A TAPERED DOUBLE-CANTILEVER-BEAM SPECIMEN DESIGNED FOR CONSTANT-K TESTING AT ELEVATED-TEMPERATURES

A compact, constant stress intensity factor, side grooved, tapered dou ble-cantilever-beam (T-DCB) specimen has been designed for measuring e levated temperature creep and fatigue crack growth rates. This specime n is much smaller than the standard DCB specimen generally used for st udying corrosion fatigue in airframe materials and it can be easily ac commodated in standard furnaces generally used in elevated-temperature fracture mechanics testing. The specimen possesses a constant-K regio n of 30 mm. This constant-K crack length range was first established a nalytically through detailed two-and three-dimensional finite-element analyses and the finite-element calculations were further verified exp erimentally through quantitative fractographic analysis using the stri ation measurement technique.