effect of rigid polyurethane foam core density on flexural and compressive properties of sandwich panels with glass/epoxy faces

sandwich panels as composite materials have two external walls of either metallic or polymer type. the space between these walls is filled by hard foam or other materials and the thickness of different layers is based on the final application of the panel. in the present work, the extent of variation in core density of polyether urethane foam and subsequent flexural and compressive changes in sandwich panels with glass or epoxy face sheets are tested and investigated. a number of hard polyether urethane foams with different middle panel layers density 80-295 kg/m3 are designed to study the effect of foam density on mechanical properties including flexural and compressive properties. flexural and compressive test resultsshow that increased core density leads to improved mechanical properties. the slope of the curve decreases beyond density of 235 kg/m3. the reason may be explained on the limitation of shear intensity in increasing the mechanical properties. in this respect an optimum density of 235 kg/m3 is obtained for the system under examinations and for reaching higher strength panels, foams of different core materials should be selected.