EVALUATION OF ENERGY RELEASE RATE FOR MODE 1 CRACK PROPRAGATION IN GLASS/EPOXY COMPOSITE

Abstract

Composite resources are replacing regular engineering metals along with alloys for several applications. Their superior specific strength and stiffness characteristics have made them very competitive in the aerospace industry. The primary limitation of fiber reinforced composites is fracture toughness, specifically delamination. Delamination failures are common due to the nature of composite construction. A variety of manufacturing techniques are available to make composites. Generally, all these methods employ a layered stacking of fibers in a primary plane. The interface between these layers is typically not reinforced with fibers and is the source of delamination or interlaminar fracture. Porosity and Other manufacturing related defects also introduce nucleation sites for delamination. Methods exist to evaluate and quantify inter-laminar fracture toughness, both experimentally and analytically. The material property that best represents resistance to delamination is the strain energy release rate (G C). This can be experimentally obtained and numerically predicted with some success. The primary focus of this study was to characterize and address interlaminar fracture in composites. An interlaminar fracture for mode I crack propagation was analysed for GFRP materials having 0 0 orientation of fibres. Experimental investigation of GC was done for 40%, 50% and 60% of fibre volume. Test was conducted using Double Cantilever Beam specimen. Results obtained were again correlated with Numerical analysis using VCCT method. Results of both experimental and numerical methods were in good agreement.