Transient Thermal-Structural Analysis of Space Structures Consisting of Thin Walled Tubes by FEM
Ding Yong, Xue Mingde, Yao Haimin
(Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China)

Abstract: Space structures consisting of thin walled beams are subjected to incident solar heat flux and emit thermal energy by radiation. To analyze the thermal-structural behavior of these structures, a rectangular tube element with relative degrees of freedom for thermal analysis is proposed in this paper. Temperature distribution along each edge of section of the tube is simulated as linear function, so that the temperature field in cross-section of the tube can be expressed by the average temperature and temperature differences of t he four corners of the section. Finally, a two-node rectangular tube element w as presented for thermal analysis. Each node of these elements possesses three degrees of freedom: the average temperature and two aberrations of temperature i n the cross-section. Therefore, in structural analysis, the initial node forces caused by thermal extension based on the present analysis will include not only axial force caused by average temperature, but also moments caused by temperature aberrations in the cross-section. Using the present rectangular tube element and the circular tube element presented in another paper, the transient thermal and structural response of space structure can be simulated accurately. Numerical calculations for the solar array with shadow demonstrate the effectiveness of the present method.
Keywords: space structure, thin walled tube, temperature field, heat transfer by radiation, finite element method, relative degree of freedom, solar array.