Dynamic punch shear characterization of plain weave graphite/epoxy composites at room and elevated temperatures

Abstract

In many situations, composite structures are subjected to dynamic loading. To design such structures, there is a need of dynamic material properties. In the current investigation, a compression Split Hopkinson Pressure Bar was modified to load the samples in punch shear mode. Experimental studies were conducted to characterize 24 layer plain weave graphite/epoxy laminate samples. Laminates were manufactured using vacuum assisted resin infusion molding process. Samples of nominal size 26 mm × 13 mm × 4 mm were subjected to dynamic punch shear test at three different pressure settings that yielded strain rates in the range of 1415–3601/s at room and elevated temperatures of 51.7 °C, 79.4 °C and 107.2 °C. Dynamic shear stress–strain properties were evaluated. Failure modes were characterized through optical and scanning electron microscopy. Results of the tests indicate that the dynamic shear strength increases with increase in the strain rate and decreases with temperature for a given strain rate. Higher temperature causes the softening of matrix.