The Stewart-platform-based bumper plays a critical role in shipborne strap-down inertial navigation systems (SINSs), effectively mitigating shock-induced disturbances to ensure measurement accuracy. Dynamic modeling for the bumper under a huge impact is a key issue in predicting the shock isolation performance of the bumper. In this paper, the dynamic modeling of shock isolation performance for Stewart-platform-based bumpers under huge impacts is proposed and validated experimentally. Firstly, a model of a Stewart-platform-based bumper is established considering the geometric configuration and dynamic parameters of the bumper by calculating the Jacobian matrix, stiffness matrix, damping matrix and mass matrix. Secondly, an analytic simulation of the impact is presented based on the measured impact acceleration, and the impact force on the load is derived according to the non-displacement assumption in the impact stage. Then, the Lagrangian formulation was systematically applied to establish governing equations characterizing the six-degree-of-freedom (DOF) dynamics of the bumper, incorporating both inertial coupling effects and nonlinear shock energy dissipation mechanisms. Afterwards, dynamic equations were solved via the Runge–Kutta method to obtain the theoretical results. Finally, the proposed dynamic modeling and shock isolation performance analysis method was validated via impact experiments for the bumper.

The application of a staged booster system can significantly extend the operational range of a supercavitating vehicle. Booster separation from the main body within the supercavity, followed by its downstream movement and exit from the cavity, constitutes a key process in the realization of this technology. To investigate the hydrodynamic characteristics of the vehicle’s main body during in-cavity booster separation, an unsteady numerical study was conducted using the finite volume method, the Volume of Fluid (VOF) multiphase flow model, and a dynamic mesh technique. The evolution of cavity morphology and the corresponding hydrodynamic characteristics of the main body during the booster separation process were obtained. Furthermore, the effects of the relative separation velocity and separation distance on the hydrodynamic characteristics of the vehicle were analyzed, and the primary mechanisms responsible for the complex variations in hydrodynamic forces were clarified. When the booster separation velocity is not greater than the free-stream velocity, the hydrodynamic forces of the vehicle remain stable. When the separation velocity exceeds the free-stream velocity, the hydrodynamic forces undergo significant changes as the booster moves to a position approximately 0.75~1.0L downstream of the vehicle. A novel numerical approach based on the conventional dynamic mesh technique was employed to simulate two-body separation inside a supercavity, providing a new perspective for future investigations of multistage booster systems for range extension of supercavitating vehicles.