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 Modeling of Size Effects in Bending of Perforated Cosserat Plates

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
Roman Kvasov ◽  
Lev Steinberg
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Numerical Study ◽  
The Finite Element Method ◽  
Classical Elasticity ◽  
Element Analysis ◽  
Plate Deformation ◽  
The Finite Element Analysis ◽  
Circular Holes ◽  
Different Shapes

This paper presents the numerical study of Cosserat elastic plate deformation based on the parametric theory of Cosserat plates, recently developed by the authors. The numerical results are obtained using the Finite Element Method used to solve the parametric system of 9 kinematic equations. We discuss the existence and uniqueness of the weak solution and the convergence of the proposed FEM. The Finite Element analysis of clamped Cosserat plates of different shapes under different loads is provided. We present the numerical validation of the proposed FEM by estimating the order of convergence, when comparing the main kinematic variables with an analytical solution. We also consider the numerical analysis of plates with circular holes. We show that the stress concentration factor around the hole is less than the classical value, and smaller holes exhibit less stress concentration as would be expected on the basis of the classical elasticity.

Development of a Hypersonic Aircraft Design Optimization Tool

2014 ◽  
Vol 553 ◽  
pp. 847-852 ◽  
Author(s):  
Benjamin J. Morrell ◽  
David J. Munk ◽  
Gareth A. Vio ◽  
Dries Verstraete
Keyword(s):  
Structural Design ◽  
Current Practice ◽  
Thermal Stresses ◽  
Aircraft Design ◽  
Material Strength ◽  
Aircraft Structure ◽  
Aerodynamic Loads ◽  
Design And Optimization ◽  
Hypersonic Aircraft ◽  
Strength And Stiffness

The design and optimization of hypersonic aircraft is severely impacted by the high temperatures encountered during flight as they can lead to high thermal stresses and a significant reduction in material strength and stiffness. This reduction in rigidity of the structure requires innovative structural concepts and a stronger focus on aeroelastic deformations in the early design and optimisation of the aircraft structure. This imposes the need for a closer coupling of the aerodynamic and structural design tools than is current practice. The paper presents the development of a multi-disciplinary, closely coupled optimisation suite for hypersonic aircraft. An overview of the setup and structure of the optimization suite is given and the integration between the Tranair solver, used to determine the aerodynamic loads and temperatures, and MSC/NASTRAN, used for the structural sizing and design, will be given.

Advancements in Micro-Structure with Multiple Stress Concentration Region for Bionic Vector Hydrophone

2015 ◽  
Vol 645-646 ◽  
pp. 555-560
Author(s):  
Guo Jun Zhang ◽  
Peng Zhao ◽  
Wen Dong Zhang
Keyword(s):  
Stress Concentration ◽  
Constant Force ◽  
Ansys Software ◽  
Micro Structure ◽  
Concentration Region ◽  
Multiple Stress ◽  
Upper Limit ◽  
Stress Concentration Region ◽  
Vector Hydrophone ◽  
Different Shapes

The method of Multiple Stress Concentration Regions (MSCRs) on the surface of MEMS Silicon micro-structure is introduced in order to enhance the sensibility of the hair vector hydrophone without reducing the working bandwidth. The MSCRs with the thickness and width smaller than the rest of the cantilever can produce localized stress concentration when constant force is applied on the structure. ANSYS software has been used as a tool to analyze the effect of different shapes and dimensions on the performance of the micro-structure. The optimum MSCR has been obtained. Results show that compared with the ordinary structure, the sensitivity of the micro-structure with MSCR can be increased by 1.5 times, and the upper limit of bandwidth can be improved from 337Hz to 500Hz. This paper provides a new method to resolve contradiction between the sensitivity and working bandwidth.

ARAMID ORGANOPLASTICS FOR INCREASING THE BIRD RESISTANCE OF ELEMENTS OF AIRCRAFT STRUCTURES

2021 ◽  
pp. 77-84
Author(s):  
A.Ch. Kan ◽  
◽  
G.F. Zhelezina ◽  
N.A. Solovieva ◽  
◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Aircraft Wing ◽  
Aircraft Structures ◽  
Optimal Ratio ◽  
External Contour ◽  
Impact Tests ◽  
Protective Screen

The possibility of using protective screens made of aramid organoplastics to ensure the bird resistance of carbon fiber wing flaps is investigated. Aramid organoplastics were selected for the production of a protective screen, taking into account the main requirements for the materials of external contour of the aircraft wing. The result of impact tests simulating the collision of a bird with carbon fiber flaps that are not protected and protected by organoplastics are presented. The optimal ratio of aramid organoplastics as part of the protective screen for carbon fiber wing flaps is presented.

Aerolelastic Analysis of a Thin-Walled Composite Aircraft Wing With an External Store Subjected to a Follower Force

2014 ◽  
Author(s):  
Alev Kacar Aksongur ◽  
Seher Eken ◽  
Metin O. Kaya
Keyword(s):  
Transverse Shear ◽  
Structural Model ◽  
Follower Force ◽  
Beam Model ◽  
Aircraft Wing ◽  
Sweep Angle ◽  
Aerodynamic Loads ◽  
Unsteady Aerodynamic ◽  
Thin Walled ◽  
The Time Domain

This study reports dynamic aeroelastic analyses of an aircraft wing with an attached mass subjected a lateral follower force in an incompressible flow. A swept thin-walled composite beam with a biconvex cross-section is used as the structural model that incorporates a number of non-classical effects such as material anisotropy, transverse shear deformation and warping restraint. A symmetric lay-up configuration i.e. circumferentially asymmetric stiffness (CAS) is further adapted to this model to generate the coupled motion of flapwise bending-torsion-transverse shear. For this beam model, the unsteady aerodynamic loads are expressed using Wagners function in the time-domain as well as using Theodorsen function in the frequency-domain. The flutter speeds are evaluated for several ply angles and the effects of follower force, transverse shear, fiber-orientation and sweep angle on the aeroelastic instabilities are further discussed.

scholarly journals Hunting Stability of High-Speed Railway Vehicles Under Steady Aerodynamic Loads

2018 ◽  
Vol 18 (07) ◽  
pp. 1850093 ◽  
Author(s):  
Xiao-Hui Zeng ◽  
Jiang Lai ◽  
Han Wu
Keyword(s):  
Stability Analysis ◽  
High Speed ◽  
Critical Speed ◽  
Railway Vehicle ◽  
Aerodynamic Load ◽  
High Speed Railway ◽  
Aerodynamic Loads ◽  
Railway Vehicles ◽  
Pitch Moment ◽  
Hunting Stability

With the rising speed of high-speed trains, the aerodynamic loads become more significant and their influences on the hunting stability of railway vehicles deserve to be considered. Such an effect cannot be properly considered by the conventional model of hunting stability analysis. To this end, the linear hunting stability of high-speed railway vehicles running on tangent tracks is studied. A model considering the steady aerodynamic loads due to the joint action of the airflow facing the moving train and the crosswind, is proposed for the hunting stability analysis of a railway vehicle with 17 degrees of freedom (DOF). The key factors considered include: variations of the wheel–rail normal forces, creep coefficients, gravitational stiffness and angular stiffness due to the actions of the aerodynamic load, which affects the characteristics of hunting stability. Using the computer program developed, numerical calculations were carried out for studying the behavior of the linear hunting stability of vehicles under steady aerodynamic loads. The results show that the aerodynamic loads have an obvious effect on the linear critical speeds and instability modes. The linear critical speed decreases monotonously as the crosswind velocity increases, and the influences of pitch moment and lift force on the linear critical speed are larger than the other components of the aerodynamic loads.

The Static Strength Reliability Analysis of Composite Aircraft Structures

2014 ◽  
Vol 488-489 ◽  
pp. 1215-1218 ◽  
Author(s):  
Long Xiang Lin ◽  
Hao Lei Mou ◽  
Jian Ren ◽  
Tian Chun Zou
Keyword(s):  
Environmental Factors ◽  
Reliability Analysis ◽  
Composite Structures ◽  
Design Principles ◽  
Static Strength ◽  
Full Scale ◽  
Basic Design ◽  
Aircraft Structure ◽  
Aircraft Structures ◽  
Strength Design

The static strength design of aircraft structure is the most basic design principles. The basic applicable conditions of composite structures static strength reliability analysis using the current methods were mentioned in this paper, and compliance analysis of these basic conditions was carried out. In addition, further studies were also conducted to research the influence of the number of full-scale structural specimens and environmental factors on the composite structures static strength reliability.

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.

Estimation Mass of the Aircraft Wing with the Multidisciplinary Process

2014 ◽  
Vol 1016 ◽  
pp. 418-422
Author(s):  
Hadjez Fayssal ◽  
Necib Brahim
Keyword(s):  
Sensitivity Analysis ◽  
Accurate Result ◽  
Aerodynamic Load ◽  
Aircraft Wing ◽  
Aerodynamic Forces ◽  
Actual Weight ◽  
Order Of Magnitude

The purpose of this project is to study and practice the techniques discussed in multidisciplinary courses aeronautical structure and load calculations to estimate the mass of an aircraft wing. The model studied is the Airbus A320. We first describe the characteristics of the wing of the aircraft. We will then study the aerodynamic forces, their distribution in the wings and aerodynamic load cases. In the next section, we will calculate the stresses induced by the bending of the wing and deduce the thickness of coatings that resist buckling. We also do a sensitivity analysis on the pitch of the ribs and stiffeners. Then, we will model the wing in SolidWorks and we will issue the card with Nastran constraints. Finally, we will provide our comments on the orders of magnitude obtained and the assumptions made the means to implement must be substantial to obtain an accurate result. The challenge of this project is to model the wing sufficiently wise to obtain an order of magnitude closer to reality. We consider an error of 15-20 % compared to the actual weight of the wing is suitable as part of a project like this [1].

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