Influence of speed on the crushing behavior of composite plates

Abstract

This paper presents a study on crushing of CFRP composite laminated plates. The objective of this study is to analyze the influence of crushing speed on the rupture behavior and the energy absorption capability of composite materials. Two materials are tested: a carbon-epoxy unidirectional prepreg, and a carbon-epoxy fabric. For both materials, three different plate configurations are tested (three different stacking sequences). The crushing device is an improved plate crushing setup with stabilizing guides, which can be used both on a standard static traction/compression test machine, or on a drop tower. For static tests, a 20 mm/min velocity is applied to the specimen all along the 100mm crushing stroke. For dynamic tests, only the initial velocity can be imposed. Three initial speeds were chosen: 2, 5 and 9 m/s. A high-speed camera is used during tests to visualize the global behavior of the plate, and the rupture modes in the crushing front. The load is also recorded, which enables to calculate the load/displacement curve of plates crushing and determinate the energy absorption capability. The analysis of these results enables to discuss on the influence of crushing speed both on the rupture modes and, as a consequence, on the energy absorption capability.