Since the carry out of such experiments is difficult, necessary strain diagrams were obtained from the calculation of the elementary Kelvin cell (tetrakaidodekaedr) suitable for describing the structure of a regular core. Cell Kelvin is a recurring form, space-filling without voids, with a minimum ratio of surface area to volume. The calculation results of the local deformation of a three-layer sandwich panel with using a model hyperelastic material Ogden Foam satisfactorily reflected the observed non-linearity diagrams in experiments and show the full energy equivalence until the destruction of skin by the shear. Thus, the developed finite element model can be used to predict the strength and energy absorption limit in low velocity impact loading studies.