Residual
Stress
Measurement -The following techniques may be used for measuring stresses in welded objects:
(a) Brittle coat method,
(b) Photostress techniques, and
(c) Strain gage method.
Stresses in welded joints are measured by strain relaxation techniques in which the job is either machined, sectioned or a hole is drilled (at a place where stress magnitude is required to be determined); the locked in residual stresses get thereby released and affect the brittle coat, photostress coat or strain gage which in turn measures this effect and the relaxed residual stresses are calculated.
