Measurement of non uniform residual-stresses by full-depth hole-drilling technique

The paper investigates the feasibility of employing an interferometric technique as an alternative to the strain gage rosette in the classical blind hole drilling method to measure uniform and non-uniform residual stress states. A procedure is proposed whereby the variation of residual stress with depth is determined by analyzing the displacement field on the surface area around a hole drilled in a single step. To verify its effectiveness, the procedure has been applied to a specimen subjected to known stress states (constant and linear) using reflection holography and speckle interferometry, respectively, to detect the displacement field.