In the context of Condition Based Maintenance (CBM) for aircrafts, Structural Health Monitoring (SHM) is one main field of research. Detection and localization of damages in a structure request reliability of the equipment and repeatability of the measurements and process. An electronic device called Lamb Wave Detection System (LWDS) have been developed and manufactured to manage piezo-electric patches either in emission or reception mode with a high commutation rate. Besides, integration of the piezo patches is another crucial aspect of reliability. Several methods as modelling and dispersion curves can define the frequency range of Lamb waves to optimize the piezo-electric coupling. This work which takes part of the H2020 ReMAP project about adaptative aircraft maintenance planning, is presented in the article.
PVDF loudspeakers are used for some applications in audio and could be used for applications in active control where light structures are needed, for example in aeronautics. For all these applications, it is necessary to be able to predict the acoustic response of such systems in order to help the designer. Some papers propose models for calculating the acoustic pressure radiated by these loudspeakers.
Required improvements of piezoelectric elements actuation and measurement system efficiency and robustness are introduced as a critical feature for structural health monitoring (SHM) applications. An electronic module (Lamb wave detection system: LWDS) allowing to use each piezoelectric element in an array either in emission or reception mode is presented. The high commutation rate between these two states, for each transducer separately, is a key enhancement for SHM methods. The robustness of the sensor integration is also studied considering the patches size and bonding method. Coupled dispersion curve are introduced Comparison of FEM simulation and experiments of the piezo-electric coupling are presented. This work takes part of the H2020 REMAP project about adaptive aircraft maintenance planning.
This paper presents comparison between two excitation solutions for tubular ultrasonic transducer. The axial excitation is widespread in conventional ultrasonic transducer. The radial excitation is proposed in order to have an uniform acoustic energy all along the tube. This excitation approach is also proposed to allow the modularity by adding several tubes.
Ultrasonic-based SHM (Structural Health Monitoring) applications usually rely on the use of piezo-electric patches to emit and receive ultrasonic surface acoustic waves. The principle is to study the propagation of the waves through a structure to assess its health. Because of the elevated number of echoes and possible modes of propagation of the acoustic waves within the structure, those applications suffer from a burden of signal processing. This paper presents a composite piezo-electric patch and its electronics that were designed and successfully tested for reducing the complexity of the SHM detection schemes.
This article deals with a stress sensor for cables which has been designed, built and test. it is based on a special magnetostrictive effect of ferromagnetic materials as high elastic limit steels used for bridge cables or prestressed concrete.