单层球面网壳风振分析的多模态效应

为研究网壳结构风振响应的主要贡献模态分布规律及模态耦合效应,有利于提高结构风振响应的计算效率,利用Ritz-POD法,综合考虑各结构振型自身参振能力的强弱及其与脉动风压空间分布模式之间的关系来识别单层球面网壳风振的主要贡献模态;利用模态广义位移协方差矩阵的特性分析其模态耦合效应.结果表明,单层球面网壳存在高阶主要贡献模态,该高阶振型通常处于结构自振频率发生突变的位置;网壳结构的风振响应以模态自相关为主,模态耦合效应相对较弱,对结构动力响应的影响大致为10%.

Multi-vibration-mode analysis of single-layer spherical reticulated shell under wind load

In order to analyze the contribution-significant modes and the mode coupling effects for the wind-induced vibrations,a Ritz-POD method is proposed for identifying the contribution-significant modes,which takes into account the vibration-participating ability of each natural mode,and the similarity between the mode and the spatial distribution of the fluctuating wind load.The evaluations of the mode coupling effects for the wind-induced vibration were performed using modal displacement covariance matrix.The results indicate that some high order modes must be considered,which locate in the frequency snap zone and contribute to the wind-induced vibration significantly.Moreover,the modal auto-correlation plays a much more important role in the wind-induced vibration than the modal cross-correlation,and the mode coupling effect for the wind-induced vibration is approximately 10%.