• Title/Summary/Keyword: Material Design Allowables

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Pooling-Across-Environments Method for the Generation of Composite-Material Allowables (환경조건간 합동을 이용한 복합재료 허용치 생성 기법)

  • Rhee, Seung Yun
    • Journal of Aerospace System Engineering
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    • v.10 no.3
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    • pp.63-69
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    • 2016
  • The properties of composite materials, when compared to those of metallic materials, are highly variable due to many factors including the batch-to-batch variability of raw materials, the prepreg manufacturing process, material handling, part-fabrication techniques, ply-stacking sequences, environmental conditions, and test procedures. It is therefore necessary to apply reliable statistical-analysis techniques to obtain the design allowables of composite materials. A new composite-material qualification process has been developed by the Advanced General Aviation Transport Experiments (AGATE) consortium to yield the lamina-design allowables of composite materials according to standardized coupon-level tests and statistical techniques; moreover, the generated allowables database can be shared among multiple users without a repeating of the full qualification procedure by each user. In 2005, NASA established the National Center for Advanced Materials Performance (NCAMP) with the purpose of refining and enhancing the AGATE process to a self-sustaining level to serve the entire aerospace industry. In this paper, the statistical techniques and procedures for the generation of the allowables of aerospace composite materials will be discussed with a focus on the pooling-across-environments method.

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

  • Suh, Jangwon
    • Journal of Aerospace System Engineering
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    • v.8 no.4
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    • pp.39-43
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    • 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.

A Methodology to Determine Composite Material Allowables and Design Values Using Building Block Approach (빌딩블록 접근법을 이용한 복합재 재료 허용치 및 설계치 설정 방법)

  • Kim, Sung Joon;Lee, Seung-gyu;Hwang, In-hee
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.6
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    • pp.377-384
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    • 2022
  • In the design of composite aircraft structures, it is very important to set material allowables and design values, which take into account certification. And when determining the material allowable and design value of composite structures, the static strength, damage tolerance requirements, and environmental effects should be considered. The building block approach has been applied to the civil and military aviation industry for a long time and provides the principal certification methodology. This current certification methodology is based on extensive testing including coupon, element, sub-component, and full scale test. In this paper, some examples of composite allowable tests have been presented and the fundamental background and application methods of the building block approach have been presented.

Certification Methodology of Aerospace Materials System (우주항공 재료시스템 품질인증)

  • Lee, Ho-Sung
    • Journal of Aerospace System Engineering
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    • v.1 no.2
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    • pp.13-20
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    • 2007
  • Structural qualification plan (SQP) for aerospace vehicle is based on material certification methodology, which must be approved by certification authority. It is internationally required to use of statistically based material allowables to design aerospace vehicles with aerospace materials. In order to comply with this regulation, it is necessary to establish relatively large amount of database, which increases test costs and time. Recently NASA/FAA develop the new methodology which results in cost, time, and risk reduction, and satisfies the regulation at the same time. This paper summarizes the certification methodology of materials system as a part of structural qualification plan (SQP) of aerospace vehicles and also thermal management of the vehicle system, like thermal protection materials system and thermally conductive material system. Materials design allowable was determined using this method for a carbon/epoxy composite material.

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Qualification of Composite Materials for Small Aircraft (소형 항공기용 복합재료 인증)

  • Suh, Jang-Won;Park, Jong-Hyuk;Lee, Jong-Hee
    • Journal of Aerospace System Engineering
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    • v.5 no.1
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    • pp.17-23
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    • 2011
  • Since the time, cost and lack of regulatory information and guidance, one of the largest regulatory obstacles for an airframe manufacturer of polymer based advanced composite materials in certified aircraft applications, is to generate design allowables that will satisfy Airworthiness Regulations. In the past two decades, the design allowables used in military aircraft had been generated and applied in Korea, however the qualification of composite materials used in certifying airframe structure was not accomplished for design and demonstration of compliance to applicable airworthiness regulation. It is the intend of this paper that provide the basis of composite material qualification for small aircraft certification to the airworthiness regulation.