Tensile dynamic behaviour of a quasi-unidirectonal E-glass/polyester composite

The objective of this study is to determine the tensile behaviour of a unidirectional E-glass/polyester composite in relation to the strain rate. Several orientations of fibres in the composite are tested with an hydraulic tensile machine, which covers a range of loading rate from quasi-static up to approximately 20 m/s. It is shown that experimentally and numerically, high velocity entails specific difficulties. In this study, some tests were improved in order to limit these effects and to obtain directly reliable material properties. The composite studied is quasi-unidirectional, the influence of 5% vol. of weft fibres is evaluated at quasi-static strain rate. It is found that the presence of the weft fibres is the source of the damage development. Longitudinal (0degrees) and transverse (90degrees) orientations of fibres in the composite are tested. The effects of strain rate on mechanical properties (maximum stress, Young's modulus, strain to failure) are noted. Damage mechanisms seem to evolve with the strain rate. (C) 2002 Elsevier Science Ltd. All rights reserved.