Dynamic Compressive Response of Stainless-Steel Square Honeycombs

The dynamic out-of-plane compressive response of stainless-steel square honeycombs has been investigated for impact velocities ranging from quasi-static values to $300ms−1$⁠. Square-honeycomb specimens of relative density $0.10$ were manufactured using a slotting technique, and the stresses on the front and back faces of the dynamically compressed square honeycombs were measured using a direct impact Kolsky bar. Three-dimensional finite element simulations of the experiments were performed to model the response and to help interpret the experimental results. The study has identified three distinct factors governing the dynamic response of the square honeycombs: material rate sensitivity, inertial stabilization of the webs against buckling, and plastic wave propagation. Material rate sensitivity and inertial stabilization of the webs against buckling cause the front and back face stresses to increase by about a factor of two over their quasi-static value when the impact speed is increased from 0 to $50ms−1$⁠. At higher impact velocities, plastic wave effects cause the front face stress to increase linearly with velocity whereas the back face stress is almost independent of velocity. The finite element predictions are in reasonable agreement with the measurements.