Initial displacement estimation based on ESA in improved digital volume correlation and its application

In order to improve the algorithm efficiency in point matching and reduce the error of displacement field in deformation calculation, an Improved Digital Volume Correlation (IDVC) method is proposed. Aimed at the problem that the accuracy of initial displacement estimation of DVC has a great influence on the convergence calculation accuracy by the sub-voxel measurement algorithm, the coordinates of the estimated points in deformation are quickly matched by the Explosion Search Algorithm (ESA), with the displacement vectors obtained. Then, the non-physical fluctuation of displacement field and the wrong strain concentration are suppressed in regularization. Finally, the deformation information obtained by correlation search is substituted into the iterative least squares algorithm to attain the sub-voxel precision displacement. The results of the simulation experiment and concrete uni-axial compression experiment show that the computational efficiency by the proposed method is 20.44% higher than that by the traditional DVC method, and that the accuracy level of displacement field measurement reaches 0.001 voxels.