Developing a Speckle Pattern to Evaluate Adhesive Joints Using Digital Image Correlation

ABSTRACT Digital Image Correlation (DIC) is a known Non-Destructive Evaluation (NDE) method used in various industries. DIC requires a randomly produced pattern, known as speckle pattern, to track and generate strain maps. The speckle patterns are fundamental for DIC applications. DIC uses images of these speckle patterns before and after a load has been applied to generate strain maps by comparing the changes between speckle pattern images. In this study, a speckle pattern is sought to implement within adhesive joints. The speckle pattern must be trackable using ultrasonic imaging; therefore, it is chosen from materials with high acoustic impedance metals. By tracking the speckle pattern and using DIC, defects within joints will be revealed. This allows non-destructive analysis to be conducted on adhesive joints to detect defects which may go undetected using conventional ultrasonic techniques.