XIGA based Intralaminar and Translaminar Fracture Analysis of Unidirectional CFRP Laminate

Abstract

Intralaminar and translaminar fracture behaviour of unidirectional carbon fibre reinforced composite laminate is investigated numerically and experimentally in the present work. Experimental determination of fracture properties associated with failure mode along the fibre direction is very important for material characterization and numerical study. The experimental fracture toughness testing is performed on compact tension (CT) specimens of unidirectional CFRP laminate manufactured by laying up 26 layers of prepreg (Hexply 914/34%/UD 160/AS4-12K). The Mode I intralaminar and translaminar fracture tests have been performed using a universal testing machine (UTM) with a loading rate of 0.1 mm/min. Fractured surfaces have been examined using scanning electrode microscope (SEM). A NURBS-based Extended Isogeometric Analysis (XIGA) code has been developed for fracture analysis of orthotropic laminate. The XIGA code is capable of an efficient analysis of crack problems using non-uniform rational B-spline basis functions for both the solution field and geometric description of the model. The level set approach is used to track the crack geometry. Crack faces are enriched by Heaviside enrichment function and crack tip singularity is captured by asymptotic crack tip enrichment functions. The domain-based interaction integral method is used to extract the stress intensity factor values. The numerical results for compact tension (CT) specimen shows a good agreement with experimental results. In case of experiment as well as numerical modelling, the initiation of crack propagation is estimated with accuracy.