Research On Damage Tolerance Evaluation And Airworthiness Of Composite Aircraft Structure

With the development of composite aircraft structure, advanced materials with excellent performance are intensively used in civil aircraft industry. Because composites anisotropic damage mechanism, characteristics, its failure form and repair technology from metal material structure has significant different. Therefore related nondestructive testing, damage tolerance and airworthiness evaluation technology is facing new development and challenges.Based on the research of composite aircraft structure damage tolerance theory and airworthiness requirements, some key problems are studied, which include composite structural characteristics,damage type,advanced nondestructive testing technology, composite structure repair technology, as well as the airworthiness. This paper introduces composite material damage tolerance characteristics in detail, in contrast with metals, as well as the research of composite material damage tolerance design and reliability analysis. Under the guidance of Advisory Circular 20-107A and B“COMPOSITE AIRCRAFT STRUCTURE”,composite material damage tolerance evaluation requirements and contents are studied in detail, considering material, components, detection methods, scope , frequency and repair, etc. Combining the test data and results of the Boeing 777 damage tolerance evaluation, the composite aircraft structure damage tolerance evaluation flow chart is summarized.Firstly,composite injury threat assessment and injury classification are carried out, damage size for residual strength assessment and initial detectable damage are defined by test data, nondestructive testing methods and detected probability, in order to verify damage with“no-growth”. Considering environmental damage impact factor, composite structure examination outline is set down eventually. Finally, the above research results are translated into the Composite material Damage Tolerance Airworthiness Evaluation System. The system can carry out composite material damage assessment and damage tolerance evaluation for composites manufacturing and research department, which has guiding role for making an economic and reasonable check outline.