Researcher:
Aghakhani, Amirreza

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PhD Student

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Amirreza

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Aghakhani

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Aghakhani, Amirreza

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2014 - 201912

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    Electroelastic modeling of thin-laminated composite plates with surface-bonded piezo-patches using Rayleigh–Ritz method
    (Sage Publications Ltd, 2018) N/A; N/A; N/A; Department of Mechanical Engineering; Gözüm, Mehmet Murat; Aghakhani, Amirreza; Serhat, Gökhan; Başdoğan, İpek; PhD Student; PhD Student; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 179940
    Laminated composite panels are extensively used in various engineering applications. Piezoelectric transducers can be integrated into such composite structures for a variety of vibration control and energy harvesting applications. Analyzing the structural dynamics of such electromechanical systems requires precise modeling tools which properly consider the coupling between the piezoelectric elements and the laminates. Although previous analytical models in the literature cover vibration analysis of laminated composite plates with fully covered piezoelectric layers, they do not provide a formulation for modeling the piezoelectric patches that partially cover the plate surface. In this study, a methodology for vibration analysis of laminated composite plates with surface-bonded piezo-patches is developed. Rayleigh-Ritz method is used for solving the modal analysis and obtaining the frequency response functions. The developed model includes mass and stiffness contribution of the piezo-patches as well as the two-way electromechanical coupling effect. Moreover, an accelerated method is developed for reducing the computation time of the modal analysis solution. For validations, system-level finite element simulations are performed in ANSYS software. The results show that the developed analytical model can be utilized for accurate and efficient analysis and design of laminated composite plates with surface-bonded piezo-patches.
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    Equivalent circuit modeling and experimental validation of a piezoelectric energy harvester attached on a thin plate with AC-DC conversion
    (International Conference on Adaptive Structures and Technologies, 2015) Erturk, Alper; Department of Mechanical Engineering; Başdoğan, İpek; Aghakhani, Amirreza; Faculty Member; PhD Student; Department of Mechanical Engineering; College of Engineering; 179940; N/A
    Plate-like structures are widely used in numerous automotive, marine and aerospace applications. Power output investigations of patch-based piezoelectric energy harvesters integrated to these structures require accurate models for energy harvesting performance evaluation and optimization. The equivalent circuit modeling of the cantilever-based vibration energy harvesters for estimation of electrical response has been proposed in the recent years for predicting the electrical outputs of the harvesters. However, equivalent circuit modeling of piezoelectric patch harvesters integrated to plate-like structures including nonlinear circuits has not been studied in the existing literature. Considering these needs, a multi-mode equivalent circuit model of a piezoelectric energy harvester integrated to a thin plate is developed and verified experimentally in the present study. Equivalent circuit parameters are obtained from analytical distributed-parameter model of the plate and harvester which governs the electromechanical coupling behavior of piezoelectric patch and vibration of the host plate. The multi-mode circuit representation of the harvester is built via electronic circuit simulation software SPICE. Using the SPICE software, electrical outputs of the piezoelectric energy harvester are computed for the standard AC input-AC output and AC input-DC output problems. In the AC-AC case, only a resistive load is connected to the harvester, whereas for the AC-DC case, a full-wave rectifier and a smoothing capacitor are connected to the circuit before the resistive load to convert the AC voltage to stable DC voltage. In the AC-AC problem, voltage FRFs are calculated for various resistive loads and validated by the published analytical closed-form solution. In the AC-DC problem, simulation results of the DC voltage and power outputs are computed for a wide range of load resistance values and validated with comparisons against the analytical single-mode representation of the harvester. Finally, experimental measurements of DC voltage FRFs are conducted for a case study and verified against the numerical model.
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    An investigation of the electromechanical coupling and broadband shunt damping in composite plates with integrated piezo-patches
    (Sage Publications Ltd, 2019) N/A; N/A; Department of Mechanical Engineering; Gözüm, Mehmet Murat; Aghakhani, Amirreza; Başdoğan, İpek; PhD Student; PhD Student; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 179940
    The popularity of laminated composite plate-like structures is increasing in various engineering applications. Piezoelectric patches with electrical circuit elements can be integrated into these structures for shunt damping applications. for analyzing the shunt damping performance of these systems, precise modeling tools are required, which consider the two-way electromechanical coupling between the piezo-patches and the host plate. This study aims to identify the system parameters which affect the electromechanical coupling coefficient, A metric for measuring the effectiveness of mechanical-to-electrical energy conversion. for that purpose, A thorough investigation is performed to determine the critical system parameters and their combined effects on the electromechanical coupling coefficient of laminated composite plates with surface-bonded piezo-patches. First, the first four natural frequencies of the electromechanical system are obtained using the Rayleigh-Ritz method for various patch sizes. then, the electromechanical coupling coefficient variations for a different set of system parameters are presented. Later, to demonstrate the applicability of the developed methodology for a broader frequency range, four independently shunted piezo-pairs are attached to the plate. the contours of electromechanical coupling coefficient values with respect to ply angle and patch-pair size are presented for the first four modes. Finally, the vibration amplitudes are successfully reduced for these modes using the optimal system parameters.
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    A general electromechanical model for plates with integrated piezo-patches using spectral-Tchebychev method
    (Elsevier, 2019) Bediz, Bekir; Department of Mechanical Engineering; N/A; Department of Mechanical Engineering; Aghakhani, Amirreza; Motlagh, Peyman Lahe; Başdoğan, İpek; PhD Student; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 355153; 179940
    This paper presents a general electromechanical model for predicting the dynamics of thin or moderately thick plates with surface-integrated piezo-patches. Using spectral Tchebychev (ST) technique, the boundary value problem governing the electroelastic dynamics of the two dimensional (2D) plate and piezo-patch structure is developed with Mindlin plate theory assumptions. Mass and stiffness contributions of piezo-patch(es) as well as two-way electromechanical coupling behavior are incorporated in the model for both modal analysis and frequency response calculations. To validate the accuracy of the developed solution technique, the modal analysis results are compared against the existing Rayleigh-Ritz solution from the literature as well as the finite-element simulation results for various piezo-patch sizes on thin and moderately thick host plates; and it is shown that the maximum difference in the predicted natural frequencies between the ST and FE results are below 1%. The electromechanical frequency response functions (FRFs) including the vibration response and electrical output of the system under a transverse point force excitation are obtained using the ST model and the results are shown to match perfectly with the finite element (FE) simulations. Additionally, comparisons of the electromechanical FRFs calculated based on Rayleigh-Ritz method from the literature versus the developed framework is presented to highlight that the exclusion of shear deformation terms in the former model leads to an inaccurate estimation of electroelastic behavior for the case of thicker plates with integrated piezo-patches. Finally, the investigated case studies demonstrate that the computational efficiency of the developed method is significantly higher than that of FE simulations. (C) 2019 Elsevier Ltd. All rights reserved.
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    Equivalent impedance electroelastic modeling of multiple piezo-patch energy harvesters on a thin plate with AC-DC conversion
    (IEEE-Inst Electrical Electronics Engineers Inc, 2017) N/A; Department of Mechanical Engineering; Aghakhani, Amirreza; Başdoğan, İpek; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 179940
    Piezo-patch energy harvesters can be readily attached to plate-like structures in automotive, marine, and aerospace applications, in order to exploit the broadband vibration of the host system. Power output investigations of such patch-based harvesters, when connected to practical interface circuits, require accurate models for harvesting performance evaluation and optimization. This paper proposes an analytical approach to derive the closed-form mechanical and electrical response expressions of the multiple piezo-patch energy harvesters (MPEHs) by integrating an equivalent load impedance, which consists of the harvesting circuit and the overall piezo-patch capacitance into a distributed-parameter model of the plate. Moreover, an equivalent circuit model of the electromechanical system is developed in a circuit simulator software SPICE for system-level simulations, taking into account the interconnection of piezo-patches and multiple vibration modes of the plate. Numerical SPICE simulations are then validated for the conventional ac input-ac output problem by the experiments and existing analytical solution. The proposed analytical model is validated by the experiments for the standard ac input-dc output problem. Finally, the analytical and numerical results for the peak power output of the MPEHs in series/parallel configuration with ac and dc interface circuits are presented, and shown to be in good agreement with the experimental results.
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    Piezoelectric patch-based energy harvesting on a heavy duty vehicle panel
    (Web Portal ASME (American Society of Mechanical Engineers), 2014) N/A; N/A; N/A; Department of Mechanical Engineering; Bayık, Buğra; Aghakhani, Amirreza; Arıdoğan, Mustafa Uğur; Başdoğan, İpek; Master Student; PhD Student; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 179940
    Vibration-based energy harvesting has drawn significant attention from different engineering disciplines over the last two decades. The studies in this research area have mostly concentrated on cantilevered piezoelectric beam harvesters under base excitations. As an alternative to beam arrangements, patch-based piezoelectric energy harvesters can be integrated on large plate-like structures such as panels of automotive, marine and aerospace applications to extract useful electrical power during their operation. In this paper, electroelastic finite element (FE) simulations of a patch-based piezoelectric energy harvester structurally integrated on a panel of a heavy duty vehicle are presented during different phases of operation. FE model of the panel together with a piezoceramic harvester patch is built using ANSYS software. The FE model takes into account coupled electromechanical dynamics and the fully-conductive electrode layers of the harvester patch. The vibration response of the panel as well as the voltage output of the harvester patch under operating conditions is simulated using the forces obtained from experimental measurements on the heavy duty vehicle. Excitation forces are calculated from operational acceleration measurements using matrix inversion method, which is a force identification technique. Two different operating conditions of the heavy duty vehicle are considered: stationary and moving on a test track while the engine was running. Using the excitation forces in the FE simulations, the electrical power generation of the harvester patch is predicted for a wide range of resistive loads. Electrical power outputs are then presented for short-circuit and open-circuit conditions. The numerical results show that the use of a harvester patch attached on a panel of a heavy duty vehicle generates reasonably well electrical power outputs.
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    Equivalent circuit modeling of a piezo-patch energy harvester on a thin plate with AC-DC conversion
    (Iop Publishing Ltd, 2016) Ertürk, A; N/A; N/A; Department of Mechanical Engineering; Bayık, Buğra; Aghakhani, Amirreza; Başdoğan, İpek; Master Student; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 179940
    As an alternative to beam-like structures, piezoelectric patch-based energy harvesters attached to thin plates can be readily integrated to plate-like structures in automotive, marine, and aerospace applications, in order to directly exploit structural vibration modes of the host system without mass loading and volumetric occupancy of cantilever attachments. In this paper, a multi-mode equivalent circuit model of a piezo-patch energy harvester integrated to a thin plate is developed and coupled with a standard AC-DC conversion circuit. Equivalent circuit parameters are obtained in two different ways: (1) from the modal analysis solution of a distributed-parameter analytical model and (2) from the finite-element numerical model of the harvester by accounting for two-way coupling. After the analytical modeling effort, multi-mode equivalent circuit representation of the harvester is obtained via electronic circuit simulation software SPICE. Using the SPICE software, electromechanical response of the piezoelectric energy harvester connected to linear and nonlinear circuit elements are computed. Simulation results are validated for the standard AC-AC and AC-DC configurations. For the AC input-AC output problem, voltage frequency response functions are calculated for various resistive loads, and they show excellent agreement with modal analysis-based analytical closed-form solution and with the finite-element model. For the standard ideal AC input-DC output case, a full-wave rectifier and a smoothing capacitor are added to the harvester circuit for conversion of the AC voltage to a stable DC voltage, which is also validated against an existing solution by treating the single-mode plate dynamics as a single-degree-of-freedom system.
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    Equivalent circuit modeling of patch-based piezoelectric energy harvesting on plate-like structures with AC-DC conversion
    (International Conference on Adaptive Structures and Technologies, 2015) Erturk, Alper; Department of Mechanical Engineering; Başdoğan, İpek; Aghakhani, Amirreza; Faculty Member; PhD Student; Department of Mechanical Engineering; College of Engineering; 179940; N/A
    The equivalent circuit modeling of the vibration-based energy harvesters for accurate estimation of electrical response has drawn much attention over the recent years. Different methods have been proposed to obtain the equivalent circuit parameters using analytical and finite element models of the piezoelectric energy harvesters. In such methods, the structure is a typical cantilever beam with piezoelectric layers under base excitation. As an alternative to beams, piezoelectric patch-based harvesters attached to thin plates can be considered due to the wide use of plate-like structures in automotive, marine and aerospace applications. Considering these needs, a multi-mode equivalent circuit model of a piezoelectric energy harvester integrated to a thin plate is developed in this study. Equivalent circuit parameters are obtained from analytical distributedparameter model of the harvester which covers the electromechanical coupling behavior of the piezoelectric patch and vibration of the host plate. The multi-mode circuit representation of the harvester is built via electronic circuit simulation software SPICE. Using the SPICE software, electrical outputs of the piezoelectric energy harvester connected to linear and nonlinear circuit elements are computed. Simulation results are then validated for the standard AC-AC and AC-DC configurations. For the AC configuration, voltage Frequency Response Functions (FRFs) are calculated for various resistive loads and they exhibit excellent agreement with the published analytical closed-form solution. For the fullwave rectifier configuration, simulation results of the DC voltage and power outputs are calculated for a wide range of load resistance values and compared with the analytical singlemode expression of the harvester in the literature. © Copyright 2015 by ASME.
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    PublicationOpen Access
    Multiple piezo-patch energy harvesters on a thin plate with respective AC-DC conversion
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2018) Department of Mechanical Engineering; Aghakhani, Amirreza; Başdoğan, İpek; PhD Student; Department of Mechanical Engineering; College of Engineering; N/A; 179940
    Piezoelectric patch energy harvesters can be directly integrated to plate-like structures which are widely used in automotive, marine and aerospace applications, to convert vibrational energy to electrical energy. This paper presents two different AC-DC conversion techniques for multiple patch harvesters, namely single rectifier and respective rectifiers. The first case considers all the piezo-patches are connected in parallel to a single rectifier, whereas in the second case, each harvester is respectively rectified and then connected in parallel to a smoothing capacitor and a resistive load. The latter configuration of AC-DC conversion helps to avoid the electrical charge cancellation which is a problem with the multiple harvesters attached to different locations of the host plate surface. Equivalent circuit model of the multiple piezo-patch harvesters is developed in the SPICE software to simulate the electrical response. The system parameters are obtained from the modal analysis solution of the plate. Simulations of the voltage frequency response functions (FRFs) for the standard AC input - AC output case are conducted and validated by experimental data. Finally, for the AC input - DC output case, numerical simulation and experimental results of the power outputs of multiple piezo-patch harvesters with multiple AC-DC converters are obtained for a wide range of resistive loads and compared with the same array of harvesters connected to a single AC-DC converter.
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    PublicationOpen Access
    Passive vibration control of a plate via piezoelectric shunt damping with FEM and ECM
    (Society of Photo-optical Instrumentation Engineers (SPIE), 2018) Department of Mechanical Engineering; Aghakhani, Amirreza; Başdoğan, İpek; Motlagh, Peyman Lahe; PhD Student; Department of Mechanical Engineering; College of Engineering; N/A; 179940; N/A
    Two-dimensional thin plates are widely used in many aerospace, automotive and marine applications. Vibration attenuation can be achieved in these structures by attaching piezoelectric elements on to the structure integrated with shunt damping circuits. This enables a compact vibration damping method without adding significant mass and volumetric occupancy, unlike the bulky mechanical dampers. Practical implementation of shunt damping technique requires accurate modeling of the host structure, the piezoelectric elements and the dynamics of the shunt circuit. Unlike other studies in the literature of piezoelectric shunt damping, this work utilizes a multi-modal equivalent circuit model (ECM) of a thin plate with multiple piezo-patches, to demonstrate the performance of shunt circuits. The equivalent system parameters are obtained from the modal analysis solution based on the Rayleigh-Ritz method. The ECM is coupled to the shunt circuits in SPICE software, where the shunt configuration consists of three branches of electrical resonators, each tuned to one vibration mode of the structure. Using the harmonic analysis in SPICE for a range of excitation frequencies, current output of each ECM branch is calculated for open-circuit and optimum shunt circuit conditions. The current of ECM branches are then converted to the displacement outputs in physical coordinates and validated by the finite-element simulations in ANSYS. It is shown that the vibration attenuation of a vibration mode can be successfully achieved when there is a reduction in the corresponding current amplitude of the ECM branch. This correlation can be utilized in the design of efficient linear/nonlinear shunt circuits.