This paper presents a critical review of the current work of experiment, theory of micro-nano

In this paper, a detailed description for the ETDR distributed strain sensing mechanism of a coaxial cable was presented, and a signal calibration algorithm for interpreting ETDR signal waveforms was developed. In addition, a prototype coaxial ETDR distributed strain sensor with improved signal sensitivity was presented. The ETDR signal responses of the prototype sensor subjected to a concentrated lateral compression load and distributed axial tension load were experimentally tested. The test results showed that the prototype sensor has a substantially improved signal sensitivity over a commercial RG-174 cable of comparable size. It was also shown that the relation between the impedance change of the sensor and the applied axial tensile strain depends primarily on the mechanical stress–strain response of the sensor. From the test results, it was demonstrated that this relation could be empirically established with the aid of the calibration algorithm.

Downloaded from 869 DISCUSSION An impact load identification method has been proposed for estimating the location and force history of an impact in structures. The method has been successfully applied to beams containing distributed piezoelectric sensors. It is possible to extend the method to more complicated structures. Some modifications of the comparator are expected, while the system model will have to be developed based on the type of structures considered.ACKNOWLEDGEMENT Partial support of the program by a grant from AFOSR is gratefully appreciated.ABSTRACT: For the past decade, much research effort has been devoted to finite element formulation for the electromechanical coupling effects of piezoelectric materials, and yet, fully electromechanical coupled piezoelectric elements have just recently become available in commercialized finite element analysis packages. This paper surveys the capabilities of the piezoelectric elements provided by commercial FEA codes. Two major packages, ANSYS by Swanson, Inc. and ABAQUS by HKS, Inc., have been reviewed. The finite element formulation of the piezoelectric elements are outlined and available element and analysis types are summarized. A simple case of static and dynamic finite element analysis involving piezoelectric and structural coupling has been performed. It has been shown that the piezoelectric elements in the commercial FEA codes give results comparable with those obtained from proven analytical methods.

No abstract

No abstract