单向悬挂屋盖结构的风致气弹耦合效应数值模拟

Numerical simulation on the aeroelastic effects of uni-directional suspension structures

综合运用计算流体力学和计算结构力学技术,建立了适用于索膜结构流固耦合风振分析的CFD数值模拟方法,并编制了相应的有限元计算程序。应用该程序对具有不同参数的大跨度单向屋盖结构进行了风振响应分析,探讨了来流风速、屋面质量和初始预张力等参数对结构流固耦合特性的影响。研究表明,由于屋盖前缘周期脱落的大尺度旋涡是诱导结构振动的主要原因,随着大尺度旋涡沿屋面向下游移动,其动能逐渐转化为结构变形能,使结构振动形态呈现明显的涡激振动特征。屋面质量、来流风速和初始预张力是影响结构流固耦合性能的主要参数。对于索膜结构,仅通过刚性模型来确定结构风压并进行风振响应分析,其结果是不可靠的。

A computer-aided simulation approach for wind-structure interaction analysis of flexible roof structures was presented.This approach was performed by a partitioned solution strategy,which include three modules.In CFD module,the Taylor-Galerkin method was adopted for finite element solution of the unsteady Navier-Stokes equations and using Large Eddy Simulation method for turbulence. In CSD module,the dynamic non-linear structural response was described by Update Lagrangian formulation and an implicit time-stepping procedure was adopted.In CMD module,an ALE formulation was used to describe the moving grids.The timedependent simulation process was controlled by an iteration procedure between these three modules until convergence was reached within each time-step.Finally, the aeroelastic response of the one-way type suspension roofs was simulated by the coupled algorithm.The effects of several factors,such as wind speed,roof mass and prestress et al,were studied to investigate the behaviors of wind-structure interaction.It was shown that,the wind-induced dynamic responses of tension structures can be characterized by forced vibration process.The excitation of roof structures is due to vortex shedding.When these vortices flow downstream,the kinetic energy of the turbulent motion will transform to structural elastic potential energy,which makes the roof vibration like vortex-induced one.Wind speed,structural mass and prestress play important role to the behavior of wind-structures interaction.It would be unreliable when the wind-induced analysis is carried out without consideration of the wind-structure interaction for some cases,especially for flexible roof structures.