Abstract: Multi-satellite stack represents a launch configuration well-suited for large-scale constellation deployment. Flat-panel satellites are interconnected through load-bearing columns distributed across the upper and lower layers, with axial preload applied to the top layer to compress the assembly. The connection surfaces between satellites introduce typical nonlinear structural dynamic behaviors. Consequently, establishing a reasonable equivalent model and accurately identifying the parameters of the connection surfaces are critical challenges in advancing this technology. To address these issues, this paper employs the constrained substructure super-element method to condense the flat-panel satellite model and the thin-layer element method to develop an equivalent model of the connection surfaces. The substructures are then assembled using constraint conditions to form a simplified finite element model of the entire assembly. A scaled physical model of the multi-satellite stack is designed to validate the finite element model and identify the parameters of the connection surfaces. Modal experiments are conducted to obtain the frequency response function under varying preload torques. The stiffness parameters of the connection surfaces are identified by optimizing the three modulus parameters of the thin-layer element material using the first three modal frequencies of the assembly as objectives. The damping parameters are identified by optimizing the damping coefficient of the thin-layer material using the first-order resonance peak amplitude of the frequency response function as the objective. Finally, the influence of preload torque on the nonlinear dynamic characteristics of the multi-satellite stack is analyzed through changes in the frequency response function.

Key words: multi-satellite stack, thin-layer element, nonlinear dynamics, satellite-rocket connection mechanism, parameter identification