Highly Flexible lead-free piezoelectric composites- For vibration damping and noise cancellation application

Vibrations are inherent part in an aircraft system and supressing them has always been a technological challenge. Over the recent years, damping of mechanical vibrations is becoming increasing important to improve the reliability and performance of the aircraft systems and also increase the safety of passengers. As a response to these issues, much effort has been expended in the development and exploitation of damping materials. Among the various damping materials, piezoelectric particulate polymer composite have shown great potential towards damping due to the specialised damping mechanism based on the unique energy transferring effect between the viscoelastic polymer matrix and piezoelectric ceramic filler. As a results, the main objective of the master thesis is to develop a highly flexible and highly voltage sensitive vibration damper with piezoelectric particular composite. Lead free system with sodium potassium niobate (KNN) ceramics doped with lithium is identified has the suitable ceramic filler system applicable for this purpose. Hence, the effect of lithium dopant on dielectric and piezoelectric properties on the structured and random KNN/Epoxy composites is explored in order to identify the optimal ceramic filler composition with the highest dielectric and piezoelectric properties. To increase the passive damping potential of the composite, a flexible PDMS polymer matrix with excellent damping capabilities is selected and mixed with the optimal ceramic filler composition to investigate further on the piezoelectric voltage sensing properties in combination with the passive damping capabilities of the composite to be usable as vibration damper is presented. Finally, moving towards real-time application, feasibility study on processing relatively large area flexible piezoelectric sensor with high voltage sensitivity and capability of dampening vibrations is investigated.Novel Aerospace MaterialsAerospace Design, Integration & OperationsAerospace Engineerin