• Title/Summary/Keyword: 스트링거

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A Study on the Mechanical Properties of Braid Composites for the Manufacture of Aircraft Stringer (항공기용 스트링거 제작을 위한 브레이드 복합재료의 물성에 관한 연구)

  • Eun, Jong Hyun;Lee, Joon Suck;Park, Seung Hwan;Kim, Dong Hyun;Chon, Jin Sung;Yoo, Ho Wook
    • Composites Research
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    • v.31 no.6
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    • pp.293-298
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    • 2018
  • In this paper, we have studied the physical properties of braided composites for use as aircraft stringers. Process variables such as drum winder speed, braid velocity, and mandrel diameter for $30^{\circ}$, $45^{\circ}$ and $60^{\circ}$ braid preforms were quantified and different epoxy resin types were applied to the braided preform using TGDDM, YD-128. Physical properties such as tensile strength and flexural strength of braided composites were investigated. Thermal properties and decomposition temperature of epoxy resin were investigated by TGA analysis. As a result, the lower the angle of the braid composites, the higher the tensile strength and the Flexural strength. The physical properties of braided composites fabricated using TGDDM epoxy resin were superior to the physical properties of braided composites fabricated using YD-128 epoxy resin. This is because the molecular weight of TGDDM epoxy resin was higher than that of YD-128 epoxy resin.

Free Vibration and Buckling Analysis of the Composite Laminated Cylindrical Shells with the Orthogonal Stiffeners (직교보강된 복합재료 원통셀의 진동 및 좌굴해석)

  • 이영신;김영완
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1996.04a
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    • pp.349-354
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    • 1996
  • The analytical solutions for the free vibration and buckling of cross-ply laminated composite cylindrical shell with axial stiffeners(stringers) and circumferential stiffeners(rings), that is, orthogonally stiffened shells, are presented using the energy method. The stiffeners are assumed to be an integral part of the shell and have been directly included in analysis(it's called discrete stiffener theory). The effect of the parameters such as the stacking sequences, the shell thickness, the shell length-to-radius ratio are studied. By comparison with the previously published analytical results for the stiffened cylindrical shells, it is shown that natural frequencies can be determined with adequate accuracy.

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Development of Deburring System for Aircraft Components (Membrane 제거를 위한 전용 시스템 개발)

  • 최운집;정원재;성승학;이득우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.1070-1073
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    • 2004
  • This paper is on the development of a system for removing membranes which is designed exclusively for aircraft components. Membrane removal solution is a most critical issue in aerospace industries since a method of manufacturing the components tends to be changed from fabrication of many parts to cutting into one body. The cutting method inevitably produces a huge amount of chips and then membranes remain in the body. The membrane removal process, as a result, becomes an important issue since it is directly related to productivity. We tried to develop a new machine which will replace the conventional method that uses a handy tool. The machine has been designed for a cutting tool set to follow the unique shape of the slot in the body by a cam follower and cut the membrane automatically. The design has been checked by structural analysis: stress and vibration analysis. A prototype test has been finished. This paper summarizes a series of development process of the deburring machine and some design issues are discussed.

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Free Vibration of the Composite Laminated Cylindrical Shells Stiffened with the Axial Stiffeners (길이방향으로 보강된 복합재료 원통쉘의 자유진동)

  • Lee, Young-Shin;Kim, Young-Wann
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.7
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    • pp.2223-2233
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    • 1996
  • The analytical solutions for the free vibration of cross-ply laminated composite cyllindrical shell with axial stiffeners(stringers) are presented usint the energy method. The stiffeners are taken to be smeared over the surface of shell with the smeared stffener theory. The effect of the parameters such as the stacking sequences, the shell thichness, the shell radius-to stringer depth ratio, the stringer depth-to width ratio, the shell length-to radius ratio are studied. By comparison with the previously published experimental results and the analytical results for the stiffened isotropic cylindrical shell and the unstiffened orthotropic composite laminated cylindrical shell, it is shown that natural frequencies can be determined with adequate accuracy.

Study on the Orthogonal Stiffening Characteristics for the Natural Frequencies and Buckling Loads of the Composite Laminated Cylindrical Shells (복합재료원통셸의 고유진동수 및 좌국하중에 대한 직교보강 특성 연구)

  • 이영신;김영완
    • Journal of KSNVE
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    • v.6 no.4
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    • pp.457-467
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    • 1996
  • The analytical solutions for the free vibration and buckling of cross -ply laminated composite cylindrical shell with the orthogonal stiffeners, i. e., axial stiffeners(stringers) and circumferential stiffeners(rings), are presented using the energy method. The stiffeners are assumed to be an integral part of the shell and have been directly included in analysis(it's called discrete stiffener theory). The effect of the parameters such as the stacking sequences, the shell thickness, the shell length-to-radius ratio are studied. By comparison with the previously published analytical results for the stiffened cylindrical shells, it is shown that natural frequencies can be determined with adequate accuracy.

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E/R Stringer Deck Strength Calculation of CSR Bulk Carrier (CSR Bulk Carrier의 E/R Stringer Deck 구조 강도 계산)

  • Choi, Sung-Bin;Kim, Dong-Keun;Kim, Kyoung-Rae
    • Special Issue of the Society of Naval Architects of Korea
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    • 2011.09a
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    • pp.47-50
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    • 2011
  • E/R bulkhead is watertight bulkhead between engine room and cargo hold. So, it must have sufficient strength about cargo load of aft hold. Especially, partial stringer deck between tank top and $2^{nd}$ deck of engine room must have sufficient strength because it has function of primary supporting member. Generally, cargo hold structure is verified through the direct calculation as finite element analysis of cargo hold, but engine room structure doesn't perform it. Therefore, we have performed finite element analysis of engine room stringer deck which considered cargo hold load. And then, it will be able to apply similar ship design.

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Crippling Test of Graphite/Epoxy Stringers (Graphite/Epoxy 스트링거의 크리플링 실험)

  • 최상민;권진회
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.11a
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    • pp.157-160
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    • 2000
  • In author's previous paper, a finite element algorithm was presented to calculate the buckling and crippling stresses of composite laminated stringers. In this study, for the validation of the finite element analysis, Z-section composite stringers of different lengths and flange-widths were tested in axial compression. The stacking sequence of graphite/epoxy is [$\pm$45/0/90]s. Strain gages were attached to each specimen to get the strain response. Deflection and end-shortening were obtained by a displacement transducer. The buckling and crippling loads are determined from the strain response, load vs. end-shortening curves, and load vs. out-of-plane deflection curves. Comparison between finite element and experimental results shows good agreement in the buckling, local buckling, and crippling stresses.

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Minimum Weight Design for Web Frames of Cargo Tanks in the LPG Carrier (LPG 운반선 화물창의 웨브 프레임 최소중량설계)

  • Park, Myeong-Chul;Shin, Sang-Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.103-108
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    • 2020
  • Generally, the cargo tank of LPG carriers corresponds to an independent tank Type A defined by the International Maritime Organization (IMO). The outside of the tank is insulated by polyurethane foam, and the tank is made of expensive low temperature steel that can withstand temperatures as low as -50℃. The cargo tank is composed of outer shell plates, bulkheads, stiffeners, web frames, and stringers. Among them, the outer shell plates, bulkheads, and stiffeners can be designed without structural analysis by the Classification Rules and are constructed easily through optimal design. On the other hand, optimal design, including numerous structural analysis, is not performed because web frames and stringers should be designed and approved through structural analysis. Only adequate design, which determines the design dimensions through several dozen structural analysis, is performed. In this study, for finite element analysis, eight loading conditions were applied, and the deformation of the entire ship for each loading condition was considered. The minimum weight design was performed for the web frames of cargo tanks in the 82,000 ㎥ LNG carrier through the gradient-based optimization technique, and the weight was reduced by approximately 108 tons per ship.

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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Development of Structural Analysis System of Bow Flare Structure(3) - Dynamic Structural Analysis - (선수 구조부 구조해석 시스템 개발(3) - 동적 구조해석 -)

  • S.G. Lee;C.K. Park
    • Journal of the Society of Naval Architects of Korea
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    • v.37 no.1
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    • pp.99-110
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    • 2000
  • The damages due to wave impact loads are largely affected by impact pressure impulse and impact load area. The objective of this study is, as the third step, to perform dynamic structural analysis of bow flare structure of 300,000 DWT VLCC using LS/DYNA3D code, and to verify its dynamic structural behaviors. The impact load areas of stiffener space $1.5s{\times}1.5s$ and $2.5s{\times}2.5s$ are applied to bow flare structure part with relatively flexible stiffeners, and with stiff members such as stringers, webs etc., respectively, under the wave impact load with peak height 6.5MPa, tail 1.0MPa, and duration time 5.0msec. Through the dynamic structural analysis in this study, it might be thought that the structural strength of bow flare structure is generally sufficient for these wave impact load and areas, except that large damages were found at bow flare structure area with flexible wide span stiffeners.

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