A Comparison of Fracture Toughness of Matrix Controlled Failure Modes:

Delamination and transverse cracking failure modes of composites have been char-acterized by using the width tapered double cantilever beam test and the double torsion test, respectively. The fracture toughness GIC values obtained from the two tests are found to be quite comparable. This indicates that the two failure modes have similar failure mechanisms. The phenomenon of fibers bridging between crack surfaces observed in the tests is also discussed for its relevance to the laminate fracture