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Title |
Stereo Vision-Based 3D Displacement Measurement and Modal Analysis of a Shaking Table-Excited Frame Structure
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Authors |
이승재(Seung-Jae Lee) ; 최경규(Kyoung-Kyu Choi) ; 박성호(Sung-Ho Park) ; 김승희(Seung-Hee Kim) |
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DOI |
https://doi.org/10.11112/jksmi.2025.29.5.1 |
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Keywords |
3차원 스테레오 화상정보 계측 시스템; 비접촉 계측; 진동대 실험; 모드형상; 감쇠비; 모달 해석; MAC; 고유진동수 Stereo vision-based measurement system; Non-contact measurement; Shaking table test; Mode shape; Damping ratio; Modal analysis; ; MAC; Natural frequency |
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Abstract |
This study presents and validates a stereo vision-based non-contact system for measuring the dynamic responses of structures. A four-story steel frame specimen was tested on a uniaxial shaking table using five types of ground motions scaled to three peak ground acceleration (PGA) levels (0.1g, 0.3g, and 0.5g). The stereo vision measurement system, comprising synchronized high-resolution cameras, was calibrated through reprojection error minimization and coordinate alignment using physical reference points on the specimen. Vision-based displacement measurements were quantitatively compared with wire-type LVDTs and accelerometers, showing maximum errors within ±2 mm and an average root mean square error (RMSE) of 1.06 mm. Frequency response functions (FRFs) were derived from the vision data to extract natural frequencies and mode shapes, which closely matched accelerometer-based modal results, achieving modal assurance criterion (MAC) values above 0.9 in most modes. Damping ratios were also estimated using the half-power bandwidth method and compared with Rayleigh damping models. The findings demonstrate that the proposed stereo vision-based system provides sufficient accuracy and resolution for experimental modal analysis of multi-story structural frames and offers potential for application in structural health monitoring.
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