Dynamic Response Of Skeleton-Supported Saddle Membrane Structures Under Wind Loads:Theory And Experiment

In the rapid development of national modernization,construction is one of the most basic items to measure development.With the improvement of people’s quality of life,there are higher requirements for the functionality and form of buildings.As a new type of large-span structure in development,membrane structure is widely favored due to its own advantages.Most of it appears in large public buildings such as sports stadiums,railway stations,and large comprehensive shopping malls that are constructed in the form of membrane structures.It is due to the widespread application that construction accidents occur frequently.According to statistics and reports,most accidents occur in harsh natural climate conditions,and most of them are accompanied by strong winds.According to the research of many scholars,membrane structures are wind-sensitive structures and wind load is the main factor causing structural damage and failure.However,building load design codes is often relied on rigid building design in currently,and rarely mentions flexible structure-membrane structure.Its wind load design standard is to adapt to the convenience of engineering calculations will be defined as static load,with a simple geometry of the building’s volume constants used to calculate.Obviously,this method is not suitable for curved membrane structures with exotic shapes.Moreover,for such wind-sensitive structures,the wind load cannot be regarded as a constant load and its randomness can be ignored.Therefore,it is important to study the vibration law of membrane structures under wind loads.In this paper,the skeleton-supported saddle membrane structure is taken as the research object,and the research is carried out as follows:Firstly,the basic mathematical means to study the vibration characteristics of structures is based on the analysis of the shell theory from small deflection problems.The theoretical equations of large deflection deformation applicable to membrane structures are derived,and a set of vibration control equations for membrane structures consisting of equilibrium equations and deformation coordination equations is established.Secondly,in the study of wind load,the method of basic fluid dynamics is returned.By establishing the state equation of gas and combining with the theory of potential flow,the aerodynamic function model of wind is established.By combining the governing equation with the aerodynamic term which needs to be input into the system,the nonlinear vibration differential equation of the saddle membrane structure under wind load is obtained.The wind speed signal input into the aerodynamic equation is analyzed,and the conditions that can meet the approximate solution of the nonlinear vibration differential equation are obtained.The truncation method of ignoring high order cumulants is used to solve the nonlinear vibration differential equation,in order to obtain the important statistical parameters,mean value and standard deviation,for the study of random vibration law.At the same time,perturbation method is used to solve the vibration function of membrane surface constructed by Galerkin method.Finally,a numerical example analysis was carried out to achieve the purpose of controlling variables by changing and fixing the important physical parameters of the membrane structure.It was concluded that the change of wind speed did not affect the mean value of the membrane surface vibration displacement,and the increase of wind speed led to the more obvious random vibration of the structure.In order to study the mechanism of random vibration of membrane structure and verify the feasibility and reliability of theoretical examples,the scaled model of skeleton-supported saddle membrane structure and wind tunnel test were carried out.According to the similarity ratio relationship between the test wind field and the model to the prototype model and its wind field,the similarity theory conforming to the conditions of this paper is used to transform the test data,and the transformed prototype test data is compared with the theoretical example for verification.The final comprehensive theoretical and experimental results propose the control relationship between the important physical parameters of the saddle membrane structure and the structural vibration response,providing theoretical reference and basis for the random wind vibration research of the saddle membrane structure.