An improved collapse axis on the R6 FAD for combined tension and bending loading

Abstract

Abstract

Experimental and computational studies were made of a number of single edge notch (SEN) specimens loaded through eccentric pins with notch depth ratios 0.21 and 0.52. It was found that as the applied load was increased the formation of a plastic hinge mechanism caused the ligament to shift sideways and in turn alter the ratio of bending to tension loading. The two different assumptions, constant and variable bending to tension ratio, gave very different paths in the moment-load (M-Q) space, and failure lines when plotted on the R6 Fracture Analysis Diagram (FAD). An improved expression for normalized load, S_r, for SEN geometries under a linear loading system was obtained by including a plastic constraint factor in the uncreacked lower bound solution. For the pin-loaded SEN specimens under a non-linear loading system, it was shown that S_r based on ‘true path lengths’ in the yield diagram gave a failure curve which was in good agreement with the R6 Rev3 solution.