An Investigation of the Electroaeroelastic Behavior of a Locally Resonant Piezoelectric Metastructure

2018 ◽  
Author(s):  
Gabriel B. Schiavon ◽  
Joao H. R. Dainezi ◽  
Carlos De Marqui
Keyword(s):  
Control Systems ◽  
Smart Materials ◽  
Passive Control ◽  
Flexible Substrates ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Control Schemes ◽  
Piezoelectric Layers ◽  
Rotary Wings ◽  
Resonant Shunt

The literature of aeroelasticity includes the use of smart materials to modify the aeroelastic behavior of fixed or rotary wings. In some cases, they are employed as actuators in active control systems while in others the use of smart materials in passive control schemes is investigated. In this work a different approach is investigated. The aeroelastic behavior of a locally resonant electromechanical metastructure made from flexible substrates with piezoelectric layers connected to resonant shunt circuits is investigated. An electromechanically coupled finite element plate model is employed for predicting the electroelasatic behavior of the wing. The unsteady aerodynamic loads are obtained from the doublet lattice model. By combining the structural and aerodynamic models, the aeroelastic behavior of the metastructure over a range of airflow speeds is studied.

scholarly journals Analysis of the Aerodynamic and Structural Performance of a Cooling Fan with Morphing Blade

2017 ◽  
Author(s):  
Alessio Suman ◽  
Annalisa Fortini ◽  
Nicola Aldi ◽  
Michele Pinelli ◽  
Mattia Merlin
Keyword(s):  
Control Systems ◽  
Passive Control ◽  
Structural Performance ◽  
Shape Variation ◽  
Axial Fan ◽  
Aerodynamic Loads ◽  
Cooling Fan ◽  
Blade Shape ◽  
Shape Characterization

The concept of smart morphing blades, which can control themselves to reduce or eliminate the need for active control systems, is a highly attractive solution in blade technology. In this paper an innovative passive control system based on Shape Memory Alloys (SMAs) is proposed. On the basis of previous thermal and shape characterization of a single morphing blade for a heavy-duty automotive cooling axial fan, this study deals with the numerical analysis of the aerodynamic loads acting on the fan. By coupling CFD and FEM approaches it is possible to analyze the actual blade shape resulting from both the aerodynamic and centrifugal loads. The numerical results indicate that the polymeric blade structure ensures proper resistance and enables shape variation due to the action of the SMA strips.

Full-scale tests of unsteady aerodynamic loads and pressure distribution on fast trains in crosswinds

Measurement ◽  
2021 ◽  
Vol 186 ◽  
pp. 110152
Author(s):  
Hongrui Gao ◽  
Tanghong Liu ◽  
Houyu Gu ◽  
Zhiwei Jiang ◽  
Xiaoshuai Huo ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Full Scale ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Full Scale Tests

Periodic Material-Based Passive Control Systems for Engineering Structures

2018 ◽  
Author(s):  
Witarto Witarto ◽  
Shiang-Jung Wang ◽  
Cho-Yen Yang ◽  
Xin Nie ◽  
Y. L. Mo ◽  
...  
Keyword(s):  
Control Systems ◽  
Passive Control ◽  
Engineering Structures

scholarly journals Unsteady loads for coaxial rotors in forward flight computed using a vortex particle method

2018 ◽  
Vol 122 (1251) ◽  
pp. 693-714 ◽  
Author(s):  
J. Tan ◽  
Y. Sun ◽  
G. N. Barakos
Keyword(s):  
Flow Model ◽  
Particle Method ◽  
Reversed Flow ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Vortex Particle Method ◽  
Coaxial Rotor ◽  
Aerodynamic Interaction ◽  
Coaxial Rotors ◽  
Vortex Particle

ABSTRACTRecent advances in coaxial rotor design have shown benefits of this configuration. Nevertheless, issues related to rotor-head drag, aerodynamic performance, wake interference, and vibration should also be considered. Simulating the unsteady aerodynamic loads for a coaxial rotor, including the aerodynamic interactions between rotors and rotor blades, is an essential part of analysing their vibration characteristics. In this article, an unsteady aerodynamic analysis based on a vortex particle method is presented. In this method, a reversed-flow model for the retreating side of the coaxial rotor is proposed based on an unsteady panel technique. To account for reversed flow, shedding a vortex from the leading edge is used rather than from the trailing edge. Moreover, vortex-blade aerodynamic interactions are accounted for. The model considers the unsteady pressure term induced on a blade by tip vortices of other blades, and thus accounts for the aerodynamic interaction between the rotors and its contribution to the unsteady airloads. Coupling the reversed-flow model and the vortex-blade aerodynamic interaction model with the viscous vortex-particle method is used to simulate the complex wake of the coaxial rotor. The unsteady aerodynamic loads on the X2 coaxial rotor are simulated in forward flight, and compared with the results of PRASADUM (Parallelized Rotorcraft Analysis for Simulation And Design, developed at the University of Maryland) and CFD/CSD computations with the OVERFLOW and the CREATE-AV Helios tools. The results of the present method agree with the results of the CFD/CSD method, and compare to it better than the PRASADUM solutions. Furthermore, the influence of the aerodynamic interaction between the coaxial rotors on the unsteady airloads, frequency, wake structure, induced flow, and force distributions are analysed. Additionally, the results are also compared against computations for a single-rotor case, simulated at similar conditions as the coaxial rotor. It is shown that the effect of tip vortex interaction plays a significant role in unsteady airloads of coaxial rotors at low speeds, while the rotor blade passing effect is obviously strengthened at high-speed.

scholarly journals Numerical Validation of Floating Offshore Wind Turbine Scaled Rotors for Surge Motion

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2578 ◽  
Author(s):  
Krishnamoorthi Sivalingam ◽  
Steven Martin ◽  
Abdulqadir Singapore Wala
Keyword(s):  
Wind Turbine ◽  
Turbine Rotor ◽  
Power Converter ◽  
Experimental Results ◽  
Offshore Wind ◽  
Speed Ratio ◽  
Offshore Wind Turbine ◽  
Floating Offshore Wind Turbine ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic

Aerodynamic performance of a floating offshore wind turbine (FOWT) is significantly influenced by platform surging motions. Accurate prediction of the unsteady aerodynamic loads is imperative for determining the fatigue life, ultimate loads on key components such as FOWT rotor blades, gearbox and power converter. The current study examines the predictions of numerical codes by comparing with unsteady experimental results of a scaled floating wind turbine rotor. The influence of platform surge amplitude together with the tip speed ratio on the unsteady aerodynamic loading has been simulated through unsteady CFD. It is shown that the unsteady aerodynamic loads of FOWT are highly sensitive to the changes in frequency and amplitude of the platform motion. Also, the surging motion significantly influences the windmill operating state due to strong flow interaction between the rotating blades and generated blade-tip vortices. Almost in all frequencies and amplitudes, CFD, LR-BEM and LR-uBEM predictions of mean thrust shows a good correlation with experimental results.

Control of Full-Size Frame Structures via Optimum Tuned Mass Dampers

2021 ◽  
Vol 10 (1) ◽  
pp. 47-61
Author(s):  
Apaer Mubuli ◽  
Sinan Melih Nigdeli ◽  
Gebrail Bekdaş
Keyword(s):  
Control Systems ◽  
Structural Control ◽  
Passive Control ◽  
Structural Model ◽  
Frame Structures ◽  
Tuned Mass Dampers ◽  
Element Analysis ◽  
Quarter Century ◽  
Full Size ◽  
Stiffness Properties

Structural control techniques are widely used to reduce the maximum values of the vibrations caused by strong earthquakes and winds and to rapidly dampen them. Among them, passive control systems have been used effectively to protect structural and non-structural elements from the destructive effects of earthquakes in the past quarter-century. Tuned mass dampers (TMD) that are part of passive control systems have been widely used in civil structures with their alternative benefits. In this study, the optimal adjustment of the parameters of a passive TMD placed on the top floor of the 10-story symmetrical structure was performed by a metaheuristic method called Jaya algorithm. The structural model was modeled in the SAP2000 finite element analysis software to obtain mass and stiffness properties. The results of the numerical analysis showed that the optimization of the TMD parameters is highly effective in reducing the total shear forces of the base of the full-size frame structures and reducing displacement in the event of seismic loads.

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