Single‐camera special stereo‐digital image correlation applied for accurate virtual fields method identification

Abstract

A single-camera special stereo-DIC (SS-DIC) is proposed for accurate virtual fields method (VFM) identification. The single-camera SS-DIC allows accurate surface 3D deformation measurements using a single colour camera and a specially designed colour separation device. It not only effectively eliminates the unavoidable out-of-plane movement/rotation due to unideal in-plane loading but also delivers uniformly distributed measurement points that brings great simplicity and convenience for internal virtual work calculation in VFM. In addition, since only a single camera is used for stereovision, the proposed SS-DIC system requires no complicated synchronisation devices. The effectiveness and practicality of the proposed method are evaluated by heterogeneous deformation experiments of a holed aluminium alloy and 304 stainless steel plate. Combined with a high-speed colour camera, the proposed method is expected to be a simple and practical method for the calibration of material constitutive model under intermediate and high strain rate conditions using VFM. KEYWORDS full-fields measurement, stereo-digital image correlation, virtual fields method