【作者】 杜振勇；

【导师】 谭惠丰； 王长国；

【作者基本信息】 哈尔滨工业大学 ， 工程力学， 2012， 博士

【摘要】 充气展开支撑结构是近期航空航天可展开飞行器中出现的一类新型展开结构，具有重量轻、折叠体积小、展开可靠性高、展开后承载范围大等特点。充气展开支撑结构中的充气梁是其典型结构部件，为提高充气梁的承载性能，本文建立了充气梁承载特性分析方法，并对其承载规律进行了数值分析和试验验证。充气梁在弯曲载荷作用下产生局部压应力，弯曲载荷达到起皱载荷时充气梁产生褶皱，随着弯曲载荷的增加褶皱区域进一步扩展，当弯曲载荷达到失效载荷时充气梁失稳无法进一步承受更大弯曲载荷。充气梁的承载规律和弯皱特性可以用起皱载荷、失效载荷、褶皱区域进行表征。本文对充气梁的承载过程中的弯皱特性进行了系统研究。对充气梁褶皱产生、褶皱扩展、刚度退化机理以及网格增强结构进行了理论研究、数值模拟和试验研究，主要内容包括：本文首先针对充气梁在弯曲载荷作用下褶皱的轴向扩展进行分析，提出弯皱因子的概念，进行褶皱区域表征，首先建立基于弯皱因子的变截面充气梁褶皱轴向扩展特性分析模型，确定弯曲载荷作用下变截面充气梁起皱弯矩预报模型、初始起皱位置预报模型、褶皱区域轴向边界预报模型和失效载荷预报模型。然后针对褶皱区域的环向扩展进行分析，确定基于弯皱因子参数的褶皱角和中性轴偏移量预报模型，利用拟合多项式方法获得褶皱区域内褶皱角和中性轴偏移量的分布规律，完成基于弯皱因子的变截面充气梁褶皱区域产生扩展分析方法，以获得充气弯皱状态褶皱区域的完整描述。最后建立变截面充气梁的抗弯测试实验装置，获得变截面充气梁在弯曲载荷作用下的弯皱行为实验结果，结合有限元数值模拟，验证变截面充气梁褶皱区域产生和扩展分析方法的准确性和有效性。在基于弯皱因子的变截面充气梁褶皱区域产生扩展分析方法基础上，针对充气梁弯皱状态力学模型，引入等效充气压力方法建立了充气压力、中心轴偏移、变形幅度和管壁刚度等的平衡弯矩分析模型，建立充气梁弯皱变刚度分析模型，解析弯皱状态充气梁的刚度变化和抗弯平衡机理，获得抗弯刚度与弯皱因子和褶皱角的变化关系，建立考虑褶皱区域和褶皱区域曲率变化影响的充气梁弯皱变刚度分析模型。与数值模拟结果对比证明本文充气梁弯皱变刚度分析模型的正确性。在基于弯皱因子和等效充气压力的弯皱充气梁变刚度分析模型基础上，提出能够考虑褶皱区域和褶皱曲率变化等褶皱效应的弯皱充气梁有限元分析模型，给出形函数和刚阵的具体形式，建立弯皱充气梁单元的求解过程，编制有限元分析验证程序，对不同载荷状态和结构形式的充气梁承载特性进行了数值分析，得到弯皱状态下充气梁褶皱区域扩展规律和大变形因素对充气梁承载性能的影响。通过和文献结果对比验证本文弯皱充气梁单元的准确性和有效性，为大型充气结构承载性能高效率分析和优化奠定了基础。利用本文充气梁单元和同样工况下加密的有限元细化分析模型对网格增强充气梁的载荷挠度曲线进行了对比分析，并通过试验验证了本文充气梁单元的准确性和高效性。为了利用本文充气梁单元分析网格增强充气梁，本文首先对网格增强充气梁管壁的表观工程常数进行了等效分析，并通过实验和数值分析验证了等效模型的准确性。本文的研究成果将为大型充气结构承载性能分析，结构优化设计和弯皱行为分析提供依据和基础。更多还原

【Abstract】 Inflatable deployable structure is an emerging class of supporting structuresfor deployable spacecrafts in aeronautics and astronautics, which has theadvantages of light weight, small compact volume, high reliability, and large loadsbearing capacity, etc. Inflatable beams are main typical inflatable deployablestructures. In order to improve their loads bearing capacity, this research establishedtheoretical analyzing method, and conducted numerical analysis and experimentalvalidation for inflatable beams to investigate their loads bearing performance.Bending load will induce local compressive stress on inflated beam, andwrinkles occurred when bending load is larger than wrinkling load. Along withincreasing of bending load, wrinkled region will be further extended. When bendingload reaches collapse load, inflated beam are instable, and it could not undertakeany larger load. For inflated beam, load bearing performance and bending-wrinkling characteristic can be described by wrinkling load, collapse load andwrinkled region.This investigation analyzed bending-wrinkling characteristics of inflated beamunder bending load systematically. Including wrinkling occurrence, wrinklingevolution, stiffness degeneration mechanism as well as grid reinforced structures.All parameters were analyzed theoretically, numerically and experimentally. Themain contexts in this dissertation are as follows:This investigation based on wrinkling evolution of inflatable beams underbending load. For wrinkled region extended along axial direction, we proposedbending-wrinkling factor to characterize wrinkled region. Based on bending-wrinkling factor, we established theoretical analyzing model for wrinkle axialevolution of varying cross-section inflated beams, set up wrinkling bendingmoment predicative model, wrinkled region predicative model, wrinkled regionaxial boundary predicative model and collapse load predicative model, etc. For wrinkled region extended in circumferential direction, we established wrinklingangle and central axis offset predicative model based on bending-wrinkling factor,obtained wrinkling angle and central axis offset distribution based on polynomialmethod, got the method for analyzing wrinkling occurrence and extension ofvarying cross section inflated beams, and fully characterized wrinkled region.Besides, experimental system was set up for bending-wrinkling test of varyingcross section inflatable beam, combined with finite element analysis, which verifiedand validated the wrinkling occurrence predictive methods and extension analyzingmethods.Based on bending-wrinkling mechanical model of inflated beams, weintroduced equivalence pressure method and set up equilibrium bending momentanalyzing model, which for establishing inflatable pressure, central axis offset,deformation range and tube stiffness, etc. We set up varying stiffness analyzingmodel and further examined their stiffness variation and anti-bending equilibriummechanism. We got relationship between anti-bending stiffness and bending-wrinkling factor as well as wrinkling angle, obtained varying stiffness analyzingmodel considering wrinkled region and curvature variation of wrinkled region.Finally, all results were compared with numerical analyzing calculation, and ournew bending-wrinkling varying stiffness analyzing model for inflated beams aretestified to be correctly.Finite element models for inflated beams considering wrinkled region andcurvature variation of wrinkled region were brought out, corresponding shapefunction as well as stiffness expression were given, and solution process forbending-wrinkling inflated beams were established. By adopting finite elementanalyzing programs, loads bearing characterizes with different loads condition andvarious structural modals were numerical analyzed, effects of wrinkling evolutionand geometrical large deformation on inflatable beam loads bearing performancewere achieved. Those results were compared with archive references, and newbending-wrinkling inflatable beam elements introduced in this research were validated.The load deflection curves of grid reinforced inflatable beam were comparedusing bending-wrinkling inflated beam element brought in this paper and finiteelement refining analyzing model under the same condition, correctness andeffectiveness of this new inflatable beam element were validated throughexperimental test. In order to analyze grid reinforced beam with this bending-wrinkling inflated beam element, equivalent engineering constants of thin walledgrid reinforced beam were analyzed firstly, and then it was validated byexperimental and numerical analysis.All research achievements within this dissertation lay a foundation for efficientloads bearing performance analysis, structural optimization design, and bending-wrinkling characterization of large inflatable structures.更多还原