Indentation-Based Residual Stress Measurement Using Digital Image Correlation

Conventional indentation techniques for assessing residual stresses typically rely on detecting changes in indentation force at a fixed depth. While effective for gauging overall stress levels, these methods lack directional sensitivity due to the force being applied perpendicular to the surface. They also require extensive material-specific calibration and a stress-free reference specimen. This study introduces a novel approach that overcomes these limitations by using Digital Image Correlation (DIC) to measure in-plane surface displacements around the indentation, enabling directional stress analysis. Finite element-based calibration data are employed to eliminate the need for experimental calibration and reference specimens. This initial investigation focuses on equi-biaxial stress conditions as a precursor to broader applications. In example tests, axisymmetric residual stresses were quantified to within 8% of the material yield stress.