Experimental and numerical characterization of Mode I fracture in unidirectional CFRP laminated composite using XIGA-CZM approach

This article presents an effective study for characterization of interlaminar Mode I fracture process zone (FPZ) in unidirectional CFRP laminated composite structure. Mode I fracture toughness testing has been carried out on double cantilever beam (DCB) specimens. Experimental studies have been carried out on non-precraked DCB specimens in order to obtain the amount of energy released during crack initiation from the natural crack front. The energy release rate (ERR) is obtained from experimental data as a function of crack growth (Delta a) and pre-crack tip opening displacement (delta*) by utilizing five data reduction schemes. The analytical function between ERR and delta* is used to construct fibre bridging law using J-integral approach. The obtained traction separation laws from each data reduction scheme is implemented into cohesive zone modelling (CZM) for numerical simulation. Fractured surfaces have been examined by means of Scanning electron microscope (SEM). Numerical studies have been carried out for both non-precracked and precracked specimens using combined framework of fracture mechanics using extended isogeometric analysis (XIGA) and damage mechanics using CZM approach. It has been observed that crack travels catastrophically in non-precracked (NPC) specimens due to fast dissipation of excess energy. Introduction of fibre bridging law, obtained from experimental investigation, into CZM in combined framework of XIGA methodology shows a good agreement with experimental results.