The effect of the notch root radius on the fracture toughness was investigated with HMS(high modulus carbon fiber) and HTS (high strength carbon fiber) [0˚] CFRP laminates. HTS [0˚] CFRP laminate showed notch insensitive while HMS [0˚] CFRP laminate showed notch sensitive. This observation was in agreement with Tirosh where he predicted that the failure mode varied with types of fibers.
The influence of stacking sequence on the crack growth resistance curve was investigated with [0˚/±45˚/90˚$]_{3s}$ and [0˚_2/±$45]_{3s}$ CFRP laminates by the compliance matching from the load-displacement obtained during three point bending test. The values of effective crack length and corresponding crack resistance at the oneset of instability was independent of initial crack length.
The contour of isostatic strain field varied with laminate geometry and contour radius in each laminate was found to be propotional to applied load and inply-damage zone.
