Residual stresses in crack starter sections of double tension crack arrest specimens - preliminary results

TWI Industrial Member Report Summary 459/1992

By C S Wiesner, R H Leggatt and B Hayes

Background

The crack arrest concept for fracture prevention is generally a safer alternative to the fracture initiation avoidance approach. To assess the crack arrest capability of materials under structurally realistic
conditions, wide plate double tension crack arrest tests may be used. A fast running crack is initiated in an embrittled electron beam melt run which is introduced at the edge of the plate. The crack then propagates into the test material where it is arrested when the material exhibits sufficient crack arrest toughness. The remelting of the crack starter section produces residual stresses which can affect the result of the test. This report describes the results of surface and bulk residual stress measurement in the crack starter section and the adjacent region of test material.