Two-dimensional Moire phase analysis for accurate strain distribution measurement and application in crack prediction

Aimed at the low accuracy problem of shear strain measurement in Moire methods. a two-dimensional (2D) Moire phase analysis method is proposed for full-field deformation measurement with high accuracy. A grid image is first processed by the spatial phase-shifting sampling Moire technique to get the Moire phases in two directions, which are then conjointly analyzed for measuring 2D displacement and strain distributions. The strain especially the shear strain measurement accuracy is remarkably improved, and dynamic deformation is measurable from automatic batch processing of single-shot grid images. As an application, the 2D microscale strain distributions of a titanium alloy were measured, and the crack occurrence location was successfully predicted from strain concentration. (C) 2017 Optical Society of America