民机机身结构适坠性研究

以民机机身结构为研究对象, 按照积木式研究方案的不同层级, 即材料级、元件级、细节件级、子部件级、部件级、整机, 阐述了民机机身结构适坠性试验及数值模拟方法; 总结了世界范围内在子部件级(货舱地板下部机身框段)和部件级(机身框段)开展的适坠性研究, 对比分析了机身框段结构坠撞破坏模式, 阐述了机身框段适坠性设计方法; 阐述了民机机身结构适坠性符合性验证及评估方法, 展望了民机机身结构适坠性设计、验证及审定的未来发展方向。研究结果表明: 材料失效和连接结构失效是民机机身坠撞过程中的主要失效模式, 材料本构模型和连接结构失效模型对适坠性仿真分析有重要影响, 需发展更为准确的材料本构模型及连接结构建模技术, 提高其动态仿真成熟度; 在机身结构中布置吸能结构可有效改善其适坠性能, 需发展更加高效稳定的吸能结构设计及布置方案, 以最大化提升机身结构适坠性能; 细节件级和子部件级试验及仿真分析提供了评估失效模式、破坏机理和吸能能力的解决方案, 需进一步发展高精度测试技术及有限元仿真分析技术, 以有效支持部件级和整机适坠性设计、验证及适航审定; 发展含不确定参数的适坠性优化设计方法及评估方法, 以避免额外试验和后期结构更改; 系统开展适坠性积木式试验, 有效支持有限元模型验证及评估工作, 发展经积木式方法验证的有限元仿真分析来表明适坠性符合性, 以减少适坠性验证时间及成本, 并指导适坠性试验设计及结构设计。 

Research on crashworthiness of civil aircraft fuselage structures

The civil aircraft fuselage structure was considered as the study objective, according to the different levels of crashworthy building block approach, including coupons, elements, details, sub-components, components, and full-scale aircraft, the crashworthy tests and numerical simulation of civil aircraft fuselage structures were elaborated. The crashworthy researches on sub-components(sub-cargo fuselage sections) and components(fuselage sections) in the world were summarized, the crash failure modes of fuselage section were compared and analyzed, and the crashworthy design methods of fuselage sections were described. The crashworthy compliance verification and evaluation methods of civil aircraft fuselage structures were elaborated, and the prospect of future researches on the crashworthy design, verification and certification of civil aircraft fuselage structures was proposed. Research result shows that the failures of materials and connection structures are the main failure modes during the crash process of civil aircraft fuselage section, the material constitutive model and the connection structure failure model can significantly affect the crashworthy simulation analysis. The more accurate material constitutive models and connection structure modeling techniques need to be developed to improve the dynamic simulation maturity. The crashworthiness can be effectively improved by arranging the energy-absorbing structures in the fuselage structure, the more efficient and stable design scheme and layout of energy-absorbing structures need to be developed to maximize the crashworthy performance. The tests and simulation analysis of details and sub-components can provide the innovative solutions to evaluate the failure modes, damage mechanisms and energy-absorbing capabilities, and the high-precision test technology and finite element simulation analysis technology need to be developed to effectively support the crashworthy design, verification, and certification for the components and full-scale aircraft. The crashworthy evaluation methods and optimization methods with uncertain parameters need to be developed to avoid additional tests and later configuration changes. The crashworthy building block approach can be systematically conducted to effectively support the finite element model verification and evaluation, and the finite element simulation technology verified through the crashworthy building block approach needs to be developed to reduce the crashworthy verification time and cost, and to guide the crashworthy test design and structural design.