A Multi-Mode Distributed Sensor for Vibrating Beams

Abstract

A new class of distributed sensors is presented which can measure both the modal and physical displacements of vibrating composite beams. The sensor relies in its operation on a set of super-elastic Shape Memory Alloy (SMA) wires which are embedded off the neutral axes of the vibrating beams. The wires are arranged in a special manner which allows continuous monitoring of the deflection curve of the beam. The output signals of the SMA wires are processed to determine the modal displacements of the beam and the physical displacements at critical discrete points along the beam axis.The theoretical and experimental performance of the sensor is presented in both the time and frequency domains. Comparisons are given between the experimental performance of the SMA distributed sensor and that of conventional laser sensors, in order to demonstrate the accuracy and merits of the distributed SMA sensor. The results obtained suggest the potential of this new class of sensors as a viable means for controlling the vibrations of flexible composite beams and plates, particularly with modal control algorithms.