Effect of Crack Extension in a Compact Tension C(T) Specimen Containing a Residual Stress on the Stress Intensity Factors

Compact tension C(T) specimens with a blunt notch are mechanically pre-compressed to introduce a tensile residual stress ahead of the notch. The specimens are then thermally soaked which results in crack extension due to the presence of the tensile residual stress. Neutron diffraction measurements are performed on the pre-compressed specimens and after thermal soaking, to determine the redistribution of the residual stress as the crack extends. Stress intensity factors (SIF’s) are estimated using an upper-bound linear distribution to model the redistribution of residual stress as the crack extends. These are compared with the SIF’s using a membrane stress of yield magnitude which ignores redistribution of residual stress with crack extension.