A combined temporal tracking and stereo-correlation technique for accurate measurement of 3D displacements: application to sheet metal forming

Abstract

To cite this version:D Garcia, Jean-José Orteu, Luc Penazzi. A combined temporal tracking and stereo-correlation technique for accurate measurement of 3D displacements: application to sheet metal forming. Journal of Materials Processing Technology, Elsevier, 2002Elsevier, , 125-126, pp.736-742. 10.1016 AbstractOptical methods that give displacement or strain fields are now emerging significantly in the mechanical sciences. Much work has been done on two dimensional (2D) displacement/strain measurement from a single camera but the proposed methods give only in plane strains. A binocular correlation based stereovision technique has been developed: (a) to measure the three dimensional (3D) shape of a static object or (b) to measure the strains of an object undergoing some 3D mechanical or thermal stress.In this paper, the application of the stereo correlation technique to measure accurately the 3D shape of a stamped sheet metal part or the surface strain field undergone by the part during the stamping process is presented.

A Space-Time PGD-DIC Algorithm:

“…These models depend on a set of intrinsic (focal length, distortions, etc.) and extrinsic (position/orientation of the camera with respect to the specimen) parameters that must be identified in a calibration phase (see [16][36] [29]). …”

Calibration of constitutive models of steel beams subject to local buckling by using digital image correlation

“…One alternative is then to only use measurements outside of this zone, as shown in Section 3.1, and extrapolate the results up to the junction. Another choice is to resort to more detailed analyses of the local field by using stereovision [21,22] since out of plane motions may cause in-plane distorsions. It was followed to analyze buckling in composite materials [23].…”

Single point incremental sheet forming investigated by in-process 3D digital image correlation

“…After determining the calibration parameters for each camera as well as the 3-D relative position/orientation of the two cameras (pinhole model and radial distortion of 1rd order), the 3-D shape of the object can be reconstructed by triangulation from the image-points correspondences founded by DIC. To determine the 3-D displacement field, DIC is also used to determine image-points correspondences between the stereo pairs acquired before and after deformation (temporal tracking) [7]. The Hencky logarithmic surface strain field tensor is obtained from the displacement field by numerical differentiation.…”