Theory Analysis And Numerical Simulation Study On Wind-Structure Interaction In Wind-induced Vibration And Snow Pressure Of Membrane Structure

Characterized as flexible, lightweighted, the main external loads of membrane structure are wind and snow loads. For wind resisting design of membrane structures, the most predominant feature is the existence of fluid-structure interaction in wind-induced vibration. Currently, theory analysis and related numerical simulation methods of fluid-structure interaction in wind-induced virbration of membrane structures is on the starting phase at home and abroad. Fluid-structure interaction is a key factor of restricting wind-resisting theory development of membrane structures. For snow resisting design of membrane structures, drifing and accumulating of snow on structure surface occurs under wind, causing uneven disttibution of snow on structure surface, forming wind-induced snow pressure. Uneven distribution of snow load should be considered to avoid oo much snow on the roof. It is difficult to determine snow pressure of membrane structures according to present load codes. And there is no study on wind-induced snow pressure of membrane structures yet. Thus, it is of great importance to study fluid-structure interaction in wind-induced virbration and wind-induced snow pressure of membrane structures for supplementing wind and snow resisting theory and guiding engineering practice.The first part of the work here proposes simultaneous strong coupling theory to solve wind-structure interaction problem in wind-induced virbration of membrane structures. To solve data transfer between air fluid domain and structural domain, pseudo-solid model is introduced to deal with mesh distortion between fluid and structure interface. A new mesh updating method is proposed according to the cause of element distortion. The method is applied to a fluid-structure interaction problem of a membrane structure. And the results prove the accuracy and superiority of the method.Based on pseudo-solid model, a simultaneous strong coupling method is proposed to calculate interaction between viscous incompressible fluid and nonlinear structure undergoing large deformation. Strong coupling of the system is achieved through fluid formulation, structural formulation and pseudo-solid formulation. And simultaneous formula the interaction system is derived. Then numerical simulation program MWISP is developed based on the simultaneous strong coupling method.The simultaneous strong coupling method is applied to studying fluid-structure interaction of different shape membrane structures. Key parameters such as wind pressure coefficient, wind-induced vibration of double-slope and saddle membrane structures are calculated when considering and not considering interaction effects. And wind pressure coefficients of double-slope membrane structure compare well with those obtained in wind tunnel experiment, which proves simultaneous strong coupling method and the program applies well in calculating fluid-structure interaction in virbration of membrane structures. Meanwhile, wind velocity, pressure field distribution around membrane structures are calculated, and changing rules of air flow are obtained. Solutions obtained using simultaneous strong coupling method has good convergence. Simultaneous strong coupling method is highly effective for system with strong interaction.In the second part of the work here, wind-induced snow pressure of membrane structures is studied. Snow drifting process and principles are presented in detail,and then governing equations of air-phase and snow-phase are given based on two-phase flow theory. Then CFD technique is used to calculate snow drifting around saddle membrane structures and snow pressure on the roof surface. And distribution rules of wind-induced snow pressure on the surface are summarized. Snow drifting process of double-slpoe membrane structure is simulated, and influences of different geometrical parameters on wind-induced snow pressure are analyzed. It provides scientific basis for wind-snow resisting design of membrane structures in more secure and economic way.