Image based non-contact deformation measuring technique

Abstract

Deformation and strain measurements play a vital role in civil engineering. The current practice is to use dial gauges to measure deformation over a large area and strain gauges when interested in a localised point of a structure. Both techniques use a contact based approach which may damage or introduce a significant change in structural response depending on material and structural properties. Digital Image Correlation (DIC) is a non-contact imaged based technique where the deformation of a specimen is determined by calculating changes in two images taken before and after applying a certain load. An automated software programme is developed to capture a given target and calculate the deformation using difference between two photographs taken during an experiment. Software outcome was verified against a dial gauge with 0.01 mm minimum count.