A novel testing facility for fracture mechanics analysis of plates

This paper deals with a novel test facility, developed to study surface crack propagation in a non-standard plate specimen. This specimen effectively simulates various aspects of the large diameter pipes and main vessel of a liquid metal fast breeder reactor (LMFBR). Experiments are carried out on SS 316L(N) plates, containing a semi-elliptical surface crack, subjected to pre-dominantly bending loads. This is a critical mode of loading for the associated full-scale components. The machine is ideal and cost-effective for pre-cracking the specimen, which has an initial notch. The experiments carried out on this machine have yielded interesting results, like evolution of the crack front across the thickness as a function of applied cycles and the difference in the crack propagation behaviour in the surface and depth directions. This system in conjunction with crack depth measurement techniques has got high potential for further applications in the domain of leak before break (LBB) investigations.