Various experimental applications of digital image correlation method

Despite the powerful of current calculus codes by finite element or analytical, their reliability and validity must be justified by experimental tests. An original software for the displacement field measurement is presented in this paper. This software use the digital picture correlation principle. Due to this technique, the accuracy of the measure could reach 1/60 th of a pixel and, it is possible to measure strains between 5.10-5 to 0.8. Initially, this software was developed for measuring strains on a sheet testing in metal forming. But, it is revealed that this application field is more important : biomechanical field, geotechnical field, metal characterization, control tests,..... This software could be used, nowadays, for all application which need the knowledge of displacement and strain field for a plane surface. Of course, the experimental conditions must be made in such a way that any deterioration of the random aspect, deposed on the piece, will occur. Lost, alteration or little modification of the speckle aspect will not guarantee the success of the measure. Finally, the purpose of this paper will be, first, to give clearly the mathematical principle of the displacement field determination by a correlation method. Then, various experimental tests using the correlation method, are presented. The powerful of this technique is show by their variety. This method of measure without contact can be an another tool for validating, in a short time, a numerical or analytical result.