Simulation on Propagation and Coalescence of Fatigue Crack by Automatic Three-Dimensional Finite Element Crack Propagation System

Verification analyses of the CRACK-FEM developed to predict the propagation of age-related cracks detected in complicated-shaped components of nuclear power plants are presented. Four fatigue crack propagation tests for plate specimens with one and two initial surface cracks subjected to cyclic tensile and bending load respectively are simulated using the CRACK-FEM, and the analysis results are compared with the experimental data of the tests in literature. For the specimens with one crack, the relation between the number of load cycles and the crack size obtained by the analyses agrees with the experimental data. For the specimens with two cracks, the analysis results until the crack coalescence and the timing of the crack coalescence obtained by the analyses agree with the experimental data. In tensile fatigue test for specimen with two cracks, the relation between the number of load cycles and the crack size after the crack coalescence obtained by the analysis almost agrees with the experimental data, although a little difference of analysis from the experimental data is seen. However, in bending fatigue test for specimen with two cracks, the analysis results for all the number of load cycles show good agreement with the experimental data.