Crushing of soft-core sandwich profiles: experiments and analysis

The present paper investigates the mechanics of the crushing of sandwich profiles through component testing and theoretical analysis. Experiments were run showing that the underlying folding mechanism of sandwich profiles is very different from that of solid-section thin-walled structures. In particular, the shear behavior of the core material was found to strongly influence the mechanics of energy absorption. The analysis focuses on the crushing behavior of double-cell profiles that are made of soft-core hybrid stainless steel assembly (HSSA) sheets. Both material and structural tests were performed. It is demonstrated that the shear strength of the HSSA fiber core is small as compared to the face sheet properties. When subjected to bending, the core deformed in the shear mode, whereas the facings bent independently. Based on this mechanism, a new shear-folding model for sandwich profiles is derived, incorporating the “shear crushing” of the sandwich core material. Theoretical predictions of the mean crushing force based on the present model compared very well with the experimental data.