A Study On The Influence Of Aircraft Landing On Ship Cabin Noise

For some special ships and large surface ships,it is usually to equip with marine helicopters,carrier-based aircraft and other equipment in order to meet the operational requirements.When the aircraft lands on the ship,it will inevitably generate transient shock loads on the ship deck,resulting in a more severe transient shock response in the landing area.The instantaneous shock response of the ship caused severe vibration of the ship.The energy generated by violent vibration is transmitted along the hull structure to the cabins on each deck,resulting in a significant increase in the noise level of the cabins inside the ship,which will interfere with the voice commands during landing.Therefore,this paper focuses on the prediction and protection of impact noise under ship and aircraft landing conditions,and conducts research on the impact of aircraft landing on ship cabin noise.It provides methods and means for cabin noise prediction and control under ship and aircraft landing conditions.Firstly,arriving at the problem of aircraft landing impact noise,a computational method for the impact noise in the full-band ship and aircraft landing area was proposed.This method mainly included a low frequency impact noise calculation method based on the hybrid finite element/boundary element method and a medium and high frequency impact noise calculation method based on the virtual mode synthesis method and the statistical energy method.Then the validity of the method was verified by model tests and simulation calculations.Furthermore,the shock vibration response and the noise source of the aircraft landing area were input into the aircraft landing acoustic evaluation model as the vibration source and the noise source to predict the aircraft landing cabin noise.So far,the cabin noise prediction process under the action of aircraft landing load has been formed.Secondly,this paper analyzed the shock vibration response and the temporal and spatial distribution of shock noise in the helicopter landing area,taking the helicopter landing on a scientific research ship as the research background,and discussed the effects of different landing speeds on the impact response and noise in the helicopter landing area.The research results showed that the deck vibration acceleration response in the landing area of the aircraft was mainly concentrated on the landing positions of the main wheels on both sides of the aircraft when 0～0.1s.And the impact response and noise of helicopter landing area increased significantly with the increase of helicopter landing speed.Thirdly,this paper studied the noise characteristics of the helicopter landing ship cabin in the shock environment,combined with the vibration source and the noise source in the helicopter landing shock environment,and further analyzed the influence of typical cabin position,landing speeds and landing areas on the noise of typical cabins of ships.The research results showed that the ship cabin noise in the shock environment showed a downward trend with the increase of the number of ship deck layers,and the falling speed had a great impact on the typical cabin noise of the ship.Finally,this paper discussed the protective effect of cabin noise in the shock environment of a single helicopter landing,forecasts and evaluates the noise of ship cabins,analyzed the dominant components of noise in each cabin with excessive noise,considers the influence of other noise sources on the ship,and finally put forward pointed acoustic protection measures.The research results showed that the noise caused by helicopter landing was the main factor,accounting for more than 30% of the total noise.Structural optimization had a significant protective effect on cabin noise caused by aircraft landing loads.