A bundle-based shear-lag model for tensile failure prediction of unidirectional fiber-reinforced polymer composites

Abstract

In this study, a novel shear-lag model based on impregnated fiber bundle (IFB) element is developed to predict the tensile behavior of unidirectional fiber-reinforced polymer (FRP) composites. Rather than using a fiber element, the new model enables a full-field failure simulation due to its finite number of elements. Based on the micromechanical difference equation, we validated the effectiveness of the model and identified the damage evolution pattern by applying it to a basic model of 6 mm FRP tendon. Then, the effect of varied constituent properties, hybrid fibers and initial defects were investigated using the Monte Carlo (MC) method. Several interesting results were found and compared with the findings of earlier studies. For instance, it was found that a more stable IFB strength and higher matrix shear strength reduced variations in composite strength. A moderate hybrid ratio and careful packing of high- and low-elongation fibers helped to achieve optimum composite properties. In the thin-ply composite, transverse initial defects were more detrimental to composite strength than longitudinal defects. These findings prove the value of the bundle-based model, which can be used in future studies as an effective tool for evaluating the strength of various composites.