Structural Design And Mechanical Analysis Of Spacecraft In Complex Mechanics Environment

With the development of space technology,scientific detection of spacecraft requires higher detection accuracy,lighter structural quality and lower cost.However,in the process of launch and orbit,the spacecraft must go through all kinds of complicated mechanical environment.Rocket launch stage,the spacecraft subjected to vibration,shock,noise,overload and other loads;in orbit operation stage,the spacecraft is facing the gravity gradient torque,aerodynamic moment,solar radiation torque and geomagnetic moment and other space environment torque.Which puts forward higher requirements for the design and analysis of spacecraft structures.The virtual prototype technology is used to build the digital model of the spacecraft,which can speed up the design process and reduce the cost of research and development.Based on the design of spacecraft structure and mechanical properties analysis as the main content,focus on three parts: design and analysis of balloon satellite structure,the feed structure of reflector antenna,sounding rocket flight simulation.A satellite structure scheme of the combination of balloon and inflatable gravity gradient rod is proposed.The spatial dynamic moments of balloon satellites are analyzed,and the dynamic gradient model of gravity gradient is established.The overall design of the balloon satellite structure,including the choice of the method of folding and the rigidity of inflatable structure;determination of the attitude control of the balloon satellite;layout and structure design of the load cell;a new method for calculating the length of the gravity gradient rod of a balloon satellite is presented;on orbit life analysis of balloon satellite.Based on the finite element modeling of the balloon satellite,the coupling between the natural frequency and the libration and the orbital frequency of the structure is analyzed.According to the design requirements of the feed structure,combined with the overall configuration of the satellite,a preliminary design scheme of feed structure is proposed.The feed structure consists of four parts: a multi frequency feed array,a feed array support plate,a feed load box and a connecting frame.The feed structure is composed of a honeycomb sandwich plate and an aluminum alloy truss.Optimization of feed structure optimization includes :the body part into the horn antenna structure to feed the star;merge the repeated load;cancel the heavier connection frame;the structural form of the honeycomb sandwich plate;the layout of the feed box.The overall quality of the feed structure is reduced and the space utilization is improved.The finite element model of feed structure is established,and the shell element of the feed structure is divided by quadrilateral element;honeycomb sandwich plates are simulated using sandwich theory;the hinge is simulated by Bush element.The modal analysis of the feed structure and the unfolded state is carried out,and the frequencyresponse analysis of the static state and the dynamic response analysis are carried out.The results of mechanical properties show that the strength and stiffness of the feed structure meet the design requirements.The simulation platform of the dynamic model of the sounding rocket flight process is established in the Multi-body dynamics simulation software ADAMS.Firstly,the reference coordinate system of sounding rocket is defined,and its force is analyzed.Secondly,establish the dynamic sounding rocket model in ADAMS software,including 3D modeling,definition of force and constraint conditions,the atmospheric wind field input data,calculation equation of dynamic equations,aerodynamic coefficient.An equivalent method is presented to simulate the change of the mass and mass of the rocket.Finally,the whole flight process of sounding rocket simulation analysis,three aspects of acceleration,velocity and displacement including sounding rocket,combined with the real data and sounding rocket flight GPS flight simulation results were compared to verify the rationality of the simulation analysis method.The establishment of the simulation platform will be beneficial to the simulation of the coupling between the motion of the mechanism and the attitude of the rocket.