A TEST SPECIMEN WITH CONSTANT STRESS INTENSITY FACTOR FOR PRESCRIBED DISPLACEMENT

A test specimen has been developed that gives a constant value of the stress intensity factor in mode I under fixed displacement loading con ditions. The test specimen is a double contoured cantilever beam speci men whose shape is derived from engineering beam theory. A final shape for a range of crack extensions where stress intensity is constant wa s established using a finite element analysis. It is believed that thi s specimen could be useful for many applications where a constant stre ss intensity factor is needed over a range of crack extension for cons tant displacement loading e.g. viscoelastic crack growth in an adhesiv e layer or stress corrosion cracking.