Akademik Veri Yönetim Sistemi
Jordan Journal of Mechanical and Industrial Engineering, cilt.15, sa.5, ss.461-474, 2021 (ESCI, Scopus)
The two-dimensional digital image correlation (2D-DIC) technique is used for making full-field in-plane deformation/strain measurements on planar surfaces. One of the basic requirements for making measurements using 2D-DIC is to observe the target surface perpendicularly by the camera. Ensuring camera perpendicularity before starting to make measurements using 2D-DIC is important because errors will be induced in the measured displacements/strains if the camera is not oriented properly. During the initial setting of an experimental setup, small camera misalignment angles of one or two degrees can easily go undetected. This paper reports a simple and reliable approach for verifying the camera perpendicularity in 2D-DIC experiments, and for measuring the tilt angle(s) if the camera is not perpendicular to the surface. The approach uses in-plane rigid-body-translation where the strain error(s) obtained from DIC measurements are used to calculate the tilt angle(s). The translation can be either parallel to the target plane (done by moving the target) or parallel to the camera plane (done by moving the camera) where a different set of equations is used for calculating the tilt angles in each scenario. A translation of a known magnitude in any in-plane direction (parallel to the x or y axes of the image, or at any angle in between) is all what is required to calculate the tilt angle(s). The approach is also capable to determine the tilt angles if the target is tilted about any of the two in-plane axes (x or y) or about the two axes simultaneously. Several rigid-body-translation experiments are performed under different conditions to evaluate the validity and accuracy of this approach at tilt angles between 1° and 4°. The results show that tilt angles as small as 1° can be calculated accurately, and that rigid-body-translation as small as 2% of the field-of-view width can be used for making measurements with good accuracy.