Use of Macro Fibre Composite Transducers as Acoustic Emission Sensors

Abstract

Abstract:The need for ever lighter and more efficient aerospace structures and components has led to continuous optimization pushing the limits of structural performance. In order to ensure continued safe operation during long term service it is desirable to develop a structural health monitoring (SHM) system. Acoustic emission (AE) offers great potential for real time global monitoring of aerospace structures, however currently available commercial sensors have limitations in size, weight and adaptability to complex structures. This work investigates the potential use of macro-fibre composite (MFC) film transducers as AE sensors. Due to the inhomogeneous make-up of MFC transducers their directional dependency was examined and found to have limited effect on signal feature data. However, signal cross-correlations revealed a strong directional dependency. The sensitivity and signal attenuation with distance of MFC sensors were compared with those of commercially available sensors. Although noticeably less sensitive than the commercial sensors, the MFC sensors still had an acceptable operating range. Furthermore, a series of compressive carbon fiber coupon tests were monitored in parallel using both an MFC sensor and a commercially available sensor for comparison. The results showed good agreement of AE trends recorded by both sensors.

Numerical approach to absolute calibration of piezoelectric acoustic emission sensors using multiphysics simulations

“…Lee and Kuo [21] design a miniature acoustic transducer with two conical PZT elements to measure the surface wave velocity by using PZT ceramic (PZT-5H) as the sensing element. Other piezoelectric elements reported in literature for AE sensing are polyvinylidene fluoride-trifluonoethylene (PVDF-TrFE) copolymer [22], embedded polyvinylidene fluoride (PVDF) [23], PTCa/PEKK piezo-composites [24,25], piezoelectric polymer-ceramic composites [26], macro-fiber composite (MFC) film [27].…”

Damage detection using the signal entropy of an ultrasonic sensor network

“…To test the performance of the proposed algorithm, macro fiber composite (model MFC-M2814) sensors manufactured by Smart Material Inc., with an active area of 28 mm x 14 mm and a bandwidth of kHz, were used. The typical physical structure of an MFC sensor is formed by rectangular piezoceramic fibers locked in an epoxy matrix and sandwiched between two arrays of integrated electrodes (see for example (Eaton, et al, 2009) for details). The rectangular piezoceramic fibers are arranged in a regular spacing and precise parallel alignment to form the MFC transducer.…”

“…This value is close to that reported in the literature and indicates that monitoring of the vibrational modes up to a 0.4 m distance (considering the distance among the sensors in the experimental setup) should be feasible. The directionality sensitivity is also a concern with MFC sensors (Eaton, et al, 2009). To characterize the response of a typical MFC sensor, a set of preliminary tests was carried out on a thin aluminum plate with dimensions of 600 x 600 mm 2 and 1.9 mm in thickness.…”

Pattern recognition by wavelet transforms using macro fibre composites transducers

“…One of the most prominent MFC utilizations is linked to health monitoring systems and the evaluation of damages (Park et al, 2006;Hameed et al, 2009). MFC sensors are capable of recording AE and detecting damages (Eaton et al, 2009). Some vibration tests under optimal running conditions revealed that the monitoring and control can be done with a limited number of actuators, which reduces costs (Sohn et al, 2011).…”