SAMPLING MOIRE METHOD IN MICRO-SCALE MECHANICAL MEASUREMENT

Sampling moiré method, as a novel optical measurement technique, has achieved automatic phase analysis through digital image processing, which can realize surface deformation measurement of objects with low-cost, high-efficiency, and high-precision. The method allows flexible adjustment of sampling parameters to meet the requirements of different experimental scenarios, making it compatible with scanning electron microscopy (SEM) for microscopic mechanical analysis under variable magnification parameters. However, high-precision micro-scale deformation measurement using sampling moiré requires the gratings or dot-array structures with clear contours and regular distributions, imposing high demands on micro-scale grating fabrication techniques. In order to further promote the application of sampling moiré method in micro-scale mechanical measurement, this paper introduces the basic principles of orthogonal sampling moiré method, which can simultaneously perform dual-directional phase analysis and deformation reconstruction. Meanwhile, a micro-scale grating fabrication technique based on laser direct writing lithography is developed. By using the self-developed high density grating, fatigue failure behavior of nickel-based alloy GH4169 is studied, fatigue damage evolution and crack closure effects are characterized. The obtained results verify that the sample moiré method has a good potential for further application in micro-scale deformation measurement.