Efficiently determining the R-curve and bridging traction-separation relation of mode I delamination in a simple way

Abstract

R-curve and bridging traction-separation relation play important roles for characterizing the large scale fibre bridging behavior during the delamination growth process whereas their accurate determinations are laborious. Existing methods depend on complex devices or visual measurements of the delamination length and the crack opening displacement (COD) during tests. To deal with this problem, a simple semi-analytical method is proposed in this study. Using this method, only experimentally recorded load and displacement are required. Difficult measurements of the delamination length and the COD are avoided. The relation between the strain energy release rate (SERR) and the delamination length, and the relation between the SERR and the COD can be easily and efficiently determined, from which the bridging traction-separation relation can be calculated. Validation on this method is performed by comparing the obtained R-curve and bridging traction-separation relation with the experimental results. Furthermore, the determined bridging traction-separation relation is integrated into a tri-linear cohesive zone model for delamination simulation. Experimental load–displacement responses can be accurately predicted, which again illustrates the applicability of the proposed method. The proposed method provides a simple and efficient way for determining the R-curve and the bridging traction-separation relation of mode I delamination.