Indentation of rigidly supported sandwich beams with core gradation

165Diagrammatic sketch of indentation of sandwich structures with core gradient, and normalized failure load surface versus core thickness ratio a = C1/C2 and core strength ratio ۚ = σ1/σ2 as well as normalized failure load surface versus core thickness ratio a = C1/C2 and face sheet strength σ¯. Configuration 1 and Configuration 2 are with changed positions of two foam core layer.