Research On Prediction Method Of Ship Compartment Noise Subjected To Shock Load

Due to the large transient peak sound pressure during an extremely short period, shock noise can cause lots of harms. And corresponding safety criterions about shock noise have been composed all over the world. Because of the complexity, the vibration and noise problems resulting from transient shock have been neglected by most researchers. The generating mechanism and calculating methods of shock noise have not been researched deeply. At present, domestic research on this field has been maintained blank.This paper briefly introduces research status about shock noise at home and abroad, as well as the main problems faced during the exploring process. Simple analysis about the generating mechanism of shock noise is undertaken based on existing results. Performances and classification are presented, especially for characteristics and harmfulness of shock noise on warships.The vibration occupies an important position in the noise prediction, so the whole acoustics can say is vibration. The calculation method and theory of structural vibration and noise prediction are introduced in this paper. Calculation theory of more popular finite element method and statistical energy analysis are mainly introduced, not only the advantages of the two methods are summarized, but also the limitations of the two methods in solving the unsteady impulsive noise prediction are presented.In order to solve the transient shock vibration noise prediction problem, a method named virtual modal synthesis (VMS) is put forward, and the calculation theory is made a detailed derivation. This method is validated through response analysis of the single-skin construction, coupling double plate structure, box structure, and it provides reference for the wide application of this method.The structural response of the XXX ship under impact loading is predicted by the application of virtual modal synthesis method. Through a lot of calculation conditions, the structural response characteristics of the XXX ship under different types of impact loading are analyzed, and the influence of impact loading acting time and impact loading type on the structural vibration velocity and structural vibration amplitude is researched. Finally, steady noise of the XXX ship with outfitting and without outfitting is predicted, and the peak value of cabin transient noise for the ship under a certain impact loading is predicted.