Biaxial crushing of honeycombs: —Part 1: Experiments

The in!plane compression and crushing of honeycombs is known to be closely related to the crushing behavior of the broader class of space _lling cellular solids[ Previously\ the authors conducted an extensive study of uniaxial crushing of a polycarbonate honeycomb with circular cells[ In this paper the same honeycomb is crushed biaxially[ The crushing was performed in a custom testing facility between rigid platens which can be moved independently in two orthogonal directions[ The facility allows testing at various biaxiality ratios and volume reductions as high as 84)[ The facility was used to conduct several series of biaxial crushing experiments on nearly square honeycomb specimens "07 10 cells#[ In each experiment we recorded the true stress displacement responses in the x! and y!directions as well as full _eld views of the deformation using a video camera[ Biaxial crushing is quite complex and the prevalent mechanisms of collapse depend on the biaxiality ratio "g#[ As is the case in uniaxial crushing\ the onset of collapse involves localized instabilities\ however\ the extent of localized deformation varies with g[ The energy absorption capacity of the material depends on g[ The highest energy is required when the specimen is crushed at the same rates in the two directions