带张拉整体环的自平衡索穹顶结构体系及其冗余特性研究

Self-balance cable dome with a tensegrity ring instead of rigid ring beam is a new type of tensegrity structure. The structural system and the reduncdancy characteristic of the new structure is intensively studied by the means of theoretical analysis, numerical simulation and experimental research. It will provide theory foundation and technology support for the practical engineering application of self-balance cable dome. The tensegrity ring with geometric stability and good rigidity is first investigated. The topology, classification and form finding method of self-balance cable dome is then studied. Followed that, the effect of tensigrity ring on the behavior of the dome is inspected as well as the non-conservative propety of the structure under different load path. The loading process analysis of structure is simulated by considering buckling of compression bars and slack of tension cables. The ultimate bearing capacity of the dome is analyzed as well as the failure mode. Finally，the redundancy degree theory and calculation method for flexibility cable-strut system is established. The sensitivity to the installation error and the prestress level is researched by the redundancy analysis. The rationality of member layout is also evaluated and the improvement scheme then proposed based on the distribution of redundancy degree. The above work will provide new idea in analysis, design and optimization of cable-strut systems, and furth enhance the level of theoretical research and technical appliaction of our country in this field.

自平衡索穹顶结构是在现有索穹顶基础上，由张拉整体环代替刚性环梁生成的新型张拉整体结构。项目拟采用理论分析、数值模拟、试验研究等手段，对该结构体系及其冗余特性进行深入研究，为新型自平衡索穹顶结构的工程应用提供理论基础和技术支持。项目在构造几何稳定且具有较好刚度的张拉整体环基础上对自平衡索穹顶结构的拓扑、分类和协同找形进行研究；考察张拉整体环对整体结构性能影响和不同荷载路径下结构的非保守性，通过模拟压杆屈曲、拉索松弛实现结构受力全过程分析，研究结构极限承载力及破坏模式；建立柔性索杆体系冗余度分析理论和方法，研究基于冗余度的安装误差、预应力敏感性分析，对结构体系布置合理性进行评价，并提出优化方案。上述研究可为包括索穹顶在内的索杆张力结构分析、设计和优化提供新的方法和思路，并进一步提升我国在该领域的理论研究和应用技术水平。

项目采用理论分析、数值模拟、试验研究等手段对带张拉整体环的自平衡索穹顶结构体系及其冗余特性进行了深入研究。提出了基于遗传算法的张拉整体环拓扑优化方法，开发了新型可刚化的张拉整体环结构，研究了新型张拉整体环的结构刚度和静动力性能，验证了其替代传统索穹顶中刚性环梁的可行性。建立了基于Levenberg–Marquardt方法的张拉整体找形方法，提出了索穹顶拓扑优化和两阶段最小质量设计法，通过张拉整体环和内部索杆体系的协同找形确定了自平衡索穹顶的整体预应力，通过跟踪压杆屈曲、拉索松弛或破断模拟了不同荷载作用下自平衡索穹顶的受力全过程，研究了结构极限承载力及破坏模式，为该类结构的工程应用提供了理论基础和技术支持。发展了刚性结构冗余度理论，提出了针对杆系和梁系结构的冗余特性评价指标，建立了基于剩余结构冗余分布指数判定构件重要性的方法；推导了包括静不定冗余和动不定冗余的柔性索杆体系冗余度理论，基于冗余度及可靠度理论研究了索杆体系索长误差敏感性和索长误差控制限值确定方法，为索杆体系拉索加工制作和结构施工精度控制提供了科学依据；通过考察结构线性及非线性冗余度、构件冗余分布及冗余均衡性等一系列指标形成了一套索杆体系冗余特性评价方法，为新结构体系优化设计和结构体系布置合理性判定提供了新思路新方法。上述研究将进一步提升我国在柔性索杆体系方面的理论研究和应用技术水平。