Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2025Scopus SJRQ1Joule heating of carbon fiber in hybrid composites with glass fibers: Investigation of electro-thermal and vibration characteristics
Uslu, Emin; Yilmaz, Galip; Uyar, Mehmet
This study explores the innovative dual-purpose use of carbon fiber, functioning both as a structural and a heating element, expanding its potential in hybrid composites. A prototype composite was fabricated using the vacuum infusion process, featuring a single carbon fiber layer at the core for dual-purpose and two outer layers of glass fiber. Electrical heating tests revealed a stable relationship between voltage, resistance, power, and temperature, demonstrating efficient heat generation as the voltage increased. Thermal imaging confirmed uniform heat distribution with minor variations. Free vibration tests evaluated the composite's dynamic behavior under various electro-thermal conditions. Results showed that increasing temperature reduced the natural frequencies, particularly in the second vibration mode. Changes in Rayleigh damping coefficients at higher temperatures highlighted the composite's sensitivity to thermal inputs. These findings underline the potential of hybrid composites for advanced applications like turbine blades and aerospace components, where multifunctionality, self-heating, and vibration control are critical.
- MakaleAçık Erişim2025Scopus SJRQ2Performance analysis of piezoelectric-based energy harvesting in reinforced concrete buildings under seismic and live loads
Ergün, Mustafa; Uyar, Mehmet; Malgaca, Levent
The demand for autonomous energy solutions in seismic regions is increasing for the uninterrupted operation of structural health monitoring systems. In this context, energy harvesting systems offer a solution for low-power devices, especially in earthquake zones where external energy sources may be interrupted. This study evaluates the energy harvesting capacity of a piezoelectric energy harvesting mechanism placed at specific locations in the columns of a reinforced concrete structure, considering both earthquake and live load conditions. A smart building model is developed by placing sensor modules with piezoelectric material on the columns of a three-story reinforced concrete building. The finite element model of the smart building, which is formed by integrating various technologies and sensors, is created in ANSYS, and specific locations on the columns are selected as sensor points. Dynamic analyses are performed under earthquake conditions by considering seismic records from the Imperial Valley, Erzincan, and Darfield earthquakes. Experimental results of a smart structure with patched piezoelectric material are used to verify the simulation results. The voltage, current, and power responses obtained from the sensor points are examined with the payload effect placed at the end point of the sensor module. When the power values collected from the sensor points are compared, it can be said that the maximum power obtained from the smart building under both earthquake and live load is 0.355 W, while the minimum power value reaches 0.168 W. The results show that the energy harvesting mechanism can provide external power to support electronic devices in regions where earthquake effects are frequent and high. Thus, this study presents an innovative contribution to smart building systems by investigating the energy harvesting potential under earthquake and live loads in a reinforced concrete structure equipped with piezoelectric sensors. The model, validated with numerical and experimental analyses, proposes a sustainable energy source for structural health monitoring systems in seismic regions.
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İncele - MakaleAçık Erişim2024Seismic behavior assessment of RC buildings controlled by passive and active techniques
Uyar, Mehmet; Ergün, Mustafa
In 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.
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İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ1Enhanced thermal and angular velocity-induced hybrid piezoelectric energy harvesting of smart turbine blades
Uyar, Mehmet
In 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.
AtıfScopus5WoS5OpenAlex3İncele - MakaleAçık Erişim2024Scopus SJRQ2Analysis of an actively controlled composite box manipulator without external actuator
Lök, Şefika İ; Malgaca, Levent; Uyar, Mehmet
This 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.
AtıfScopus3WoS3OpenAlex2İncele - MakaleAçık Erişim2023Study on dynamic modelling and vibration analysis of single-link flexible manipulator
Uyar, Mehmet
In 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.
AtıfOpenAlex3İncele - MakaleYalnız künye2023Scopus SJRQ1Investigation of vibration performance of pure active single and multi-feedback controls for a tall RC building
Uyar, Mehmet; Ergün, Mustafa
Structural 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 performance. 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.
AtıfScopus6WoS5OpenAlex5İncele - BildiriAçık Erişim2022Experimental Active Vibration Control of a Highly Flexible Composite Manipulator with Acceleration Feedback
Uyar, Mehmet; Malgaca, Levent; Lök, Ş.İpek; Can, Seda Vatan; Herisanu, N.; Marinca, V.
In 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.
AtıfScopus2OpenAlex2İncele - MakaleAçık Erişim2018Farklı Karakteristikli Piezoelektrik Algılayıcıların Dinamik Performanslarının Karşılaştırılması
Uyar, Mehmet; Malgaca, Levent
Günümüzde 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.
AtıfOpenAlex1İncele - MakaleAçık Erişim2018Vibration Analysis of a Cantilever Composite Beam by Equivalent MassSpring-Damper Systems
Uyar, Mehmet; Malgaca, Levent; Yavuz, Sahin; Karagülle, Hira
Composite materials are widely used in industrial structures such as manipulators because they are lightweight and durable. In this work, the vibration analysis of a cantilever composite beam with [0/90] lay-up was studied. An end point mass was added to the structure. An initial displacement was applied to the end point and the free vibration was analyzed experimentally first. Exponential decay was found. Natural frequencies were determined by taking the Fast Fourier Transform of the vibration signal. The system was analyzed in ANSYS and simulation results were obtained. The damping coefficient was determined by trial using the experimental exponential decay. An equivalent massspring-damper model (MSD) was established using static deflection, natural frequency and exponential decay obtained experimentally or by simulation. MSD-analytical results were obtained by the Laplace transform method. The experimental, simulation, and analytical results were compared for different end point initial displacement values. It was observed that the results are in good agreement.
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