1. State Key Laboratory of Mechanical System and Vibration, Shanghai JiaoTong University, Shanghai 200240, China;
2. Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240, China;
3. Beijing Mechanical Equipment Institute, Beijing, 100854, China
Abstract:Successive launches of underwater projectiles cause problems of vibration superposition and sudden changes of mass and stiffness of their launch system, and this situation needs to adopt the non-linear method to do shock response analysis.Here, the underwater launch system (ULS) was simplified as a multi-DOF nonlinear time-varying system.The governing dynamic equations of the system were derived with Newton’s second law, where the system’s mass, damping, stiffness and external load matrices changed with variation of time.Non-linear shock responses of the system were numerically solved with Newmark direct integration method.Numerical examples were given using the proposed method.The correctness of the method was verified by comparing the calculated results with those obtained using the finite element method (FEM).The system’s shock response characteristics were analyzed.Finally, a method was proposed to optimize stiffness and damping parameters of the system’s vertical shock isolator.The study results provided an effective analysis means for design and parametric optimization of launch systems’ shock isolators in engineering practice.
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