Contact law for composite sandwich beams

In sandwich structures with soft foam core materials, the relationship between load and deflection under the load, also called contact law or indentation, plays a very important role. This work presents a combined experimental and analytical study of the contact behavior of sandwich beams with polyvinyl chloride (PVC) foam cores. The mechanical properties of the sandwich constituents were fully determined and sandwich beams, facesheet-foam and foam blocks were tested under quasi-static loading. These experimental results were used to model the load-deflection curve that includes a linear range followed by a nonlinear portion. The linear model was derived from the Winkler foundation theory and the nonlinear one was obtained by fitting experiments.