The Cluster Approach Applied to Multi-Camera 3D DIC System

Abstract

In material testing optical techniques take more and more over the role of classical mechanical length changing tools. Beside simple 1-dimensional measurement methods, full field techniques like digital image correlation (DIC), allow 2- or 3-dimensional characterisation of the materials and components. Especially for anisotropic materials the multidimensional information is important. E.g. up to now this is limited to 2D strain information on plane surfaces.

Nowadays, the application of the DIC technique moves from academic to industrial fields. In this interest, one needs to prove the DIC technique on real components. The conventional 2-cameras 3D DIC inspection becomes then non-optimal since complex geometries imply hidden areas. The approach of using more than minimum required number of camera views overcome these limitations. An efficient way to overcome these limitations is to take advantage of the use of multi-cameras DIC system. This idea is already commonly used in other fields like photogrammetry.

This publication describes the idea and principle of using the Cluster Approach for multi-cameras DIC systems. In order to illustrate the implications of this new technique, we present strain measurements in tensile testing and deformation measurements on complex geometrical structures.