Yung-Hwan Byun

Optimal Design of High Temperature Vacuum Furnace Using Thermal Analysis Database

Optimization study has been carried out to design an energy efficient, high temperature vacuum furnace which satisfies users` design requirements. First of all, the transient temperature distribution and the uniform temperature zone results have been compared with the steady state results to validate the feasibility of using steady state solution when constructing the thermal analysis DB. In order to check the accuracy, the interpolated results using thermal analysis DB have been compared with the computational and the experimental results. In this study, total heat flux is selected as the objective function, and the geometry parameters of vacuum furnace including the thickness of insulator, the heat zone sizes and the interval between heater and insulator are the design variables. The Uniform temperature zone sizes and the wall temperature are imposed as the design constraints. With negligible computational cost a high temperature vacuum furnace which has reduction in total heat flux is designed using thermal analysis DB.

Preliminary Design of the Hybrid Air-launching Rocket for Nanosat

Air-Launching is an effective method that can launch the Nanosat for low launching cost. In this study, the preliminary design of the air-launching micro rocket was performed. Mission and trajectory optimization was performed and the propulsion system was designed based on the mission design. A supersonic air launching rocket with total weight of 830.95 kg, the payload weight of 3.56 kg and the propulsion system length of 5.89 m has been designed.

Development of requirement driven design concept selection process in aerospace system

A Design Space Model has been developed to find a design requirements by analyzing design sensitivity and by searching for the feasible design region. In addtion, the best configuration concept that satisfies the design requirements has been identified using Quality Function Deployment and the Configuration Concept Selection Matrix. These Concept Selection Process can contribute to reduce the time and effort during early design stage.

A System Design of the MIRINAE II, Air-Launching Rocket for Nanosat

Air-Launching is an effective method that can launch the `Nanosat` with low launching cost. In this study, system and subsystem design of the air launching rocket for nanosats which perform a simple mission, have been performed. For this purpose, the WBS of the MIRINAEⅡ, and the subsystem schematics have been defined first. Based on these results, detailed configuration and DMU have been developed.

Aircraft configuration selection method using the airworthiness certification and the decision making process

For the very light jet aircraft design, the design baseline configuration has been selected using the logical decision making process, and the design optimization problem is formulated by considering the airworthiness regulations as design constraints. Airworthiness regulations are the minimum requirements for the safe aircraft flight and must be considered from the conceptual design stage. After carefully selecting the airworthiness constraints and the user specified requirements, a series of design making models including the affinity diagram, nested column diagram, quality function deployment (QFD), Pugh concept selection matrix, are used to find and evaluate alternative configuration baselines. From the feasible design space searching process, the best altenative design, which satisfies the airworthiness constraints while excluding the user subjective decisions as much as possible, has been successfully derived.

Integrated analysis of an air-launching rocket maneuvering at high angle of attack

The rocket design requires all aspects of aerodynamics, structure analysis, controllability and other technologies. More sophisticated design and analyses methods are required to enhance design results. Computational Fluid Dynamics (CFD) and the Finite Element Method (FEM) are used for the fluid-structure interaction analysis of air-launching rocket. In this study, the aerodynamics-structure coupled analysis procedure for the air-launching rocket is established and is applied to accurately predict the surface pressure and rocket deformation during the pull-up maneuver of the air-launching rocket. Euler equations and FEM are employed for the analyses. For the case considered in this study, convergent solutions are reached within 5 iterations. The rocket thickness case satisfies the structural constraint. The results of analysis presents drag coefficient decrease at convergence process.

Design for Reliability of Air-Launching Rocket, MirinaeII Using FMEA(Failure Modes and Effects Analysis)

The procedure of design for reliability which consists of reliability analysis and Failure Modes and Effects Analysis(FMEA) is established and reliability assesment is performed for the nano-satellite air-launching rocket, Mirinae II. By means of using the reliability analysis result, the feasibility to insert the Mirinae II to the target orbit for given mission time under operating environment is assessed. During the reliability analysis process, the system is categorized by Work Breakdown Structure(WBS), and reliability structure is defined by both Reliability Block Diagram(RBD) and schematics of the system. FMEA is used to determine the risk priority number of components and parts. The target reliability is satisfied by changing the design of components and parts with high-risk, hence the design for reliability to put the satellite in to the target orbit safely has been performed.

FSI(Fluid-Structure Interaction) Analysis for Harmonious Operation of High-Speed Printing Machine

Proper amount of entrained air and nip force should be also considered to minimize ballooning phenomenon since tight contact between a roller and web is required. In this paper, various web materials, PET(Polyester) and OPP(Oriented Poly Propylene) have been selected and investigated to satisfy high-speed printing requirement. Several web speeds, web tensions, and temperature conditions are imposed on each web materials and the pressure and gap profiles as well as nip force have been calculated. Increase of both the winding roller radius and the incoming wrap angle is considered under proper taper tension at 500 m/min of rewinding roller. By solving coupled Reynolds equation and web deflection equation simultaneously, the fluid-structure interaction process has been developed and is applied to the rewinding roller to investigate the ballooning phenomenon which causes guiding problems in high-speed printing performance conditions. By adjusting the linear taper tension, stress distribution between rewinding webs can be remarkably reduced and stable pressure and gap profile with ignorable ballooning phenomenon have been found.

Development of Integrated Missile System Design Framework Using Distributed Computing Environment

In this study, framework is developed for integrated missile system design and optimization using distributed computing environment. Analysis tools, optimization tools, database, and CAD are integrated in the missile MDO framework. All components are integrated with middleware for distributed computing environment.

A New Process for the Requirements Based Aerospace System Design and Optimization

In this study, a robust aerospace system design process for the aerospace system is developed by considering the uncertainties of user requirements, manufacturing errors, and operational environment variation. User requirements are analyzed and quantified by decision making models and system engineering methods to select alternative concepts which satisfies the various requirements. Robust design and optimization method is applied to derive the robust solution of the selected system. First, a variance of objective function is calculated, and a mean value and a variance of target value are determined by the deterministic design optimization results of the system. A robust optimum design formulation is then needed to derive the robust solution that minimizes the variance of the response and moves the mean values to the target value. It is applied to Very Light Jet (VLJ) aircraft to which much attention is paid recently in civil aerospace market.