Study on Improvement of Accuracies of Hole Drilling Method for Measurement of Residual Stresses.

Abstract

The hole drilling method is a well-established technique for measuring residual stresses in a wide range of materials. In this paper, in order to improve the measurement accuracies of hole drilling method, several numerical results are shown in two cases such that radial strains and tangential strains around the circular hole are detected, by consideration of strain variation in the finite region of each gage area. The results obtained are summarized as follows. (1) The measurement accuracies become higher by detection of tangential strains than radial one. (2) It is necessary to calculate the strain average in each gage area for residual stress measurement. (3) The analytical theory which considers the strain variation are proved to be valid by the experiment using steel specimens.

Evaluation of residual stress in pre-stressed concrete material by digital image processing photoelastic coating and hole drilling method

“…This practical hybrid technique for measuring residual stress is the hole drilling strain gage method [4], and it involves measurement of the change in strain produced when a small hole is drilled into a component containing residual stresses. However, the principal limitation of the strain gage method is that it is a point measurement only, and it is usually required to have the hole drilled exactly in the center of the strain gage rosette in order to avoid sizable errors [5,6]. To overcome these disadvantages, the stress field around the hole was measured using photoelastic techniques [7][8][9], which are capable of generating an isochromatic stress fringe field around the drilling hole.…”