Displacement measurement of concrete bridges by the sampling Moiré method based on phase analysis of repeated pattern

Ri, Shien; Wang, Qinghua; Tsuda, Hiroshi; Shirasaki, H.; Kuribayashi, Kenichi

doi:10.1111/str.12351

Cited by 23 publications

(15 citation statements)

References 31 publications

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“…In recent years, the sampling moiré (SM) method has rapidly developed as a new moiré technique and has been widely applied in deformation measurements at the macro-and micro-scales. [24][25][26][27][28] Compared with MI, the SM method does not require highdensity diffraction gratings and can achieve high-precision measurements using low-frequency gratings. Moreover, the fabrication procedure for gratings in the SM method is simpler, more efficient and low-cost, especially for heat-resistant gratings.…”

Section: Introductionmentioning

confidence: 99%

Identification of thermomechanical parameters based on the virtual fields method combined with the sampling moiré method

Xie

2022

Strain

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Thermomechanical parameters are important indicators for evaluating the mechanical properties of superalloys and generally include the coefficients of stiffness and thermal expansion at high temperatures. At present, there are few methods for simultaneously characterising the thermomechanical parameters of superalloys, especially single‐crystal superalloys. To satisfy the demand for simultaneously identifying the thermomechanical parameters of orthotropic superalloys, an optimised virtual fields method for decoupling the thermomechanical parameters was developed in this study by combining the self‐developed heat‐resistant grids and the sampling moiré method. First, several factors, including the oblique angle of the grids, image noise and thermomechanical coupling phenomena, were studied through numerical experiments to analyse their influences on the identification accuracy. Then, an optimised identification strategy was established. Finally, the thermomechanical parameters of Ni‐based polycrystalline and single‐crystal superalloys were successfully identified and comparatively studied. The identification results demonstrate that the proposed method is highly accurate and robust. This research will provide an effective way to accurately characterise the multiple parameters of superalloys at high temperatures.

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Section: Introductionmentioning

confidence: 99%

Identification of thermomechanical parameters based on the virtual fields method combined with the sampling moiré method

Xie

2022

Strain

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“…This method uses a charge-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) sensor to capture a single image of a specimen grating of known pitch during deformation. Only one image is handled to evaluate the phase distribution by generating multiple phase-shifted moiré patterns by the thinning-out, down-sampling, and interpolation of the sequential pixels through phase analysis [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Through the phase difference of the moiré fringe prior to deformation to that of post-deformation, the displacement distribution is attained.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, this has been expanded to the displacement measurement of a concrete bridge for a high-speed railway in Japan using retroreflective moiré markers. The two-dimensional (2-D) in-plane displacements at multiple locations could be easily measured from recorded digital images [11], even for the measurement of the deflection and vibration of a large-scale concrete bridge from captured video with a commercial cinema camera [12] in recent times. Further, in terms of experiments, comparative experiments conducted in a columnar cantilever beam connected to a loading jack and laser displacement meter demonstrated the effectiveness of the method for deformation measurement when the errors between the measurements were compared [14,21].…”

Section: Introductionmentioning

confidence: 99%

CCTV Camera Array for the Displacement and Strain Measurement of a Beam Specimen in a Laboratory

2022

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The available conventional sensors, like displacement transducers, used in the Structural Engineering Laboratory are expensive. In addition to that, the need for data acquisition devices also escalates the expense invested in point contact measurement systems. The recent appeal of vision-based measurement and the search for cost-effectiveness has led to an exploration of the established sampling moiré method using cheap closed-circuit television (CCTV) cameras as a viable option. The sampling moiré method is simple and analyzes the displacements from grating images by a phase-shifting method. Several trial experiments were conducted, which demonstrated that the setup is at least as accurate as the traditional measuring system. An experiment was conducted on a steel I-beam for displacement measurement, which displayed satisfactory results. In addition, the setup was also tested for strain measurement, and it has yielded promising results that need fine-tuning. This paper discusses the challenges, findings, and the possibility of incorporating vision-based displacement measurements in laboratory platforms.

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“…A vision method based on optical flow tracking to monitor deflection of structure was proposed by Yoon et al (2016). In Japan, a sampling Moiré method was presented for deflection measurement of high-speed railway bridge, which is made of concrete (Ri et al, 2020). Yu et al proposed a method that traces the features of structures through feature points matching to measure the deflection of bridge (Yu & Zhang, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…(2016). In Japan, a sampling Moiré method was presented for deflection measurement of high‐speed railway bridge, which is made of concrete (Ri et al., 2020). Yu et al.…”

Section: Introductionmentioning

confidence: 99%

Noncontact deflection measurement for bridge through a multi‐UAVs system

Zhuge

Zhong

et al. 2021

Computer aided Civil Eng

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Deflection measurement is the research focus of health monitoring for bridges during the operation period. This study develops a contactless measurement technique to monitor the bridge deflection, leveraging visual information from a team of unmanned aerial vehicles (UAVs). On the basis of the collinearity of the laser spots projected on the plane by the coplanar laser indicator, we can eliminate the motion of UAV, and calculate the vertical displacement of the position to be measured relative to the bridge pier. In the proposed method, the center of the laser spot is extracted through a method based on deep learning, and an algorithm based on scale-invariant features registration was developed to track the feature points of the bridge in the image sequence. According to the algorithm, we demonstrate the accuracy and feasibility of our approach through simulation and simulated bridge experiments. The result shows that the root mean squared error (RMSE) of measurement through our technique is less than 0.5 mm in the laboratory conditions. In addition, the limits and scalability of the presented method have been explored through a field experiment.

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Displacement measurement of concrete bridges by the sampling Moiré method based on phase analysis of repeated pattern

Cited by 23 publications

References 31 publications

Identification of thermomechanical parameters based on the virtual fields method combined with the sampling moiré method

Identification of thermomechanical parameters based on the virtual fields method combined with the sampling moiré method

CCTV Camera Array for the Displacement and Strain Measurement of a Beam Specimen in a Laboratory

Noncontact deflection measurement for bridge through a multi‐UAVs system

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