Accurate evaluation of strain-energy release rate in unidirectional FRP compact-tension specimen

Strain-energy release rate of a standard compact-tension unidirectional C(T) specimen of S-glass-epoxy Scotchply 1002 is evaluated using a finite element method (FEM). Initially failure mode (cracking direction) is theoretically predicted and the strain-energy release rate is estimated using a crack-closure integral approach where branch-crack is modelled along the cracking direction instead of fibre orientation. The strain-energy release rate is evaluated for fibre orientations of 0 degrees, 45 degrees, 60 degrees, 75 degrees and 85 degrees and compared with the fracture toughness (available in literature) and thus the fracture loads (crack initition loads) obtained. The results are found to be in very good agreement with the test data. This approach is simple and accurate for the evaluation of strain-energy release rate of the unidirectional fibre reinforced composite C(T)specimen. (C) 1997 Elsevier Science Ltd.