Nonlinear flexural deflection of thermoplastic foam core sandwich beam

Nonlinear flexural deflection behavior of foam core sandwich beams has been experimentally investigated. The experimental data were compared with the predicted results obtained from a proposed analytical method and the finite element analysis. Sandwich beams with thermoplastic foam core and carbon/epoxy fabric faces were manufactured using the vacuum bagging process. To investigate the effect of the face thickness on the nonlinear flexural deflection, three types of specimens with different face thickness were prepared and tested using the four-point bending test method. Basic engineering data and nonlinear mechanical properties of the face sheet and the foam core were obtained from the tensile and shear tests. An analytical model was proposed to predict the global nonlinear flexural deformation of the foam core sandwich beams. In the model, measured material nonlinear behavior of the foam core was implemented. The predicted global nonlinear deflection of the foam core sandwich beam using the proposed analytical model and the finite element analysis agreed well with the experimental data up to the local indentation failure point within some scattered range.