Design optimization of foam-reinforced corrugated sandwich beams

A combined analytical and numerical study is carried out for the structural stiffness, collapse strength and minimum mass design of foam-filled corrugated sandwich beams under transverse three-point bending. Both close-celled aluminum foam and polymer foam as the filling material are considered. Based upon a micromechanics-based model, effective elastic constants of foam-filled corrugations are derived using the homogenization method. To analytically predict the initial collapse strength, six different failure modes are considered, with the effect of loading platen width accounted for. Finite element simulations are performed to validate the analytical predictions, with good agreement achieved. Minimum mass design is obtained as a function of structural strength, and the influence of foam material and loading platen width is quantified. The structural efficiency of foam filling to reinforce the sandwich is assessed on the basis of equal mass and the underlying mechanisms explored. It is shown that polymer foam-filled corrugations are more weight efficient than unfilled ones of equal mass.