Mechanical examination of crack length dependency and material dependency on threshold stress intensity factor range with Dugdale model

The threshold stress intensity factor range ΔKth was analytically calculated under stress control conditions using the plasticity-induced crack closure analysis with the Dugdale model. Before obtaining ΔKth, the accuracy of the method was verified. The characteristics of the crack closure behavior were discussed by specifying the small-scale yielding (SSY) and large-scale yielding (LSY). The analysis results of ΔKth were discussed systematically by non-dimensionalizing them with the Dugdale model. Under the SSY condition, ΔKth was dependent on Young’s modulus and Poisson’s ratio. Under the LSY condition, ΔKth increased when the initial crack length or yield strain increased.