Out-of-plane behavior of honeycombs under dynamic combined compressive and shear loading

Abstract
A new testing method, together with a large diameter nylon Split Hopkinson Pressure Bar (SHPB) has been employed to investigate the response of honeycomb under dynamic combined compressive and shear loading. Two short cylindrical bars with one bevel end were used to introduce a combined shear-compression shear loading. A series of experiments were performed at loading angle ranging from 0° (corresponding to pure compression) to 60°. The results show that the biaxial behavior of honeycomb in terms of overall pressure/crush curves varies significantly with the angle. Further investigation was numerically conducted on a virtual honeycomb specimen using Finite Element Method (FEM) in order to reproduce the experiments and study the shear and normal behaviors separately. A comparison between the calculating results and experimental ones shows a good agreement to each other. The calculation results indicate that the normal strength of honeycomb under combined compressive and shear loading decreases with increasing loading angle, but the shear component of material strength behaves in the opposite way. In the end, a crushing envelope of normal strength vs. shear strength plane was determined on the basis of these simulations.