An in-situ self-calibration method for non-contact full-field strain measurement. (1st October 2020)

• Record Type: Journal Article
• Authors: Deng, Huaxia; Wang, Jun; Zhang, Haicong; Zhang, Jin; Ma, Mengchao; Zhong, Xiang
• Is Part Of: Measurement. Volume 162(2020)
• Publication Date: 2020-10-01
• Subjects: Full-field strain -- Self-calibration technology -- In-situ measurement; Weights and measures -- Periodicals; Measurement -- Periodicals; Measurement; Weights and measures; Periodicals; 530.8
• DOI: 10.1016/j.measurement.2020.107871
• Languages: English
• ISSNs: 0263-2241

Abstract

Highlights: An in-situ self-calibration method for full-field strain measurement is proposed. The proposed method is also applicable to other displacement measurement methods. The full-field displacement and strain information can be obtained simultaneously. Abstract: Online calibration is important for strain measurement especially for non-contact full-field strain measurement. A self-calibration method based on modal expansion and strain–displacement relationships is developed for full-field strain measurement. The proposed method has the capability to calibrate the in–situ measured data with ground truths continuously without shutting down the test equipment. To validate the methodology for strain calibration, a simulated beam, and a cantilever beam under sinusoidal and random excitations are investigated. The post-calibrated strain of the simulated beam is better agreement with ground truths, and the TRAC ε at three points are greater than 99%. The post-calibrated strain the by videometric method, is consistent with measured data using strain gauges. And the accuracy of post-calibrated strain under sinusoidal or random excitation, is higher than that of the pre-calibrated strain. The results of experiments indicate that the proposed method is effective for calibrating strain obtained by visual measurement methods.