Kinematic Field Measurements During Orthogonal Cutting Tests via DIC with Double-frame Camera and Pulsed Laser Lighting

Abstract

The measurement of machined-part strain fields induced by the cutting process remains a challenge because of the presence of highly intensive and localised strains. In this study, a high-speed double-frame imaging device with pulsed laser lighting is used in order to obtain sharp and highly resolved images during orthogonal cutting tests performed in an aluminium alloy. The displacement fields are then measured using a global Q4–digital-image-correlation (DIC) method and several strategies, facilitating calculation of the total displacements due to the cut, along with the residual strains in the machined part. Numerical procedures are developed to manage the removed material that disturbs the DIC. An automatic primary shear angle detection procedure using DIC is also proposed. Five different markings, which are produced via chemical etching and micro blasting, are applied to the observed surfaces. Their effects on the kinematic fields and the uncertainties are then studied. Three surface parameters are proposed as indicators for determining the surface preparation suitability for the DIC. The repeatability of the kinematic fields induced during the cutting process is studied, because of the ease with which testing can be performed. Finally, the plastically deformed layer engendered by the cutting process is measured using the calculated residual strains.