Stress Analysis of an Arbitrarily-Shaped Structure with an Irregularly-Shaped Hole using Digital Image Correlation

Abstract

Engineering structures commonly have arbitrarily-shaped geometry and contain irregularly-shaped cutouts. The integrity of these structures is significantly influenced by the boundary stresses associated with these cutouts. This paper focuses on the evaluation of the stress of a complicated-shaped structure with an irregularly-shaped hole using a single measured displacement component. Digital Image Correlation (DIC) was utilized herein to record the in-plane displacements of the loaded structure. Considering the complications in providing solely analytical solutions for finite structures or numerical solutions in case of insufficient knowledge of the boundary and loading conditions, this paper demonstrates an effective hybrid technique of experimentally stress analyzing in such situations. Processing only one component of the in-plane displacement information with a stress function provides the full-field stresses, including the edges of the plate. Without the knowledge of the external loading conditions nor the need of physically differentiating the measured displacement to obtain strains, and hence stresses, the proposed hybrid technique simultaneously smoothes the recorded displacement information and evaluates the individual stresses full-field in a strong mechanics foundation (equilibrium and compatibility). To validate and support the proposed hybrid technique based on Airy stress function, the obtained results were compared with the those obtained through thermoelastic stress analysis, finite element analysis, and strain gauges.