Vibration And Noise Analysis For Submarine-launched Missile Based On SEA

Missile will get intermediate frequency excitation, which mainly includes the jet noise and the aerodynamic noise and so on, when flying in the air. These cause the fierce vibration while give a huge acoustic pressure level to the internal body. Under such environment, there may be a disturbance on the internal instrument, and the precision may be seriously reduced. This article has done some research on the dynamic response when the Chinese submarine-launched missile get a intermediate frequency excitation. The traditional method such as FEM, BEM only applies to low-frequency analysis. This article choose SEA and FE-SEA Hybrid analysis the dynamic response.This article has firstly described the basic principles of SEA, and explained the basic assumptions of SEA, then derived the power flow balance equations. This paper outlined the determination of model parameters such like modal density, damping loss factor, coupling loss factor and input power. Then briefly described the general process that how to get dynamics response by using of SEA method. In Va One, the SEA model is established, and the modal parameters have been determined, among which the damping loss factor is determined by experience or empirical formula. The excitation can be determined by simulation, to determine the jet noise, the real jet engine is simplified to a ideal engine, and then can get the force spectrum. To determine the aerodynamic noise, Fluent is used to analyze the unsteady field around the missile, then the surface pressure spectrum can be got. In consideration of the limitation of SEA. The FE-SEA Hybrid method is used to finish mid-frequency response analysis, and SEA method is used to finish high- frequency response analysis. In order to research the damping loss factor's validation, this article also finished the sensitivity analysis.After above analysis, the jet noise has a greater impact at the tail while the aerodynamic noise mainly impacts at the head. And as the frequency increases, the impact of aerodynamic noise gradually increases. The damping loss factor sensitivity analysis shows that different value within experience not impact greatly.