DIC-hole drilling method for in-situ residual stress measurement

摘要

Residual stress measurement carries an important significance in ensuring safety and reliability of steel structures. In order to simplify the measurement procedure and enhance flexibility of the conventional hole drilling method to adopt in in-situ residual stress measurement, digital image correlation (DIC) is applied to measure the displacement field caused by the localized stress relief associated due to hole drilling. It is referred to as DIC-hole drilling method. The residual stress theoretical expressions of the DIC-hole drilling method are discussed. The requirements of drilling device, camera and lens are determined by accounting for the accuracy of the in-situ residual stress measurement. A benchmark experiment by using steel beam specimens is developed to verify the feasibility and reliability of DIC-hole drilling method. Test data are compared with theoretical calculations and FEM results. The comparison indicates the DIC-hole drilling method has enough accuracy for the in-situ residual stress measurement. The displacement field in the regions centred at 2 to 2.5 times drilling hole radius far from the hole is proposed for the accurate residual stress measurement.