Compressive strength prediction of fibre reinforced polymer composites under lateral disturbance

A study on lateral disturbance, which is regarded as a factor that causes imperfect loading, is presented herein. The rationale behind the study is that fiber misalignment has always been regarded as the cause of an imperfect structure. The main purpose of this paper is to establish that even for a perfect structure, lateral disturbance can cause compression instability in a composite. In this paper, a novel numerical model has been established, in which the lateral disturbance effect is applied to a long fiber with perfect alignment to study the compressive instability behavior. The numerical results show that even in the case of perfect structure, lateral disturbance is still the key factor that causes compressive bucking of a composite. In our experiments, the lateral disturbance is observed in-suit from the deformation of the unidirectional (UD) composite using the digital image correction (DIC) technology. Finally, a theoretical prediction model of the compressive strength of fibre reinforced polymers (FRPs) and the effects of lateral disturbance and loading path dependency on compressive behavior of the FRP are also discussed. These results can provide a more comprehensive understanding for the instability mechanism and the compressive strength of FRPs composite.