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A simple numerical methodology for thermal-fluid-structural interactions of air damping over heated micro-cantilevers

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MICROFLUIDICS AND NANOFLUIDICS 2012年第1期13卷 131-140页

作者： Miana, M. Bernal, E. Paniagua, J. Valdes, J. R. Izquierdo, S. Pellejero, I. Inst Tecnol Aragon Area Invest Zaragoza 50018 Spain Univ Zaragoza Inst Nanociencia Aragon Zaragoza 50018 Spain

This paper proposes a simple methodology to analyse numerically the effects of air damping on the oscillatory motion of heated micro-cantilevers. The proposed methodology is fully solved by the fluid solver, because the solid domain is embedded into a subroutine executed at the end of each time step. The methodology is first validated against numerical and experimental data yielding acceptable results. Next, it is applied to predict the quality factor of a micro-cantilever heated by an electric resistance inserted inside it. The transferred heat flow and the evolution in time of temperature are analysed and the quality factors of both heated and isothermal micro-cantilevers are compared.

关键词： computational fluid dynamics computational structural dynamics Thermal-fluid-structure interaction MEMS sensors Air damping Quality factor Micro-cantilever heater

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Supersonic Flutter Analysis of Vehicles at Incidence Based on Local Piston Theory

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JOURNAL OF AIRCRAFT 2012年第1期49卷 333-337页

作者： Shi, Xiaoming Tang, Guoan Yang, Bingyuan Li, Haidong Fudan Univ Dept Mech & Engn Sci Shanghai 200433 Peoples R China Shanghai Acad Spaceflight Technol Shanghai 200233 Peoples R China

The article focuses on a study which analyzed the flutter of supersonic vehicles based on local piston theory. Expression of the flutter model disregarding structural damping is given. Three mode branches of the vehicle were determined by the branch mode method depending on the symmetrical and antisymmetrical mode shape. Conclusions derived from the study include a decrease in flutter boundary with increasing of angle of attack.

关键词： computational structural dynamics Piston Theory Angle of Attack Aerodynamic Damping Fuselages CFD Stiffness Matrices Slender Body Theory Aircraft Design Potential Flow

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Aeroelastic Analysis of a Hingeless Rotor Using a Dynamic Wake Model

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JOURNAL OF AIRCRAFT 2011年第5期48卷 1817-1822页

作者： Lee, Joonbae Yee, Kwanjung Yoo, Seung-Jae Lee, In Shin, SangJoon Kim, Deog-Kwan Pusan Natl Univ Dept Aerosp Engn Pusan 609735 South Korea Korea Adv Inst Sci & Technol Sch Mech Aerosp & Syst Engn Taejon 305701 South Korea Seoul Natl Univ Sch Mech & Aerosp Engn Seoul 151742 South Korea Korea Aerosp Res Inst Dept Rotor Syst Taejon 305333 South Korea

HELICOPTERS operate various excitations, such as aerodynamic loads impinging upon the rotating rotor and mechanical loads due to engine reactions. Hence, they sometimes experience severe vibrations. These vibrations may restrain the helicopter from performing its full capability and may reduce the life of the vehicle. In particular, extreme vibrations due to aeroelastic instability, which is induced between the unsteady aerodynamic forces and the flexible rotor blades, may degrade safety of the whole aircraft. Therefore, an accurate estimation of the aeroelastic characteristics is essential to successful design and development of a helicopter.

关键词： Aeroelastic Stability Aerodynamic Coefficients Rigid Rotor Blades structural Analysis CFD Finite Element Method computational structural dynamics Free Wake Analysis Blade Element Momentum Theory Rotor Wake

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computational Aeroelasticity Framework for Analyzing Flapping Wing Micro Air Vehicles

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AIAA JOURNAL 2009年第8期47卷 1865-1878页

作者： Chimakurthi, Satish Kumar Tang, Jian Palacios, Rafael Cesnik, Carlos E. S. Shyy, Wei Univ Michigan Dept Aerosp Engn Ann Arbor MI 48109 USA Univ London Imperial Coll Sci Technol & Med Dept Aeronaut London SW7 2AZ England

Because of their small size and flight regime, coupling of aerodynamics, structural dynamics, and flight dynamics are critical for micro aerial vehicles. This paper presents a computational framework for simulating structural models of varied fidelity and a Navier-Stokes solver, aimed at simulating flapping and flexible wings. The structural model uses either 1) the in-house developed UM/NLABS, which decomposes the equations of 3-D elasticity into cross-sectional and spanwise analyses for slender wings, or 2) ***, which is a commercial finite-element solver capable of modeling geometrically nonlinear structures of arbitrary geometry. The flow solver employs a well-tested pressure-based algorithm implemented in STREAM. A NACA0012 cross-sectional rectangular wing of aspect ratio 3, chord Reynolds number of 3 x 10(4), and reduced frequency varying from 0.4 to 1.82, with prescribed pure plunge motion is investigated. Both rigid and flexible wing results are presented, and good agreement between experiment and computation are shown regarding tip displacement and thrust coefficient. Issues related to coupling strategies, fluid physics associated with rigid and flexible wings, and implications of fluid density on aerodynamic loading are also explored in this paper.

关键词： Flapping Frequency Aeroelastic Analysis Micro Air Vehicle Freestream Velocity Aspect Ratio computational structural dynamics structural Modeling Kinematic Viscosity Navier Stokes Solver Elasticity

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Algorithms by design: A new normalized time-weighted residual methodology and design of a family of energy-momentum conserving algorithms for non-linear structural dynamics

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INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING 2009年第9期79卷 1094-1146页

作者： Masuri, S. U. Hoitink, A. Zhou, X. Tamma, K. K. Univ Minnesota Dept Mech Engn Minneapolis MN 55455 USA

A new approach termed as the hybrid displacement-strain-based normalized time-weighted residual approach is presented to accurately model non-linear structural dynamic problems. The focus here is restricted to all possible algorithmic designs within the class of linear multi-step methods that fall under the umbrella of the generalized single solve single step linear dynamic framework originally developed via the classical time-weighted residual approach involving a single solve within each time step as such designs are the most predominant in research and commercial software (Int. J. Numer Meth. Engng 2004;59:597-668;Int. J. Numer Meth. Engng 2006;66:1738-1790). However, traditional practices via classical time-weighted residual approaches fail to preserve the underlying physics and stability and do not serve the purposes of extensions to non-linear dynamic situations. In contrast, a new normalized time-weighted residual approach is proposed that naturally enables such extensions leading to the design of a family of conserving time operators for unconstrained conservative dynamic systems without resorting to enforcing energy constraints as in past practices. Consequently, the algorithmic stability (in the sense of energy stability) via this approach for non-linear dynamic problems is also preserved. For linear dynamic situations, it reverts to the classical paradigm. Only simple numerical illustrations are purposely presented to demonstrate the basic concepts. Copyright (C) 2009 John Wiley & Sons, Ltd.

关键词： time integration energy-momentum conservation finite elements computational structural dynamics non-linear structural dynamics

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AEROELASTIC PHENOMENA OF FLIGHT VEHICLES IN TRANSONIC REGION

AEROELASTIC PHENOMENA OF FLIGHT VEHICLES IN TRANSONIC REGION

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The Second International Symposium on Physics of Fluids(第二届流体物理国际学术研讨会)

作者： In Lee Jong-Yun Kim Kyung-Seok Kim In-Gyu Lim DEPARTMENT OF AEROSPACE ENGINEERING KAISTKOREA

Flight vehicles experience aeroelastic problems due to the interaction between structures and aerodynamic *** instability is usually a critical problem in transonic and lower supersonic *** present study, the aeroelastic analyses of several flight vehicles have been performed using the coupled techniques of computational fluid dynamics (CFD) and computational structural dynamics (CSD).

关键词： Aeroelasticity Transonic Region computational Fluid dynamics computational structural dynamics

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Higher-order time-integration schemes for aeroelastic applications on unstructured meshes

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AIAA JOURNAL 2007年第1期45卷 138-150页

作者： Yang, Zhi Mavriplis, Dimitri J. Univ Wyoming Dept Engn Mech Laramie WY 82071 USA

Efficient techniques for computational aeroelasticity on unstructured meshes are investigated. These include the formulation of a fourth-order implicit Runge-Kutta time-integration scheme, a third-order backward-difference time-integration scheme, and a second-order backward-difference time-integration scheme for the coupled system of How and structural equations. Strong coupling between the flow solution and structural equations is maintained by fully converging the fully coupled system at each time step or stage. The time-integration schemes are constructed such that discrete conservation is maintained in the flow solution in the presence of dynamically deforming meshes, by verifying the discrete geometric conservation law. Efficient multigrid solution techniques are devised for solving both the governing How equations and the mesh motion equations, using the same agglomerated coarse levels for both problems. The flutter boundary prediction of the AGARD 445.6 wing is used to demonstrate the accuracy and efficiency of these techniques as well as the sensitivity of flutter boundary prediction to time-step size and temporal errors.

关键词： computational structural dynamics CFD Freestream Mach Number Flow Equations Unsteady Flows Arbitrary Lagrangian Eulerian Aeroelasticity Multigrid Methods Multigrid Algorithm Wing Root

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Reduced-order-model-based flutter analysis at high angle of attack

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JOURNAL OF AIRCRAFT 2007年第6期44卷 2086-2089页

作者： Zhang, Weiwei Ye, Zhengyin NW Polytech Univ Natl Key Lab Aerodynam Design & Res Xian 710072 Peoples R China

The article presents a study which examined the reduced-order-model-based flutter analysis at high angle of attack. It states that configurations with a highly flexible delta wing are necessary for the next generation of unmanned air vehicles. Delta wing flowfield is dominated by vortical structures at high angle of attack in which the most prominent is called leading-edge vortex. Many researchers used computational fluid dynamics-based unsteady aerodynamics reduced-order modeling to improve the aeroelastic computational efficiency.

关键词： Angle of Attack computational structural dynamics Cropped Delta Wing Vortex Breakdown CFD Aerodynamic Force Coefficients Arbitrary Lagrangian Eulerian Unsteady Flows Aeroelastic Analysis Dynamic Pressure

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Effect of responding and failing structural components on the airblast pressures and loads on and inside of the structure

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COMPUTERS & STRUCTURES 2007年第11-14期85卷 891-910页

作者： Baylot, James T. Bevins, Tommy L. USA Engn Res & Dev Ctr Vicksburg MS 39180 USA

The presence of non-structural exterior walls can affect the loads on structural columns when high explosives detonate near that column. Numerical simulations and physical experiments were used to determine the effect of exterior (no wall and solid masonry wall) type on the loads on and response of exterior columns. Both the simulations and the experiments indicate that although the exterior wall fails very quickly, it still significantly affects the loads on the column and the airblast pressures entering the structure. (C) 2007 Elsevier Ltd. All rights reserved.

关键词： fluid-structure interaction finite element analysis computational fluid dynamics airblast structure response computational structural dynamics

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Research on coupling arithmeric of wind-induced response of membrane structure

Research on coupling arithmeric of wind-induced response of ...

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9th International Conference on Steel, Space and Composite Structures

作者： Wang, Bin Yang, Qingshan Beijing Jiaotong Univ Beijing Peoples R China

ISBN: (纸本)9789810575890

Researches on fluid-structure interaction effect of wind-induced vibration response of membrane structure were discussed.. Two methodologies for solving this problem were introduced. The first was a simplified aeroelastic model method. In this method, the additional aerodynamic feedback terms were described as added mass and aerodynamic damping. The second was computational fluid dynamics simulation method. In this paper loosely coupling arithmetic for fluid-structure interaction on membrane structures is chiefly provided by coupling two codes developed for flow simulation and structural dynamics. The geometrical model of the structure is built in FE software and the fluid is modeled in CFD software. The finite volume based CFD code is able to compute three-dimensional, incompressible, turbulent flows. The structure simulations are performed using a finite element program including algorithms for geometrically problems. Each simulation code runs on its own processor within each time-step. The results computed from former code are put on the latter one as outside loads. Based on this methods, corresponding works were done and some preliminary understandings of the mechanism of wind and membrane structures interaction were gotten.

关键词： fluid-structure interaction membrane structure computational structural dynamics computational fluid dynamics

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