Research On Identification Methods Of Aeroelastic Response Parameters Of Tensile Membrane Structures

The identification of aero-elastic response parameters of membrane structures is an indispensable item in related research.In the existing researches,a parameter identification method is usually specified.After identifying the result,it focuses on the analysis of the result,but not the accuracy of the method and the difference of identification ability among methods.Therefore,this paper summarizes the existing methods of modal parameter identification,and introduces cluster ing analysis to improve the accuracy of identification results,compares and selects the method with identification advantages to establish a parameter identification strategy suitable for membrane structure,and finally applies to identification of aero-elastic response parameters of membrane structure.The main contents are as follows:(1)The existing parameter identification methods a re summarized.It is found that SSI and NExT-ERA which based on the state-space model and HHT which based on time-frequency analysis are accurate and stable,which are suitable for membrane structure.These three methods,SSI,NExT-ERA and HHT are programmed and verified by the analyt ical flat-plate model.The identification efficiency of each method is quantified.The reason for the low identification efficiency is analyzed,which is the lack of elimination of the false modes.(2)Introducing an elimination method of the false modes based on hierarchical clustering which improves the identification efficiency of methods effectively.The parameter identification method combined with OPTICS clustering is proposed,which further improves the identification efficiency.The identification efficiency and anti-noise performance of these methods are compared.On this basis,a aero-elastic response parameter identification strategy which is suitable for membrane structure is proposed.(3)Based on the wind tunnel experiment of aero-elastic membrane structure model,the aero-elastic response parameters are identified.The aero-elastic response parameters such as frequency,damping ratio,vibration mode and addit ional mass ratio under different working conditions are obtained.The variation of parameters with wind velocity under different pre-tensions and wind directions is analyzed.It is the found that the damping ratio of the one-way tensile membrane structure can reach up to 13%.The additional mass ratio of the closed one-way tensile membrane structure can reach up to 1.07.The addit ional mass ratio of the open one-way tensile membrane structure is up to 3.21.The additional mass of the closed structure is about 3 times that of the open structure.The damping ratio of the saddle-shaped tensile membrane structure is up to 3.8%.The additional mass ratio of saddle-shaped tensile membrane structure can reach up to 1.43.