• Title/Summary/Keyword: composite aircraft

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Structural Modelling of Tapered Composite Aircraft Wings with Initial Angle of Attack using Thin-Walled Beam (얇은 벽 보를 이용한 초기 받음각이 있는 테이퍼형 복합재료 항공기 날개의 구조 모델링)

  • Kim, Keun-Taek;Song, Ohseop
    • Journal of Aerospace System Engineering
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    • v.3 no.2
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    • pp.1-11
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    • 2009
  • A structural modelling for study on dynamic characteristics of tapered composite aircraft wings in the form of thin-walled beam is presented. The proposed structural model includes effects of transverse shear flexibility exhibited by the advanced composite materials and warping restraint characterizing elastic anisotropy and induced structural couplings. The complex effects of these factors could have a role in more efficient analysis on those structural models.

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Structural Health Monitoring Techniques for Composite Aircraft (복합재료 항공기의 구조진단 기술)

  • Choi, Heung-Soap;Cho, Youn-Ho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.1
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    • pp.54-59
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    • 2010
  • After the advent of B787(Boeing Co.), a civil aircraft using composite materials more than 50% of it total structural weight for weight savings,best performances and efficiencies, various endeavors to develop and apply the state of art of structural health monitoring(SHM) technologies for composite aircraft have been made for many years. Despite their plentiful advantages composite aircraft structures are susceptible to the hidden or barely visible impact damages(BVID) and excessive loads that if unchecked may lead to lower structural integrity, loss of operational performance and finally a sudden catastrophic failure of the aircraft structure. In this paper background of SHM technology and relevant technologies for application of SHM technology to the composite aircraft in the near future and requirements for certification of SHM system are shortly presented.

A Study on Calculation of Test Load for Full-Scale Airframe Structural Test of Composite Aircraft (복합재 항공기 전기체 구조시험 시험하중 산출 방법 연구)

  • Choi, Ik-Hyeon;Ahn, Seok-Min
    • Aerospace Engineering and Technology
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    • v.10 no.2
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    • pp.146-153
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    • 2011
  • Some methods of calculation of test load value from design load data were investigated which will be applied at strap installed full-scale airframe of composite aircraft. These methods were applied to left wing of KC-100 composite aircraft and the calculated test load values were compared with each others. Generally since test load values are differently calculated according to each aircraft type and position of straps, all calculation methods mentioned at this study need to be applied and compared to each aircraft. Finally the most appropriate method needs to be selected.

Experimental studies on impact damage location in composite aerospace structures using genetic algorithms and neural networks

  • Mahzan, Shahruddin;Staszewski, Wieslaw J.;Worden, Keith
    • Smart Structures and Systems
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    • v.6 no.2
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    • pp.147-165
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    • 2010
  • Impact damage detection in composite structures has gained a considerable interest in many engineering areas. The capability to detect damage at the early stages reduces any risk of catastrophic failure. This paper compares two advanced signal processing methods for impact location in composite aircraft structures. The first method is based on a modified triangulation procedure and Genetic Algorithms whereas the second technique applies Artificial Neural Networks. A series of impacts is performed experimentally on a composite aircraft wing-box structure instrumented with low-profile, bonded piezoceramic sensors. The strain data are used for learning in the Neural Network approach. The triangulation procedure utilises the same data to establish impact velocities for various angles of strain wave propagation. The study demonstrates that both approaches are capable of good impact location estimates in this complex structure.

A Study on the Aileron Reversal Characteristics of CAS Composite Aircraft Wings (CAS 복합재료 항공기 날개의 에일러론 역전 특성 연구)

  • Song, Oh-Seop;Kim, Keun-Taek
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.12
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    • pp.1192-1200
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    • 2009
  • This paper deals with an analytical study on the aileron reversal characteristics of anisotropic composite aircraft wings modelled as thin-walled beam and having bending-torsion structural couplings caused by Circumferentially Asymmetric Stiffness layup scheme. For a study on the aileron reversal of CAS composite wings, it is essential to consider the following effects such as warping restraint, transverse shear flexibility, bending-twist structural coupling, wing aspect ratio, ratio of span-wise and chord-wise length of aileron to wing, and sweep angle, etc. The results on the aileron reversal could have a significant role in more efficient designs of thin-walled composite wing aircraft for which this aeroelastic instability is one of the most critical ones.

A Study on the Aileron Reversal Characteristics of CUS Composite Aircraft Wings (CUS 복합재료 항공기 날개의 에일러론 역전 특성 연구)

  • Kim, Keun-Taek;Song, Oh-Seop
    • Aerospace Engineering and Technology
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    • v.8 no.2
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    • pp.149-159
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    • 2009
  • This paper deals with an analytical study on the aileron reversal characteristics of anisotropic composite aircraft wings modelled as thin-walled beam and having extension-twist structural couplings caused by Circumferentially Uniform Stiffness (CUS) layup scheme. For a study on the aileron reversal of CUS composite wings, it is essential to consider the following effects such as extension-twist structural coupling, wing aspect ratio, and ratio of span-wise and chord-wise length of aileron to wing, initial angle of attack, and sweep angle, etc. The results on the aileron reversal could have a significant role in more efficient designs of thin-walled composite wing aircraft for which this aeroelastic instability is one of the most critical ones.

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A Study on the Bearing Strength of Bolt Jointed Section for Composite Aircraft Radome Under Hygrothermal Environments (열습환경을 고려한 항공기용 레이돔 볼트 체결부의 베어링 강도에 관한 연구)

  • Kim, Ho Il;Ryu, Guh Yun;Kim, Joon;Kim, Kwang Min;Lee, Kyu Song;Park, Young Ju;Park, Byum Jun;Ryu, Hong Kyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.8
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    • pp.759-764
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    • 2017
  • This research investigated the hygrothermal effect on the strength of bolt jointed section and moisture contents of composites exposed to hygrothermal environment for composite aircraft radome. The decrease in strength in the test environment is mainly attributed to the change in the material properties of the matrix due to temperature and moisture. The composite specimens were tested in three different environmental conditions: RTD(room temperature and dry), CTD(cold temperature and dry) and ETW(elevated temperature and wet). The failure mode of the bolt jointed composite specimens were studied using tests and finite element analysis. Finite element analysis reasonably predicted the failure load and mode of the joints. A reliability-based design was carried out for the bolt jointed composites of radome.

AFP mandrel development for composite aircraft fuselage skin

  • Kumar, Deepak;Ko, Myung-Gyun;Roy, Rene;Kweon, Jin-Hwe;Choi, Jin-Ho;Jeong, Soon-Kwan;Jeon, Jin-Woo;Han, Jun-Su
    • International Journal of Aeronautical and Space Sciences
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    • v.15 no.1
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    • pp.32-43
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    • 2014
  • Automatic fiber placement (AFP) has become a popular processing technique for composites in the aerospace industry, due to its ability to place prepregs or tapes precisely in the exact position when complex parts are being manufactured. This paper presents the design, analysis, and manufacture of an AFP mandrel for composite aircraft fuselage skin fabrication. According to the design requirements, an AFP mandrel was developed and a numerical study was performed through the finite element method. Linear static load analyses were performed considering the mandrel structure self-weight and a 2940 N load from the AFP machine head. Modal analysis was also performed to determine the mandrel's natural frequencies. These analyses confirmed that the proposed mandrel meets the design requirements. A prototype mandrel was then manufactured and used to fabricate a composite fuselage skin. Material load tests were conducted on the AFP fuselage skin curved laminates, equivalent flat AFP, and hand layup laminates. The flat AFP and hand layup laminates showed almost identical strength results in tension and compression. Compared to hand layup, the flat AFP laminate modulus was 5.2% higher in tension and 12.6% lower in compression. The AFP curved laminates had an ultimate compressive strength of 1.6% to 8.7% higher than flat laminates. The FEM simulation predicted strengths were 4% higher in tension and 11% higher in compression than the flat laminate test results.

A Design Guide for Composite Laminates by the Compressive after Impact Tests (충격후 잔류압축강도시험에 의한 복합재료 적층판의 설계)

  • 정태은;박경하;류정주
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.9
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    • pp.2105-2113
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    • 1995
  • The compressive tests under impact conditions were performed to establish a design guide for impact damage tolerance. The composition of layup was selected for the real cases of composite aircraft structure. The energy level of visible of visible damage threshold was determined as 7 Joules. It was found that the normalized bending stiffnesses in the direction of closely fixed boundary affected the area of damage. Graphite/epoxy used in the tests exhibited 60% reduction in compression strength at the energy level of visible damage threshold. Wet-conditioned specimens represented 9% reduction in residual compressive strength in comparison with room temperature ambient specimens. In this study, a design factor of 2.1 was proposed for the low velocity impact damage.