A Review of Generalized Failure Criteria Based on the Plastic Yield Strip Model

A review is given of the failure criteria developed by Hahn and Sarrate for through-cracked pressure vessels, whereby they established three failure categories. This work was based on the Dugdale and Bilby-Cottrell-Swinden (D-BCS) model for the crack-tip opening displacement (CTOD) in an infinite plate. The model was extended in an approximate way by Heald-Spink-Worthington (D-BCS-HSW) to finite geometries and structures by combining the effects of plasticity and geometry as multiplicative factors. In this paper the criteria of Hahn and Sarrate are extended to the D-BCS-HSW model. The three failure categories are relabelled: (1) linear-elastic fracture mechanics (LEFM), (2) elastic-plastic fracture mechanics (EPFM), and (3) plastic collapse (PC). The model is plotted in a variety of dimensionless forms and several related developments also are reviewed: (1) the two-criteria approach and universal failure curve, (2) the CTOD design curve, and (3) the Failure Assessment Diagram. Finally, the residual strength diagram for the D-BCS-HSW model is presented. In all these presentations the three failure categories based on Hahn and Sarrate's criteria are included. Thus, it is shown that the D-BCS-HSW model, though approximate, presents a unified picture that embodies many features of fracture mechanics from LEFM through EPFM to PC.