Surface strain distribution method for delamination detection using piezoelectric actuators and sensors

Abstract

This paper presents an experimental study into detection of delamination in composite beams by using surface strain distribution method. Two piezoelectric (PZT) patches were surfaced bonded to each composite beam; one was used as actuator to excite the beam structure whereas the other was custom-designed and used as sensor. The custom-fabricated PZT sensor has 15 evenly-distributed electrode strips which enable measurement of 15 surface strain readings in the form of electric charge output. The effects of various parameters, e.g., vibration modes, excitation frequency and sensor debonding, on damage detection sensitivity were investigated. It is shown that the variation in sensor charge output distribution can be an effective indicator of the presence, size and location of localized delamination in composite beam and debonding between a sensor and its host beam.