Papers by Author: Stephane Avril

Abstract: The virtual fields method is a tool dedicated to the identification of the mechanical properties of materials from full-field deformation measurements. It is now validated in elasticity and plasticity but one of the remaining problems is the fact that researchers wanting to use the method must invest significant time in order to programme the routines. To help them, a software called CamFit has been developed. The purpose of this paper is to present this software. It is based on MATLAB® and uses a graphical pre-processing interface to produce the geometry, the conditions on the virtual fields, to choose the type of behaviour etc... Then, series of displacement maps are uploaded and the identification is launched. Since no iterative solution of the direct problem is required, computation times are very small compared to updating techniques. An important step in the procedure is the smoothing of the displacement measurements to produce strains. FE based approximations are presently available in the software. The final purpose is to introduce the software onto the market. This will be done in the very near future.

Abstract: This paper deals with the simultaneous identification of the four through-thickness orthotropic rigidities of a thick composite tube. A diametral compression test has been carried out on a glass/epoxy ring cut from the tube. The full strain field has been measured over one face of the sample with the grid method. The measured fields have been processed with the Virtual Fields Method to identify the rigidities of the material. At the beginning, discrepancies and significant variations occurred in the identified moduli due to inhomogeneous distribution of the strains through the thickness. A method based on a simultaneous measurement on both sides of the ring has been adopted. Very satisfactory results have been obtained using this methodology.