Finite Element Evaluation of Composite Sandwich Panel Under Static Four Point Bending Load

Abstract

The sandwich composites are multilayered materials made by bonding stiff, high strength skin facings to low density core material. The main benefits of using the sandwich concept in structural components are the high stiffness and low weight ratios. These structures can carry in-plane and out-of-plane loads and exhibit good stability under compression, keeping excellent strength to weight and stiffness to weight characteristics. In order to use these materials in different applications, the knowledge of their static behavior is required and a better understanding of the various failure mechanisms under static loading condition is necessary and highly desirable. The objective of this study is to develop a modeling approach to predict response of composite sandwich panels under static bending conditions. Different models including 2D and 3D with orthotropic material properties were attempted in advanced finite element (FE) software Ansys. Comparison of FE model predictions with experimental data on sandwich panel bending properties helped in establishing appropriate modeling approach. Analytical solutions were also used to verify the some of the mechanical properties such as bending stress and shear stress with the FEM results. For this study nomax flex core is used as a core material (thickness 15mm) and carbon fiber reinforced polymer composite (thickness 1.2mm each) is used as face sheet material. The experimental load of sandwich panels was taken and applied in steps through FEM and compared the results with experimental one at all steps.