Dynamic modeling and thermally induced vibration of the sun-facing beam under gravity gradient

In order to obtain more solar energy, most solar-powered satellites (SPS) adjust their attitude uniformly to maintain solar orientation. As the flexible attachment of the SPS, the dynamic model of the uniformly rotating sun-facing beam is established in this paper. Compared to the previous methods, both gravity gradient and solar thermal radiation are considered. First, considering geometric nonlinearity and thermoelastic deformation, the transverse nonlinear dynamic equation of the sun-facing beam is derived by using the hybrid coordinate method and Hamilton's variational principle. Then, the equation is discretized by using the assumed mode method. Finally, the mechanisms of the effects of the gravity gradient and solar thermal radiation are analyzed, with validation performed by using COMSOL software. The numerical results indicate that the influence of the gravity gradient on the response is harmonic. Solar thermal radiation induces a temperature difference between the upper and lower surfaces of the beam, which causes thermal vibration.