Membrane Antenna Dynamics Analysis Based On Absolute Nodal Coordinate Formulation

In recent years,with the development of engineering materials,new materials emerge in an endless stream.As one of the new materials,membrane is applied to satellite antennas,and the deployable space membrane antenna is unveiled at the same time.Membrane deployable antenna has many advantages,such as low cost,high reliability of deployment,large ratio of shrinkage,small mass per unit area and so on.As a result,it has become one of the hotspots of attention and study of aerospace scientists recently.However,flexible deformation of membrane is easy to arise during the deployment of antenna,which will further affect the accuracy of the working state of membrane antennas.Therefore it is rightly necessary to study the membrane's dynamics.Compared with other traditional finite element formulations,the absolute nodal coordinate formulation can accurately describe the motion of flexible bodies for large deformation and large rotation of flexible systems,which provides a direct and effective idea to explore the motion of membrane.On basis of absolute nodal coordinate formulation and taking the membrane antenna as the object of study,firstly the dynamic characteristics of the rectangular plate element is studied in this paper,and then which is extended to quadrilateral plate element.Finally the theory of plate elements is employed to the dynamic analysis of membrane antenna.The specific works are as follows:1.Rectangular plate element based on absolute node coordinate formulation is studied.According to the geometric description of the rectangular plate element,and the fact that arbitrary rigid body motion can be described by using the introduced shape function and the nodal coordinate vector is proved.The mass matrix,the elastic force matrix,stiffness matrix and generalized force matrix of the rectangular plate element are derived.The convergence of rectangular plate element model is verified by static numerical simulation and dynamic properties of rectangular plate element is proved by pendulum simulation of flexible plate.2.The rectangular plate element is generalized to the quadrilateral element,and the quadrilateral plate element based on the absolute node coordinate formulation is studied.Simultaneously,the motion equation of the quadrilateral plate element is established,and the mass matrix,the elastic force matrix,the stiffness matrix and the generalized force matrix of the quadrilateral plate element are derived.Then the reasonability of the proposed method is certified by numerical examples the static and dynamic analysis.3.The mechanics of the membrane reflecting surface is analyzed.The first step is to build the finite element model in ANSYS,and the static analysis of the whole reflector surface during the folding process is finished.The second step is to establish the membrane reflector surface model in MATLAB on basis of the chapter two and three,then the dynamics of the 1/6 substructure of the model under different conditions is analyzed.4.Umbrella membrane deployable antenna prototype is developed.Firstly,the prototype furling mechanism is designed,the membrane is attached,and the experimental system is established.Secondly,the surface accuracy of working state of the antenna prototype is obtained using the three-dimensional photogrammetry system.Finally,the measured experimental data postprocessing is compared with ideal parabolic surface,and the reasons of error are analyzed.