基于时域分析方法对预应力双层柱面网壳结构的风振响应进行研究,采用Welch谱分析法对谐波叠加法与线性滤波技术(AR法)模拟得到的脉动风速时程进行功率谱精度评价;分析了预应力双层柱面网壳的矢跨比、跨度、厚度、长宽比、支座弹性刚度、预应力取值等结构参数对结构风振响应的影响,结果表明:网壳的矢跨比、跨度、长宽比是影响预应力双层柱面网壳结构风振响应的主要因素;预应力拉索有效地减小了结构的脉动风响应,但由于平均风响应同时也大幅减小,其位移风振系数仍较普通网壳结构大。基于包络的概念,采用以最大动响应和最大平均风响应为控制指标的整体风振系数计算方法,研究了常见设计参数情况的预应力双层柱面网壳结构整体风振系数,可为预应力双层柱面网壳的抗风设计提供实用方法。
The wind-induced response of prestressed double-layer cylindrical reticulated shells is researched based on the time-domain analytical method. The Welch spectrum analysis method is presented to evaluate the power spectrum accuracy of the fluctuating wind speed time-history simulated by the harmony superposition method and linear filter technique (AR method). The influence of structural design parameters on the wind-induced response is investigated, including rise-span-ratio, span, thickness, length-width-ratio and the elastic support stiffness of the structure. Results show that the rise-span-ratio, span and length-width-ratio are the main factors influencing the structural wind-induced response. The existing of prestressed cable efficiently reduces the fluctuating wind induced response of the structure, while the displacement wind vibration coefficient is still greater than that of common non-prestressed reticulated shells since the average wind induced response is also reduced greatly. The global wind vibration coefficient method is introduced based on the envelope concept, which takes the maximum structural vibration response and maximum average wind induced response as controlled indexes. In the end, the global wind vibration coefficients of prestressed double-layer cylindrical reticulated shells under various design parameters are calculated.