Nonlinear Vibration Analysis For Variable Section Of Super Tallbuilding Under Turbulent Wind

With the increasing use of lightweight materials on super tall buildings, the structure of wind sensitivity enhancement, risk of galloping under the turbulent wind will also increase. However, this is always using the theory of linear dynamic analysis on the structure, geometry of high-rise building structures with tapered nonlinear and turbulent component in the wind load parameters of nonlinear factors, it will cause strong nonlinear building behaviors. These nonlinear behaviors in tall building vibration induced by some linear analysis cannot reveal. In this paper, with the variable section of super tall building structure as the research object, combing the nonlinear dynamics theories, nonlinear vibration of building structure model and study the nonlinear vibration behavior of turbulent wind action and galloping motion stability analysis, thus to solve this kind of variable section of tall building engineering structure design and vibration control to provide ideas and suggestions. This paper mainly includes the following 3 parts:The nonlinear dynamic response of variable section of super tall building system whose consider the central axis boundary conditions that tall building structure is not stretchings. The combined effects of nonlinear term due to seismic load and wind load behavior are considered. The nonlinear partial-differential equations are derived by Hamiltonian principle. The Taylor formula is applied to expansion to three times in differential equations of nonlinear polynomial, simplification to dimensionless equation, senior architectural structure of nonlinear dynamic equations.Combined with analysis of the nonlinear vibration method, researching on numerical calculation of wind-induced vibration in turbulent flow model to get the modal time-history curves. Considering of high-rise building structures with tapered damping, vibration of the initial conditions and effect of slenderness ratio on the nonlinear dynamic response. Applied the method of multiple scales to the variable section of tall building structure, study on principal-primary parameter resonance of 1:1 and 1:2 both cases under average equation. The bifurcation and choatic dynamics of a super tall building system under internal resonances of 1:2 are investigated. Based on the outside control parameters, the vibration mode of tall building structures with excitation amplitude increases and bifurcation behaviors and effects is investigated. Finally, choosing the parametric excitation as a controlling parameter, the chaotic dynamics are investigated using the bifurcation diagrams, phase portraits, and Poincare maps.In the variable section of tall building, the wind-induced response of harm under turbulent wind that is causing galloping oscillation, it is analyzed to galloping stability. The galloping motion equation of super tall building structure is established, applying the precise time-integration method for solving nonlinear equation of galloping, the critical wind speed and comparison with wind tunnel tests to verify the feasibility. The effects of the slenderness ratio and thickness parameters, such as aspect ratio, mass density and damping effects on critical wind velocity of galloping are then evaluated. Then, the effects of these parameters on the parametric vibration characteristics of the model are investigated. Exploring of fluctuation in turbulent wind components, turbulent wind load parameters, such as amplitude and frequency effects on critical wind velocity of galloping, to provide important reference value for the similar design of the variable section of super tall building.