Fatigue growth models for multiple long cracks in plates under cyclic tension based on △K_I, △J-integral and ACTOD parameter

摘要

This paper presents the implementation of fatigue crack growth power law equations based on △K, △J-integral and ACTOD fracture mechanics parameters determined in an FE analysis, to plates with multiple site damage (MSD). Results of fatigue tests with constant amplitude tensile loading carried out on mild steel plate specimens damaged with a single central crack and with three collinear cracks are presented. A relatively larger plastic zone occurred in the crack tip region at higher fatigue crack growth rate (FCGR), from 10~(-7) to 10~(-6) m/cycle. The crack growth models based on the elastic-plastic fracture mechanics (EPFM) parameters describe better fatigue crack growth in this range as compared to the liner elastic models.