Cohesive cracking in negative geometries

An isolated cohesive crack loaded by a central concentrated load and a cohesive edge crack loaded by concentrated loading at the crack mouth are examined. In the cohesive zones of both cases, rectangular softening and linear softening are investigated. A distinct peak load does not occur for these negative geometries. The traction-free crack grows at the instant that the process zone is fully developed. In a negative geometry, in order to maintain traction-free crack propagation, the load ratio must always increase, ensuring that stable crack growth always occurs.