Shear and Compression Wrinkling Experimental Analysis with a Sandwich Beam Submitted to Three-Point Bending.

Wrinkling is a localized buckling phenomenon that significantly compromises the structural integrity of lightweight sandwich structures. The objective of this study was to validate the experimental design of a sandwich beam to observe the initiation of wrinkling under compression and, more specifically, under shear stresses. The specimen under consideration consists of glass fibre-epoxy skins with polymethacrylimide (PMI) ROHACELL foam cores. The experimental tests were monitored using Digital Image Correlation (DIC) techniques, in conjunction with displacement and force sensors. A linear buckling simulation was performed using Finite Element Analysis (FEA) in ABAQUS and was compared with both the experimental test results and analytical predictions. The simulations demonstrated a good correlation with both the experimental data and analytical models for compression wrinkling. In the case of shear wrinkling, the numerical analysis significantly overestimated the wrinkling load in comparison to the experimental results.