Experimental and analytical study of three point bend specimen and throughwall circumferentially cracked straight pipe

Abstract

Transferability of the specimen J– R/ J– T curve to the component level is an important issue in the field of fracture mechanics. Towards this goal, fracture experiments have been carried out on three point bend (TPB) specimen and throughwall circumferentially cracked straight pipe of 219 and 406 mm outer diameter under four point bending load. The pipe material is SA333Gr6 and TPB specimens are machined from pipes. The image processing technique has been used to measure the crack growth and crack opening displacement in pipes. Component J– R curves have been generated from the load-deflection and load-crack growth data of pipe fracture experiments. These are compared with the TPB specimen J– R curves. Power law and second order polynomial fitting are done on the specimen and component J– R curves and J– T curves are generated. Specimen and component J– T curves are compared. Maximum moments in the pipe fracture experiments are also compared with the critical moments predicted by the ‘ G factor’, ‘ Z factor’ and limit approach.