Equivalent modeling and thermal deformation analysis of solar array sandwich substrates with composite grid panels

Accurate prediction of thermal deformation in spacecraft solar array substrates is critical for ensuring structural stability and reliability. This study derives an analytical method for the equivalent orthotropic properties of the composite grid panels. To further enhance predictive fidelity, a hybrid modeling approach is proposed that combines analytical methods (AM) with refined finite element methods (FEM) based on extended representative volume elements (E-RVE). Based on this approach, a finite element equivalent model of the solar array substrate was developed to investigate its thermal deformation behavior under spatially uniform cyclic temperature conditions over an orbital-relevant temperature range. Experimental results demonstrate that the proposed approach can effectively predict the thermal deformation behavior of the substrate, with an average relative error of approximately 17%, compared with values generally exceeding 48% for the alternative AM/FEM parameter combinations, corresponding to an error reduction of approximately 65%. Furthermore, the analysis reveals that the substrate’s thermal deformation is closely related to the grid panel layups and the relative density of the honeycomb core. Consequently, the validated equivalent modeling framework provides practical methodological guidance for predicting thermal deformation and optimizing the design of solar array sandwich substrates under under cyclic thermal loading over an orbital-relevant temperature range.