EFFECT OF STRAIN RATE ON THE TENSILE FAILURE OF GLASS-FIBRE BRAIDED TUBES

Tensile tests have been performed at up to five different displacement rates, from about 1 mm/s to over 20,000 mm/s, on braided glass-fibre tubes of both square and circular cross-section and the corresponding force-displacement curves have been derived. In general both the maximum tensile force and the displacement at failure increase with increasing loading rate, implying a greater energy absorbing capability at the higher deformation rates. At all rates of loading the square cross-section tubes support a lower maximum force and fail at a higher overall deformation. Two stages in the failure process are considered, the realignment of the fibres against the resistance of the matrix followed by the tensile failure of the fibres. Both these processes are found to be rate dependent.