Accession Number : ADP010156

Title :   Solid-State Active Sensing for In-Situ Health Monitoring

Corporate Author : VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG CENTER FOR INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES

Personal Author(s) : Rogers, Craig A. ; Lalande, Frederic

PDF Url : ADP010156

Report Date : APR 1996

Pagination or Media Count : 8

Abstract : Currently, there exists a need for sensors which can perform on-line health monitoring of structures. Such sensors will lead to utilization of a greater fraction of useful life, greater reliability, and reduced maintenance and inspection cost. An on-line health monitoring sensor system must meet three requirements: i) it must be small, non-intrusive, and must offer the possibility of being located in inaccessible remote areas of the structure and, as yet, it must be able to transmit information easily to a central processor; ii) it must be as sensitive as conventional non- destructive evaluation (NDE) techniques, i.e., it must be able to detect minor cracks; and iii) it must be able to monitor a certain minimum area of the structure as opposed to the point measurements offered by presently available NDE equipment. Our recent research efforts indicate that the piezoelectric (PZT) materials used as sensory actuators may meet these requirements. The method being investigated relies on tracking the high-frequency (typically > 50 kHz) point impedance of the structure through a surface-bonded PZT to qualitatively identify damage. At such high frequencies, the technique is comparable in sensitivity to sophisticated traditional NDE techniques, and is capable of qualitatively detecting incipient-type damage by looking at changes in structural impedance. As yet, it can be implemented in a remote sensing scenario. Several case studies involving built-up complex structures will be presented to demonstrate the potential benefits of the technique.

Descriptors :   *SYMPOSIA, *PIEZOELECTRIC MATERIALS, NONDESTRUCTIVE TESTING, MONITORING, IMPEDANCE.

Subject Categories : Miscellaneous Detection and Detectors
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE