• Title/Summary/Keyword: structural sizing

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Observer-Teacher-Learner-Based Optimization: An enhanced meta-heuristic for structural sizing design

  • Shahrouzi, Mohsen;Aghabaglou, Mahdi;Rafiee, Fataneh
    • Structural Engineering and Mechanics
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    • v.62 no.5
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    • pp.537-550
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    • 2017
  • Structural sizing is a rewarding task due to its non-convex constrained nature in the design space. In order to provide both global exploration and proper search refinement, a hybrid method is developed here based on outstanding features of Evolutionary Computing and Teaching-Learning-Based Optimization. The new method introduces an observer phase for memory exploitation in addition to vector-sum movements in the original teacher and learner phases. Proper integer coding is suited and applied for structural size optimization together with a fly-to-boundary technique and an elitism strategy. Performance of the proposed method is further evaluated treating a number of truss examples compared with teaching-learning-based optimization. The results show enhanced capability of the method in efficient and stable convergence toward the optimum and effective capturing of high quality solutions in discrete structural sizing problems.

Suggestion of Structural Sizing Methodology on a Coaxial Double-tube Type Hot Gas Duct for the VHTR (초고온가스로의 동심축 이중관형 고온가스덕트에 대한 구조정산 방법론 제안)

  • Song, Kee-Nam;Kim, Y.W.
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.717-724
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    • 2008
  • Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source for nuclear hydrogen generation, which can produce hydrogen from water or natural gas. A primary hot gas duct (HGD) as a coaxial double-tube type cross vessel is a key component connecting the reactor pressure vessel and the intermediate heat exchanger for the VHTR. In this study, structural sizing methodology for the primary HGD with a coaxial double-tube of the VHTR that produces heat at temperatures in the order of $950^{\circ}C$ was suggested and a structural pre-sizing of it was carried out as an example.

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Structural Sizing for Optionally Piloted PAV Preliminary Design (유무인 겸용 개인항공기(OPPAV) 개념설계를 위한 구조물 사이징)

  • Kim, Sung Joon;Lee, Seung-gyu
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.28 no.1
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    • pp.83-89
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    • 2020
  • Personal air vehicle (PAV) is considered by aviation engineers as a solution to provide fast urban mobility. The purpose of designing a optionally piloted PAV (OPPAV) is to provide an individual air vehicle. The airframe structure is designed with high strength carbon fiber composite to reduce the aircraft weight. This paper presents an overview of sizing process for OPPAV at the conceptual design level. It consists of load analysis, structural sizing and development of efficient design allowable values for composite material. The weight is estimated based on sizing process, including strength and stiffness requirements. The objective of this study is to present a overview of structural sizing procedure and fast tool for preliminary design phases.

Investigation of FIV Characteristics on a Coaxial Double-tube Structure (동심축 이중관 구조에서 유동기인진동 특성 고찰)

  • Song, Kee-Nam;Kim, Yong-Wan;Park, Sang-Chul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.10
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    • pp.1108-1118
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    • 2009
  • A Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source of the order of $950^{\circ}C$ for nuclear hydrogen generation, which can produce hydrogen from water or natural gas. A primary hot gas duct (HGD) as a coaxial double-tube type cross vessel is a key component connecting a reactor pressure vessel and an intermediate heat exchanger in the VHTR. In this study, a structural sizing methodology for the primary HGD of the VHTR is suggested in order to modulate a flow-induced vibration (FIV). And as an example, a structural sizing of the horizontal HGD with a coaxial double-tube structure was carried out using the suggested method. These activities include a decision of the geometric dimensions, a selection of the material, and an evaluation of the strength of the coaxial double-tube type cross vessel components. Also in order to compare the FIV characteristics of the proposed design cases, a fluid-structure interaction (FSI) analysis was carried out using the ADINA code.

Preliminary Structural Sizing of the Co-axial Double-tube Type Primary Hot Gas Duct for the Nuclear Hydrogen Reactor (수소생산용 원자로에서 동심축 이중관형 1차 고온가스덕트의 예비 구조정산)

  • Song, Kee-nam;Kim, Y-W
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.4 no.2
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    • pp.1-6
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    • 2008
  • Very High Temperature Gas Cooled Reactor (VHTR) has been selected as a high energy heat source for nuclear hydrogen generation. The VHTR can produce hydrogen from heat and water by using a thermo-chemical process or from heat, water, and natural gas by steam reformer technology. A co-axial double-tube primary hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger (IHX) for the VHTR. In this study, a preliminary design analysis for the primary HGD of the nuclear hydrogen system was carried out. These preliminary design activities include a determination of the size, a strength evaluation and an appropriate material selection. The determination of the size was undertaken based on various engineering concepts, such as a constant flow velocity model, a constant flow rate model, a constant hydraulic head model, and finally a heat balanced model.

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Development of a Physics-Based Design Framework for Aircraft Design using Parametric Modeling

  • Hong, Danbi;Park, Kook Jin;Kim, Seung Jo
    • International Journal of Aeronautical and Space Sciences
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    • v.16 no.3
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    • pp.370-379
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    • 2015
  • Handling constantly evolving configurations of aircraft can be inefficient and frustrating to design engineers, especially true in the early design phase when many design parameters are changeable throughout trade-off studies. In this paper, a physics-based design framework using parametric modeling is introduced, which is designated as DIAMOND/AIRCRAFT and developed for structural design of transport aircraft in the conceptual and preliminary design phase. DIAMOND/AIRCRAFT can relieve the burden of labor-intensive and time-consuming configuration changes with powerful parametric modeling techniques that can manipulate ever-changing geometric parameters for external layout of design alternatives. Furthermore, the design framework is capable of generating FE model in an automated fashion based on the internal structural layout, basically a set of design parameters describing the structural members in terms of their physical properties such as location, spacing and quantities. The design framework performs structural sizing using the FE model including both primary and secondary structural levels. This physics-based approach improves the accuracy of weight estimation significantly as compared with empirical methods. In this study, combining a physics-based model with parameter modeling techniques delivers a high-fidelity design framework, remarkably expediting otherwise slow and tedious design process of the early design phase.

DESIGN SENSITIVITY ANALYSIS AND OPTIMIZATION OF ZWICKER'S LOUDNESS (Zwicker 라우드니스에 대한 설계 민감도 해석 및 최적화)

  • Kang, Jung-Hwan;Wang, Se-Myung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.149-154
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    • 2004
  • The design sensitivity analysis of Zwicker's loudness with respect to structural sizing design variables is developed. The loudness sensitivity in the critical band is composed of two equations, the derivative of main specific loudness with respect to 1/3-oct band level and global acoustic design sensitivities. The main specific loudness is calculated by using FEM, BEM tools. i.e. MSC/NASTRAN and SYSNOISE. And global acoustic sensitivity is calculated by combining acoustic and structural sensitivity using the chain rule. Structural sensitivity is obtained by using semi-analytical method and acoustic sensitivity is implemented numerically using the boundary element method. For sensitivity calculation, sensitivity analyzer of loudness (SOLO), in-house program is developed. A 1/4 scale car cavity model is optimized to show the effectiveness of the proposed method.

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Global Acoustic Design Sensitivity Analysis using Direct BEM and Continuum DSA (직접 경계요소법과 연속계 설계민감도 해석법을 이용한 소음 설계 민감도 해석)

  • 왕세명;이제원
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1998.04a
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    • pp.81-87
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    • 1998
  • In this paper, a global acoustic design sensitivity analysis (DSA) of field point pressure with respect to structural sizing design variables is developed. Firstly acoustic sensitivity is formulated and implemented numerically. And it is combined with continuum structural sensitivity to obtain the global acoustic, design sensitivity. For this procedure, GASA (global acoustic design sensitivity analyzer) has been developed. A half scale of automobile cavity model is considered in this paper. In order to confirm accuracy of the results of global acoustic DSA obtained by GASA, it is compared with the result of central finite difference method. In order to reduce computation time, Rayleigh approximated solution is evaluated and compared with the solution which used every nodal velocities. Also the acoustic optimization procedure is performed using design sensitivities. From these numerical studies, it can be shown that global acoustic DSA is a useful tool to improve acoustic problems.

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Structural Analysis of Fuselage and Empennage of High Altitude Long Endurance UAV (고고도 장기체공 무인기 동체 및 미익부 구조해석)

  • Kim, Hyun-gi;Kim, Sung Joon;Kim, Sung Chan;Shin, Jeong-Woo;Lee, Seunggyu;Park, Sang-Wook;Kim, Tae-Uk
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.24 no.4
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    • pp.35-43
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    • 2016
  • UAV has been promoted for practical use in the field of civilian and military. Recently, UAV is required high-specification performance such as long-term flight and precision observation. Among these UAVs, High Altitude Long Endurance UAV(HALE UAV) has been developed for the purpose to replace some of the functions of the satellite such as meteorological observation, communications and internet relay while flying a long period in the stratosphere. In order to fly a long period in harsh environment of the stratosphere, aircraft needs high Lift-Drag-Ratio and weight reduction of the structure. This paper performed the structural analysis for fuselage and empennage of HALE UAV. Critical loading conditions for structural analysis are acquired from flight load analysis and finally the results of structural sizing for weight reduction is presented.

KSLV-1 1st stage Rear Fuselage Upper Compartment Detail Design (KSLV-1 1단 후방동체 상부 조합체 상세설계)

  • Yoo, Jae-Seok;Jeong, Ho-Kyeong;Jang, Soon-Young
    • Aerospace Engineering and Technology
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    • v.8 no.1
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    • pp.117-131
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    • 2009
  • In this study, a detail design was conducted for KSLV-1 1st stage Rear Fuselage Upper Compartment assembly. A basic structural sizing was done by the aircraft fuselage sizing in-house program. The frame structural design and the interface check were conducted by the FE and the CAD program. The structural margin of safety was conformed by FE analysis for the normal section model and duct cut-out section models which are the weakest parts of the rear fuselage. The shear stress analysis was performed for a fastener design of the skin-stringer which is most affected by the shear stress induced by the shear load.

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