Experimental determination of crack growth resistance of ductile materials

A method of determining the fracture resistance of ductile materials is presented in this paper. The method employs a renforced DCB test specimen to characterize stable crack growth in a large structure. From the consideration of the quasi-static energy balance during slow stable crack growth, the fracture resistance was measured using the J approach. By repeated partial unloading during slow stable crack growth the need for multiple specimens with virgin crack length was eliminated. The fracture resistance of three different materials was measured for comparison. Results indicated that the fracture resistance increases significantly during the nitial stage of crack growth. When the crack propagation reaches an equilibrium state of stable crack growth the fracture resistance remains fairly constant over a large crack increment.