考虑索杆损伤累积的弦支穹顶结构强震失效机理研究

Compared with single-layer reticulated shells, suspen-dome structures are superior in their mechanical properties and stability, which have been increasingly applied in the practical engineering. At present, many researches have been carried out on the failure mechanism of single-layer reticulated shell strong earthquakes and great achievements have been made. However, the investigation on seismic performance of suspen-dome structures is far from the depth of single-layer reticulated shell structures. Above all, theoretical analysis, numerical simulation and experimental study will be used in this subject. Based on the prominent characteristics of twisted truss structure and non-ideal articulation of strut node, the failure mechanism of severe earthquakes of suspen-dome structure system will be studied in depth. First of all, the constitutive model of the cables under cyclic loading will be established to reveal the response behavior of the cables under the action of the earthquake. After that, the out-of-plane moment-rotation curve of ear-plate joint will be deduced from free rotation to constrained rotation. The simplified simulation method of substructure of the cable and strut will be verified and corrected by the test. At last, the model shaking table test will be carried out. Based on test results, a finite element numerical model of the suspen-dome structure that is suitable for the simulation analysis of the entire seismic process will be established. A uniform failure criterion of suspen-dome will be proposed by thoroughly analyzing the seismic response laws and failure modes of suspen-dome structures under various structural parameters. The failure mechanism of strong earthquakes of suspen-dome structures will be revealed comprehensively, which will lay a theoretical and experimental foundation for seismic analysis and design of suspen-dome structures.

与单层网壳相比，弦支穹顶受力及稳定性能更优越，已经得到越来越多的工程应用。目前在单层网壳强震失效机理方面已有很多研究并取得了丰硕的成果，但是弦支穹顶抗震性能研究远没有单层网壳深入。因此，本课题拟采用理论分析、数值模拟与试验研究相结合的方式，针对拉索绞捻特性和撑杆节点非理想万向铰接这两个突出特点，对弦支穹顶强震失效机理进行深入研究。首先，建立拉索构件循环荷载本构模型，揭示拉索构件在地震作用下的响应行为；其次，推演耳板式节点平面外自由转动到约束转动全过程弯矩转角曲线，试验验证并修正索杆子结构节点简化模拟方法，揭示撑杆构件在地震作用下的响应行为；最后，开展弦支穹顶模型振动台试验，建立适用于抗震全过程模拟分析的弦支穹顶精细化有限元数值模型，深入分析各种结构参数条件下该类结构地震响应规律、失效模式，提出弦支穹顶失效判别准则，全面揭示弦支穹顶强震失效机理，为该类结构的抗震分析与设计奠定理论和试验基础。

随着社会经济与技术的发展和人民生活水平的提高，人们对于大跨度建筑的需求越来越多，如大型的体育场馆、会展中心、车站候机厅、飞机库等。适用于建造大空间的网格结构已经成为首选结构体系，大跨空间结构抗震性能研究是工程防灾减灾技术进步的重要依据，弦支穹顶结构受力性能高效、应用前景广阔，国内外学者在网壳结构方面已经进行了大量研究并取得了丰富的成果，然而目前尚未见到对弦支穹顶结构强震方面的深入研究，其抗震性能急需深入研究。.因此，本课题首先围绕拉索构件本构模型和索杆平面子结构（张弦桁架结构）这两个方面入手，从研究新型高强钢丝考虑损伤累积的本构模型和撑杆耳板节点极限转动能力出发，对拉索构件低周循环荷载作用下本构关系模型进行系统研究，基于此建立了普通高钒索与密封高钒索的精细化有限元模型，并进行有限元数值模拟分析，与试验结果进行对比验证了有限元模型的正确性，得到了不同拉索在单调拉伸及循环加载过程中各层钢丝应力、钢丝间接触压力、钢丝间摩擦耗能、拉索应变内能和拉索的径向收缩等发展变化情况；之后，通过张弦桁架结构循环荷载试验及数值模拟研究，揭示了带约束撑杆平面子结构（张弦桁架）在循环荷载作用下的滞回性能，得到了其薄弱位置及失效破坏模式；为研究弦支穹顶结构的地震响应，进行了弦支穹顶结构振动台试验及有限元数值模拟研究，全面系统的分析研究了在地震输入作用下弦支穹顶结构的动力特性及地震时程响应；通过建立弦支穹顶原型结构有限元模型，进行强震作用下有限元数值分析，研究了结构在不同支座条件及地震幅值作用下的杆件内力变化趋势，进而研究分析了弦支穹顶结构的失效模式，为完善预应力空间钢结构抗震分析设计理论奠定基础，从而推动预应力空间结构体系的防灾减灾技术的发展，具有重要的科学意义和工程应用价值。