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A novel formulation for efficient flutter analysis of rotating composite blades based on referenced nodal coordinate formulation

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COMPOSITE STRUCTURES 2025年 359卷

作者： Ren, Shuangxing Hou, Lei Yuan, Tengfei Duraihem, Faisal Z. Awwad, Emad Mahrous Saeed, Nasser. A. Harbin Inst Technol Sch Astronaut Harbin 150001 Peoples R China King Saud Univ Coll Sci Dept Math POB 2455 Riyadh 11451 Saudi Arabia King Saud Univ Coll Engn Dept Mech Engn POB 800 Riyadh 11421 Saudi Arabia Menoufia Univ Fac Elect Engn Dept Phys & Engn Math Menoufia 32952 Egypt Appl Sci Private Univ Appl Sci Res Ctr Amman Jordan

A precise and cost-effective method for flutter analysis is essential for the structural design of aero engine blades. This paper presents an efficient approach that first determines the reference flutter dynamic pressure via the eigenvalue method, followed by a rapid evaluation of the vibration response through the referenced nodal coordinate formulation (RNCF), which is particularly suitable for high-speed rotation, to assess flutter occurrence. The blade is modeled as a rotating plate made of graphene platelet-reinforced metal foam (GPLRMF). The effective material properties are derived from the modified Halpin-Tsai model and the effect of metal foam. The correctness of the structural model is confirmed by comparison with published results. The efficiency is demonstrated by its computational speed, being approximately ten times faster than the absolute nodal coordinate formulation (ANCF). The proposed formulation offers an accurate and efficient tool for obtaining the vibration response and assessing the occurrence of flutter.

关键词： Aero engine blades Rotating graphene platelets Referenced nodal coordinate formulation flutter analysis

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Isogeometric flutter analysis of a heated laminated plate with and without cutout

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THIN-WALLED STRUCTURES 2025年 206卷

作者： Yu, Wenliang Guo, Rongshen Zhao, Yuhao Chen, Mingfei Guizhou Univ Coll Mech Engn Guiyang 550025 Peoples R China Chinese Acad Sci Shenyang Inst Automat State Key Lab Robot Shenyang 110016 Peoples R China Guizhou Univ Minist Educ Key Lab Adv Mfg Technol Guiyang 550025 Peoples R China

Understanding the flutter characteristics of heated laminated plates, both with and without cutout, is crucial. This study presents the first exploration of flutter analysis in a thermal environment for a laminated plate featuring a cutout. To facilitate this study, the motion equations of the heated laminated plate with a cutout are derived using the first-order shear deformation theory (FSDT), incorporating a nonlinear term. Employing the isogeometric method combined with multi-path coupling technology, we establish accurate geometric and solution domains for the laminated plate. The effects of the thermal stresses and the aerodynamics calculated by the linear piston theory are considered. The accuracy and effectiveness of the proposed model are validated through several comparisons with ANSYS results and existing solutions. Additionally, the study examines the impact of key parameters on flutter characteristics, including thermal conditions, number of layers, lay-up angles, inflow angles, and cutout dimensions. The insights gained from this research will serve as a valuable benchmark for future analyses and design concerning flutter characteristics.

关键词： flutter analysis Thermal conditions Isogeometric method Laminated plate Cutout

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flutter analysis of contra-rotating blade rows

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AIAA JOURNAL 2006年第11期44卷 2612-2620页

作者： Namba, Masanobu Nishino, Ryohei Sojo Univ Dept Aerosp Syst Engn Kumamoto 8600082 Japan

To investigate the flutter characteristics of cascading blades in multiple blade rows, the computation program to calculate the unsteady blade loading based on. the unsteady lifting surface theory for contra-rotating annular cascades was formulated and coded. Then a computation program to solve the coupled bending-torsion flutter equation for the contra-rotating annular cascades was also developed. Some results of the flutter analysis are presented. It is shown that the presence of the neighboring blade row gives rise to substantial change in the critical flutter condition irrespective of the blade row gap when the main acoustic duct mode is of cut-on state. The effect of the neighboring blade row is also significant irrespective of the state of the main acoustic duct mode when the blade rows are very closely placed.

关键词： flutter analysis Blade Loading Acoustic Ducts Aerodynamic Damping Stiffness Matrices Flow Velocity Aspect Ratio Incompressible Flow Elastic Properties Radius of Gyration

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flutter analysis of a wraparound fin projectile considering rolling motion

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JOURNAL OF SPACECRAFT AND ROCKETS 2002年第1期39卷 66-72页

作者： Paek, SK Bae, JS Leet, I Korea Adv Inst Sci & Technol Dept Aerosp Engn Taejon 305701 South Korea

The aeroelastic stabilities of curved fins (or wraparound fins) in rolling motion are investigated in the supersonic flow region. Because of their inherent roll, wraparound fins are subjected to both aerodynamic and centrifugal forces. The aerodynamic force is computed by solving Euler equations in a body-fixed rotating coordinate frame. The normal mode analyses of the spinning structure are performed by using a multipurpose finite element code. For the consistent analysis a nondimensionalized aeroelastic equation considering the rolling motion is derived and aeroelastic parameters, such as velocity index and mass ratio, are devised. From the flutter analyses for wraparound fins, it is observed that the flutter characteristics with roll are very different from those without roll. It indicates that the consideration of the rolling motion must be made to predict the flutter stability accurately. Because of the geometric asymmetry of the wraparound fin, the flutter characteristics in each roll directions are different from each other. flutter analyses indicate that there exists a more stable roll direction for flutter.

关键词： flutter analysis Rolling direction Aeroelastics Euler equations flutter Rolling motion

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flutter analysis of a flag of fractional viscoelastic material

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JOURNAL OF SOUND AND VIBRATION 2014年第26期333卷 7183-7197页

作者： Chen, Ming Jia, Lai-Bing Chen, Xiao-Peng Yin, Xie-Zhen Northwestern Polytech Univ Sch Mech Civil Engn & Architecture Xian 710072 Shanxi Peoples R China Univ Sci & Technol China Dept Modern Mech Hefei 230027 Anhui Peoples R China

We develop a two-dimensional model to study the effects of the material viscoelasticity on the dynamics of a flag in flow. Two periodic states of an elastic flag are firstly identified with different dimensionless bending stiffness: a lower frequency state and a higher frequency state. The Scott-Blair model and the fractional Kelvin-Voigt model are further used to represent the viscoelasticity of the flag material. When the Scott-Blair model is used, with the increase of the fractional derivative order alpha, the flag flapping frequency of the higher frequency state decreases abruptly, and that of the lower frequency state also shows a downward trend. When the system parameters are in a certain range, an interesting phenomenon is observed, where the time needed to achieve the periodic steady state initially increases and then decreases with increasing alpha. The phenomenon implies that the flag has a higher energy harvesting speed when alpha approaches 1. When the fractional Kelvin-Voigt model is used, the increasing alpha also causes the transition from the higher frequency state to the lower frequency state, and quasi-periodic states are observed during the transition. The fractional Kelvin-Voigt type viscoelasticity produces complex effects on the lower frequency state. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： two-dimensional effects material viscoelasticity flutter analysis fiberoptic link around the globe viscoelasticity Countries (nations) system parameter Viscoelastic materials

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flutter analysis OF THE CF-18 AIRCRAFT AT SUPERSONIC SPEEDS

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JOURNAL OF AIRCRAFT 1989年第6期26卷 588-590页

作者： LEE, BHK National Research Council Ottawa Ontario Canada

The harmonic gradient and the source distribution methods for computing supersonic aerodynamics are compared using the F-18 as a test case. For rigid-body modes, good agreement in pressure distributions is observed except for high reduced frequencies and near the wing tip. For oscillating flaps and control surfaces, the SPIP program requires a large number of source points to give the proper pressure jump across the hinge line, while the ZONA51C code handles the sharp pressure change quite satisfactorily without requiring additional elements to be placed near the hinge line. flutter results for the F-18 wing agree very well between these two aerodynamic methods.

关键词： flutter analysis CF 18 Aircraft Supersonic Speed Stress analysis Aerodynamics Leading Edge Flap Nastran Control Surfaces Thin Wings Wing Tip

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flutter analysis OF THIN CRACKED PANELS USING THE FINITE-ELEMENT METHOD

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AIAA JOURNAL 1985年第5期23卷 795-801页

作者： CHEN, WH LIN, HC National Tsing Hua University Hsinchu Taiwan China

An assumed hybrid-displacement finite element model is presented to deal with the flutter problems of thin cracked panels. Based on a modified Hamilton’s principle for nonconservative systems with relaxed continuity requirements for deflections and normal slopes at the interelement boundary, the aerodynamic properties of rectangular-shaped hybrid crack elements around the crack tip embedded with proper stress singularities are derived. Interelement compatibility conditions are satisfied through the use of a Lagrangian multiplier technique and the assumption of interelement boundary deflections. First, for verification purposes, the flutter analyses of noncracked panels are illustrated. Excellent agreement between the computed results and referenced solutions is observed. To investigate the nature of the fluttering instability, both the divergent- and oscillatory-type fluttering instabilities are discussed in detail. Several typical types of cracked panels found in aeronautical structures in arbitrarily directed supersonic flows are then studied. The influences of crack lengths and flow directions on the evaluation of the critical speed and type of instability are also drawn. Finally, the important role of the hybrid crack element in dealing with flutter problems of thin cracked panels is demonstrated. © 1985 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.

关键词： Finite Element Formulation flutter analysis Aerodynamic Properties Supersonic Flow Critical Speed Dynamic Pressure Cantilever Stress Intensity Factor Transverse Shear Bending Moment

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flutter analysis of Aerostructures Test Wing with Test Validated Structural Dynamic Model

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JOURNAL OF AIRCRAFT 2011年第4期48卷 1263-1272页

作者： Pak, Chan-gi Lung, Shun-fat NASA Dryden Flight Res Ctr Struct Dynam Grp Aerostruct Branch Edwards AFB CA 93523 USA NASA Dryden Flight Res Ctr Tybrin Corp Edwards AFB CA 93523 USA

Tuning a finite element model using measured data to minimize the model uncertainties is a challenging task in the area of structural dynamics. A test-validated finite element model can provide a reliable flutter analysis to define the flutter placard speed to which the aircraft can be flown before flight flutter testing. Minimizing the difference between numerical and experimental results is a type of optimization problem. Through the use of the NASA Dryden Flight Research Center's multidisciplinary design, analysis, and optimization tool to optimize the objective function and constraints, the mass properties, natural frequencies, and mode shapes are matched to the target data and the mass matrix orthogonality is retained. The approach in this study has been applied to minimize the model uncertainties for the structural dynamic model of the Aerostructures Test Wing, which was designed, built, and tested at the NASA Dryden Flight Research Center. A 25% change in flutter speed has been shown after reducing the uncertainties. Therefore, without reducing the uncertainties, 40% of the flutter margin (15% MIL-SPEC requirement + 25% modeling uncertainties) would be needed for the safety of flight test.

关键词： flutter speed modal response design analysis finite element model Wings flutter dynamic structural analysis flutter flight tests flutter analysis model uncertainty National Aeronautics and Space Administration Research centers aircraft structures

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flutter analysis OF STIFFENED LAMINATED COMPOSITE PLATES AND SHELLS IN SUPERSONIC-FLOW

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AIAA JOURNAL 1993年第10期31卷 1897-1905页

作者： LIAO, CL SUN, YW National Taiwan Institute of Technology Taipei 107 Taiwan Republic of China

This paper investigates the flutter instability of stiffened and nonstiffened laminated composite plates and shells subjected to aerodynamic forces in the supersonic now. The equation of motion of the present problem is formulated using Hamilton's principle. Then, using the finite element method along with three-dimensional degenerated shell elements and three-dimensional degenerated curved beam elements, the equation of motion is discretized. The characteristic equation to study the flutter instability of the present problem is obtained from the previous finite element equation of motion. Finally, natural frequency, critical dynamic pressure, and corresponding flutter mode shape are found by solving the characteristic equation. The effects of various parameters, such as skew angle, lamination scheme, subtended angle, and stiffening scheme on the flutter instability of stiffened and nonstiffened plates and shells in the supersonic now are demonstrated through the numerical examples.

关键词： Laminated Composites Supersonic Flow flutter analysis Two Dimensional Elements Aerodynamic Damping Dynamic Pressure Curved Beam Cylindrical Shells Poisson's Ratio Aircraft Structures

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flutter analysis OF ANISOTROPIC PANELS WITH PATCHED CRACKS

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JOURNAL OF AIRCRAFT 1991年第12期28卷 899-907页

作者： LIN, KJ LU, PJ TARN, JQ National Cheng Kung University Tainan Taiwan Republic of China

A finite element approach is developed to analyze the panel flutter problems of thin plate-like composite panels with patched cracks. The panel studied is a compound structure that comprises three layers including a thin cracked panel, an adhesive, and a thin patch. A 48-degree-of-freedom (DOF) triangular crack patching element is derived for numerically analyzing the compound structure. The aerodynamic pressure acting on the panel is estimated using linearized piston theory with aerodynamic damping effect neglected. By a proper tailoring of the materials, very high flutter and/or divergence boundary could usually be obtained for the composite panels. The existence of a crack usually reduces the aeroelastic stability boundary;however, some exceptions were found for the composite panel within certain range of specific filament orientation. The deterioration in flutter/divergence performance due to a crack can, in general, be cured by means of patching, and anisotropic patching is more effective as compared to the isotropic patching provided that the tailoring of the structural parameters is done correctly.

关键词： flutter analysis Freestream Mach Number Piston Theory Aeroelastic Stability Dynamic Pressure Finite Element Formulation Poisson's Ratio Stress Corrosion Cracking Laminated Composites Structural Element

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