Measuring fracture energy of interfaces under mode I loading with the wedge driven test

Abstract

The wedge driven test is a valuable tool to determine the mode I fracture energy (GIc) of adhesives or interfaces in composites. At first glance, the test is simple enough (introduction of a wedge into the specimen midplane to progagate a crack) to be a good alternative to the standard method, the DCB test. However, friction between the wedge and the specimen’s arms is not properly dealt in existing studies and, consequently, there is still a need for a reliable test procedure. In this work, we present a test methodology and its associated data reduction procedure to obtain GIc. The test does not need to measure the crack length and the friction coefficient is determined as the wedge is introduced in between the specimen’s arms. The new testing methodology is validated experimentally comparing the GIc obtained from the wedge driven and the DCB tests. A very close agreement is obtained between them.