摘要
为从数字图像相关方法得到的含噪位移场中提取到光滑、准确的应变场,引入移动最小二乘(MLS)拟合方法进行计算.针对MLS拟合方法对大量数据求解困难且求解不稳定的问题,提出逐点移动最小二乘(PMLS)拟合方法进行改进,以提高计算效率和稳定性.采用PMLS拟合方法对模拟实验在连续位移场和不连续位移场两种情况下拟合的应变场精度和可行性进行分析和验证,进而获取连续位移场实验和带裂缝实验两组实测数据图像的应变场.将PMLS拟合方法与经典的逐点最小二乘(PLS)法和MLS拟合方法进行对比.结果表明:所提方法的精度较PLS法得到有效提高,且在窗口较大时可提高16%以上;计算效率较MLS法提高27倍以上,并显著提高MLS法的稳定性;对于不连续位移场,能够有效解决不连续区域出现应变值失真的问题,证明了对不连续位移场的适用性.
To extract a smooth and accurate strain field from a noisy displacement field obtained by digital image correlation method,the moving leastsquare(MLS)fitting method is often adopted.However,as the MLS fitting method is computationally expensive and unstable when applied to large datasets,the pointwise moving leastsquare(PMLS)fitting method is proposed herein to improve the computational efficiency and stability.The feasibility and accuracy of the strain field fitted by the PMLS fitting method were explored on simulation experiment under two conditions of continuous displacement field and discontinuous displacement field,and then the strain field of the two groups of measured data images of the continuous displacement field experiment and the crack experiment were obtained.The PMLS fitting method was compared with the classical pointbypoint leastsquare(PLS)method and the MLS fitting method.The results show that the accuracy of the proposed method is effectively improved compared to the PLS method by more than 16%when a large window is used,the computational efficiency increases by more than 27 times compared to the MLS method,and the stability of the MLS method is significantly enhanced.For the discontinuous displacement field,the problem of strain distortion in the discontinuity regions can effectively be addressed,which confirms the applicability of the proposed method to discontinuous displacement fields.
作者
樊爽
郭玉荣
Fan Shuang;Guo Yurong(College of Civil Engineering,Hunan University,Changsha 410082,Hunan,China;Key Laboratory of Building Safety and Energy Efficiency,Ministry of Education,Changsha 410082,Hunan,China)
出处
《激光与光电子学进展》
CSCD
北大核心
2023年第6期230-240,共11页
Laser & Optoelectronics Progress
基金
国家自然科学基金(51878259)。
关键词
测量
数字图像相关
应变场
逐点移动最小二乘拟合
measurement
digital image correlation
strain field
pointwise moving least square fitting
