Prediction of mechanical behavior of composites under high strain rate tensile loading

Non-standardization of specimen size and shape, complexities involved in specimen fabrication and its mounting on split Hopkinson pressure bar (SHPB) make it difficult to achieve reliable high strain rate mechanical properties under tensile loading experimentally. A formulation based on variable rate power law is proposed to predict the tensile strength at higher strain rates based on the experimentally obtained values at comparatively lower strain rates. Experiments were conducted on typical plain weave composite along warp direction, unidirectional composite along and across fiber direction made of E-glass/epoxy and epoxy resin along in-plane direction in the strain rate range up to 470/s using a tensile SHPB apparatus. Predictions of high strain rate tensile behavior of all the four materials have been made up to strain rate of 2000/s. A comparison between analytical predictions and available experimental data is also made and a good match is observed.