Abstract
Ultra-large structures serve as core aerospace equipment for missions such as Earth observation and deep space exploration. With dimensions reaching hundreds of meters or even kilometers, they require advanced technologies, including on-orbit assembly, modular integration, and robot-assisted construction, to achieve high-precision structural formation and stable operation. For on-orbit assembly of these structures, critical attention must be paid to their inherent vibration characteristics to evaluate on-orbit service stiffness and stability. Additionally, the static deformation behavior during assembly must be examined to assess the impact of assembly loads on overall structural deformation and surface accuracy. To efficiently evaluate the above-mentioned characteristics, an equivalent scale analysis method for the on-orbit assembly of space-based megastructures is established. Through theoretical modelling, it establishes scaling relationships between mechanical properties-such as structural natural vibration and static deformation-and module diameter dimensions. The numerical results indicate that halving the module diameter results in the natural frequency of the assembled structure increasing by about four times and the static deformation decreasing by about eight times, in agreement with the scaling law. This method enables accurate inference of the full-scale structure's on-orbit mechanical behavior, thereby facilitating precise evaluation of typical mechanical characteristics during ultra-large structure on-orbit assembly.