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Öğe Analysis of an actively controlled composite box manipulator without external actuator(Sage Publications Ltd, 2024) Lok, Sefika, I; Malgaca, Levent; Uyar, MehmetThis study focuses on active vibration control for a single-link composite box manipulator by using a single actuator for driving and control actions. Model extraction and system identification techniques are studied to obtain mathematical models of the manipulator. The state space model is extracted from the finite element model using modal analysis conducted in ANSYS, while the system identification approach is an experimental modeling method using the input and output signals of the system. The input signals are defined as triangular and trapezoidal motion profiles, while the output signals are the acceleration signals of the manipulator. Proportional derivative and positive position feedback controllers are implemented on the obtained mathematical models to reduce residual vibrations. The simulation results are successfully verified by experiments, and uncontrolled/controlled results are evaluated with reduction rates.Öğe Enhanced thermal and angular velocity-induced hybrid piezoelectric energy harvesting of smart turbine blades(Elsevier, 2024) Uyar, MehmetIn this study, an approach is proposed to examine hybrid piezoelectric energy harvesting performances from vibrations induced by thermal and angular velocity loads in order to generate energy from the smart turbine blade. In the proposed method, a smart turbine blade is formed by patching the piezoelectric material to the root surface of the turbine blade. A finite element (FE) model of the smart turbine blade is established and then it is validated with a smart blade model in a reference study to test the reliability and accuracy of the FE method. The defined loads are applied to the smart blade to obtain energy from mechanical vibrations induced by thermal and angular velocity loads. Temperature distribution, voltage, and vibration results obtained from energy harvesting analysis under different thermal and angular velocity loads are presented. In order to investigate the energy conversion efficiency of the energy obtained from the system, the energy harvesting circuit is tested in terms of battery discharge times and power output values. The results show that while the maximum energy conversion in the thermally induced smart turbine blade is 11.9 W, a power output of 12.3 W is obtained from the hybrid energy harvesting mechanism under angular velocity and heat flux loads.Öğe Eşdeğer Kütle-Yay-Sönüm Elemanı Kullanılan Ankastre Kompozit Bir Kirişin Titreşim Analizi(2018) Yavuz, Şahin; Uyar, Mehmet; Malgaca, Levent; Karagülle, HiraKompozit malzemeler hafif ve dayanıklı oldukları için manipülatör olarak endüstriyel yapılarda yaygın olarak kullanılmaktadır. Bu çalışmada, [0/90] oryantasyona sahip ankastre kompozit bir kirişin titreşim analizi çalışılmıştır. Yapının ucuna kütle eklenmiştir. Başlangıç koşulu olarak deplasman uç noktaya uygulanmış ve deneysel sistemin serbest titreşimi elde edilmiştir. Eksponansiyel sönüm bulunmuştur. Titreşim sinyalinin Hızlı Fourier dönüşümü kullanılarak doğal frekanslar hesaplanmıştır. Sistem ANSYS programında analiz edilmiş ve simülasyon sonuçları elde edilmiştir. Sönüm katsayısı, deneyden elde edilen eksponansiyel sönümden yararlanılarak hesaplanmıştır. Deneysel ya da simülasyondan elde edilen statik çökme, doğal frekans ve eksponansiyel sönüm kullanılarak sistemin eşdeğer kütle-yay-sönüm elemanı oluşturulmuştur. Eşdeğer kütle-yay-sönüm elemanı sonuçları Laplace dönüşüm metodu ile elde edilmiştir. Deneysel, simülasyon ve analitik sonuçlar uç noktanın farklı başlangıç yer değiştirme değerleri için karşılaştırılmıştır. Sonuçların uyumluluğu gözlemlenmiştirÖğe Experimental Active Vibration Control of a Highly Flexible Composite Manipulator with Acceleration Feedback(Springer Science and Business Media Deutschland GmbH, 2022) Uyar, Mehmet; Malgaca, Levent; Lök, Ş.İpek; Can, Seda VatanIn this study, vibration control of a single-link flexible smart composite manipulator (FSCM) is experimentally studied. The experimental system includes a real-time data acquisition control card, accelerometer, amplifier, servo motor, and driver. The FSCM is an epoxy-glass composite manipulator with the piezoelectric actuator and has the orientation of [0/90] lay-up. Modal analysis is experimentally conducted to find the natural frequencies by applying a chirp signal to the piezoelectric actuator. Natural frequencies are found by taking the Fast Fourier Transform (FFT) in MATLAB. Triangular motion profiles are used to drive the FSCM. Motion parameters are found by utilizing the natural frequencies of the system for different deceleration times (tdec). with different deceleration times (tdec). Residual vibrations are suppressed by using PID control with acceleration feedback. The acceleration signals at the tip point are measured by utilizing the accelerometer. The controller gains are determined with the trial and error method. Experimental residual vibration results are presented for the active control. It is observed that the suppression of vibration amplitudes further increases with active control. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.Öğe Farklı Karakteristikli Piezoelektrik Algılayıcıların Dinamik Performanslarının Karşılaştırılması(2018) Malgaca, Levent; Uyar, MehmetGünümüzde piezoelektrik malzemeler algılayıcı veya uyarıcı olarak mühendislik uygulamalarında sıklıkla kullanılmaktadır. En yaygın kullanılan piezoelektrik malzeme kurşun-zirkonyumtitanyum (PZT) piezo seramiktir. Piezo seramikler karakteristik özelliklerine göre yumuşak ve sert olarak iki ana sınıfa ayrılırlar ve PZT-2, PZT-4, PZT-5A, PZT-5H, PZT-8 olarak isimlendirilirler. Bu çalışmada, akıllı bir kirişte farklı karakteristikti piezoelektrik algılayıcının dinamik cevapları sonlu elemanlar yöntemi kullanılarak ANSYS/Workbench programında incelenmiştir. Akıllı kiriş, alüminyum kiriş ile bir piezoelektrik algılayıcı ve bir piezoelektrik uyarıcıdan oluşmuştur. Akıllı kirişte hem uç noktasına tekil kuvvet, hem uyarıcıya voltaj, darbe ve adım girdiler şeklinde uygulanmıştır. Algılayıcı ve yer değiştirme sinyalleri dinamik analiz yapılarak elde edilmiştir. Akıllı kirişin piezoelektrik algılayıcı konumu ve karakteristiğine göre farklı dinamik cevaplar verdiği gözlemlenmiştir.Öğe Investigation of vibration performance of pure active single and multi-feedback controls for a tall RC building(Elsevier Science Inc, 2023) Uyar, Mehmet; Ergun, MustafaStructural control methods are applied to eliminate the structural damages caused by the vibrations in the buildings and to improve their dynamic behavior of them under dynamic lateral loads. In this paper, the pure active control performance of a tall building under the influence of earthquake records, in which the effective time duration is determined by considering the ARIAS energy distribution, is presented. The building's pure active control performance in the period when the earthquake records have the maximum effect on the structure is examined. Eleven earthquake records are selected to better evaluate the effect of vibration control perfor-mance. A genetic algorithm is used to determine the parameters of single and multi-feedback controllers, and its effect on the vibration eliminations at the top and all floors is studied. Also, the effect of displacement and velocity feedback on seismic vibration control is evaluated. To carry out the vibration control studies of the building, the mathematical model is extracted from the finite element model created in ANSYS and verified with finite element analysis. It is observed that the displacement value at a reference location on the building is reduced from 0.735 m to 0.019 m, 0.004 m, and 0.002 m, respectively, by the Proportional-Integral-Derivative, Direct Velocity Feedback, and Optimal controllers. The results show that the multi-feedback control is more effective than the single-feedback control application in reducing the vibration amplitudes at all floors in the pure active control system.Öğe Seismic behavior assessment of RC buildings controlled by passive and active techniques(2024) Ergün, Mustafa; Uyar, MehmetIn this paper, a numerical study was carried out on the effectiveness of the active earthquake control method in improving the earthquake response of RC buildings. High damping rubber bearing design was made according to the criteria of the Uniform Building Code. Three different types of isolators were obtained geometrically. Passive earthquake control of the building was provided by placing these isolators under the columns. For active earthquake control of the building, controller design was realized by integrating it into the FE transient analysis in ANSYS. The active earthquake control design was studied using a force-based and displacement-based controller with acceleration and displacement feedback. The linear dynamic earthquake analysis in the time history of all three states of the building (un-controlled, passive, and active-controlled) was made using the acceleration record of the Seferihisar (İzmir) earthquake. When the results are examined, it is seen that the active earthquake control method provides almost all of the positive behavior expected from the passive earthquake control method. In addition, it eliminates some of the disadvantages of the passive earthquake control method.Öğe Study on dynamic modelling and vibration analysis of single-link flexible manipulator(2023) Uyar, MehmetIn this study, SimMechanics-based dynamic modeling and vibration analysis of a single-link flexible manipulator are studied. A flexible beam model is set up for modeling the manipulator. Transient analysis is performed to obtain the endpoint acceleration vibration responses of the manipulator moved with different motion profiles. Both the experimental and simulation acceleration results are presented for different cases. The root means square (RMS) values of the acceleration responses are calculated to evaluate the compatibility performance in verifying the simulation results with the experimental results. It has been observed that the results match each other successfully for different cases. The reliability of the SimMechanics-based dynamic modeling method of manipulators is discussed with the experimental results.
