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Advances in Materials Science and Engineering
Volume 2018, Article ID 1954573, 8 pages
https://doi.org/10.1155/2018/1954573
Research Article

Real-Time and Quantitative Measurement of Crack-Tip Stress Intensity Factors Using Digital Holographic Interferometry

1Faculty of Civil Engineering and Mechanics, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
2Key Laboratory of Yunnan Province for Disaster Reduction in Civil Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China

Correspondence should be addressed to Rongxin Guo; nc.ude.tsumk@xroug

Received 8 December 2017; Accepted 22 March 2018; Published 16 May 2018

Academic Editor: Hiroshi Noguchi

Copyright © 2018 Haiting Xia et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Detection of the crack in an object is a critical problem for the health monitoring of a transparent object. The real-time and quantitative measurement of the crack-tip stress intensity factor (SIF) remains an open issue. In this paper, an approach for real-time and quantitative measurement for the SIFs of a Mode I crack is presented based on digital holographic interferometry (DHI). A transmission digital holographic system is established to measure the phase difference of an object wave during loading. The expression to achieve the SIF from the phase difference is formulated. To enhance the accuracy of measurement, calibrated phase unwrapping based on least-squares and iteration and median filtering is applied to retrieve the actual phase from the noisy wrapped one. The SIFs of the Mode I crack in a transparent polymethyl methacrylate (PMMA) specimen are measured by this approach. The results are compared with the theoretical ones to demonstrate the feasibility of the proposed approach.