• International Journal of Aeronautical and Space Sciences
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• 제7권1호
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• pp.99-105
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• 2006

In this study, nonlinear static and dynamic aeroelastic analyses for a high-aspect-ratio wing have been performed. To achieve these aims, the transonic small disturbance (TSD) theory for the aerodynamic analysis and the large deflection beam theory considering a geometrical nonlinearity for the structural analysis are applied, respectively. For the coupling between fluid and structure, the transformation of a displacement from the structural mesh to the aerodynamic grid is performed by a shape function which is used for the finite element and the inverse transformation of force by work equivalent load method. To validate the current method, the present analysis results of a high-aspect-ratio wing are compared with the experimental results. Static deformations in the vertical and torsional directions caused by an angle of attack and gravity loading are compared with experimental results. Also, static and dynamic aeroelastic characteristics are investigated. The comparisons of the flutter speed and frequency between a linear and nonlinear analysis are presented.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.141-144
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• 2005

The fluid-structure interaction analysis such as a static aeroelastic analysis requires the result of each analysis as an input to other analysis. Usually the grids for the fluid analysis and the structural analysis are different, so the results should be transformed properly for each other. The Infinite Plate Spline(IPS) and the Thin Plate Spline(TPS) are used in interpolating the displacement and the pressure. In this study, such interpolation methods are compared with kriging which provides a precise response surface. The static aeroelastic analysis is performed for the supersonic flow field with shock waves and the pressure field is interpolated by the TPS and kriging. The TPS shows tendency to weaken the shock stength, whereas kriging preserves the shock strength.

• Wind and Structures
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• 제20권5호
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• pp.683-699
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• 2015

Lighting poles and antenna masts are typically high, slender and light structures. Moreover, they are often characterized by distributed eccentricities that make very complex their shape. Experience teaches that this structural type frequently suffers severe damage and even collapses due to wind actions. To understand and interpret the aerodynamic and aeroelastic behavior of lighting poles and antenna masts, this paper presents the results of static and aeroelastic wind tunnel tests carried out on a complex prismatic element representing a segment of the shaft of such structures. Static tests are aimed at determining the aerodynamic coefficients and the Strouhal number of the test element cross-section; the former are used to evaluate the critical conditions for galloping occurrence based on quasi-steady theory; the latter provides the critical conditions for vortex-induced vibrations. Aeroelastic tests are aimed at reproducing the real behavior of the test element and at verifying the validity and reliability of quasi-steady theory. The galloping hysteresis phenomenon is identified through aeroelastic experiments conducted on increasing and decreasing the mean wind velocity.

• 한국항공우주학회지
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• 제34권3호
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• pp.31-36
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• 2006

본 연구에서는 천음속미소교란 및 대변형 보 이론을 이용하여 대변형이 발생되는 가로세로비가 큰 날개의 비선형 정적 공탄성 해석 시스템을 개발하고 검증하였다. 유체/구조간 직접 연계를 위하여 구조 격자에서 유체 격자로의 변위의 변환은 보 유한 요소 모델에 사용된 형상 함수를 유체 격자에서 구조 격자로의 힘의 변환은 일 등가 하중의 개념을 사용하였다. 그리고 이러한 날개의 정적 공탄성 해석 시, 이론적으로 TSD 공기력 사용의 타당성을 보였다. 또한 본 연구에서의 검증은 직접 연계된 공탄성 시스템의 효율적인 힘/변위 변환 기법의 검증을 포함한다.

• 한국전산유체공학회지
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• 제13권1호
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• pp.41-48
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• 2008

The fluid-structure interaction analysis such as a static aeroelastic analysis requires the result of each analysis as an input to the other analysis. Usually the grids for the fluid analysis and the structural analysis are different, so the results should be transformed properly for each other. The Infinite Plate Spline(IPS) and the Thin Plate Spline(TPS) are used in interpolating the displacement and the pressure. In this study, such interpolation methods are compared with kriging which provides a precise response surface. The static aeroelastic analysis is performed for the supersonic flow field with shock waves and the pressure field is interpolated by the TPS and kriging. The TPS shows tendency to weaken the shock strength, whereas kriging preserves the shock strength.

• 한국항공우주학회지
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• 제35권4호
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• pp.287-294
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• 2007

전산유체와 전산구조 연계 방법을 사용하여 하부에 외부 장착물이 부착된 초음속 비행체의 날개에 대한 정적 공탄성 해석을 수행하였다. 전산유체와 전산구조의 연계를 위하여 두 개의 사상 알고리즘, 즉 압력 사상 알고리즘과 변위 사상 알고리즘이 사용되었다. 공력해석은 날개주위의 유동장을 구하기 위하여 비정렬 3차원 오일러 방정식을 이용하였고 구조변위를 구하기 위하여 유한요소해석 프로그램을 사용하였다. 연계 절차는 특정 수렴조건을 만족할 때까지 반복 수행되며, 전형적인 초음속 비행체 날개에 대한 정적 공탄성 해석을 수행하여 수렴된 날개 형상을 얻었다.

• International Journal of Aeronautical and Space Sciences
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• 제14권4호
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• pp.310-323
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• 2013

In this paper, the aeroelastic static response of flexible wings with arbitrary cross-section geometry via a coupled CUF-XFLR5 approach is presented. Refined structural one-dimensional (1D) models, with a variable order of expansion for the displacement field, are developed on the basis of the Carrera Unified Formulation (CUF), taking into account cross-sectional deformability. A three-dimensional (3D) Panel Method is employed for the aerodynamic analysis, providing more accuracy with respect to the Vortex Lattice Method (VLM). A straight wing with an airfoil cross-section is modeled as a clamped beam, by means of the finite element method (FEM). Numerical results present the variation of wing aerodynamic parameters, and the equilibrium aeroelastic response is evaluated in terms of displacements and in-plane cross-section deformation. Aeroelastic coupled analyses are based on an iterative procedure, as well as a linear coupling approach for different free stream velocities. A convergent trend of displacements and aerodynamic coefficients is achieved as the structural model accuracy increases. Comparisons with 3D finite element solutions prove that an accurate description of the in-plane cross-section deformation is provided by the proposed 1D CUF model, through a significant reduction in computational cost.

• Wind and Structures
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• 제31권5호
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• pp.459-472
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• 2020

This study focused on the non-synoptic, tornado-like wind-induced effects on flexible horizontal structures that are extremely sensitive to winds. More specifically, the nonuniform, intensive vertical wind-velocity and transient natures of tornado events and their effects on the global behavior of a long-span bridge were investigated. In addition to the static part in the modeling of tornado-like wind-induced loads, the motion-induced effects were modeled using the semi-empirical model with a two-dimensional (2-D) indicial response function. Both nonlinear wind-induced static analysis and linear aeroelastic analysis in the time domain were conducted based on a 3-D finite-element model to investigate the bridge performance under the most unfavorable tornado pattern considering wind-structure interactions. The results from the present study highlighted the important effects due to abovementioned tornado natures (i.e., nonuniform, intensive vertical wind-velocity and transient features) on the long-span bridge, and hence may facilitate more appropriate wind design of flexible horizontal structures in the tornado-prone areas.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.453-457
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• 2011

In this study, transonic aeroelastic response analyses haw been conducted for the business jet aircraft configuration considering shockwave and flow separation effects. The developed fluid-structure coupled analysis system is applied for aeroelastic computations combining computational structural dynamics(CSD), finite element method(FEM) and computational fluid dynamics(CFD) in the time domain. It can give very accurate and useful engineering data on the structural dynamic design of advanced flight vehicles. For the nonlinear unsteady aerodynamics in high transonic flow region, Navier-Stokes equations using the structured grid system have been applied to wing-body configurations. In transonic flight region, the characteristics of static and dynamic aeroelastic responses have been investigated for a typical wing-body configuration model. Also, it is typically shown that the current computation approach can yield realistic and practical results for aircraft design and test engineers.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.299-299
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• 2011

In this study, transonic aeroelastic response analyses have been conducted for the business jet aircraft configuration considering shockwave and flow separation effects. The developed fluid-structure coupled analysis system is applied for aeroelastic computations combining computational structural dynamics(CSD), finite element method(FEM) and computational fluid dynamics(CFD) in the time domain. It can give very accurate and useful engineering data on the structural dynamic design of advanced flight vehicles. For the nonlinear unsteady aerodynamics in high transonic flow region, Navier-Stokes equations using the structured grid system have been applied to wing-body configurations. In transonic flight region, the characteristics of static and dynamic aeroelastic responses have been investigated for a typical wing-body configuration model. Also, it is typically shown that the current computation approach can yield realistic and practical results for aircraft design and test engineers.