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Ultrasonic Lateral Displacement Sensor for Health Monitoring in Seismically Isolated Buildings.

Matsuya I, Matsumoto F, Ihara I - Sensors (Basel) (2015)

Bottom Line: The transmitters are immobilized at a fixed point, whereas the receiver set-up is separately arranged on the opposite side.In order to improve measurement accuracy, a correction method that utilizes polynomial approximation is introduced.When five transmitters are arranged, their measurement range is easily extended up to ±60 mm with an accuracy of 0.7 mm.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka 940-2188, Niigata, Japan. matsuya@mech.nagaokaut.ac.jp.

ABSTRACT
An ultrasonic lateral displacement sensor utilizing air-coupled ultrasound transducers is proposed. The normally-distributed far field of an ultrasound transducer in a lateral direction is taken advantage of for measuring lateral displacement. The measurement system is composed of several air-coupled ultrasound transducers as a receiver and several transmitters. The transmitters are immobilized at a fixed point, whereas the receiver set-up is separately arranged on the opposite side. In order to improve measurement accuracy, a correction method that utilizes polynomial approximation is introduced. The difference between the corrected lateral displacement and the reference displacement is estimated to be 0.2 mm at maximum for the two transmitters system. A good responsiveness is demonstrated by conducting a dynamic response experiment. When five transmitters are arranged, their measurement range is easily extended up to ±60 mm with an accuracy of 0.7 mm. In both cases, the fluctuations to the measurement ranges show less than 1%. These results indicate that the developed sensor system is useful for measuring relative lateral displacement of a seismically isolated building in the field of structural health monitoring.

No MeSH data available.


Related in: MedlinePlus

The dynamic response experiment in 0.6 Hz movement. (a) Estimated lateral displacement; (b) Corrected lateral displacement.
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sensors-15-17000-f010: The dynamic response experiment in 0.6 Hz movement. (a) Estimated lateral displacement; (b) Corrected lateral displacement.

Mentions: Figure 10 shows the results of the dynamic response experiment. The solid line shows the reference displacement and the open circles show the estimated displacement in Figure 10a as well as the corrected displacement in Figure 10b. In both Figure 10a,b, a good capability for the dynamic response can be seen. By using the correction method, as expected, better accuracy was achieved compared to methods utilizing only Gaussian distributions as shown in Figure 10a,b. Generally, a building shakes with high frequency over a small displacement region compared rather than a large displacement region. Therefore, our sensor system required a high responsiveness performance appropriate for small displacement regions. However, the sensor application in this paper is applied to a seismically isolated building that is shaken with several Hz at most. Additionally, the ultrasound propagates at around 340 m/s, which is much faster than the movement of the seismically isolated layer. Because the distance between transducers is set to be very close in the sensor application, it is considered that this sensor follows the seismic motion well over both small and large displacement regions.


Ultrasonic Lateral Displacement Sensor for Health Monitoring in Seismically Isolated Buildings.

Matsuya I, Matsumoto F, Ihara I - Sensors (Basel) (2015)

The dynamic response experiment in 0.6 Hz movement. (a) Estimated lateral displacement; (b) Corrected lateral displacement.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541918&req=5

sensors-15-17000-f010: The dynamic response experiment in 0.6 Hz movement. (a) Estimated lateral displacement; (b) Corrected lateral displacement.
Mentions: Figure 10 shows the results of the dynamic response experiment. The solid line shows the reference displacement and the open circles show the estimated displacement in Figure 10a as well as the corrected displacement in Figure 10b. In both Figure 10a,b, a good capability for the dynamic response can be seen. By using the correction method, as expected, better accuracy was achieved compared to methods utilizing only Gaussian distributions as shown in Figure 10a,b. Generally, a building shakes with high frequency over a small displacement region compared rather than a large displacement region. Therefore, our sensor system required a high responsiveness performance appropriate for small displacement regions. However, the sensor application in this paper is applied to a seismically isolated building that is shaken with several Hz at most. Additionally, the ultrasound propagates at around 340 m/s, which is much faster than the movement of the seismically isolated layer. Because the distance between transducers is set to be very close in the sensor application, it is considered that this sensor follows the seismic motion well over both small and large displacement regions.

Bottom Line: The transmitters are immobilized at a fixed point, whereas the receiver set-up is separately arranged on the opposite side.In order to improve measurement accuracy, a correction method that utilizes polynomial approximation is introduced.When five transmitters are arranged, their measurement range is easily extended up to ±60 mm with an accuracy of 0.7 mm.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka 940-2188, Niigata, Japan. matsuya@mech.nagaokaut.ac.jp.

ABSTRACT
An ultrasonic lateral displacement sensor utilizing air-coupled ultrasound transducers is proposed. The normally-distributed far field of an ultrasound transducer in a lateral direction is taken advantage of for measuring lateral displacement. The measurement system is composed of several air-coupled ultrasound transducers as a receiver and several transmitters. The transmitters are immobilized at a fixed point, whereas the receiver set-up is separately arranged on the opposite side. In order to improve measurement accuracy, a correction method that utilizes polynomial approximation is introduced. The difference between the corrected lateral displacement and the reference displacement is estimated to be 0.2 mm at maximum for the two transmitters system. A good responsiveness is demonstrated by conducting a dynamic response experiment. When five transmitters are arranged, their measurement range is easily extended up to ±60 mm with an accuracy of 0.7 mm. In both cases, the fluctuations to the measurement ranges show less than 1%. These results indicate that the developed sensor system is useful for measuring relative lateral displacement of a seismically isolated building in the field of structural health monitoring.

No MeSH data available.


Related in: MedlinePlus