检索结果-内蒙古大学图书馆

56th AIAA/ASME/ASCE/AHS/ASC Structures, structural dynamics and Materials Conference / 33rd Wind Energy Symposium / 23rd AIAA/AHS Adaptive Structures Conference

作者： Mishra, Asitav Mavriplis, Dimitri Sitaraman, Jay Univ Michigan Dept Aerosp Engn Ann Arbor MI 48109 USA Univ Wyoming Dept Mech Engn Laramie WY 82071 USA Parallel Geometr Algorithms LLC Sunnyvale CA 94087 USA

ISBN: (数字)9781624103421

ISBN: (纸本)9781624103421

A formulation for sensitivity analysis of fully coupled time-dependent aeroelastic rotors in forward flight with trim constraints is given in this paper. The formulation includes the effect of blade shape parameters as well as blade cyclic pitch control parameters to enable analysis and optimization of rotors in a trimmed condition. Both forward sensitivity and adjoint sensitivity formulations are derived that correspond to analogs of the nonlinear aeroelastic analysis problem. Both sensitivity analysis formulations make use of the same iterative disciplinary solution techniques used for analysis, and they make use of an analogous coupling strategy. The fully coupled aeroelastic analysis formulation is first verified to effectively perform performance predictions of a four-bladed rotor in forward flight started impulsively from rest. Upon successful verification of the fully coupled adjoint formulation, it is used to perform trim and aerodynamic shape design optimization for helicopter rotors in forward-flight conditions.

关键词： Helicopter Rotor Aerodynamic Shape Optimization Shape Optimization Sensitivity Analysis Aeroelastic Analysis computational Fluid dynamics Arbitrary Lagrangian Eulerian Reynolds Averaged Navier Stokes Fluid Structure Interaction computational structural dynamics

来源：评论

学校读者我要写书评

暂无评论

Biodynamic Model of a Seated Occupant Exposed to Intense Impacts

引用

AIAA JOURNAL 2015年第2期53卷 426-435页

作者： Singh, Harinder J. Wereley, Norman M. Univ Maryland Dept Aerosp Engn College Pk MD 20742 USA Univ Maryland Dept Aerosp Engn Chair Aerosp Engn College Pk MD 20742 USA

Quantitative comparison of biodynamic responses, simulated using the Patil or Liu lumped parameter models, were carried out with respect to experimental anthropomorphic test dummy response data obtained from the Sikorsky advanced composite airframe program helicopter crash test. The biodynamic responses obtained from these models were characterized by large offsets from the experimental peak magnitudes, large perturbations in biodynamic displacements, and delayed response. The inability to accurately predict biodynamic response using either model led to development of a new four-degree-of-freedom nonlinear biodynamic model corresponding to a Hybrid II 50th-percentile male occupant, the parameters of which were identified by minimizing the least-square error between the simulated and advanced composite airframe program experimental responses. The new model accurately predicts peak magnitude, overall shape, and duration of the biodynamic transient response, with minimal phase shift. The biodynamic model was further validated using data from the crashworthy composite fuselage drop experiment conducted by Fasanella and Jackson ("Impact Testing and Simulation of a Crashworthy Composite Fuselage Section with Energy-Absorbing Seats and Dummies," Journal of the American Helicopter Society, Vol. 49, No. 2, 2004, pp. 140-148). The biodynamic model overpredicted the peak lumbar loads by 1.06% when compared to the pilot's anthropomorphic test dummy response from the Sikorsky advanced composite airframe program experiment, and it predicted lumbar loads within +/- 10% when compared to crashworthy composite fuselage experiments.

关键词： Lumped Parameter Model Helicopters Airframes American Helicopter Society Four Degree of Freedom Transient Response Copilot Finite Element Modeling Damping Coefficient computational structural dynamics

来源：评论

学校读者我要写书评

暂无评论

computational wind engineering and its application in civil engineering. Aerodynamic and aeroelastic analysis

引用

REVISTA INTERNACIONAL DE METODOS NUMERICOS PARA CALCULO Y DISENO EN INGENIERIA 2015年第1期31卷 55-64页

作者： Awruch, A. M. Braun, A. L. Greco, M. Univ Fed Rio Grande do Sul PPGEC Porto Alegre RS Brazil Univ Fed Minas Gerais Programa Posgrad Engn Estruturas Belo Horizonte MG Brazil

Experimental tests in wind tunnels have been traditionally employed as a fundamental tool to evaluate aerodynamic and aeroelastic effects due to wind action on civil engineering structures, such as bridges and slender buildings. In the last decades, due to the versatility presented by numerical methods to change physical as well as geometrical parameters, numerical simulation has become a very attractive tool. computational Fluid dynamics (CFD), computational structural dynamics (CSD) together with Fluid-Structure Interaction (FSI) techniques are employed in aerodynamic and aeroelastic analysis in several engineering fields. Aerodynamic and aeroelastic behavior due to wind action on the Guama River Bridge, located at Para State, Brazil, is first studied, taking into account experimental tests performed in the Wind Tunnel Joaquim Blessman of the Building Aerodynamic Laboratory, UFRGS. Numerical procedures are used to simulate experimental tests in order to determine aerodynamic and aeroelastic characteristics of the bridge, which is idealized by sectional models. Finally, an aeroelastic analysis of a flexible slender building is presented. Good results are obtained using numerical simulation, when compared with experimental tests. (C) 2013 CIMNE (Universitat Politecnica de Catalunya). Published by Elsevier Espa (n) over tildea, S.L.U. All rights reserved.

关键词： computational wind engineering computational fluid dynamics computational structural dynamics Aerodynamics Aeroelasticity

来源：评论

学校读者我要写书评

暂无评论

Modern computational Fluid dynamics/structural dynamics Simulation for a Helicopter in Descent

引用

JOURNAL OF AIRCRAFT 2013年第5期50卷 1450-1464页

作者： You, Young H. Sa, Jeong H. Park, Jae S. Park, Soo H. Jung, Sung N. Konkuk Univ Dept Aerosp Informat Engn Seoul 143701 South Korea

In this work, several computational-fluid-dynamics-based approaches are employed to validate the airloads, trim angles, blade elastic motions, vortex positions, and structural loads of a rotor in low-speed, descending flight. To this end, two different comprehensive codes, CAMRAD II and DYMORE, are coupled with a computational fluid dynamics code, KFLOW, using a loose coupling methodology. A computational fluid dynamics approach using the measured blade motions is also carried out for the validation. For both clarity and consistency required in the relative comparison between different methods, an identical computational fluid dynamics grid system is used for the study. A fuselage effect is considered in the analysis. The predicted results are correlated against the measured data. CAMRAD II coupling shows good prediction for low-frequency loadings, elastic motions, and structural lag bending and torsion moments. DYMORE coupling demonstrates good matches on trim control angles, blade vortex interaction airloads, and structural flap bending but less satisfactory for lag motions. Initial results indicate poor correlation on aeropitching moments. This discrepancy is seen to be fixed when considering the actual pressure sensor locations used in the test. The blade-vortex miss distance at a desired instant is also evaluated. About 25% larger miss distance is obtained with a higher harmonic control input.

关键词： CFD Analysis computational structural dynamics Rotor Systems Vortex Strength Blade Vortex Interaction structural Load Pressure Sensors Fuselage Configurations computational Fluid dynamics Code Aerodynamic Damping

来源：评论

学校读者我要写书评

暂无评论

Assessment of Beam and Shell Elements for Modeling Rotorcraft Blades

引用

JOURNAL OF AIRCRAFT 2014年第2期51卷 520-531页

作者： Kang, Hao Chang, Chongseok Saberi, Hossein Ormiston, Robert A. Adv Rotorcraft Technol Inc Sunnyvale CA 94085 USA US Army Aeroflightdynam Directorate AMRDEC Moffett Field CA 94035 USA

A geometrically exact shell element is developed within the finite-element, multibody dynamics-based Rotorcraft Comprehensive Analysis System. The shell element accommodates transverse shear deformation as well as arbitrarily large displacements and rotations. The shell element is developed using an approach that allows for compatibility with other structural elements in the Rotorcraft Comprehensive Analysis System. It is validated by comparing its predictions with benchmark problems. The two-dimensional shell and one-dimensional beam finite-element analyses are compared for three typical blade configurations of varying slenderness ratio: a swept-tip blade, a blade with discontinuous chordwise elastic axis and center-of-gravity locations, and a blade with a flex beam. The purpose is to quantify the differences between two-dimensional-shell one-dimensional-beam finite elements for modeling rotor blades. There is good agreement between the one- and two-dimensional analyses in predicting the natural frequencies of straight blades with a slenderness ratio of greater than 12.5. However, there are up to 16.5% differences in frequency predictions for a slenderness ratio of 17.5 or less and a tip sweep angle of 30deg or higher. The differences increase with decreasing slenderness ratio and increasing tip sweep angle. For a blade with a discontinuous center-of-gravity offset, frequencies predicted using the two- and one-dimensional analyses show up to 12.5% difference and increase with the center-of-gravity offset. For a blade with discontinuous elastic axis offset, the frequencies predicted using the two analyses have good agreement. The differences are observed when both approaches calculate the structural loads (bending moments) and deformations of a blade with an elastic axis offset.

关键词： Rotorcrafts structural Element Sweep Angle Hingeless Rotor Blade Multibody dynamics Shear Deformation Poisson's Ratio Finite Element Analysis Control Surfaces computational structural dynamics

来源：评论

学校读者我要写书评

暂无评论

Transonic Limit Cycle Oscillation Analysis Using Aerodynamic Describing Functions and Superposition Principle

引用

AIAA JOURNAL 2014年第7期52卷 1393-1403页

作者： He, Shun Yang, Zhichun Gu, Yingsong Northwestern Polytech Univ Sch Aeronaut Inst Struct Dynam & Control Xian 710072 Peoples R China

Limit cycle oscillation for an airfoil in transonic air flow considering aerodynamic nonlinearity is studied. Transonic nonlinear aerodynamic forces are calculated by solving Euler equations or Navier-Stokes equations with respect to harmonic airfoil plunging/pitching motion, and then the aerodynamic describing functions and the super position principle are used to build an equivalent linearized aerodynamic model in the frequency domain;hence, the transonic limit cycle oscillation solutions can be obtained by the frequency domain flutter analysis method. The procedures for building the aerodynamic describing function and obtaining the limit cycle oscillation solution are described in detail. Four examples are adopted to verify the accuracy of the present method. The Isogai wing model with NACA 64A010 airfoil is used as the first example to verify the accuracy of the transonic linear flutter solution of the present method. Another NACA 64A010 airfoil model with different structural parameters is then adopted to study its transonic limit cycle oscillation characteristics considering only aerodynamic nonlinearity, and the NACA 0012 airfoil model with both aerodynamic and structural nonlinearities is investigated for its transonic limit cycle oscillation properties. The NLR 7301 airfoil is studied for its limit cycle oscillation characteristics in inviscid and viscous transonic flows, respectively. The results obtained by the present method are in good agreement with those obtained by the existing research with the harmonic balance method and time-marching method. The limitations of the present method are also discussed.

关键词： Single Input Single Output Aerodynamic Force Coefficients NACA 64A010 computational structural dynamics Euler Equations Frequency Response Functions Transonic Flow Navier Stokes Equations structural Nonlinearities CFD Simulation

来源：评论

学校读者我要写书评

暂无评论

Aeroelastic Behavior of Bird-Damaged Fan Blades Using a Coupled CFD/CSD Framework

Aeroelastic Behavior of Bird-Damaged Fan Blades Using a Coup...

引用

作者： Muir, Eric Raymond University of Michigan

学位级别：doctor

Bird strike is a growing concern in the design of modern high-bypass turbofan engines. Predicting the aeroelastic behavior of a bird-damaged fan blade represents a significant barrier in the development of improved-efficiency turbofan engines. In this dissertation, the aeroelastic response of a bird-damaged fan stage at the inlet of a high-bypass ratio turbofan engine is examined using a combined computational fluid dynamics (CFD) and computational structural dynamics framework. The damaged fan contains a sector of 5 damaged blades obtained from accurate numerical simulation of the bird impact. Unsteady aerodynamic and aeroelastic response calculations are performed at 100%, 75%, and 60% take-off thrust conditions to investigate the role of engine speed on the fan response.A CFD-based aerodynamic model is utilized to perform the steady and unsteady aerodynamic calculations for the undamaged and damaged fan. An automated mesh deformation scheme using radial basis function interpolation is developed to generate a high quality computational mesh for the damaged geometry. The steady calculations of the damaged fan predict significant flow loss with the fan operating near stall where unsteadiness is significant. The unsteady calculations of the damaged fan exhibit a periodic behavior dominated by the progression and regression of a stall cell that produces significant unsteady aerodynamic loads on the fan *** aerodynamic model is coupled with a finite element based structural dynamics model to perform both one-way forced response and fully-coupled aeroelastic response calculations. The undamaged blades downstream of the damaged sector exhibit the greatest structural response that is dominated by the first bending mode. When compared to the forced response calculation, the aeroelastic response includes increased participation of the higher structural modes, especially for the damaged blades, that grow in time or exhibit beating. Examination of the work e

关键词： Aeroelasticity Bird Strike Turbomachinery computational Fluid dynamics computational structural dynamics Aerospace Engineering Engineering

来源：评论

学校读者我要写书评

暂无评论

Wake Effects on Aeroelastic Stability of Hingeless and Bearingless Rotors

引用

JOURNAL OF AIRCRAFT 2013年第6期50卷 1938-1943页

作者： Jeong, Min-Soo Lee, In Yoo, Seung-Jae Yun, Chul Yong Kim, Deog-Kwan Korea Adv Inst Sci & Technol Sch Mech Aerosp & Syst Engn Taejon 305701 South Korea Hyundai Heavy Ind Co Ltd Maritime Res Inst Ulsan 682792 South Korea Korea Aerosp Res Inst Dept Rotor Syst Taejon 305806 South Korea

The article discusses a study that investigated the flap-lag-torsion stability of helicopters' hingeless and bearingless rotors in forward flight using a finite element formulation based on a Hamilton's principle. A free-wake method for an aeroelastic analysis and a linear inflow model were introduced for predicting the wake more accurately. The researchers used three different aerodynamic models in addition to a nonlinear beam model based on a large deflection beam theory.

关键词： Aeroelastic Stability Aerodynamic Coefficients Helicopter Rotor Hingeless Rotor Blade Finite Element Formulation Fluid Structure Interaction computational structural dynamics computational Fluid dynamics Angle of Attack Modal Analysis

来源：评论

学校读者我要写书评

暂无评论

Numerical simulation on fluid-structure interaction of wind around super-tall building at high reynolds number conditions

引用

structural ENGINEERING AND MECHANICS 2013年第2期46卷 197-212页

作者： Huang, Shenghong Li, Rong Li, Q. S. Univ Sci & Technol China Sch Engn Sci Hefei 230026 Peoples R China City Univ Hong Kong Dept Bldg & Construct Kowloon Hong Kong Peoples R China

With more and more high-rise building being constructed in recent decades, bluff body flow with high Reynolds number and large scale dimensions has become an important topic in theoretical researches and engineering applications. In view of mechanics, the key problems in such flow are high Reynolds number turbulence and fluid-solid interaction. Aiming at such problems, a parallel fluid-structure interaction method based on socket parallel architecture was established and combined with the methods and models of large eddy simulation developed by authors recently. The new method is validated by the full two-way FSI simulations of 1:375 CAARC building model with Re = 70000 and a full scale Taipei101 high-rise building with Re = 1e8, The results obtained show that the proposed method and models is potential to perform high-Reynolds number LES and high-efficiency two-way coupling between detailed fluid dynamics computing and solid structure dynamics computing so that the detailed wind induced responses for high-rise buildings can be resolved practically.

关键词： fluid-structure interaction computational fluid dynamics computational structural dynamics large Eddy simulation tall building wind effect

来源：评论

学校读者我要写书评

暂无评论

Efficient Mesh Deformation Using Radial Basis Functions on Unstructured Meshes

引用

AIAA JOURNAL 2013年第3期51卷 707-720页

作者： Sheng, Chunhua Allen, Christian B. Univ Toledo Dept Mech Engn Toledo OH 43606 USA Univ Bristol Dept Aerosp Engn Bristol BS8 1TR Avon England

An efficient mesh-deformation algorithm has been developed within an unstructured-grid computational-fluid-dynamics solver framework based on a radial-basis-function volume-interpolation method. The data-transfer problem between fluid and structural solvers is simplified here using a beam structural representation, with surface mesh deformation given directly via translational and rotational deformations. The volume mesh deformation is then performed using a radial-basis-function method, which requires no mesh-connectivity information and allows straightforward implementation in an unstructured computational-fluid-dynamics solver in a parallel fashion. However, the pure method is impractical for large meshes, and a novel "greedy" data-reduction algorithm is presented here to select an optimum reduced set of surface mesh points, which makes the mesh-deformation method extremely efficient. Several two- and three-dimensional test cases are presented to validate the algorithm performance, including a realistic aircraft Bell M427 main rotor. It is shown that the approach can handle effectively very large mesh deformations of complex geometries using unstructured viscous meshes while maintaining good mesh quality and geometric accuracy, and generally requires less than 25% of the computational-fluid-dynamics flow-solver cost.

关键词： CFD Simulation Unstructured Grid Data Reduction Algorithm Performance Greedy Algorithm computational structural dynamics Pitching Moment NACA 0012 Rotor Blades Selection Algorithm

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：