Compact sensor combining DSPI and the hole-drilling technique to measure non-uniform residual stress fields

Abstract

This paper presents a portable device to essentially measure residual stress fields outside the optical bench. This system combines the hole drilling technique with Digital Speckle Pattern Interferometry (DSPI). The novel feature of this device is its high degree of compaction since only one base supports simultaneously the measurement module and the holedrilling device. A new version of the ASTM E837 standard for the measurement of residual stresses has been improved including the computation method for non-uniform residual stresses. According to this standard, a hole with depth of 1.0 mm should be introduced into the material to assess the stress distribution. The discretization of the stress distribution along the hole depth is performed in 20 equal steps of 0.05 mm, getting the deformations generated for stress relief in every drilling step. A description of the compact device showing the solution for a fast and easy interchanging process between modules is performed in this paper. The proposed system is used to evaluate the residual stress distribution into a sample with a rod welded by friction hydro pillar processing (FHPP)