SAMPLING MOIRÉ METHOD IN MICRO-SCALE MECHANICAL MEASUREMENT: FUNDAMENTALS, METHODS, AND APPLICATIONS

Sampling moiré method, as a novel optical measurement technique, has achieved digitalization and automation of phase analysis through digital image processing. This enables low-cost, high-efficiency, and high-precision surface deformation measurement of objects. The method allows flexible adjustment of sampling parameters to meet the scale requirements of different experimental scenarios, making it compatible with scanning electron microscopy (SEM) for microscopic mechanical analysis under variable magnification conditions. However, conducting high-precision sampling moiré measurements in micro-scale environments requires gratings or dot-array structures with clear contours and regular distributions, imposing high demands on micro-scale grating fabrication techniques. To further expand the application potential of sampling moiré 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. A micro-scale grating fabrication method based on laser direct writing lithography is developed, and the quality of the fabricated gratings is evaluated using two indicators: grating structure similarity and phase average relative error. Taking the fatigue fracture of nickel-based alloy GH4169 as an example, this study characterizes material damage accumulation and crack closure effects, exploring the application of sampling moiré method in micro-scale mechanical measurement.