Determination of J_R Resistance Curve of Metallic Materials by Single-Sample Three-Point Unload Compliance Method

Based on the threecurve method and unload compliance method,the singlesample threepoint unload compliance method was put forward for testing the ductile fracture toughness of metallic materials.In addition to possessing merits of the threecurve method and unload compliance method,it possesses merits for delaying the elasticity lag and reducing unload times.The resistance curves were tested using this method and J integral testing software developed by the authors.The results tally with those of the multi-sample method.