Strain rate effects on failure of a toughened matrix composite

Abstract

The objective of this study was to characterize the quasi-static and dynamic behavior of a toughened matrix composite (IM7/8552) and apply the Northwestern (NU) failure theory to describe its strain-rate dependent failure under multi-axial states of stress. Unidirectional and off-axis experiments were conducted at two strain rates, quasi-static (10-4 s-1) and intermediate (∼1 s-1) using a servo-hydraulic testing machine. Stress-strain curves were obtained and the nonlinear response and failure were measured and evaluated based on classical failure criteria and the NU theory. Predicted failure envelopes were compared with experimental results. The NU theory was shown to be in excellent agreement with experimental data. © The Society for Experimental Mechanics, Inc. 2014.