| A two-parameter fracture criterion (TPFC), relates the linear-elastic stress intensity factor KIe and net-section stress Sn at failure with two-material parameters, KF and m. The objective of this work was to validate the TPFC. Two-dimensional elastic-plastic finite-element analyses (FEA) were used with the critical crack-tip-opening-angle fracture criterion and a plane-strain-core height to match failure loads on middle-crack-tension, M(T), specimens made of 2014-T6 (LT) aluminum alloy. The same analyses were used on single-edge-crack-tension, SE(T), and-single-edge-crack-bend, SE(B), specimens. A wide range in specimen widths (w = 0.75 to 24 in.) were considered. The finite-element code, ZIP2D, was used to calculate critical stress-intensity factors at failure corresponding to all crack configurations for crack-length-to-width ratios of 0.2 to 0.8. The results from FEA agreed very well with the TPFC predictions for net-section stresses less than the material proportional limit. Further study is needed for higher net-section stresses on SE(T) and SE(T) specimens. |
