格构式高耸结构基于大位移和稳定性的抗风优化设计方法研究

The wind effect on the high-rise structures such as lattice towers would be studied in the proposed research project. First the "lumped multi-mass" baseline finite element model for the stidied lattice towers would be established by the finite element model updating technique. An innovative HFFB wind tunnel tests with segemental rigid models would be conducted to obtain the along-wind, cross-wind and torsional wind loads on each model in different height levels. The POD analysis were then conducted on the mesured wind load, and the load-dependent Ritz vectors were obtained for the solution of the wind-induced respoonses and its corresponding Equivalent Static Wind Loads (ESWLs) on such structures. Based on the linear buckling stability analysis and nonlinear static analysis of the lattice towers allowing for the large displacements and second order geometrical nonlinear effect, the wind resistant structural optimized design procedure for the lattice tower systems was proposed in this study. With the seemless intergration of the Optimality Criteria method and SAP2000 API, the wind resitant optimized design was conducted for the lattice tower structures to obtain the minimized structural weight while meeting the requirement of constraint conditions in wind-induced displacemt and linear buckling critical load capcity. The research studies proposed in the project would be helpful to promote the wind resistant design of high-rise strctures such as lattice towers in wind engineering.

本申请项目以格构式高耸结构的风效应入手，结合有限元模型修正技术获得格构式高耸结构的"串联多质点"基准有限元模型，同时通过片段刚性高频动态天平测力模型，获得作用在各刚性片段的顺风向，横风向及扭转气动力，在此基础上利用POD法和基于荷载的Ritz向量叠加法来进行格构式高耸结构的整体结构风致响应及等效静力风荷载分析。以针对钢结构体系的线性屈曲稳定分析和以考虑节点大位移为基础的二阶几何非线性静力分析为研究手段，通过SAP2000应用程序接口和最优准则优化算法的无缝集成，研究和探讨格构式高耸结构在承受风荷载作用下，同时满足节点大位移条件下的位移变形限值和线性屈曲临界荷载的约束条件，以结构重量最轻为优化目标的格构式高耸结构抗风优化设计理论和方法。预计上述相关研究工作的开展，对促进风工程研究成果更好地为格构式高耸结构抗风设计的应用，具有较为重要的借鉴和指导意义。

本申请项目以格构式高耸结构的风效应入手，结合脉动风荷载的空间分布形式，通过本征特征分解和Ritz模态分析相结合的Ritz-POD算法求解Ritz振型，结合谐波激励法和荷载-响应相关法，实现了结构风振响应和等效静力风荷载的高效分析。另一方面通过考虑线性与几何非线性分析的风致响应对优化设计变量的敏感度分析，结合改进的最优准则优化算法和大型有限元软件SAP2000的API开发环境，实现了一套对此类结构在考虑几何非线性受力条件下，对其满足刚度（位移）、强度（应力）和临界荷载因子等约束条件，集节点风荷载时程和等效静力风荷载的更新为一体化的抗风优化设计系统。. 另一方面以一高285m、4层牵拉的桅杆结构为研究实例，对其在顺风向荷载作用下考虑缆绳预拉力和结构几何非线性影响，采用几何非线性时程动力分析方法评估其风致响应，并与气动弹性风洞实验结果和Patch Load简化计算方法进行了对比分析。. 同时采用了改进自适应遗传算法，以前述桅杆结构空间结构杆件的截面尺寸、纤绳的截面面积和初始拉力、纤绳在地面锚固位置作为优化设计变量，结构的杆件应力、结构顶部的水平风致位移作为优化设计的约束条件，进行了此类桅杆结构重量最小为目标的抗风优化设计方法研究。. 最后以一格构式高耸塔架结构为研究对象，采用改进的自适应遗传算法，对此结构进行了以不同类别的结构稳定临界荷载因子（分别采用一阶弹性、二阶弹性和一阶弹塑性三种结构分析方法进行求解）为约束条件，结构模型用钢量最小化为目标的抗风优化设计方法研究。. 上述相关研究工作的开展，对促进风工程研究成果更好地为格构式高耸结构抗风设计的应用，具有一定的借鉴和指导意义。