Abstract:

A new technique of specimen grating copy is introduced in this paper. In combination with the techniques of space filtering, fringe multiplication and optical pattern handling, it can measure the elastic-plastic strain field at the crack tip in a curved surface, such as the surface of an axle, a pivoting wing, a pillar shell or a cone shell. This new technique even can be employed to measure the surface strain field in a rotary wing, a rotary axle or a flywheel.