Bio-inspired vs. conventional sandwich beams: A low-velocity repeated impact behavior exploration

A new bio-inspired honeycomb sandwich beam (BHSB) based on the woodpecker's head configuration was developed for repeated low-velocity impact resistance improvement. The new design contains four main layers: carbon fiber reinforced plastic top and bottom skins sandwiching rubber and aluminum honeycomb cores. Impact loadings were performed numerically and experimentally in a repeated manner with a hemispherical steel impactor for three energy levels: 7.28 J, 9.74 J, and 12.63 J. In all cases, stresses developed at the bottom skin of BHSB were significantly smaller with substantially lower damage area while sustaining more number of impact than those of conventional honeycomb sandwich beam (HSB). Also, the impact resistance efficiency indices, Ie, which assess overall performance, of both beam designs were compared. Ie of BHSB were 1.65-16.22 times higher, conclusively exhibiting its superiority to HSB in repeated impact resisting performance.