scholarly journals The effect of laminate lay-up on the flutter speed of composite wings

2003 ◽  
Vol 217 (3) ◽  
pp. 115-122 ◽  
Author(s):  
S J Guo ◽  
J R Bannerjee ◽  
C W Cheung
Keyword(s):  
Dominant Role ◽  
Torsional Rigidity ◽  
Minimum Weight ◽  
Laminated Composite ◽  
Flutter Speed ◽  
Design Variables ◽  
Torsional Coupling ◽  
Wing Structure ◽  
Laminated Composite Material ◽  
Composite Wing

This paper presents an analytical study on optimization of a laminated composite wing structure for achieving a maximum flutter speed and a minimum weight without strength penalty. The investigation is carried out within the range of incompressible airflow and subsonic speed. In the first stage of the optimization, attention has been paid mainly to the effect on flutter speed of the bending, torsion and, more importantly, the bending-torsional coupling rigidity, which is usually associated with asymmetric laminate lay-up. The study has shown that the torsional rigidity plays a dominant role, while the coupling rigidity has also quite a significant effect on the flutter speed. In the second stage of the optimization, attention has been paid to the weight and laminate strength of the wing structure, which is affected by the variation in laminate lay-up in the first stage. Results from a thin-walled wing box made of laminated composite material show that up to 18 per cent increase in flutter speed and 13 per cent reduction in weight can be achieved without compromising the strength. The investigation has shown that a careful choice of initial lay-up and design variables leads to a desirable bending, torsional and coupling rigidities, with the provision of an efficient approach when achieving a maximum flutter speed with a minimum mass of a composite wing.

Optimal Design of Composite Wing-Box by Genetic Algorithm

2014 ◽  
Vol 697 ◽  
pp. 365-368
Author(s):  
Guang Rong Pu ◽  
Peng Gang Mu
Keyword(s):  
Genetic Algorithm ◽  
Minimum Weight ◽  
Design Problems ◽  
Finite Element Program ◽  
Structural Layout ◽  
Design Variables ◽  
Load Factors ◽  
Element Program ◽  
Composite Wing ◽  
Wing Box

With the increasing use of composite materials in aviation structures, stability and weights of wing-box are important projects that engineers care about. In this paper, the genetic algorithm is chosen to deal with the conceptual design problems of composite wing-box. For the more excellent capabilities in optimization computation of multi-dimensional functions, particularly when overcoming local-best solutions, genetic algorithm is presented to determine the design variables of complicated wing-box. Optimization algorithm is realized with MATLAB software, which calls the finite element program MSC.Nastran to get buckling load factors, and structural layout, thickness of plies and minimum weight of wing-box are obtained simultaneously. The results show that the approach proposed is available, effective to preliminary design of the mainly aeronautical structures.

scholarly journals Flutter Characteristic Study of Composite Sandwich Panel with Functionally Graded Foam Core

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Peng Jin ◽  
Xiaoping Zhong
Keyword(s):  
Sandwich Panel ◽  
Minimum Weight ◽  
Functionally Graded ◽  
Foam Core ◽  
Minimum Weight Design ◽  
Direction Parallel ◽  
Composite Sandwich ◽  
Flutter Speed ◽  
Design Variables ◽  
Weight Design

This paper attempts to investigate the flutter characteristic of sandwich panel composed of laminated facesheets and a functionally graded foam core. The macroscopic properties of the foam core change continuously along this direction parallel to the facesheet lamina. The model used in the study is a simple sandwich panel-wing clamped at the root, with three simple types of grading strategies for FGM core: (1) linear grading strategy in the chord-wise direction, (2) linear grading strategy in the span-wise direction, and (3) bilinear grading of properties of foam core across the panel. The results show that use of FGM core has the potential to increase the flutter speed of the sandwich panel. Finally, a minimum weight design of composite sandwich panel with lamination parameters of facesheet and density distribution of foam core as design variables is conducted using particle swarm optimization (PSO).

Comparative Structural Optimization Study of Composite and Aluminum Horizontal Tail Plane of a Helicopter

2019 ◽  
Author(s):  
Bertan Arpacioglu ◽  
Altan Kayran
Keyword(s):  
Structural Optimization ◽  
Minimum Weight ◽  
Local Buckling ◽  
Laminated Composite ◽  
Element Model ◽  
Aerodynamic Load ◽  
Preliminary Design ◽  
Design Phase ◽  
Design Variables ◽  
Discrete Design Variables

Abstract This work presents structural optimization studies of aluminum and composite material horizontal tail plane of a helicopter by using MSC. NASTRAN SOL200 optimization capabilities. Structural design process starts from conceptual design phase, and structural layout design is performed by using CATIA. In the preliminary design phase, study focuses on the minimum weight optimization with multiple design variables and similar constraints for both materials. Aerodynamic load calculation is performed using ANSYS and the finite element model of the horizontal tail plane is created by using MSC.PATRAN. According to the characteristics of materials, design variables are chosen. For the aluminum horizontal tail, thickness and flange areas are used as the design variables; and for composite horizontal tail, attention is mainly focused on the ply numbers and ply orientation angles of the laminated composite panels. By considering the manufacturability issues, discrete design variables are used. For three different mesh densities, different initial values of the design variables, and similar design constraints, optimizations are repeated and the results of optimizations are examined and compared with each other. In the optimizations performed, constraints are taken as strength and local buckling constraints. It is shown that the optimization methodology used in this study gives confident results for optimizing structures in the preliminary design phase.

CAD and Optimization of Helical Torsion Springs

1994 ◽  
Author(s):  
Sayed M. Metwalli ◽  
M. Alaa Radwan ◽  
Abdel Aziz M. Elmeligy
Keyword(s):  
Iterative Process ◽  
Minimum Weight ◽  
Design Parameters ◽  
Optimal Parameters ◽  
Direct Evaluation ◽  
Torsion Spring ◽  
Performance Requirements ◽  
Design Variables ◽  
Method Of Lagrange Multipliers ◽  
Torsion Springs

Abstract The convensional procedure of helical torsion spring design is an iterative process because of large number of requirements and relations that are to be attained once at a time. The design parameters are varied at random until the spring design satisfies performance requirements. A CAD of the spring for minimum weight is formulated with and without the variation of the maximum normal stress with the wire diameter. The CAD program solves by employing the method of Lagrange-Multipliers. The optimal parameters, in a closed form are obtained, normalized and plotted. These explicit relations of design variables allow direct evaluation of optimal design objective and hence, an absolute optimum could be achieved. The comparison of optimum results with those previously published, shows a pronounced achievement in the reduction of torsion spring weight.

Selection of the Optimal Structural Design of a Spar Composite Wing

2021 ◽  
pp. 90-99
Author(s):  
O.V. Tatarnikov ◽  
W.A. Phyo ◽  
Lin Aung Naing
Keyword(s):  
Optimal Design ◽  
Element Analysis ◽  
Minimal Weight ◽  
Wing Structures ◽  
Optimization Parameters ◽  
Nonlinear Static ◽  
Wing Structure ◽  
Pareto Method ◽  
Selection Of ◽  
Composite Wing

This paper describes a method for optimizing the design of a spar-type composite aircraft wing structure based on multi-criterion approach. Two types of composite wing structures such as two-spar and three-spar ones were considered. The optimal design of a wing frame was determined by the Pareto method basing on three criteria: minimal weight, minimal wing deflection, maximal safety factor and minimal weight. Positions of wing frame parts, i.e. spars and ribs, were considered as optimization parameters. As a result, an optimal design of a composite spar-type wing was proposed. All the calculations necessary to select the optimal structural and design of the spar composite wing were performed using nonlinear static finite element analysis in the FEMAP with NX Nastran software package.

scholarly journals Optimization of Laminated Composite Plates for Maximum Biaxial Buckling Load

2020 ◽  
Vol 36 (2) ◽  
Author(s):  
Pham Dinh Nguyen ◽  
Quang-Viet Vu ◽  
George Papazafeiropoulos ◽  
Hoang Thi Thiem ◽  
Pham Minh Vuong ◽  
...  
Keyword(s):  
Fiber Orientation ◽  
Orientation Angle ◽  
Laminated Composite ◽  
Optimization Procedure ◽  
Composite Plates ◽  
Buckling Load ◽  
Biaxial Compression ◽  
Laminated Composite Plates ◽  
Design Variables ◽  
Fiber Orientation Angle

This paper proposes an optimization procedure for maximization of the biaxial buckling load of laminated composite plates using the gradient-based interior-point optimization algorithm. The fiber orientation angle and the thickness of each lamina are considered as continuous design variables of the problem. The effect of the number of layers, fiber orientation angles, thickness and length to thickness ratios on the buckling load of the laminated composite plates under biaxial compression is investigated. The effectiveness of the optimization procedure in this study is compared with previous works.

Static and Dynamic Analysis of Aluminium Composite in Wing Section Using ANSYS

2014 ◽  
Vol 984-985 ◽  
pp. 367-371
Author(s):  
E.S. Esakkiraj ◽  
S. Anish ◽  
V. Anish
Keyword(s):  
Static Analysis ◽  
Minimum Weight ◽  
Equivalent Stress ◽  
Model Analysis ◽  
Aluminium Composite ◽  
Aircraft Wing ◽  
Lower Stress ◽  
Static And Dynamic Analysis ◽  
Finite Element Software ◽  
Composite Wing

The cold of this cardboard is to abstraction and analyze the amount accustomed accommodation and weight accumulation of blended aircraft (Aluminium Silicon Carbide) addition with that of Aluminium wing and appropriately access the acceptable aircraft addition of minimum weight accomplished of address a accustomed changeless amount after failure. And also this paper presents a model and a static analysis of the aircraft wing, using the finite element software ANSYS. The geometry was created in CATIA V5 R18 and imported. The static and model analysis are carried out in analysis software ANSYS. The result of from the static analysis refers to the total deformation, equivalent stress, shear stress and shear intensity on the skin of the aircraft wing. The model analysis will be carried out to find out the first six modes of vibrations and the different mode shape in which wing can deform without the application of load. Compared to the conventional Aluminium wing, the hybridized composite wing experience far lower stresses and the aircraft wing weight nearly 40% and 50% lower stress.

Optimization of Magnetorheological Brake

2011 ◽  
Author(s):  
Snegdha Gupta ◽  
Harish Hirani
Keyword(s):  
Minimum Weight ◽  
Hybrid Genetic Algorithm ◽  
Brake System ◽  
Outer Diameter ◽  
Current Accounting ◽  
Hydraulic Brake ◽  
Rate Dependent ◽  
Design Variables ◽  
Braking Torque ◽  
Gradient Based

Quick response and rheological properties as a function of magnetic field are well known features of MR fluids which inspire their usage as brake materials. Controllable torque and minimum weight of brake system are the deciding functions based on which the viability of the MR brake against the conventional hydraulic brake system can be judged. The aim of this study is to optimize a multi-disk magneto-rheological brake system considering torque and weight as objective functions and geometric dimensions of conventional hydraulic brake as constraints. The electric current accounting magnetic saturation, MR gap, number of disk, thickness of disk, and outer diameter of disk have been considered as design variables. To model the behavior of MR Fluid, Bingham and Herschel Bulkley models have been compared. To implement these models in estimating the braking torque a modification in shear rate dependent component has been proposed. The overall design of MR brake has been optimized using a hybrid (Genetic algorithm plus gradient based) optimization scheme of MATLAB software.

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