Composite materials response under low-velocity impact

Abstract A simple model, based on energy considerations, has been tested to predict the maximum contact force during a low-velocity impact between an impactor and a composite plate. Three different composites, i.e. glass cloth-polyester, carbon cloth-polyester and nylon cloth-polyester, were examined. The results reported here, obtained using an instrumented apparatus, show that the total energy applied during the impact is the governing parameter of the phenomenon, rather than the impactor speed or mass. All the composites under evaluation did not show any variation of elastic modulus with impact velocity. Moreover, the dynamic behaviour of carbon-polyester and nylon-polyester composites can be predicted by simple static tests, because of their insensitivity to rate-dependent phenomena; for these materials a simulation of impact tests by static tests is therefore suggested. Glass-polyester composites did show a rate-dependent behaviour, by an increase in strength of about 70% with respect to the static case; a small number of dynamic tests is, however, sufficient to characterise their behaviour under impact conditions.