【摘要】 弦支穹顶结构的自振特性是其本身固有的重要力学性能.运用有限元方法,基于ADINA软件建立了大跨度Kiewitt型弦支穹顶结构非线性动力特性分析的有限元模型.首先对35.4m跨度的K6型弦支穹顶结构进行了自振性能分析,得出结构前15阶自振频率及振型,由于弦支穹顶结构的对称性,其前15阶自振频率数值密集且变化均匀,说明结构的刚度分布均匀合理;前两阶振型水平与竖向振动同时存在,后几阶以竖向振动为主.着重针对环索预应力、撑杆长度、杆件截面、矢跨比四个因素对自振频率的影响进行了分析,拉索预应力及杆件截面对自振频率的影响非常小,矢跨比是影响自振性能最敏感的因素.更多还原

【Abstract】 Natural vibration characteristic is an extremely important inherent mechanical property of suspendome structure.By using finite element method,nonlinear dynamic models of large-span Kiewitt suspendome were built based on ADINA.The first 15 modes and 15 frequencies of a K6 suspendome with 35.4 meters span were obtained.Because of the symmetry of structure,the former 15 natural frequencies have only small changes,which indicates the stiffness is uniformly distributed.The first two mode shapes are both in horizontal and vertical direction,and the latter modes are mainly vertical.The influences on natural frequency of four parameters including prestress,bar length,section area and rise to span ratio were studied.The results show that cable prestress and section area have little impact on the natural frequencies,while the rise-to-span ratio is the most sensitive factor.更多还原