Study of stable crack growth resistance based on local displacement at the crack tip: Study of evaluation of stable crack growth resistance of mismatched welded joints (3rd Report)

Summary The previously reported numerical results of stable crack growth simulations (three-dimensional FEM analysis) using equivalent plastic strain show good agreement with the experimental results despite heterogeneous specimens being tested. The results show that the equivalent plastic strain is a characteristic value not susceptible to the effect of strength mismatch in the ductile fracture process. To determine the equivalent plastic strain, however, it is necessary to perform three-dimensional FEM calculations, whereas the local displacement is satisfactorily obtainable by experimental measurements regardless of numerical simulations. The local displacement is affected by the measurement distance from the initial crack tip. The value of the local displacement at the shifted location of the crack tip does not change with an increase in stable crack growth. The authors also specify a similar relationship between the equivalent plastic strain and stable crack growth in a previous publication. The loca...