• Composites Research
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• v.25 no.6
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• pp.224-229
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• 2012

The structural performance is degraded in case of embedding the array antenna for reconnaissance and surveillance into the wing skin structures. In this paper, the optimal design for the thickness of composite hat-shaped stiffener which is reinforced embedded array antenna on the simplified composite wing box was conducted. To select the basic shape of hat-shaped stiffener, structural analysis was carry out using the commercial finite element analysis program while changing the web slope and flange length of hat-shaped stiffener. The optimal thickness of the composite hat-shaped stiffeners was determined by using commercial optimization program such as VisualDOC and commercial FEA program with considering stresses and buckling constraints.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.615-622
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• 1995

It may be inefficient to conduct the aeroelastic analysis by using full-scale conventional finite-element analyses or experiments, from the initial design phase, for an aircraft wing which can be considered as the discontinuum complex structure with composite laminated skins. In this paper, therefore more efficient aeroelastic analysis has been conducted for a box-beam typed aircraft wing by using the equivalent continuum beam-rod model which is derived from the concept of energy equivalence. Equivalent structural properties of the continuum beam-rod model are obtained from the direct comparison of the finite-element matrices of continuum beam-rod model with those of box-beam typed aircraft wing. Numerical results by the continuum beam-rod model approach are compared with those by the conventional finite-element analysis approach to show that the continuum beam-rod model proposed herein is quite satisfactory as a simplified model of aircraft wing structure for aeroelastic analyses.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.74-81
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• 2004

In this study preliminary structural design has been performed to develop an all composite wing box for experimental aircraft(classified in FAR Part 21). Considerations on composite materials and their manufacturing process were taken into account throughout the design phase. Aerodynamic loads were estimated by using Shrenk method(NACA TM No 948) and FAR Part 23 Appendix A. The structural layout has been determined to carry effectively the critical loads and to maximize the benefit of composite structure. Maximum strain failure allowable and first ply failure criteria were applied for the sizing of major structural members. Finally, the designed composite wing box structure is presented in the form of drawings, which include material specifications, stacking sequences and joint design.

• Advances in aircraft and spacecraft science
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• v.7 no.4
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• pp.353-369
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• 2020

This paper presents the flutter analysis and optimum design of axially functionally graded box beam cantilever wing section by considering various geometric and material parameters. The coupled dynamic equations of the continuous model of wing system in terms of material and cross-sectional properties are formulated based on extended Hamilton's principle. By expressing the lift and pitching moment in terms of plunge and pitch displacements, the resultant two continuous equations are simplified using Galerkin's reduced order model. The flutter velocity is predicted from the solution of resultant damped eigenvalue problem. Parametric studies are conducted to know the effects of geometric factors such as taper ratio, thickness, sweep angle as well as material volume fractions and functional grading index on the flutter velocity. A generalized surrogate model is constructed by training the radial basis function network with the parametric data. The optimized material and geometric parameters of the section are predicted by solving the constrained optimal problem using firefly metaheuristics algorithm that employs the developed surrogate model for the function evaluations. The trapezoidal hollow box beam section design with axial functional grading concept is illustrated with combination of aluminium alloy and aluminium with silicon carbide particulates. A good improvement in flutter velocity is noticed by the optimization.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.1-8
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• 2004

In this study, the method of computing and extracting the generalized unsteady aerodynamic matrices using MSC/NASTRAN and MSC/NASTRAN DMAP ALTER has been suggested for the analysis and control of aeroelastic phenomena such as flutter and gust response analysis. In addition to that, the method of approximating the generalized unsteady aerodynamic matrices using minimum state approximation method has been proposed in order to cast the aeroelastic equations of motion in state space form for aeroelastic analysis and control application. Simplified aircraft wing box model has been used for the validation of the methods suggested in this study.