Strain in transition joints measured by high-resolution moiré photography

The strain distribution produced by heating in a plate cut from a welded austenitic-ferritic steel transition joint has been measured using high resolution moiré photography Two methods of doing this are discussed one using a random pattern on the specimen surface and the other using a regular, orthogonal grating stencilled on to the surface. The strains parallel and perpendicular to the interface are presented and show strain peaks near the interface. The effect on strain of introducing a simulated crack along the interface was also examinec. The measurements are compared with the strains computed from a finite-element analysis.