Mechanical behavior and modeling of honeycomb cored laminated fiber/polymer sandwich structures

Abstract

The use of composite sandwich structures is increasing in aerospace and civil infrastructure applications due to their high flexural and transverse stiffness and light weight. Considering different mechanical properties, sandwich structures can be manufactured from various core and facesheet materials.In this study, hand lay up technique was used for the fabrication of sandwich structures made of polypropylene based honeycomb core and glass fiber reinforced polymer (GFRP) facesheets. The non-crimp glass fibres and epoxy matrix were used for the production of GFRP laminates. The variation of the core thickness was the major parameter for considering the mechanical behaviour and failure mechanisms of the sandwich structures. Based on flatwise compression tests, an increase in compressive modulus and strength was observed with the increase of core thickness. For edgewise compression tests, peak loads up to crush of the sandwich panel was discussed by means of core thickness. According to the three point bending tests, a decrease in core shear stress and facesheet bending stress was observed as the core thickness increases.The modeling of sandwich structures were also carried out with three dimensional finite element models. The ANSYS 11 software was used for utilizing the test data in order to predict the mechanical behavior of the sandwich structures. In the finite element analysis, the test results of each constituent were employed as the input data for ANSYS. The experimental data and predicted results were found to be in good agreement in the elastic region, therefore the model can be used to predict the behavior of similar structures in elastic region.