RESIDUAL-STRESS MEASUREMENTS WITH LASER SPECKLE CORRELATION INTERFEROMETRY AND LOCAL HEAT-TREATING

A new experimental technique has been devised to measure residual stre sses in ductile materials with a combination of laser speckle pattern interferometry and spot heating. The speckle pattern interferometer me asures in-plane deformations while the heating provides for very local ized stress relief. The residual stresses are determined by the amount of strain that is measured subsequent to the heating and cool-down of the region being interrogated. A simple lumped-parameter model is pre sented to provide a description of the method. This description is fol lowed by presentation of the results of finite-element analyses and ex perimental results with uniaxial test specimens. Excellent agreement b etween the experiments and the computer analyses was obtained,