Modeling and application of non-uniform engineering structures coupled with FGM and piezoelectric materials in stability enhancement and energy harvesting

Thumbnail Image
Keshmiri, Alireza
Journal Title
Journal ISSN
Volume Title
Dynamic analysis of non-uniform beams with tapered geometry and functionally graded material properties to achieve a better design for stability enhancement and energy harvesting applications is the main interest and focus of this thesis. A powerful and reliable theoretical model to derive the vibration response of nonlinearly tapered beams with axially functionally graded material properties within the framework of classical Euler–Bernoulli beam theory is developed and presented. The effect of geometry and material properties variation for different nonlinear profiles is comprehensively studied. It is demonstrated that piezoelectric layers and their coupling effect in addition to the non-uniform geometry, significantly enhance the stability of the smart non-uniform beam. The effects of compressive follower force, geometry taper ratio, boundary condition, and external piezoelectric voltage on flutter and buckling capacities of the non-uniform beam are examined. In addition, the model is also employed to present an analytical approach for the development of a non-uniform piezoelectric energy harvester. It is applied to surface bonded piezoelectric beams with non-uniform geometry and material variation profiles to derive the dynamic response of the structure to external environmental excitations and efficiently harvest the subsequent mechanical vibration energy. It is proved that the non-uniform configuration improves the electromechanical outputs. Additionally, an array of non-uniform harvesters is deployed to design a wideband piezoelectric energy harvesting system. It is shown that with the proposed formation, the system can optimally function over a wide frequency domain. Lastly, two new energy harvester configurations by using piezoelectric stacks are analytically developed. By benefiting from in-plane piezoelectric polarization, electrical outputs compared to a conventional harvester are considerably improved. At the end, an initial optimization model by using simulation-based optimization technique and machine learning algorithms is presented.
Non-uniform structures, FGM, Piezoelectric materials, Stability enhancement, Energy harvesting