Thermoelastic-structural Dynamics Analysis Of Spacecraft Structures

The spacecraft periodically enters and exits the illumination area which can absorb the solar thermal radiation and the shadow area in the deep cold space during its service.Therefore,the heat flux received by the spacecraft changes periodically and the transient temperature field is generated in the flexible structure of the spacecraft.Transient temperature field not only causes large deformation of flexible structure,but also causes thermal vibration of flexible structure when it changes dramatically.Thermally induced vibration can also induce attitude disturbance of the spacecraft body,which makes it impossible for the spacecraft to complete its tasks.Therefore,it is necessary to study the thermal vibration of flexible spacecraft structures.First,thermal-structural-elastic coupling equations of the thin-walled circular tube structure subjected to solar heat flux are established based on Hamilton principle and the law of thermodynamics.The fourth-step Runge-Kutta method is used to analyze the thermoelastic-structural coupling dynamic response of the thin-walled tube structure,it is found that the tip-displacements considering strain rate is always less than the tip-displacements without considering strain rate.In addition,it is also find that there must be a specific solar angle,which makes the structure stable when considering strain rate,and the structure is unstable when the strain rate is not considered through the stability analysis of Routh-Hurwitz criterion.Then,considering the strain rate,the dynamic model of rigid-flexible coupling system of spacecraft structure is established.The thermoelastic-structural coupling equation considering rigid-flexible coupling of spacecraft structure is established based on Lagrange principle and thermodynamic law.The displacement dynamic response of flexible structure of spacecraft is solved by separating variable method and weighted residual method.Finally,the attitude disturbance of spacecraft and the displacement dynamic response of flexible structure are analyzed by numerical calculation.It is found that when the damping ratio is fixed,the initial dynamic displacement response amplitude of the spacecraft body decreases gradually with the increase of the sunlight angle,and the angle of the equilibrium position deviating from the initial position decreases.The initial dynamic displacement response amplitude of the flexible structure decreases gradually,and the distance of the equilibrium position deviating from the initial position decreases gradually.Whether the structure is stable or not,the dynamic response amplitude of top displacement considering rigid-flexible coupling of spacecraft-flexible structure is always larger than that without rigid-flexible coupling of spacecraft-flexible structure.And with the increase of time,the difference of its amplitude becomes larger and larger.The stability analysis based on Routh-Hurwitz criterion proves the necessity of considering rigid-flexible coupling of spacecraft-flexible structure.