单层柱面网壳结构抗风敏感度研究

Wind-sensitivity of single-layer latticed cylindrical shells

以风敏感度概念为基础,对结构风敏感度计算理论中的若干关键问题进行探讨,并对相关计算方法进行改进,推导了背景效应系数、耦合效应系数以及系统应变能等公式。以单层柱面网壳结构为研究对象,系统研究了跨度、杆件截面、矢跨比、约束形式等参数对结构风敏感度的影响,建立了单层柱面网壳结构风敏感度分级体系。研究发现:单层柱面网壳结构风敏感度主要受结构刚度和振动模式的影响,实际设计中可通过结构自振基频、矢跨比和约束形式三个参数来判断;以结构自振基频等于1.5 Hz作为分界线,小于该值时结构共振响应较大,需进行结构动力分析,大于该值时结构以背景响应为主,据此提出了以背景响应为基础的简化风致振动计算方法。

Based on the conception of wind-sensitivity, some key issues of wind sensitivity theory were discussed in this thesis, and the calculation algorithm of wind-sensitivity was improved. The coefficient of background response effect, coefficient of coupling effect for background and resonance response and calculation formula of strain energy were defined and deduced theoretically. The influence of span, cross-sectional area, rise-span ratio and boundary conditions on the wind sensitivity of cylindrical shells was studied systematically. Then, the classification system for the wind sensitivity of cylindrical shells was established. The study indicates that, the wind-sensitivity of cylindrical shells is mainly affected by the stiffness and vibration mode, which are expressed by structural basic frequency, rise-span ratio and boundary conditions. When the structural basic frequency is smaller than 1.5 Hz, the resonant response can＇t be omitted. When the structural basic frequency is larger than 1.5 Hz, the wind-induced responses can be calculated by simplified algorithm that merely considers the background response.