Experimental and numerical studies on the quasi-static and dynamic crushing responses of multi-layer trapezoidal aluminum corrugated sandwiches

• Multi-layering decreased buckling stress.
• Bonded specimens experienced higher crushing stresses.
• The simulation and experimental post-bucking stresses increased with constraining.
• The multilayer samples in 0°/90° core orientation showed higher buckling stress.
• The presence of interlayer sheets induced progressive deformation of fin layers.

The axial crushing responses of bonded and brazed multi-layer 1050 H14 trapezoidal aluminum corrugated core (fin) sandwich structures, with and without aluminum interlayer sheets in 0°/0° and 0°/90° core orientations, were both experimentally and numerically investigated at quasi-static and dynamic strain rates. Multi-layering the core layers decreased the buckling stress and increased the densification strain. The experimental and simulation compression stress–strain curves showed reasonable agreements with each other. Two main crushing modes were observed experimentally and numerically: the progressive fin folding and the shearing interlayer aluminum sheets. Both, the simulation and experimental buckling and post-buckling stresses increased when the interlayer sheets were constraint laterally. The multi-layer samples without interlayer sheets in 0°/90° core orientation exhibited higher buckling stresses than the samples in 0°/0° core orientation. The increased buckling stress of 0°/0° oriented core samples without interlayer sheets at high strain rate was attributed to the micro-inertial effects which led to increased bending forces at higher impact velocities.