Piezoelektrik malzemeler ile plaka yapıların titreşimlerinden elektrik enerjisi üretimi

Vibrational energy harvesting has received considerable attention in recent years to develop self-powered devices that can offer many advantages for a wide variety of medical and aerospace applications. As a part of this trend, piezoelectric resonant beams have been extensively studied over the past decade. As an alternative to harvester beams, patch-based piezoelectric energy harvesters integrated to thin plates can be more convenient and practical for use on the surfaces of aerospace, automotive, and marine applications. However, piezoelectric energy harvesting on two-dimensional lightweight and flexible structures has been rarely reported in the existing literature and accurate mathematical models are required for the design and analysis of patch-based harvesters. Considering these needs, for the first time in the literature, this dissertation introduces analytical electroelastic models of patch-based piezoelectric energy harvesters attached on thin plates along with experimental validations and performance investigations for periodic and random vibrations. At first, distributed-parameter electroelastic model of a single patch-based piezoelectric harvester attached on a thin plate is developed. Exact solutions for steady-state electrical and structural responses are derived and closed-form expressions for electroelastic frequency response functions (FRFs) are obtained. Experimental measurements are carried out on a piezoceramic patch harvester structurally integrated on an all-four-edges clamped aluminum plate. Analytical electroelastic model is validated by comparing analytical predictions and experimental results. Power generation performance of the harvester patch from multiple vibration modes is investigated for a wide range of resistive loads. The single-patch model is extended to multiple patches connected in series and parallel. Coupled electroelastic models of multiple harvesters are developed and closed-form steady-state response expressions are derived for the series and parallel connection configurations. Experimental and analytical case studies of series- and parallel-connected double patch harvesters are given for validating predictions of multiple-patch models. Finally, patch-based harvesting from broadband and band-limited random vibrations of thin plates is studied. Analytical and numerical solutions for the expected power output and mean-square vibration response are obtained based on multiple-patch electroelastic models. Experiments for random vibration energy harvesting are conducted with the experimental setup having triple patch-based harvesters connected in series. It is shown that analytical and numerical predictions of expected structural and electrical responses agree well with experimental measurements for a wide range of resistive loads. Finally, random vibrational energy harvesting scenarios are studied to explore the effects of the excitation bandwidth on the expected power output and the optimal position of the piezoelectric energy harvester. The studies presented in this dissertation demonstrate that the developed analytical models successfully predict the electroelastic behavior of patch-based harvesters attached on thin plates. The analytical and experimental results also show that patch-based harvesting is an effective interface for vibrational energy harvesting from two-dimensional thin structures. Therefore, this dissertation contributes to the energy harvesting field by presenting accurate and compact analytical models of patch-based piezoelectric harvesters.