Abstract In composite plates, there are generally amounts of residual stresses that can have adverse effects in final parts. So, it is very important to know about the residual stress's type, location and amounts in composite plates. The measurement methods of the residual stress are commonly indirect and the displacement and strain is calculated at first. Two-dimensional digital image correlation (2D DIC) is a practical and effective tool for quantitative in-plane deformation measurement of a planar object surface and now widely accepted and commonly used in the field of experimental mechanics. In the hole drilling method, the residual stress is measured immediately just after drilling and the other researchers have paid less attention to the amount and pattern of changes in released stress around the hole after drilling at different times. It can be stated that the novelty of this research may identify the optimal measurement time after the drilling and the holes with different diameters is considered and the displacement and strain fields are measured at different times. So in this research, the residual stress measurement of a composite plate in the time elapsed is discussed. Also, the effects of hole's diameter and elapsed time after drilling in amount of released residual stresses are investigated by 2D DIC method. The point-wise local least-squares fitting technique (PLS) is used for strain estimation from displacement fields. The residual stress is calculated by the estimated strain, determination of calibration constants in orthotropic materials and considering the properties of composite plate that has already been calculated. The finite element method (FEM) is used for determination of calibration constants and the correction factor in FEM is obtained by comparing of the FEM and experimental tensile test results.

中文翻译：

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用 DIC 方法研究复合板残余应力测量的时间流逝影响

摘要 在复合板中，通常存在大量残余应力，会对最终零件产生不利影响。因此，了解复合板中残余应力的类型、位置和数量是非常重要的。残余应力的测量方法通常是间接的，首先计算位移和应变。二维数字图像相关（2D DIC）是一种实用且有效的平面物体表面面内变形测量工具，现已被广泛接受并普遍用于实验力学领域。在钻孔方法中，残余应力是在钻孔后立即测量的，其他研究人员很少关注钻孔后不同时间孔周围释放应力的变化量和模式。可以说，本研究的新颖之处在于可以确定钻孔后的最佳测量时间，并考虑不同直径的孔，并在不同时间测量位移和应变场。因此，在本研究中，讨论了复合板随时间推移的残余应力测量。此外，通过二维 DIC 方法研究了孔的直径和钻孔后经过的时间对释放的残余应力量的影响。逐点局部最小二乘拟合技术 (PLS) 用于从位移场估计应变。残余应力是通过估计应变、确定正交各向异性材料的校准常数并考虑已计算的复合板的特性来计算的。