High temperature deformation measurement based on ultraviolet DIC

Abstract

High temperature deformation and strain are important measures for characterizing behaviors of structural components under high temperature conditions. Digital Image Correlation (DIC) is a full-field technique based on white-light illumination for displacement and strain measurement. But Light spectrum on the sample surface at high temperature affect the quality of acquired speckle pattern images for traditional DIC measurement. This paper proposes an innovative UV-DIC system which in conjunction with ultraviolet illumination and a filtering system to minimize the surface radiation effect and enable deformation and strain measurements at high temperatures. The test sample with a specially-selected coating material was heated by means of high temperature furnace, which process to form stable speckle pattern on the sample surface. The surface was illuminate by UV light and simultaneously an UV sensitive CCD camera was used to record digital speckle image of test sample surface under different temperatures. Using DIC method for image analysis and processing obtains full-field thermal deformation, which implements a set of image average algorithms for eliminates interference of vibration and noise. The experimental results show that the UV-DIC can achieve high temperature measurement, and effectively remove the interference of vibration and noise in high temperature measurement.