Characterization of non‐planar crack tip displacement fields using a differential geometry approach in combination with 3D digital image correlation

This paper describes a novel differential geometry method that is used in combination with 3D digital image correlation (3D-DIC) for crack tip field characterization on non-planar (curved) surfaces. The proposed approach allows any of the two-dimensional models currently available literature to be extended analysis developable surface zero Gaussian curvature. was validated by analyzing displacement fields hollow thin-walled cylindrical specimens, manufactured from either 304L or 2024-T3 alloy contained central circumferential crack. checked via comparison between experimentally measured and those reconstructed modified 2D model (utilizing 2, 3, 4 terms William's expansion series) implementing geometrical correction. Further validation provided comparing model-derived stress intensity factors values empirical correlations.