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Experimental estimating deflection of a simple beam bridge model using grating eddy current sensors.

Lü C, Liu W, Zhang Y, Zhao H - Sensors (Basel) (2012)

Bottom Line: Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints.In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection.Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches.

View Article: PubMed Central - PubMed

Affiliation: Department of Instrument Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. chunfenglv@sjtu.edu.cn

ABSTRACT
A novel three-point method using a grating eddy current absolute position sensor (GECS) for bridge deflection estimation is proposed in this paper. Real spatial positions of the measuring points along the span axis are directly used as relative reference points of each other rather than using any other auxiliary static reference points for measuring devices in a conventional method. Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints. In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection. Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches. Principles of the three-point method and displacement measurement of the GECS are introduced in detail. Both static and dynamic experiments have been carried out on a simple beam bridge model, which demonstrate that the three-point deflection estimation method using the GECS is effective and offers a reliable way for bridge deflection estimation, especially for long-term monitoring.

No MeSH data available.


Related in: MedlinePlus

Results of vibration test: (a) f = 0.2 Hz, (b) and (c) f = 1 Hz.
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f10-sensors-12-09987: Results of vibration test: (a) f = 0.2 Hz, (b) and (c) f = 1 Hz.

Mentions: In the vibration tests, frequency components of the bridge model are very complex, and among them, vibration displacement under the natural vibration frequency is the key research object rather than that of the high frequency vibration. Thus, the type of the estimating object in the bridge vibration is also the dynamic displacement, that is to say, the proposed three-point method is also ideal for dynamic vibration tests. For the laboratory model in this paper, a random vibration force is imposed on the beam, and the measuring point 2 of which the dynamic deflection variation range is more obvious than the others is taken as the observation point. Figure 10 shows the comparison results of deflection time history curves of measuring point 2 estimated by the two methods in vibration tests.


Experimental estimating deflection of a simple beam bridge model using grating eddy current sensors.

Lü C, Liu W, Zhang Y, Zhao H - Sensors (Basel) (2012)

Results of vibration test: (a) f = 0.2 Hz, (b) and (c) f = 1 Hz.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472811&req=5

f10-sensors-12-09987: Results of vibration test: (a) f = 0.2 Hz, (b) and (c) f = 1 Hz.
Mentions: In the vibration tests, frequency components of the bridge model are very complex, and among them, vibration displacement under the natural vibration frequency is the key research object rather than that of the high frequency vibration. Thus, the type of the estimating object in the bridge vibration is also the dynamic displacement, that is to say, the proposed three-point method is also ideal for dynamic vibration tests. For the laboratory model in this paper, a random vibration force is imposed on the beam, and the measuring point 2 of which the dynamic deflection variation range is more obvious than the others is taken as the observation point. Figure 10 shows the comparison results of deflection time history curves of measuring point 2 estimated by the two methods in vibration tests.

Bottom Line: Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints.In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection.Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches.

View Article: PubMed Central - PubMed

Affiliation: Department of Instrument Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. chunfenglv@sjtu.edu.cn

ABSTRACT
A novel three-point method using a grating eddy current absolute position sensor (GECS) for bridge deflection estimation is proposed in this paper. Real spatial positions of the measuring points along the span axis are directly used as relative reference points of each other rather than using any other auxiliary static reference points for measuring devices in a conventional method. Every three adjacent measuring points are defined as a measuring unit and a straight connecting bar with a GECS fixed on the center section of it links the two endpoints. In each measuring unit, the displacement of the mid-measuring point relative to the connecting bar measured by the GECS is defined as the relative deflection. Absolute deflections of each measuring point can be calculated from the relative deflections of all the measuring units directly without any correcting approaches. Principles of the three-point method and displacement measurement of the GECS are introduced in detail. Both static and dynamic experiments have been carried out on a simple beam bridge model, which demonstrate that the three-point deflection estimation method using the GECS is effective and offers a reliable way for bridge deflection estimation, especially for long-term monitoring.

No MeSH data available.


Related in: MedlinePlus