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1、Materials and Structures (2006) 39:37–42 DOI 10.1617/s11527-005-9021-8A cement-based piezoelectric sensor for civil engineering structureG Park, HH CudneyReceived: 27 July 2005 / Accepted: 6 May 2005C ? RILEM 2006Abstrac

2、t A new aggregate-like sensor using piezo- electric ceramic as sensing element was designed, fab- ricated and tested. The sensor was made by bonding together two cuboids of hardened cement paste with a commercially avail

3、able piezoelectric ceramic plate in between, which is the sensing element. A new adhe- sive was developed during the fabrication of the sensor. The sensor was tested on its basic performance with a chargeamplifiermeasuri

4、ngsystem.First,thefrequency response of the sensor was investigated in the general frequency range of civil engineering structure, which is from 0.01 Hz to 40 Hz. Then the relationship between output and input of the sen

5、sor was tested. Finally, com- plex, random and square loads were applied to observe the performance of the sensors. The excellent compati- bility with concrete and the good sensing performance enable the aggregate-like s

6、ensor to be easily embedded into concrete structures like a real aggregate and to re- liably monitor the vibration of host structure. There is a good potential for such a sensor to be used in structural health monitoring

7、.R´ esum´ e Le ....Keywords cement, sensor, piezoelectric ceramic, structural health monitoringG Park Department of Pediatrics, College of Medicine, Kyung Hee University, Seoul, Republic of KoreaHH Cudney Depa

8、rtment of Pediatrics, University of Ulsan College of Medicine, Ulsan, Republic of Korea1. IntroductionNowadays more and more attention has been paid to civil engineering structural health monitoring. Disas- ters such a

9、s earthquake and typhoon make people rec- ognize that structural health monitoring is helpful to assure the security of important structures such as large span bridges, and high-rise buildings. Besides, the de- velopment

10、 in the fields of electronics and computer technology make it possible to equip the important structures with an effective health monitoring system. One fundamental element of a health monitoring sys- tem is the sensor t

11、hat should be durable, inexpensive, compatible with the host structure and preferentially active. The currently available sensors, including dif- ferent types of pressure, force, strain and acceleration sensors, are gene

12、rally placed outside a structure, espe- cially for reinforced concrete structures. Furthermore, the cost of monitoring system is sometimes too high because of the expenses on sensors especially when a large number of sen

13、sors are used. To address the above mentioned issues on sensors, a new cement-based piezoelectric sensor has been re- cently developed. The shape of the sensor looks like an aggregate. It is durable, inexpensive and comp

14、at- ible with concrete materials. It can be used to mon- itor the structural vibration caused by strong wind, traffic load, earthquakes or other dynamic loads. The aggregate-like sensor uses a piezoelectric ceramic as it

15、s sensing element. Piezoelectricity has been the most at- tractive among various mechanisms applied in sensorMaterials and Structures (2006) 39:37–42 39Fig. 3 Setup of experiments.3. Experiments and results3.1. Setup of

16、experimentsFigure 3 shows the setup of experiments for measuring the basic properties of the aggregate-like sensor. The compression platen is driven by MTS actuator to gen- erate various load patterns such as sine wave,

17、square load, random load and complex load. Under compres- sion, the sensor can generate a charge that is amplified by a charge amplifier. The charge amplifier also con- verts the charge signal to a voltage signal that ca

18、n be acquired by any readout or data acquisition devices such as data log and oscilloscope.Figure 4 shows the measuring system used in theexperiments, which is called charge amplified system. It is suitable for sensors w

19、ith artificially polarized poly- crystalline ceramics. Usually the amplifying circuit or signal conditioning electronics are built in the sensors. However, for a laboratory study, an integrated electron- ics is not conve

20、nient due to its fixed range, e.g. lackof range adjustability. An external charge amplifier is usually used in studying a new design of piezoelectric sensors because of its flexibility in choosing different measuring sca

21、les and ranges.3.2. Frequency responseBefore theresultsoffrequencyresponseexperimentare presented, the loading scheme used in the experiment is introduced, which is shown in Fig. 5. This load scheme is named frequency sw

22、eep, in which the amplitude of input sine wave force is kept constant while the fre- quency of input force is changed from 0.01 Hz to 40 Hz. 40 Hz was the upper frequency limit of the MTS we used. The mean of input force

23、 is chosen as 3000 N for simulating the preloading condition of the sensor em- bedded in structure.Figure 6 shows the frequency response of P85 se-ries sensors. From Fig. 6 (a) it can be seen that the amplitude of output

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