Contribution of kinematic field measurements to the modelling of the Portevin-Le Chaâtelier effect by the image correlation method

Abstract

As various studies have developed the modelling of the Portevin-Le Chaâtelier (PLC) phenomenon, the geometrical characteristics and the kinematics of the associated bands need to be experimentally evaluated to provide data for the models. This paper outlines the interest in a new experimental method which uses the measurement of the displacement field by image correlation. With the aim of emphasizing the power of this experimental tool, the characterization of continuous propagation of PLC bands, known as type A, has been chosen. Parameters such as the width of the band, the propagation velocity, and above all the distribution of the deformation inside the band have been experimentally determined by examining the kinematic field on the whole surface of the sample during a tensile test. This method is very accurate and could be a very useful tool for simulations with finite element code at two levels. Firstly, it leads to the experimental determination of geometrical parameters of the bands which are parameters of the analytical models. Secondly, it enables the kinematic fields to be quantified everywhere on the sample (inside and outside the bands), which is very useful for the validation of finite element simulations.