Study On Kink And Electromagnetic Characteristics Of Membrane Inflated Structure

Large space membrane inflated structures need to be folded before deploying in orbit to meet their high-volume efficiency.A large number of wrinkles and creases can be generated by the folding of the membrane.Local creases and kinks are attributed to the kink characteristics of the inflated beam,which have an adverse impact on the shape and performance of the membrane inflated structures,and are typical failure modes of high-precision membrane inflated structures.On the other hand,the kink characteristics can become a necessary condition for the mobility of inflated beams.In addition,many high-precision devices are designed by kink to achieve performance control.However,the kink deformation mechanism of membrane inflated structures is not clear,and the theoretical analysis method of kink deformation needs to be studied.Therefore,this paper focuses on the research of kink mechanical behavior of membrane inflated beam,analysing the kink characteristics,kink evolution,and vibration of the inflated beam.Different configurations are designed by the forward kink characteristics and the electromagnetic characteristics are analysised,which has important guiding significance for the structural design and configuration control of the membrane inflated beam.Based on the kink characteristics of membrane inflated beam,the kink model with the harmonic boundary is established.The inflatable beam is studied under uniform loading,and it is found that the phenomenon of secondary kink.The critical kink load,kink angle and kink displacement are predicted.The effects of geometric parameters,inflation pressure and boundary conditions on the kink behavior of inflated beams are discussed.In addition,based on the principle of nonlinear elastic response and minimum potential energy,the kink mechanical model of inflated beam with elliptic section is established to track the whole process from smooth bending,wrinkle,and kink of inflated beam.After studying the statics behavior of inflated beam kink deformation,in order to meet the load bearing requirements,the buckling model of cylindrical shell with initial crease defect is established,the critical buckling characteristics of the structure with partial crease defect are discussed,and the influence law of crease size and crease position on the buckling mode of cylindrical shell is obtained.In addition,the vibration equation of the inflated beam considering the kink characteristics is established,and the law of the influence of kink on the first-order natural frequency of the inflated beam is obtained.The effects of internal pressure,slenderness ratio of inflated beam and kink angle on first-order natural frequency,vibration modes and frequency amplitude response of inflatable beam are analyzed by using control variable method,and the coupling relationship between bending characteristics and vibration mode is revealed.Based on the mastering of the deformation mechanism and characteristics of the inflated beam,it is considered that the inflatable beam exists in the typical frame mode in practical application.The initial configuration design method of free-kink inflated triangle beam is proposed,and the plane geometry model of the initial opening quadrilateral beam is obtained.The characteristics of expansion deformation driven by internal pressure are determined,and the influence laws of the initial kink angle and the width of the cutting section are obtained.The triangular electromagnetic element with reconfigurable frequency is designed based on the variable configuration characteristics of the triangularinflated beam,and the electromagnetic properties such as frequency band,radiation direction and absorbing capacity are evaluated.Due to the insufficient deformation capacity of the inflated frame structure,it is necessary to obtain a kinked inflatable structure,designed with the incision on both sides,intermediate circular connection and inflated beam with connectivity of air path,studied the inflated beam flexible connection structure characteristics of bistable jump,reveals the characteristics of kink on critical jump force structure and the influence law of loop jump characteristics,by adjusting the pressure,variable stiffness and geometry size of the inflated beam jump control of the flexible connection structure.Based on the kink characteristics of flexible connection structure of inflated beam,the electromagnetic element with multistable is designed,and the coupling relationship between various steady state configurations and electromagnetic characteristics such as frequency,radiation direction and absorbing capacity is illustrated.