Finite Element Analysis Of Translational Rotational Coupling Coefficients For Satellite Flexible Attachments

With the continuous development of space industry,satellite as a kind of unmanned spacecraft needs to meet various demands of human beings.It's working environments are getting worse and worse,and it's working tasks are becoming more and more complex.As a result,the structure of satellite is becoming more and more complex and precise.The difficulty and cost of launching satellite are closely related to the weight of satellite.Under such preconditions,it is impossible for a satellite to increase its weight of the main body and the number of its accessories indefinitely.Therefore,more and more materials with low density and large deflection are being applied to the satellite.But when the satellite is in motion,the flexible accessories will produce periodic vibration with large amplitude whether they are in the state of freedom or in the case of get external excitation.The consequence of producing such vibration is to affect the overall balance of the satellite.If the vibration is uncontrolled,the dissipation of satellite energy will be happened,and the satellite will produce overall instability what are very serious.Therefore,when designing and researching satellite,it is necessary to study the flexible appendages and coupling of flexible appendages with satellite central body from the view of dynamic.Two important parameters are involved in the study of flexible accessories of dynamic: coupling coefficient of transition and coupling coefficient of rotation.They are extract from the translational and rotational dynamic equations.In this paper,the vibration characteristics of flexible appendages and two coupling coefficient matrices are studied by modal analysis which belong to satellite with different shapes flexible appendage under different constraints and loads.The main research contents are as follows:Simplify the structure of satellite and establish a structural model of satellite with one flexible appendage.Applying Newton's second law,angular momentum law and Lagrange's equation,the translational and rotational dynamic equations of the model are established.Arrange some parameters of the two equation and then translational coupling coefficient matrix and rotational coupling coefficient matrix are obtained.The flexible appendages of satellite classifies into solar panel,aerial and rigging according to their functions and shapes.This paper simplify them to the models of plate,beam and chord.Different loads and boundary conditions are applied to this models.The results of modal analysis are obtained by finite element simulation:natural frequencies and natural modes.Comparative analysis the results.Using the APDL parametric language of ANSYS,the program can read the parameters needed by the two coefficient matrices from the modal analysis results of the model.Then solve the coupling coefficient matrix of the flexible appendage relative to the central rigid body.It verify this method is feasible and convenient.Aiming at the two coupling coefficient matrices of different models which read from the result file by APDL program,comparative analysis them and get the differences of coupling coefficient matrices of the flexible appendage relative to the central rigid body under different loads and boundary conditions.Substitute the coupling coefficient matrix into the dynamic equation of satellite to study how dose plate affect working of satellite.