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Parametric study on the flutter sensitivity of a wide-chord hollow fan blade

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Chinese Journal of Aeronautics 2022年第11期35卷 277-293页

作者： Xiaojie ZHANG Yanrong WANG Weiyu CHEN Xianghua JIANG School of Energy and Power Engineering Beihang UniversityBejing 100083China Jiangxi Research Institute Beihang University Nanchang 330096China

In recent years, the hollow fan blades have been widely used to meet the demand for light weight and good performance of the aero-engine. However, the relationship between the hollow structure and the aeroelastic stability has not been studied yet in the open literature. In this paper,it has been investigated for an H-shaped hollow fan blade. Before studying the flutter behavior, the methods of parametric modeling and auto-generation of Finite Element Model(FEM) are presented. The influence of the feature parameters on the vibration frequency and mode shape(as the input of flutter calculation) of the first three modes are analyzed by the Orthogonal Experimental Design(OED) method. The results show that the parameters have a more remarkable impact on the first torsional mode and thus it is concerned in the flutter sensitivity analysis. Compared with the solid blade, the minimum aerodynamic damping of the hollow blade decreases, indicating that the hollow structure makes the aeroelastic stability worse. For the parameters describing the hollow section, the rib number N has the greatest influence on the minimum aerodynamic damping, followed by the wall thickness W5. For the parameters in the height of hollow segment, the aerodynamic damping increases with the increase of parameters M1 and M2. This means that reducing the height of the hollow segment is helpful to improve the aeroelastic stability. Compared with the impact of parameters in hollow section, the variation of aerodynamic damping caused by the height of the hollow segment is small.

关键词： Aerodynamic damping flutter Hollow fan blade Hollow structure Orthogonal experimental design

Application of output feedback sliding mode control to active flutter suppression of two-dimensional airfoil

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Science China(Technological Sciences) 2010年第5期53卷 1338-1348页

作者： YANG Chao,SONG Chen,WU ZhiGang & XIE ChangChuan School of Aeronautic Science and Engineering,Beijing University of Aeronautics & Astronautics,Beijing 100191,China School of Aeronautic Science and Engineering Beijing University of Aeronautics & Astronautics

The effectiveness of the sliding mode control(SMC) method for active flutter suppression(AFS) and the issues concerning control system discretization and control input constraints were studied using a typical two-dimensional *** airfoil has a trailing-edge flap for flutter *** aeroelastic system involves a two-degrees-of-freedom motion(pitch and plunge),and the equations were constructed by utilizing quasi-steady aerodynamic *** control system,designed by the output feedback SMC method,was incorporated to suppress the pitch-plunge ***,the system discretization and the flap deflection constraints were ***,a classical Runge-Kutta(RK) algorithm was utilized for numerical *** results indicated that the close-loop system with the SMC system could be stable at a speed above the flutter ***,when the flap deflection limits are reached,the close-loop system with the simple discretized control system loses ***,control compensation developed by theoretical analysis was proposed to make the system stable *** parameter perturbations and the time delay effects were also discussed in this paper.

关键词： aeroelasticity flutter airfoil sliding mode control output feedback control

Experimental study on flutter stability of a long-span bridge subject to wind-rain actions

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Science China(Technological Sciences) 2013年第8期56卷 2089-2098页

作者： XIN DaBo LI Hui OU JinPing WANG Liang CHEN DongYing School of Civil Engineering Harbin Institute of Technology School of Civil & Hydraulic Engineering Dalian University of Technology School of Construction Engineering Heilongjiang Institute of Technology

Based on the free vibration test method for extracting flutter derivatives,an experiment on flutter stability of a long-span bridge under simultaneous actions of wind and rain was carried out in a wind tunnel.A separated twin-box girder section model was employed as the *** flutter derivatives and critical flutter wind speed of this girder subject to both wind and rain(with various rainfall intensities,wind speeds and attack angles)were obtained,then the flutter stability of the bridge influenced by rainfall was *** results showed that the flutter derivatives of this bridge depend on the angles of attack of wind flow in the wind and rain ***,rainfall has great effect on three flutter derivatives(H2*,H4* and A4*)and has less effect on other three flutter derivatives(H1*,H3* and A3*).With the increasing rainfall density,the critical flutter velocity first increases and then *** density of rainfall has the effect of increasing mass,stiffness and damping on bridge decks,and higher density of rainfall has the effect of random inhomogeneous impact on bridge decks.

关键词： flutter long-span bridge simultaneous actions of wind and rain wind tunnel test

Robust flutter analysis based on genetic algorithm

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Science China(Technological Sciences) 2012年第9期55卷 2474-2481页

作者： GU YingSong ZHANG XinPing YANG ZhiChun Institute of Structural Dynamics and Control Northwestern Polytechnical UniversityXi'an 710072China A VIC Shaanxi Aircraft Industry(Group)Corporation LTD. Hanzhong 723213China

Robust flutter analysis considering model uncertain parameters is very important in theory and engineering *** robust flutter solution based on structured singular value subject to real parametric uncertainties may become difficult because the discontinuity and increasing complexity in real mu *** is crucial to solve the worst-case flutter speed accurately and efficiently for real parametric *** this paper,robust flutter analysis is formulated as a nonlinear programming *** proper nonlinear programming technique and classical flutter analysis method,the worst-case parametric perturbations and the robust flutter solution will be captured by optimization *** the derived nonlinear programming problem,the parametric uncertainties are taken as design variables bounded with perturbed intervals,while the flutter speed is selected as the objective *** model is optimized by the genetic algorithm with promising global optimum *** present approach avoids calculating purely real mu and makes robust flutter analysis a plain *** is illustrated by a special test case that the robust flutter results coincide well with the exhaustive *** is also demonstrated that the present method can solve the match-point robust flutter solution under constant Mach number accurately and *** method is implemented in problem with more uncertain parameters and asymmetric perturbation interval.

关键词： flutter genetic algorithm robust flutter analysis match-point solution nonmatch-point solution

Geometrically Nonlinear flutter Analysis Based on CFD/CSD Methods and Wind Tunnel Experimental Verification

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Computer Modeling in Engineering & Sciences 2023年第8期136卷 1743-1758页

作者： Changrong Zhang Hongtao Guo Li Yu Binbin Lv Hongya Xia Institute of High Speed Aerodynamics China Aerodynamics Research and Development CenterMianyang621000China

This study presents a high-speed geometrically nonlinear flutter analysis calculation method based on the highprecision computational fluid dynamics/computational structural dynamics *** the proposed method,the aerodynamic simulation was conducted based on computational fluid dynamics,and the structural model was established using the nonlinear finite element model and tangential stiffness ***,the equilibrium position was obtained using the nonlinear static aeroelastic ***,the structural modal under a steady aerodynamic load was ***,the generalized displacement time curve was obtained by coupling the unsteady aerodynamics and linearized structure motion ***,if the flutter is not at a critical state,the incoming flow dynamic pressure needs to be changed,and the above steps must be repeated until the vibration amplitude are ***,the high-speed geometrically nonlinear flutter of the wing-body assemblymodel with a high-aspect ratio was investigated,and the correctness of the method was verified using high-speed wind tunnel *** results showed that the geometric nonlinearity of the large deformation of the wing caused in-plane bending to become a key factor in flutter characteristics and significantly decreased the dynamic pressure and frequency of the nonlinear flutter compared to those of the linear flutter.

关键词： Fluid-structure coupling aeroelasticity flutter geometric nonlinearity numerical simulation

Nonlinear flutter analysis of stiffened composite panels in super-sonic flow

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Science China(Physics,Mechanics & Astronomy) 2010年第2期53卷 336-344页

作者： YUAN KaiHua & QIU ZhiPing School of Aeronautic Science and Engineering,Beijing University of Aeronautics and Astronautics,Beijing 100191,China Beijing University of Aeronautics and Astronautics School of Aeronautic Science and Engineering Beijing China (GRID:grid.64939.31) (ISNI:***)

The flutter instability of stiffened composite panels subjected to aerodynamic forces in the supersonic flow is investigated. Based on Hamilton's principle,the aeroelastic model of the composite panel is established by using the von Karman large deflection plate theory,piston theory aerodynamics and the quasi-steady thermal stress theory. Then,using the finite element method along with Bogner-Fox-Schmit elements and three-dimensional beam elements,the nonlinear equations of motion are derived. The effect of stiffening scheme on the flutter critical dynamic pressure is demonstrated through the numerical example,and the nonlinear flutter characteristics of stiffened composite panels are also analyzed in the time domain. This will lay the foundation for design of panel structures employed in aerospace vehicles.

关键词： panel flutter piston theory finite element method quasi-steady thermal stress critical dynamic pressure stiffened composite panel

Vibration and flutter of wind turbine blade modeled as anisotropic thin-walled closed-section beam

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Science China(Technological Sciences) 2011年第3期54卷 715-722页

作者： LIU TingRui REN YongSheng Mechanical & Electronical Institute Shandong University of Science & Technology Qingdao 266510 China

Based on a variational asymptotic analytical model, vibration and aeroelastic stability of rotor blades modeled as anisotropic thin-walled closed-section beams are systematically addressed. The analysis is applied to a laminated composite construction of the circumferentially asymmetric stiffness (CAS) that produces bending-twist coupling. The vibration characteristics of composite beam are determined by the Extended Galerkin Method. The unsteady aerodynamic loads and centrifugal force are integrated with the classical aerodynamic model to deal with aeroelastic stability analysis. The influence of some related factors, ply angle, rotating velocity, and wind speed, is investigated. The paper gives methods of eigenvalue analysis and aeroelastic response, and gives the approaches to restrain classical flutter.

关键词： Extended Galerkin Method bending-twist coupling circumferentially asymmetric stiffness thin-walled closed-section beam flutter

Recent progress on flutter‐based wind energy harvesting

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International Journal of Mechanical System Dynamics 2022年第1期2卷 82-98页

作者： Zhiyuan Li Shengxi Zhou Zhichun Yang School of Aeronautics Northwestern Polytechnical UniversityXi'anChina Research&Development Institute in Shenzhen Northwestern Polytechnical UniversityShenzhenChina

Wind energy harvesting technology can convert wind energy into electric energy to supply power for microelectronic *** has great potential in many specific applications and environments,such as remote areas,sea surfaces,mountains,and so *** the past few years,flutter‐based wind energy harvesting,which generates electric energy based on the limit cycle oscillation created by structural aeroelastic instability,has received increasing attention,and as a consequence,different energy harvesting structures,theories,and methods have been *** this paper,three types of flutter‐based energy harvesters(FEHs)including airfoil‐based,flat plate‐based,and flexible body‐based FEHs are reviewed,and related concepts and theoretical models are *** recent progress in FEH performance enhancement methods is classified into structural improvement and optimization,the introduction of nonlinearity,and hybrid structures and ***,the main FEH challenges are summarized,and future research directions are discussed.

关键词： dynamics flutter performance enhancement wind energy harvesting working principle

Predicting wing-pylon-nacelle configuration flutter characteristics using adaptive continuation method

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Advances in Aerodynamics 2023年第1期5卷 428-451页

作者： Qijing Yu M.Damodaran B.C.Khoo Department of Mechanical Engineering The Open University of ChinaBeijing 100039China Engineering Research Center of Integration and Application of Digital Learning Technology Ministry of EducationBeijing 100039China Temasek Laboratories National University of SingaporeSingapore 117411Singapore Department of Mechanical Engineering National University of SingaporeSingapore 117575Singapore

In this study,the aeroelastic response of a wing-pylon-nacelle system in subsonic and low supersonic flow regimes is analyzed using the continuation method in conjunction with an adaptive step size control *** the pylon and nacelle as a point mass,the computed effects of a standard structural analysis of the wing together with the pylon and nacelle are compared with those of a clean wing to build a reduced-order model for *** aerodynamic forces relating to different reduced frequencies are assessed using the Doublet Lattice Method(DLM)in the subsonic flow regime and supersonic lifting surface theory relying on the unsteady linearized small-disturbance potential flow model in the low supersonic flow *** Rational Function Approximation(RFA)method is then utilized for the state-space formulation of the system equations,appended with the continuation method for flutter ***,the linearized aeroelastic equations are resolved using the continuation method with adaptive step size,the results of which are matched with those obtained from the traditional p-k method to emphasize that the continuation method exhibits a distinct advantage in achieving better accuracy in estimating the flutter speed and identifying the“mode switching”phenomenon.

关键词： Aeroelasticity Continuation method with adaptive step-size flutter