基于数字图像相关的自适应应变场计算

Self-Adaptive Strain Field Calculation Based on Digital Image Correlation

针对基于数字图像相关(DIC)技术测量非均匀变形的应变方法需人为选择参数且精度受参数选择影响较大的问题,基于对偏最小二乘(PLS)方法和正则多项式平滑(RPS)方法的误差分析,提出了一种基于DIC的自适应应变场计算方法。该方法通过搜索给定参数范围内的最小总误差参数组合,用最佳参数得到精度较高的应变场,且测量结果受变形场类型的影响较小。模拟实验结果表明,本方法的计算精度接近最佳参数下的PLS方法,有效解决了PLS和RPS方法的最优参数选择问题。

For measurement methods of heterogeneous deformation strain with digital image correlation(DIC)technology,the accuracy of the reconstructed strain is greatly affected by the manually selected parameters.Through error analysis of the partial least squares(PLS)method and the regularized polynomial smoothing(RPS)method,a DIC-based self-adaptive strain field calculation method is proposed in this paper to solve this problem.The method searches for the parameter combination with the minimum total error within the given parameter range and uses the optimal parameters to obtain a strain field with higher accuracy.The measurement result is slightly affected by the type of the deformation field.The simulation experiment results show that the calculation accuracy of the method is close to that of the PLS method at the optimal parameters.This research effectively solves the problem of selecting the optimal parameters of PLS and RPS methods.