Background

Optical measurement techniques such as digital image correlation and speckle interferometry have been applied to hole-drilling evaluations of residual stress for some decades. These full-field non-contact measurements can have significant advantages over the traditional strain gauge method. However, optical measurements are still only rarely used for practical measurements outside the research environment. A significant barrier to such use is the mathematical challenge of analyzing the large quantity of optical data to evaluate the residual stresses.

Objective

The objective here is to provide a residual stress computation scheme that can be implemented straightforwardly and efficiently, also to provide the needed calibration data.

Method

The approach taken is to recast the optical data into a compact arrangement that parallels the established format used for strain gauge style calculations.

Results

Several computation variants are explored, some show high stress sensitivity, while others give resistance to common measurement artifacts. Surface displacement data taken from near the hole edge give the highest stress sensitivity, while more distant data give greater ability to identify interior stresses.

Conclusions

The proposed residual stress computation method is shown to be an effective and practical way to compute residual stresses from optical hole-drilling measurements.

中文翻译：

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使用应变计形式的光学钻孔残余应力计算

背景

数十年来，数字图像相关和散斑干涉等光学测量技术已应用于残余应力的钻孔评估。这些全场非接触式测量与传统的应变计方法相比具有显着的优势。然而，光学测量仍然很少用于研究环境之外的实际测量。这种使用的一个重大障碍是分析大量光学数据以评估残余应力的数学挑战。

客观的

这里的目标是提供一种可以直接有效地实现的残余应力计算方案，同时提供所需的校准数据。

方法

所采取的方法是将光学数据重新转换为紧凑的排列，与用于应变计式计算的既定格式平行。

结果

探索了几种计算变体，一些表现出高应力敏感性，而另一些则对常见的测量伪影具有抵抗力。从孔边缘附近获取的表面位移数据给出了最高的应力敏感性，而更远的数据给出了识别内部应力的更大能力。

结论

所提出的残余应力计算方法被证明是一种从光学钻孔测量中计算残余应力的有效且实用的方法。