مدل‌سازي و تحليل ارتعاشي سيستم‌هاي برداشت‌كننده انرژي پيزوالكتريك چندصفحه‌اي در محيط‌هاي سيالي

Modeling an‎d Vibration Analysis of Multiple Plate Piezoelectric Energy Harvester Systems in Fluidic Environments

مهندسي مكانيك

The influence of fluid acoustic pressure has been extensively investigated within the framework of Fluid-Structure Interaction (FSI); however, its potential for energy harvesting remains largely underutilized. This thesis introduces a novel approach for harvesting energy from flow-induced acoustic pressure using an array of parallel piezoelectric plates. The proposed system confines acoustic pressure between stacked plates, where piezoelectric patches convert the resulting mechanical vibrations into electrical energy. The nonlinear coupling effects induced by the acoustic medium are analytically modeled, an‎d the governing equations are derived using Hamilton’s principle. A semi-analytical framework is developed by integrating the Differential Quadrature Method (DQM) with Galerkin’s method to predict the system’s steady-state response under harmonic excitation. To establish the foundation for this model, some preliminary investigations are required. First, a structure comprising n elastically connected, parallel rectangular plates is considered. The dynamic behavior of the system is described by a set of n coupled partial differential equations. Through an innovative variable transformation, these equations are decoupled, effectively reducing the problem to n independent plate systems. This transformation enables the application of efficient single-plate solution techniques via DQM, significantly reducing computational complexity. The original coupled system is then reconstructed using an inverse transformation. The study further explores the impact of boundary conditions, revealing that free-edge configurations can effectively tune the frequency range for optimal energy harvesting. Second, building upon multimodal energy harvesting principles, a semi-analytical electroelastic model is proposed for the piezoelectric multi-plate harvester. The system consists of isotropic rectangular plates coupled through a visco-Pasternak foundation an‎d integrated with piezoelectric patches. The primary objective is to simultaneously enhance power output an‎d broaden the operational frequency ban‎dwidth. The analogy between this simplified model an‎d the full FSI system provides a robust foundation for accurate analysis an‎d optimization. The final stage of the study focuses on the comprehensive FSI model, validated against existing literature to ensure accuracy. Parametric analyses are conducted to assess the influence of key design variables, including the number of plates, pitch height, aspect ratio, electrical conductance, an‎d mean flow channel velocity. Results demonstrate that tuning the dimensionless mean flow velocity significantly improves both frequency ban‎dwidth an‎d output voltage, thereby optimizing the system’s energy harvesting performance. This work offers a promising pathway for leveraging fluid acoustic pressure in sustainable energy applications an‎d contributes a novel methodology for efficient energy harvesting through piezoelectric FSI systems.

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