Hybrid Digital Image Correlation

Abstract

Digital image correlation (DIC) is a commonly used full-field technique for measuring surface deformations in experimental solid mechanics. It directly provides full-field displacements by comparing digital images of the speckle pattern subsets painted on a structure’s surface in the undeformed and deformed states, respectively. Although DIC measures displacements in solid structures, it is often necessary to determine the individual stress components for proper fatigue and failure analysis. Hybrid digital image correlation (hybrid-DIC) is an experimental-analytical approach where theoretical formulations are combined with DIC displacement data for the identification of the full-field stress components. The present paper demonstrates the ability in providing reliable full-field stresses in numerous two-dimensional (2D) plane stress engineering situations involving circular and irregular geometric discontinuities in isotropic or orthotropic composite materials. Hybrid-DIC’s main advantages are (1) it does not require the differentiation of measured displacements, and (2) it provides stresses at the edges of discontinuities, often the location of maximum stress magnitudes.