Transverse compressive properties of honeycomb core under oblique loading

Abstract

The transverse compressive behavior of honeycomb cores has been widely exploited for energy absorption applications in the automotive and aerospace industry. The energy absorption in honeycomb cores with thin reinforced thermoplastic/thermoset cell walls is achieved by progressive folding/fracture of cell walls. The energy absorption by honeycomb cores has been assumed to be primarily due to loading along thickness direction. However, inclined loads cannot be precluded and their influence on energy absorption process must be measured. In this investigation, the effects of inclined/oblique loads on the compressive behavior and energy absorption of Plascore Nomex honeycomb core has been investigated experimentally under static and dynamic loading. The load inclination to the cell wall direction was varied by using off-axis core specimens. The effect of loading angle, core thickness and test speed on the resulting energy absorption has been studied. Test specimens with varying thicknesses of 0.5˝, 1˝, 1.5˝ and 2˝, with cell walls oriented at 0º, 5º, 15º, 30º and 45º to the loading axis were used in the study. These specimens are tested using a servo hydraulic testing machine at rates of 0.008333, 10-1, 1 and 10 in/s. It was observed that the initial load peak in the compression response, the sustained crushing load and energy absorption was influenced by the cell-wall orientation, core thickness and the test speed.