Response and collapse of foam-supported sheet metal beams and shallow arches

This paper considers the response and failure characteristics of beams and arches constructed by bonding a layer of foam to a single metal sheet, thus creating a “Foam-Supported Sheet Metal,” or FSSM composite. The investigation was conducted from experimental and analytical/numerical perspectives. In the experiments, strips of Rohacell foam were bonded to straight or curved aluminum 2024 strips to construct the composites. The specimens were then supported at the ends and bent under a central load such that the foam was in tension. The results showed that significant increases in stiffness and failure loads could be achieved using this concept with relatively small weight penalty. Catastrophic failure occurred when the foam reached its tensile failure stress. Formulas to predict the bending stiffness and moment at failure of the composite sections were derived from beam theory and are presented. To predict the response of arches, a nonlinear finite element model was developed. The numerical results showed good agreement with the load-deflection responses and failure loads measured experimentally.