Interlaminar shear strength of plain weave S2-glass/SC79 composites subjected to out-of-plane high strain rate compressive loadings

In this study a test methodology for measuring interlaminar shear strength of composites under both quasi-static and high strain rate loadings is developed. The test methodology is also able to study the effect of the Coulomb friction and the influence of interlaminar compressive stress acting on the failure plane. The material properties generated are used to evaluate various quasi-static and strain rate dependent failure criteria. This is accomplished by testing out-of-plane off-axis composite materials to determine the interlaminar shear strength (S13) and friction function (f) as a function of strain rate. Two different types of plane weave S2-glass/SC79 fabric composites were used in this investigation. Quasi-static v-notch shear test results for interlaminar shear strength are in excellent agreement with the results from the off-axis compression test method. The strain rate dependent behavior of the out-of-plane off-axis composites is investigated through a Split Hopkinson Pressure Bar (SHPB) test for strain rates up to 1000 s−1. The test results show that both S13 and f are strain rate sensitive for these material systems. Finally a strain rate dependent shear failure criterion incorporating the influence of interlaminar compression and Coulomb friction is identified.