A fiber-optic WIM (weigh in motion) sensor, which offers several advantages over the piezoelectric sensor, is proposed. The system consists of a pneumatic tube filled with an incompressible fluid and embedded in a rubber pad, a diaphragm designed to convert pressure into displacement, and an optical displacement sensor. A prototype of the propsed sensor is designed, manufactured, and tested in the laboratory for different load-frequency combinations using an MTS machine. Statistical analyses of data are performed to assess the response of the sensor under varying load frequencies. A piezoelectric cable also is tested under varying load frequencies for the purpose of comaprison with the proposed sensor. The piezoelectric sensor exhibits considerable dependence on the load frequency; whereas, the response of the proposed sensor is much less frequency-dependent, and unlike the piezoelectric cable, has a waveform similar to that of the applied load. This latter property can facilitate significantly the processing of the sesnsor output signal. The linearity of response over the range of applied loads also is better than that of the piezoelectric cable. The proposed sensor is not susceptible to electromagnetic interference, is less expensive, and can be installed on the surface of the pavement, thus eliminating the need to dig the pavement.

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  • Corporate Authors:

    Strategic Highway Research Program

    National Research Council, 2101 Constitution Avenue, NW
    Washington, DC  United States  20418
  • Authors:
    • Ssafaai-Jazi, A
    • Ardekani, S A
    • Mehdikhani, M
  • Publication Date: 1990-11

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 62 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00607431
  • Record Type: Publication
  • Report/Paper Numbers: SHRP-IDEA/UFR-90-002
  • Files: TRIS, TRB
  • Created Date: Apr 30 1991 12:00AM