Publication: Crack growth monitoring in concrete using moire method
Date
2008-04-01
Authors
Chan, Hooi Mei
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Abstract
This project describes the crack growth monitoring gauge developed using moiré method and determines the sensitivity of fringe pattern in measuring the small crack displacement. The gauge consists of two overlapping acrylic plates. One plate is white with a grating, while the other is transparent with a grating. Analysis have been done to determine the most sensitive set of gratings which is capable to measure small crack grow displacement. The sensitivity can be up to 0.05mm. Two steps comparison is used to analyze the sensitivity of fringe pattern. There are simulation experiment and real experiment. The database images were generated from the experimental captured images, Besides that, calibration experiment is done to determine the relationship between unit pixel for simulation images and unit millimeter for real experiment. The images are pre-processed using MATLAB image processing toolbox to filter the grating lines and then the fringe pattern images without grating line are saved as database images. Test image experiment was done to define the accuracy of results of the crack monitoring. Once the gauge is in position across a crack, the fringe pattern will be generated if movement occurs and the crack size can be measured using Matlab program.