• Title/Summary/Keyword: composite aircraft

Search Result 396, Processing Time 0.02 seconds

Probabilistic Model of Service Life to Evaluate Damage Tolerance of Composite Structure (복합재 항공구조물의 손상허용평가를 위한 운항수명의 확률적 모델)

  • A.스튜어트;A.우샤코프;심재열;황인희
    • Proceedings of the Korean Society For Composite Materials Conference
    • /
    • 2000.11a
    • /
    • pp.245-248
    • /
    • 2000
  • Modern aircraft composite structures are designed using a damage tolerance philosophy. This design philosophy envisions sufficient strength and structural integrity of the aircraft to sustain major damage and to avoid catastrophic failure. The only reasonable way to treat on the same basis all the conditions and uncertainties participating in the design of damage tolerant composite aircraft structures is to use the probability-based approach. Therefore, the model has been developed to assess the probability of structural failure (POSF) and associated risk taking into account the random mechanical loads, random temperature-humidity conditions, conditions causing damages, as well as structural strength variations due to intrinsic strength scatter, manufacturing defects, operational damages, temperature-humidity conditions. The model enables engineers to establish the relationship between static/residual strength safety margins, production quality control requirements, in-service inspection resolution and criteria, and POSF. This make possible to estimate the cost associated with the mentioned factors and to use this cost as overall criterion. The methodology has been programmed into software.

  • PDF

Evaluation of Composite Laminates for Aircraft Primary-Structure Applications Using Non-Linear Parameter of Ultrasonic Guided Wave (유도초음파의 비선형 파라미터를 이용한 항공기 구조체의 복합재료 적층판 열화 평가)

  • Cho, Youn-Ho;Kim, Do-Youn;Choi, Heung-Soap;Lee, Joon-Hyun
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.30 no.2
    • /
    • pp.126-131
    • /
    • 2010
  • The purpose of this study is to assess the condition of composites used in aircraft under varying temperature environment with ultrasound guided wave technique. Investigation of crucial influential factor on the composite health monitoring related to aircraft operational environments such as the number of thermal cycles and temperature deviation between ground level and flight altitude has been of a great concern for aircraft safety issue. In this study, ultrasonic guided wave health monitoring scheme is proposed to evaluate composite specimens damaged with the thermal fatigue simulating aircraft operational condition. Guided wave dispersion curves are used to select right modes which show a promising sensitivity to each different thermal fatigue damage level. The present approach can be also implemented as one of on-lines health monitoring tools for aircraft.

A Suggestion to Establish Statistical Treatment Guideline for Aircraft Manufacturer (국산 복합재료 시험데이터 처리지침 수립을 위한 제언)

  • Suh, Jangwon
    • Journal of Aerospace System Engineering
    • /
    • v.8 no.4
    • /
    • pp.39-43
    • /
    • 2014
  • This paper examines the statistical process that should be performed with caution in the composite material qualification and equivalency process, and describes statistically significant considerations on outlier finding and handling process, data pooling through normalization process, review for data distributions and design allowables determination process for structural analysis. Based on these considerations, the need for guidance on statistical process for aircraft manufacturers who use the composite material properties database are proposed.

An experimental and numerical investigation on fatigue of composite and metal aircraft structures

  • Pitta, Siddharth;Rojas, Jose I.;Roure, Francesc;Crespo, Daniel;Wahab, Magd Abdel
    • Steel and Composite Structures
    • /
    • v.43 no.1
    • /
    • pp.19-30
    • /
    • 2022
  • The static strength and fatigue crack resistance of the aircraft skin structures depend on the materials used and joint type. Most of the commercial aircraft's skin panel structures are made from aluminium alloy and carbon fibre reinforced epoxy. In this study, the fatigue resistance of four joint configurations (metal/metal, metal/composite, composite/composite and composite/metal) with riveted, adhesive bonded, and hybrid joining techniques are investigated with experiments and finite element analysis. The fatigue tests were tension-tension because of the typical nature of the loads on aircraft skin panels susceptible of experimenting fatigue. Experiment results suggest that the fatigue life of hybrid joints is superior to adhesive bonded joints, and these in turn much better than conventional riveted joints. Thanks to the fact that, for hybrid joints, the adhesive bond provides better load distribution and ensures load-carrying capacity in the event of premature adhesive failure while rivets induce compressive residual stresses in the joint. Results from FE tool ABAQUS analysis for adhesive bonded and hybrid joints agrees with the experiments. From the analysis, the energy release rate for adhesive bonded joints is higher than that of hybrid joints in both opening (mode I) and shear direction (mode II). Most joints show higher energy release rate in mode II. This indicates that the joints experience fatigue crack in the shear direction, which is responsible for crack opening.

Investigation on Strength Recovery after Repairing Impact Damaged Aircraft Composite Laminate (항공기 복합재 라미네이트의 충격 손상 부위 유지 보수 후 강도 복원 평가)

  • Kong, Chang-Duk;Park, Hyun-Bum;Lee, Kyung-Sun;Shin, Sang-Jun
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.38 no.9
    • /
    • pp.862-868
    • /
    • 2010
  • Development of a small scale aircraft has been carried out for the BASA(Bilateral Aviation Safety Agreement) program in Korea. This aircraft adopted all the composite structures for environmental friendly by low fuel consumption due to its lightness behavior. However the composite structure has s disadvantage which is very weak against impact due to foreign object damages. Therefore the aim of this study is focusing on the damage evaluation and repair techniques of the aircraft composite structure. The damages of composite laminates including the carbon/epoxy UD laminate and the carbon/epoxy fabric face sheets-honeycomb core sandwich laminate were simulated by a drop weight type impact test equipment and the damaged specimen were repaired using the external patch repair method after removing damaged area. The compressive strength test and analysis results after repairing the impact damaged specimens were compared with the compressive strength test and analysis results of undamaged specimens and impact damaged specimens. Finally, the strength recovery capability by repairing were investigated.

Recent Trends in Composite Materials for Aircrafts (항공기용 복합소재의 개발 및 연구동향)

  • Kim, Deuk Ju;Oh, Dae Youn;Jeong, Moon Ki;Nam, Sang Yong
    • Applied Chemistry for Engineering
    • /
    • v.27 no.3
    • /
    • pp.252-258
    • /
    • 2016
  • The weight reduction and improved mechanical property are one of the prime factors to develop new materials for the aerospace industry. Composite materials have thus become the most attractive candidate for aircraft and other means of transportations due to their excellent property and light weight. In particular, fiber reinforced polymer (FRP) composite materials have been used as an alternative to metals in the aircraft. The composite materials have shown improved properties compared to those of metal and polymeric materials, which made the composites being used as the skin structure of the airplane. This review introduces different types of materials which have been developed from the FRP composite material and also one of the most advantageous ways to employ the composites in aircraft.

Composite Fracture Detection Capabilities of FBG Sensor and AE Sensor

  • Kim, Cheol-Hwan;Choi, Jin-Ho;Kweon, Jin-Hwe
    • Composites Research
    • /
    • v.27 no.4
    • /
    • pp.152-157
    • /
    • 2014
  • Non-destructive testing methods of composite materials are very important for improving material reliability and safety. AE measurement is based on the detection of microscopic surface movements from stress waves in a material during the fracture process. The examination of AE is a useful tool for the sensitive detection and location of active damage in polymer and composite materials. FBG (Fiber Bragg Grating) sensors have attracted much interest owing to the important advantages of optical fiber sensing. Compared to conventional electronic sensors, fiber-optical sensors are known for their high resolution and high accuracy. Furthermore, they offer important advantages such as immunity to electromagnetic interference, and electrically passive operation. In this paper, the crack detection capability of AE (Acoustic Emission) measurement was compared with that of an FBG sensor under tensile testing and buckling test of composite materials. The AE signals of the PVDF sensor were measured and an AE signal analyzer, which had a low pass filter and a resonance filter, was designed and fabricated. Also, the wavelength variation of the FBG sensor was measured and its strain was calculated. Calculated strains were compared with those determined by finite element analysis.

Vibration Control of Composite Wing-Rotor System of Tiltrotor Aircraft (틸트로터 항공기 복합재료 날개의 진동 제어)

  • Song, Oh-Seop
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.35 no.6
    • /
    • pp.509-516
    • /
    • 2007
  • Mathematical modeling and vibration control of a tiltrotor aircraft composite wing-rotor system are investigated in this study. A wing-mounted rotor can be tilted from the vertical position to a horizontal one, and vice versa. Effect of vibration control of the wing-rotor system via piezoelectricity is studied as a function of tilt angle, ply angle of composite wing and rotor's spin speed. Composite wing is modeled as a thin-walled box beam having a circumferentially uniform stiffness configuration that produces elastic coupling between flap-lag and between extension-twist behavior. Numerical simulations are provided and pertinent conclusions are outlined.

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
    • /
    • v.8 no.2
    • /
    • pp.149-159
    • /
    • 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.

  • PDF

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
    • /
    • v.37 no.12
    • /
    • pp.1192-1200
    • /
    • 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.