Body waves recorded inside an elastic half-space by an embedded, wideband velocity sensor

     Steven D. Glaser
     Department of Civil and Environmental Engineering, University of 
            California, Berkeley, CA 94720-1710

     Gregory G. Weiss
     Lockheed/Martin Astronautics, P.O. Box 179, MS T500, Denver, CO
            80201

     Lane R. Johnson
     Department of Geology, University of California, Berkeley, CA
            94720-1710

(Received 10 October 1997; accepted 18 May 1998)

This paper presents a unique embeddible acoustic emission sensor. Comparison with theoretically calculated waveforms for the embedded sensor, surface step force Lamb's problem prove the sensor to be an accurate transducer of particle velocity, with a sensitivity of 2.34 V output per mm/s. Calibration as a surface sensor by the National Institute of Standards and Technology (NIST) show the sensor to be an accurate transducer of surface displacement with a sensitivity of 2.8 V/nm. The paper presents details about the design and construction of the sensor as well as calibration and verification. Unique design elements include the use of a lead-alloy backing masses, soft elastomer shear-spring isolation and mounting, and embedment. The sensor is based on the NIST conical lead zirconate-titanate (PZT) element and has a finished length of 38 mm and a diameter of 16 mm. The sensor is robust enough to work under 1 MPa of brine pressure. © 1998 Acoustical Society of America.

PII: S0001-4966(98)01409-X
PACS: 43.38.Ar, 43.40.Le, 43.38.Fx      Additional Information