Research On Dynamic Characteristics Of Truss Nuclear Powered Spacecraft

Solar energy is the main form of current space energy.With the increasing demand for deep space exploration,traditional space energy sources have been unable to meet the requirements.Space nuclear energy has become a hot research topic in the aerospace field due to its high energy density,high power and environmental independence.However,the high temperature,electromagnetic interference,that may occur during the operation of the space reactor may affect the normal operation of the instrument.Nuclear-powered spacecraft typically utilize a truss structure to maintain a safe distance between the space reactor and the instrument bay.The number of truss structural members is large and the number of degrees of freedom is large.In order to realize the accurate modeling of nuclear-powered spacecraft,the dynamic characteristics of the truss structure need to be analyzed.In this dissertation,a truss nuclear-powered spacecraft is taken as the research object.Firstly,considering the similar mechanical properties of the slender truss structure and the elongated continuous beam,the truss structure is modeled based on the equivalent beam theory,and proposed structural dynamics equivalent method to correct it.It is achieved that the nuclear-powered spacecraft truss structure is equivalent to an anisotropic continuous beamThen,according to the overall parameters of the nuclear-powered spacecraft truss structure,the modified equivalent beam model is used to determine the equivalent parameters,and then the dynamic characteristics of the equivalent beam are analyzed.The results are compared with the analysis results of the traditional equivalent beam model and the truss structure based on finite element theory.Therefore,the correctness of the equivalent beam theory and the effectiveness of the correction method are verified.On this basis,the influence of the truss structural parameters on its natural frequency and the dynamic response of the equivalent beam model are further analyzed.Finally,the modified equivalent beam model is used,and the nuclear-powered spacecraft is simplified into the form of rigid bodies and beam.Based on the Hamiltonian principle,a rigid-flexible coupled dynamic model of the continuous form in the plane of the spacecraft is established.Then the linearized dynamic equations are solved by rigid-flexible coupled modes.In order to analyze the dynamic characteristics of the system,the rigid-flexible coupled dynamic equations are discretized by the modal method discrete and finite element discrete method respectively.On this basis,the modal analysis and dynamic response analysis of the nuclear-powered spacecraft were carried out.