Strain Rate Dependent Response of Non-Crimp Fabric Composites

Abstract

The dynamic response of a unidirectional non-crimp carbon fiber/epoxy composite subjected to tension along the transverse and 45° off-axis directions was studied at different strain rates. Intermediate strain rate tests were conducted using a hydraulic intermediate strain rate test frame at approximate strain rates of 0.2/s and 5/s. High strain rate tests were performed with the Split-Hopkinson tensile bar technique at approximate strain rates of 70/s and 180/s. Pulse shaping was developed to achieve dynamic equilibrium during the Split-Hopkinson tensile bar tests, in which pure lead wire was found to be a good pulse shaper for the material tested. The results demonstrated that the applied strain rate had a significant effect on the stress-strain response for the 45° off-axis test specimens, while the transverse test specimens exhibited less strain rate dependence for the rates considered in this study.