Research On Mechanism Of Beat Vibration Of A Solar Array Structure Under Docking Condition

The solar array is the receiving device of spacecraft energy.Its main function is to convert solar energy into electrical energy,so as to ensure the continuous operation of the spacecraft.Due to the limitation of the launch weight and the requirement of the expansion mode,the solar array structure has the characteristics of large span,light weight,low stiffness and weak damping,which results in the structural dynamic characteristics of the solar array structure showing low frequency and modal density.These structural characteristics determine the complexity of the vibration,so it is difficult to reduce the vibration of the solar array once it is stirred.Beat vibration is a kind of special periodic vibration,which can make the solar array fatigue damage,reduce the service life,reduce the power generation efficiency,and affect the orientation precision and stability of spacecraft attitude.Therefore,it is necessary to restrain the beat phenomenon caused by the solar array,the main purpose of this paper is to analyze the cause of the beat phenomenon of the solar array structure in docking between spacecraft and space station,and to reduce the impact of beat vibration on the solar array,the main contents are as follows:Firstly,based on the dynamic characteristics of the solar array structure of a space station,the finite element simplified model of solar array is established by using Hypermesh software.Secondly,by using the Abaqus software,the static analysis,modal analysis and dynamic analysis of the finite element simplified model of solar wing are carried out.,It is found that the beat vibration phenomenon exists on the solar array uplift mechanism and the flexible battery array.Finally,using MATLAB software to write a fast Fourier transform program,the time domain data of the beat vibration frequency domain analysis.Through the above analysis,and according to the beat vibration evaluation method and the solar array finite element model of the first 30-order modal contrast,the following conclusions are drawn: the cause of the beat vibration phenomenon of the Y-direction displacement of the flexible battery array is due to the superposition of the 25-and 26-order modes The reason for the beat vibration phenomenon of the z-direction displacement of the solar array uplift mechanism is due to the superposition of the 15-and 18-order modes of the solar array: the cause of the multi-source beat phenomenon caused by Y-direction displacement of the solar array uplift mechanism is due to the superposition of the 14-order,15-order and 18-order modes of the solar array.In order to weaken the beat vibration phenomenon of solar array structure,the influence of the structure parameters of solar array on the phenomenon of the beat vibration is explored by using the control variable method.Aiming at the beat vibration phenomenon caused by the flexible battery array,this paper mainly studies the preload of tension rope,the influence of the modal damping of the solar array structure and the spring stiffness of the load-carrying mechanism on the beat vibration phenomenon of the flexible battery array shows that the increase of modal damping can eliminate the beat vibration phenomenon,and the increase of preload will only weaken the beat vibration phenomenon and can not be eliminated.T he spring stiffness of the load-carrying mechanism has little effect on the beat vibration phenomenon of the flexible battery array.Therefore,in the design of the tension rope,as far as possible to increase the preload,and appropriate to increase the structure of the modal damping,which is conducive to weakening the beat vibration phenomenon of flexible battery array.Aiming at the beat vibration phenomenon caused by the uplift mechanism of the solar array: Due to uplift mechanism is equivalent to Timoshenko beam,so the influence of the beam section parameters on the beat vibration phenomenon of the uplift mechanism is investigated,and the conclusion is drawn that the increase of beam section area will weaken the beat vibration phenomenon caused by the z direction.The inertia moment of beam will weaken the beat vibration phenomenon caused by the y direction.The increase of beam Yang modulus will weaken the beat vibration phenomenon caused by the y direction and z direction,therefore,in the design of beam structure,in the allowable range,the beam section area and Young's modulus of beam can be increased,and the inertia moment of beam is reduced,It is benefit to weaken the beat vibration phenomenon of uplift mechanism.