Research On Thermally Induced Vibration Of Flexible Solar Array With Consideration Of Geometric Stiffness

Flexible solar array(FSA)is consists of rigid central mast,flexible blanket and collection box.It has a light weight and higher packaging efficiency,but it has a large size,rigid-flexible coupling and relatively complicated retracting mechanism.Therefore,design and analysis for this structure are even more complex.Periodic temperature will appear in FSA when space station goes through the shadow of earth.At the same time,as effect of self-shadow of FSA,periodic thermal load will be produced and it will results in thermally induced vibration(TIV).FSA is a space structure with great flexibility.Because flexible blanket has no rigid frame,tensible force is needed to remain its stiffiness.Tensible force results in geometric stiffness that cause difficulity in computing.In this paper,TIV of FSA of a space station was studied.First of all,finite element model of central mast,flexible blanket and whole structure were established seperately.According to the results of natural mode,the effect of geometric stiffness on dynamic characteristics and representative modal are analyzed.Then,based on proper assumption,modified mode superposition method is used to calculate response of TIV of FSA in orbit,and magnitude of response is analyzed quantitatively.In order to research amplitude-frequency characteristic of the vibration,Fourier transformation has been done.Finally,control variables method is used to study effect of three structural parameters on dynamic characteristics,which are magnitude of tensile force,number of tensible cable and stiffness of tensile spring.Natural mode,response of TIV and tensible stress in flexible blanket is computed with various values of these three structural parameter,and consequences were analyzed qualitatively.Obtained results in this paper can be used to assess the security and reliability,and also offer a reference for design and improvement of FSA in the future.