High strain rate compression of fiber composites

A model is presented for the dynamic compressive behavior of fiber composites under prescribed axial strain rate. The model includes the effects of fiber misalignment and material nonlinearity. A couple stress is used to take into account the fiber bending resistance. An examination of the dynamic axial stress-strain relation shows that the model is consistent with experimental results. For a given strain rate, the axial stress goes through a maximum associated with microbuckling (i.e. the formation of kink bands). The dependence of this dynamic compressive strength on strain rate is also consistent with experiments. Finally, the model is used to predict the kink band width as a function of the strain rate; at high axial strain rates, the kink band width is about one-half that for quasi-static loading. (C) 1997 Elsevier Science Ltd.