Flexural response of polypropylene/E-glass fibre reinforced unidirectional composites

This paper presents a study of the flexural response of continuous E-glass fibre reinforced polypropylene composites. Experiments were designed to investigate monotonic and cyclic flexural response using three point bending test for laminates with different angle-ply and cross-ply arrangements. Results show that the monotonic and cyclic flexural response of the composites are influenced by the plastic deformation of the matrix. The study observed that increasing numbers of cyclic loads led to significant energy dissipation, stiffness reduction and micro-damage accumulation within the composite and especially at the matrix–fibre interface. Significant energy dissipation and damage were observed to dominate the first load-unload cycle. With subsequent cycles, the magnitude of energy dissipation and global damage reduces to a threshold value which is cycle independent. This study has also developed a phenomenological model to predict the dependence of energy dissipation with number of cycles. The experimental data generated here will be useful in the development of holistic macroscale constitutive models and finite element studies of the chosen test composite.