A damage model based on Tsai–Wu criterion and size effect investigation of pultruded GFRP

This paper presented a progressive damage model of pultruded GFRP based on the Tsai–Wu criterion. The constitution of the damage model was coded by UMAT subroutine in Abaqus. The model shows sufficient accuracy in validating against the tensile and three-point beam bending tests. It was used to obtain the size effect law of pultruded GFRP with varying sizes and fiber volume ratios. The resistance curve was then calculated by using the obtained size effect law, and the effect of composite’s material property on R-curve was discussed. The fracture toughness obtained by size effect law is within the range of typical pultruded GFRP material property, and the fiber volume’s effect on R-curve is also explored. It’s found that the fracture toughness increases from 53.68KJ/m2 to 76.18KJ/m2 as the fiber volume ratio ascends from 50% to 70%.