Impact behavior of honeycombs under combined shear-compression, Part I Experiments
Résumé
This paper presents a combined shear-compression impact test for soft cellular materials designed in order to investigate their behavior under dynamic multiaxial loading. A large-diameter Nylon Split Hopkinson Pressure Bar system (SHPB) with beveled ends of different angles is used to apply the desired shear-compression combinations. The data processing methods is studied and validated by virtual testing data generated with FEM simulations. A series of experiments on an aluminum honeycomb was performed with the loading angles ranging from 0o (corresponding to the pure compression) to 60o and at the projectile impact velocity of about 30 m/s. It shows a strong effect of combined shear that both the initial peak and the crush strength decrease with increasing loading angle. The quasi-static shear-compression experiments were also performed using the same beveled ends with a universal INSTRON machine and a notable enhancement under impact loading is observed. Images captured during quasi-static and impact tests permit for the determination of the two co-existing deforming patterns under combined shear-compression and also the influence of the loading rate on them.