Piezoelectric actuators/sensors for wavelet based failure detection in flexible structures

This paper presents an analytical and experimental survey of the methods for in-service, in real-time damage detection of bolt connection. The experimental setup is a flexible aluminum beam with one end clamped on a frame and the other end jointed on frame by a bolt. To simulate connection damage, the stress relaxing on the bolt is achieved by the action of loose rotation that is quantified by rotation angle. A piezoelectric actuator produces the exciting signal. The dynamic response of flexible beam system is monitored by a piezoelectric transducer. The voltage output signal is processed offline by a PC and in real-time by an embedded digital signal processor (DSP) chip. Wavelet analysis method investigated in this paper is used to identify early change of beam connection state so as to prevent connection failure. The wavelet analysis results are compared to frequency response analysis (FR) methods in order to identify.