Abstract
The fibre type effect on mixed-mode I/II interlaminar fracture in unidirectional fibre reinforced polymer composite beams is studied. Linear-elastic fracture mechanics is applied. Three composite systems (with three different types of reinforcing fibres) are investigated. The fracture behaviour is studied in terms of the strain energy release rate using a three-dimensional virtual crack closure technique. For this purpose, a three-dimensional linear-elastic finite element model of the composite beam is developed. The distribution of the strain energy release rate mode components along the crack front is analyzed. The findings are verified by the crack closure technique. The calculations reveal that the strain energy release rate decreases with increase of the modulus of elasticity of the reinforcing fibres. This finding is attributed to the increase of the beam stiffness with the composite modulus of elasticity.