张拉整体结构形态分析与抗冲击性能研究

In order to protect the major structure under severe impact, this project adopt the tensegrity structure to resist the impact load. Form analysis, motion control analysis, and shock resistance analysis are researched in this project. In consideration of the nondeterminacy of the geometrical boundary in practice, the research begins with the given initial gridding or the control node coordinates of the boundary. Topology models are built by using graph-theoretical algorithm. Two-layer optimization algorithm is used in the optimizing of the topology models and the form. Bars are divided in groups by using group theory and the input parameters are the topology models which have been optimized. By doing these things, all steady states can be found. The energy and the acting loads of these different steady states will be researched then. In addition, actuators which can adjust the length of the bars will be installed in inhaul cables to accomplish the active control. After doing this, the change path can be designed so that the structure can transform from the high order stable configuration to the low order stable configuration. Besides, the decoupling between the rigid body displacement and the elastic deformation will use co-rotational coordinate method and finite rotation theory. Cable element which can consider the big dip and the slacking will be built and kinetic analysis will use this cable element. As for the structural failure under the accidental loading, vector form intrinsic finite element method will be used to simulate the whole process of structural damage and the Structural robustness index can be verified in this process. Finally, the simulation of the impact process will be accomplished by doing drop-weight test. In this test, energy conversion excitation load and active control strategy can be verified, and the impact absorptivity can also be calculated.

为了保护冲击荷载下主体结构的安全，本项目采用张拉整体结构作为抗冲击结构，对其进行形态分析与抗冲击性能研究。考虑到实际中几何边界的不确定性，从给定初始网格或边界控制节点坐标出发，用图论算法建立拓扑模型，通过双层优化算法进行拓扑与形态联合优化。并以经过优化的拓扑为初始参数，通过采用群论对杆件进行分组，寻找多种稳态。在此基础上，研究不同稳态的能量及其激励荷载，从而得到体系吸能水平，并在拉索中加入能够调节索长的作动器实现主动控制，从而规划形态变化路径使结构可以恢复成低阶稳态构型。用有限转动理论进行刚体位移和弹性变形解耦，建立能够考虑索的大垂度和松弛的索单元，再采用向量式有限元对张拉整体结构受冲击及失效过程进行数值模拟并验证结构鲁棒性指标。最后，用落锤试验方式来模拟冲击过程，验证理论分析得到的能量转换激励荷载和主动控制策略，得出该结构的冲击力吸收率。

为了保护冲击荷载下主体结构的安全，本项目采用张拉整体结构作为抗冲击结构，对其进行形态分析与抗冲击性能研究。从张拉整体结构的双稳态特性出发，利用解析方法、半解析方法以及数值方法深入研究了张拉整体结构的多稳态现象，并理论推导了考虑初始缺陷的简单张拉整体结构受力全过程响应，并分析了张拉整体结构的刚度组成。将张拉整体结构的形态问题分解为找形、给定结构形态下的稳定性判定及刚度评估、初始预应力的计算及优化、外荷载作用下的形态确定、形态控制和施工成形等六个子问题，综合运用矩阵分析、非线性规划理论、有限元法、动力松弛法、遗传算法、优化控制等数学工具展开系统研究。通过引入附加索和多级压缩杆设计新型的多稳态张拉整体结构，结合拓扑组装形成张拉整体型抗冲击结构，系统研究各冲击工况下的动力学响应，验证设计的多稳态张拉整体结构优异的抗冲击性能。