Particle swarm optimization via global-local scheme for structural design of aerospace system

다국어 초록 (Multilingual Abstract)

To ensure the structure to be safely maintained in flight phase, it is important to design and optimize the structures including aerospace system such as flight wing, launch vehicle and satellite. The structures of aerospace system are usually configured with stiffener and panel. Since panel is surrounded by stiffener, it can be seen that local characteristics in a particular analysis such as buckling analysis. Because load path does not change significantly, panel is suitable to perform the local buckling analysis because the buckling mode is present in the local area surrounded by the stiffener. This buckling analysis is time consuming work in the structural design optimization. To perform the structural design optimization effectively, it is essential that separate the optimization problem into the global optimization problem and the local optimization problem.
In this study, the global-local structural optimization problem was configured for the effective optimization of the structures including aerospace system structures. Particle swarm optimization algorithm which is useful for structural design optimization was used. To apply the global-local scheme into particle swarm optimization algorithm, optimization module was developed. This module is called the global-local PSO module. This module was constructed with three interface dialog. One is for setting optimization problem. And other one is for setup optimization environmental parameter. Third interface dialog is to start optimization and monitoring. All of these functions were realized in DIAMOND/IPSAP which is being developed by Aerospace Structures Laboratory in Seoul National University.
To evaluate a performance of the particle swarm optimization algorithm using the global-local PSO module, Stiffened shell box and launch vehicle models were designed and were optimized by the global-local PSO algorithm. In case of stiffened shell box, local static buckling analysis was performed. Critical buckling load was used for constraint of the local optimization. Last example was the optimization of the launch vehicle.
The significance of this study was that it was possible to faster optimization by using the global-local PSO algorithm which is appropriate approach for the structures which are able to separate into the global and local area. Also, using the computer aided engineering including the high performance solver named IPSAP and the optimization module with in-house pre/post tools, the time and effort for finding the optimal design variables which are used in the aerospace system structures including flight wing box, launch vehicle, etc are decreased efficiently.

목차 (Table of Contents)

• Abstract ⅰ
• Table of Contents ⅲ
• List of Figures ⅳ
• List of Tables ⅴ
• 1. Introduction 1
• 1.1 Background 1
• 1.2 Research Status 2
• 1.3 Concept and Scope 4
• 1.4 Overview 4
• 2. Development of Global-Local PSO Module 5
• 2.1 Structural Design Optimization 5
• 2.2 Overview of Particle Swarm Optimization 9
• 2.3 DIAMOND/IPSAP 12
• 2.4 Globla-Local Particle Swarm Optimization Module 14
• 2.5 Objective Function and Constraint 19
• 2.5.1 Objective Function 20
• 2.5.2 Constraint: Critical Buckling Load 20
• 2.5.3 Constraint: Failure Index 22
• 3. Optimization of Stiffened Shell Box using Global-Local PSO 25
• 3.1 Optimization of Stiffened Shell Box 25
• 3.2 Optimization Results 27
• 4. Optimization of Launch Vehicle using Global-Local PSO 30
• 4.1 Optimization of Launch Vehicle 31
• 4.2 Optimization Results 36
• 5. Conclusion 38
• References 41