DETERMINATION OF FRACTURE TOUGHNESS BY UNIAXIAL TENSILE TEST

The dynamic fatigue life equation is applied to uniaxial tensile test. The resultant equations far the surface energy and fracture toughness are calculated with the data from the tensile test and compared with the ones from ASTM E399 test. During the crack propagation under model loading, the material of the crack tip undergoes the process of the elastic-plastic deformation in the uniaxial tensile test. The surface energy per unit area is proportional to the ratio of plastic and elastic elongations. The calculated fracture toughness of the metals are very well coincident to the ASTM E399's test results.