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Title: Modelling of porous piezoelectric material and potential applications to vibration energy harvesting
Author: Martinez Ayuso, German
ISNI:       0000 0004 7972 3876
Awarding Body: Swansea University
Current Institution: Swansea University
Date of Award: 2018
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Recently, the search of new materials with improved performance, such as higher strength, lower weight, fire resistance, less sensitive to fatigue, ... has been fostered and driven by industries such as aerospace, energy, and nuclear. The development of composite materials has been an important step to achieve these goals since it allows the combination of different materials in order to improve the overall performance of the resulting composite. Composites, such as layered woven composites or mixtures, are already heavy used in industry. These composite materials are tailored to improve one or several specific properties, for example higher strength or lower weight. However, composite materials are able not only to improve the existing material properties but also to add new properties. Self-sensing capabilities have drawn significant attention recently due to the increasing requirements of safety and optimization. Self-sensing structures are able to provide information in real time about its current state. Often self-sensing systems are distributed in large structures which poses a problem for the energy supply. Piezoelectric materials have been studied in depth for energy harvesting due to its capability to convert strain to charge and charge to strain. This is known as the piezoelectric effect and is used in many applications, from powering small devices to acoustic sensors. The use of these materials to harvest energy from the surrounding vibrations in the environment has been extensively studied by the scientific community, although commercial devices are still scarce. In this context, porous piezoelectric materials are a good option which can fulfil some of the above mentioned requirements: low density, strain-sensing capabilities and energy harvesting properties. Porous piezoelectric materials are composed of a piezoelectric material matrix with embedded air pores, which make them very light (up to 50% in some cases) while maintaining their piezoelectric properties. The presence of air reduces its material coeÿcients, such as stiffness, piezoelectric coupling and dielectric values, which opens the possibility to tailor the material properties by controlling the percentage of air inside the matrix. The reduction of capacitance is seen as beneficial for energy harvesting, since it reduces the wasted energy in the self-induced electric field. Therefore, the porous piezoelectric material are studied for energy harvesting applications. However, given the lack of reliable material models for these type of composite, it is seems the necessity to develop material models which can predict accurately the properties of the piezoelectric composite. This is a requirement prior to the use of the material in application or optimization.
Supervisor: Friswell, Michael I. ; Adhikari, Sondipon Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral