基于快速DIC与正则化平滑技术的结构形变测试

传统的有接触结构形变测试存在现场操作困难、多点测试不便、测试成本高等问题，难以应对工程结构形变测试中较为复杂的应用场景。为实现无需人造靶标、可远距离测试且具有较高测试精度的非接触无靶标形变测试，针对采集的结构形变视频图像，引入数字图像相关（Digital Image Correlation，DIC）技术，采用基于Fourier变换的互相关整像素匹配算法与反向组合高斯-牛顿迭代亚像素匹配算法，利用英伟达公司的CUDA并行计算平台，实现结构多点动位移时程的快速测试；基于有限元应变计算与正则化平滑理论，采用位移场后处理方式实现结构连续与非连续应变场的计算。对DIC匹配算法的精度及运算速度、应变算法处理连续与非连续位移场的性能进行对比分析；对超高性能混凝土墩柱抗冲击试验及拱桥吊杆振动试验视频数据进行处理，得到多点位移（频率）测试结果，并与传统测试方法进行对比分析；对砂体抗拔试验及混凝土梁抗弯试验视频进行处理，以云图方式展现位移场与应变场的分布，并与基于逐点最小二乘法的应变测试结果进行对比。研究结果表明：基于快速DIC与正则化平滑技术的非接触结构形变测试方法在结构多点变形、位移频谱及应变场，特别是非连续应变场的测试中得到了较理想结果，具有一定的工程应用价值。

Structural Deformation Test Based on Fast Digital Image Correlation and Regularization Smoothing Techniques

The conventional contact-based structural deformation test involves problems such as difficulty in field operations, inconveniences in multi-objective testing, and high measurement costs, all of which make it difficult to handle complex application scenarios. This study aimed to design a non-contact and target-free deformation test capable of high-accuracy remote testing without requiring an artificial target. For the captured video image sequences of the structural deformation, the fast digital image correlation (DIC) technique was introduced to construct a rapid measurement system for multi-point structural dynamic displacements. The Fourier transform-based cross-correlation (FTCC) whole-pixel registration algorithm, inverse compositional Gauss-Newton (IC-GN) iterative sub-pixel registration algorithm, and NVIDIA's CUDA parallel computing platform were used. Based on the finite-element strain calculation theory and regularized smoothing, the post-processing method for the displacement field was used to extract the continuous and discontinuous strain fields of the structure. Furthermore, the accuracy and operation speed of the DIC registration algorithm and the performance of the strain calculation algorithm in handling continuous and discontinuous displacement fields were compared and analyzed. Additionally, the video image sequences of the impact test on the ultrahigh-performance concrete pier and the vibration test on the hanger cable of an arch bridge were processed to obtain the multi-point displacement (frequency), subsequently, the impact and vibration tests were compared with the conventional test method. Finally, the video image sequences of the soil pull-out test and the concrete beam bending test were processed to obtain the displacement and strain fields in the form of a cloud diagram. They were then compared with those using the pointwise least squares (PLS) method. The results show that the structural deformation test integrating fast DIC and regularized smoothing achieved ideal results in multi-point deformation, displacement spectrum, and strain field, specifically for the discontinuous displacement field, and the proposed test can be valuable for certain engineering applications.