Identification of defect(s) where crack initiation is possible and prediction of crack propagation are of great importance in materials engineering. The current chapter analyzes the application of the acoustic emission (AE) technique for fracture monitoring in the line pipe steel during single-edge-notched tension (SENT) test and Charpy V-notch (CVN) impact test. It was found that the AE activity starts before the yield point, due to the stress concentration at the crack tip, and increases suddenly before the peak load is reached, due to the fracture initiation. Toward the end of the test, the AE hit density increases again, following intensive crack propagation. The AE analysis conducted in the present chapter showed a strong evidence of AE hit density increasing before the peak load is reached, the moment corresponding to fracture initiation.
Part of the book: Advanced Engineering Testing