微尺度力学测量中的采样云纹方法

SAMPLING MOIRE METHOD IN MICRO-SCALE MECHANICAL MEASUREMENT

  • 摘要: 采样云纹方法作为一种新兴的光学测试技术,利用数字图像处理进行光栅相位分析,可实现低成本、高效率、高精度的物体表面变形计量。该方法能灵活调整采样参数以满足不同场景的测量需求,与扫描电子显微镜(scanning electron microscopy, SEM)结合,可以实现变倍视场下的变形分析。开展微尺度下高精度的采样云纹变形场测量,需要轮廓清晰、分布规则的光栅或点阵结构,对光栅制备工艺提出了较高的要求。为进一步拓展采样云纹在微尺度力学测量中的应用,本文介绍了采样云纹法变形测量的基本原理,并且发展了一种基于激光直写光刻的微尺度制栅方法。结合自行研制的高密度光栅,进行了镍基合金 GH4169 疲劳疲劳失效行为研究,表征了疲劳过程中损伤演化与裂纹闭合效应,研究结果表明采样云纹方法在微尺度变形场测量中具有很好的应用潜力。

     

    Abstract: 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.

     

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