Residual Stress Measurement Using Hole Drilling and Integrated Digital Image Correlation Techniques

Abstract

The effectiveness of optical (mostly interferometric) methods for the measurement of residual stresses is largely demonstrated in literature. Nevertheless, these techniques are still confined to optical laboratories due to their high sensitivity to vibrations which makes it very difficult to perform the measurement in an industrial environment.\ud Digital Image Correlation (DIC) has recently been proposed as a possible solution to this problem: this\ud non-interferometric technique is much less affected by vibrations, but its sensitivity is relatively low, thus negatively affecting the accuracy of results. \ud \ud This work proposes to use a variant of Digital Image Correlation, known as Integrated DIC (iDIC), in combination with the hole drilling technique. Since iDIC directly incorporates in its formulation the displacement field related to hole drilling, it overcomes most of the problems of standard DIC; in this way it is possible to obtain accurate results without using interferometric techniques

Novel implementations of relaxation methods for measuring residual stresses at the micron scale

“…49 Some conventional methods have been adapted to estimate RSs in anisotropic materials, for example, slotting for laminated composites 84 and hole drilling for orthotropic materials. 85,86 Micro-hole drilling and micro-ring coring provide all three in-plane RS tensor components (e.g. s x , s y and s xy ), while mSC and micro-cantilevers provide the RS in a single direction only.…”

An Experimental Investigation into Additive Manufacturing-Induced Residual Stresses in 316L Stainless Steel

“…Aside from traditional strain gages, newer, whole-surface measurement methods have been used in this endeavor, including digital image correlation (in conjunction with hole drilling, [31][32][33][34] before and after thermal coating application [35] and even focused ion milling [36][37][38] ) and electronic speckle pattern interferometry (ESPI) (in conjunction with hole drilling. [39][40][41][42] Indentation [43] has been used to measure surface-level residual stresses as well.…”

Time‐resolved integrated digital image correlation

“…The derivative of the displacement field, with respect to a degree of freedom, represents the sensitivity field to that degree of freedom. For some particular cases, it is possible to formulate closed‐form relationships between the unknown material parameters and the displacement field . For cases where this is not feasible, it is possible to approximate these sensitivity maps by numerical differentiation of the simulated displacement fields .…”

“…Several successful applications of the method have been published. The first series of publications applies I‐DIC by using closed‐form solutions to describe the kinematics of the experiments . The second series applies I‐DIC by using an approximated method (e.g.…”