scholarly journals ОЦІНКА ЕФЕКТИВНОСТІ ФОРМ КРИЛА ВАЖКИХ ЛІТАКІВ НА ОСНОВІ ЇХ КОЕФІЦІЄНТА ЕЛІПТИЧНОСТІ

2021 ◽  
pp. 15-25
Author(s):  
А. З. Двейрин ◽  
В. И. Рябков
Keyword(s):  
Geometric Parameters ◽  
Refined Model ◽  
Large Area ◽  
Aircraft Wing ◽  
Aircraft Wings ◽  
Minimum Value

The most important step in the choice of the parameters of trapezoidal wings is to ensure the design of the change in the circulation on their scope, as close as possible to the distribution of circulation in the elliptic wing as possible, which leads to the minimum value of its inductive resistance at a given value of the lift.Recently, when solving such a problem, the method of forming the main geometric sizes of the wing was distributed in terms of the equality of the so-called forms of trapezoidal () and equal to the elliptic area () wings.This approach turned out to be quite effective in the formation of geometric parameters of the wings of light and medium aircraft.However, for heavy aircraft with a large area of the wing, the plan of which is formed by three and more trapezes, there were difficulties in determining the coefficients of forms, which required the specified models for determining the coefficients of ellipticity () in assessing the effectiveness of heavy aircraft wings with their multivariate modification changes.The use of a refined model of the ellipticity coefficient is made on the examples of evaluating the effectiveness  of trapezoidal  wings of such heavy aircraft as IL-86, C-5A, IL-76 and An-124-100. It has been established that the wings of IL-76 and C-5A airplanes are the highest ellipticity. An-124-100 domestic aircraft wing is somewhat inferior to them in the magnitude of the ellipticity coefficient, which should be borne in mind when developing subsequent modifications of this aircraft.

scholarly journals Geometric Parameters of Cutting Tools that Can be Used for Forming Sided Surfaces with Variable Profile

2017 ◽  
Vol 62 (1) ◽  
pp. 33-40
Author(s):  
M. Razumov ◽  
A. Grechukhin ◽  
A. Maslennikov
Keyword(s):  
Cutting Tools ◽  
Planetary Gear ◽  
Geometric Parameters ◽  
Planetary Motion ◽  
Mathematical Formula ◽  
Polyhedral Surfaces ◽  
Clearance Angle ◽  
Minimum Value ◽  
Polygonal Surface ◽  
The Impact

Abstract This article describes machining technology of polyhedral surfaces with varying profile, which is provided by planetary motion of multiblade block tools. The features of the technology and urgency of the problem is indicated. The purpose of the study is to determine the minimum value of the clearance angle of the tool. Also, the study is carried out about changing the value of the front and rear corners during the formation of polygonal surface using a planetary gear. The scheme of calculating the impact of various factors on the value of the minimum clearance angle of the tool and kinematic front and rear corners of the instrument is provided. The mathematical formula for calculating the minimum clearance angle of the tool is given. Also, given the formula for determining the front and rear corners of the tool during driving. This study can be used in the calculation of the design operations forming multifaceted external surfaces with a variable profile by using the planetary gear.

An Investigation on Vibration-Based Damage Detection in an Aircraft Wing Scaled Model

2005 ◽  
Vol 293-294 ◽  
pp. 321-328
Author(s):  
Irina Trendafilova
Keyword(s):  
Damage Detection ◽  
Element Model ◽  
Early Model ◽  
Response Functions ◽  
Aircraft Wing ◽  
Scaled Model ◽  
Aircraft Wings ◽  
Different Types ◽  
Intact Condition ◽  
Components Analysis

This work investigates the use of two different vibration-based methods for health monitoring of aircraft wings. A finite element model of a simplified wing is used to model and predict the vibration response of an aircraft wing in an intact condition and in the presence of different types and levels of damage. Two main types of damage are considered- cracks and distributed damage. This study first explores the sensitivity of the lower modal frequencies to different damage levels of the studied types. Then the employment of the frequency response functions subjected to principal components analysis is discussed. This is an early model-based study which is intended to establish if the considered procedures can be used as damage detection tools.

Computational Analysis of Fighter Aircraft Wing under Mach Number 0.7 for Small Sweep Angles

2014 ◽  
Vol 592-594 ◽  
pp. 1020-1024
Author(s):  
G. Srinivas ◽  
Srinivasa Rao Potti
Keyword(s):  
Computational Analysis ◽  
Cfd Simulation ◽  
Flow Conditions ◽  
Wing Design ◽  
Aircraft Wing ◽  
Fighter Aircraft ◽  
Aircraft Wings ◽  
Paper Work ◽  
Semi Empirical ◽  
Wing Performance

Fighter aircraft wings are the leading lift generating components for any aerospace vehicle. The recital of any flying vehicle largely depends on its wing design. Missiles and the fighter aircrafts which are having propulsion system mostly have fins to control and maneuver. In this present paper work an attempt has been made to design a fighter aircraft wing configuration which will be used in some air launched air to surface guided weapons fighter aircraft. The main focus of this paper agreement in determining the Sweep-back effects on fighter aircraft wing under transonic condition at different angles of attack (AoA) from 0 to 5 degrees. For this the fighter aircraft wing performance for various flow conditions and sweep angles are obtained based on the empirical, semi-empirical and CFD simulation results. Hence by studying these computational results would help in the optimizing geometry for better performance, an finest wing design for the air launched air to surface body with conservative wing can be obtained.

Topology Optimization-Based Design of a Compliant Aircraft Wing for Morphing Leading and Trailing Edges

2010 ◽  
Author(s):  
Pakeeruraju Podugu ◽  
G. K. Ananthasuresh
Keyword(s):  
Topology Optimization ◽  
Compliant Mechanisms ◽  
Flexible Structures ◽  
Least Square ◽  
Small Displacement ◽  
Aircraft Wing ◽  
Aircraft Wings ◽  
Shape Morphing ◽  
Geometric Moments ◽  
Trailing Edges

In this paper, we present a methodology for designing a compliant aircraft wing, which can morph from a given airfoil shape to another given shape under the actuation of internal forces and can offer sufficient stiffness in both configurations under the respective aerodynamic loads. The least square error in displacements, Fourier descriptors, geometric moments, and moment invariants are studied to compare candidate shapes and to pose the optimization problem. Their relative merits and demerits are discussed in this paper. The ‘frame finite element ground structure’ approach is used for topology optimization and the resulting solutions are converted to continuum solutions. The introduction of a notch-like feature is the key to the success of the design. It not only gives a good match for the target morphed shape for the leading and trailing edges but also minimizes the extension of the flexible skin that is to be put on the airfoil frame. Even though linear small-displacement elastic analysis is used in optimization, the obtained designs are analysed for large displacement behavior. The methodology developed here is not restricted to aircraft wings; it can be used to solve any shape-morphing requirement in flexible structures and compliant mechanisms.

scholarly journals Verification of Strain Transfer Characteristics of Distributed Surface-attached FBGs on Aircraft Wings

2020 ◽  
Vol 306 ◽  
pp. 05001
Author(s):  
Zhen Ma ◽  
Xiyuan Chen
Keyword(s):  
Strain Measurement ◽  
Matrix Material ◽  
Calibration Method ◽  
Tensile Tests ◽  
Deformation Measurement ◽  
Aircraft Wing ◽  
Full Field ◽  
Aircraft Wings ◽  
The Matrix

In order to provide higher accuracy for transfer alignment on aircraft, a surface-attached FBGs is designed for distributed deformation measurement of aircraft wing. To verify the measurement accuracy of the surface-attached FBGs, a strain calibration method of the surface-attached FBGs applied with the wing strain measurement is proposed. Two Aluminium Alloy Test Plates(AATP) with different sizes were designed as the matrix material for tensile test. The test results show that AATP-A has better test effect. Through the two sets of tensile tests, the change of wavelength measured on the surface-attached FBGs is in good agreement with the change of strain value of strain gauge.The experimental results prove that the method based on surface-attached FBGs is feasible for the strain measurement of aircraft wing. The method is simple and reliable, which lays a foundation for the follow-up study of the full-field deformation measurement of aircraft wing.

scholarly journals Effect of Cut-Out Shape on the Stresses in Aircraft Wing Ribs under Aerodynamic Load

CFD Letters ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 87-94
Author(s):  
Jaffar Syed Mohamed Ali ◽  
Wan Muhammad Hafizuddin W. Embong ◽  
Abdul Aabid
Keyword(s):  
Stress Concentration ◽  
Aerodynamic Load ◽  
Aircraft Wing ◽  
Aircraft Structure ◽  
Commercial Software ◽  
Aircraft Structures ◽  
Aerodynamic Loads ◽  
Aircraft Wings ◽  
Shear Loads ◽  
Different Shapes

Ribs in aircraft wings maintain the airfoil shape of the wing under aerodynamic loads and also support the resulting bending and shear loads that act on the wing. Aircrafts are designed for least weight and hence the wings are made of hollow torsion box and the ribs are designed with cut-outs to reduce the weight of the aircraft structure. These cut-outs on the ribs will lead to higher stresses and stress concentration that can lead to failure of the aircraft structures. The stresses depend on the shape of the cut-outs in the ribs and thus in the present work, the commercial software ANSYS was used to evaluate the stresses on the ribs with different shapes of cut-outs. Four different shapes of cut-out were considered to study the effect of cut-out shape on the stresses in the ribs. It was found that the best shape for the cut-outs on the ribs of wings to reduce weight is elliptical.

scholarly journals Numerical Investigation of Aeroelastic Mode Distribution for Aircraft Wing Model in Subsonic Air Flow

2010 ◽  
Vol 2010 ◽  
pp. 1-23 ◽  
Author(s):  
Marianna A. Shubov ◽  
Stephen Wineberg ◽  
Robert Holt
Keyword(s):  
Boundary Value Problem ◽  
Numerical Investigation ◽  
Air Flow ◽  
Affirmative Answer ◽  
Positive Answer ◽  
Aircraft Wing ◽  
Aircraft Wings ◽  
Flutter Speed ◽  
Wing Model ◽  
Analytical Formulas

In this paper, the numerical results on two problems originated in aircraft wing modeling have been presented.The first problemis concerned with the approximation to the set of the aeroelastic modes, which are the eigenvalues of a certain boundary-value problem. The affirmative answer is given to the following question: can the leading asymptotical terms in the analytical formulas be used as reasonably accurate description of the aeroelastic modes? The positive answer means that these leading terms can be used by engineers for practical calculations.The second problemis concerned with the flutter phenomena in aircraft wings in a subsonic, incompressible, inviscid air flow. It has been shown numerically that there exists a pair of the aeroelastic modes whose behavior depends on a speed of an air flow. Namely, when the speed increases, the distance between the modes tends to zero, and at some speed that can be treated as the flutter speed these two modes merge into one double mode.

scholarly journals Vibrational tests and analysis on materials used in aircraft

2018 ◽  
Vol 12 (2) ◽  
pp. 32-36 ◽  
Author(s):  
Sándor Csikós ◽  
Tamás Molnár ◽  
Péter Szuchy ◽  
László Gogolák ◽  
István Bíró ◽  
...  
Keyword(s):  
Natural Frequency ◽  
Structural Integrity ◽  
Vibrational Analysis ◽  
Aircraft Wing ◽  
Aircraft Wings ◽  
Test Pieces ◽  
Cargo Capacity ◽  
Material Sciences ◽  
Materials Used ◽  
The University

The current cargo capacity for aircraft is about 20% of their total weight, increasing this ratio would significantly increase the economics of aircraft logistics. This is why it’s important for material sciences to advance so that the materials used in aircraft construction become lighter while still retaining their structural integrity. In this paper we examined materials used in aircraft construction (steel, aluminum, plastics and composites) at the University of Szeged Faculty of Engineering. Using vibrational analysis we analyzed the test pieces for their natural frequency, we did this to gain insight to the range of frequencies that are least attenuated by the material the aircraft wings are made from. Using the data we gathered we wish to draw conclusions to which materials are more suited for aircraft wing construction.

scholarly journals The influence of Krueger flap geometric parameters on the lift of an aircraft wing

2019 ◽  
Vol 0 (37) ◽  
pp. 87-96
Author(s):  
Анатолій Станіславович Носик ◽  
Ілля Станіславович Кривохатько
Keyword(s):  
Geometric Parameters ◽  
Aircraft Wing

Convergent Beam Electron Diffraction

1978 ◽  
Vol 36 (3) ◽  
pp. 304-315
Author(s):  
G. Lehmpfuhl
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Crystal Surface ◽  
Diffraction Spot ◽  
Crystal Thickness ◽  
Large Area ◽  
Electron Microscopic ◽  
Additional Information ◽  
Microscopic Investigations

Introduction In electron microscopic investigations of crystalline specimens the direct observation of the electron diffraction pattern gives additional information about the specimen. The quality of this information depends on the quality of the crystals or the crystal area contributing to the diffraction pattern. By selected area diffraction in a conventional electron microscope, specimen areas as small as 1 µ in diameter can be investigated. It is well known that crystal areas of that size which must be thin enough (in the order of 1000 Å) for electron microscopic investigations are normally somewhat distorted by bending, or they are not homogeneous. Furthermore, the crystal surface is not well defined over such a large area. These are facts which cause reduction of information in the diffraction pattern. The intensity of a diffraction spot, for example, depends on the crystal thickness. If the thickness is not uniform over the investigated area, one observes an averaged intensity, so that the intensity distribution in the diffraction pattern cannot be used for an analysis unless additional information is available.

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