Research On The Prediction And Control Methods Of Vibration And Noise Of 100m X-BOW Polar Expedition Cruise Shi

This paper takes 100m X-BOW polar adventure cruise ship as the research object,the method of obtaining excitation loads of the main excitation sources on board is studied,the structural vibration,underwater acoustic radiation and cabin noise level are predicted by simulating.The contribution rate of major incentive sources to these responses is studied and the control of structural vibration and cabin noise is also studied.The details are as follows:The finite element model of 100m X-BOW polar adventure cruise ship is established,combined the measured data and finite element model,the propeller excitation loads and main engine excitation loads are backward deduced using the transfer path analysis principle,the calculated response of the backward deduced excitation load is compared with that of the empirical excitation load,by comparison,it is found that the backward deduced excitation load derived in this paper is more suitable for 100m X-BOW new polar adventure cruise ship,which provides reference for solving the excitation load of other similar types of ships.The vibration characteristic of 100m X-BOW polar adventure cruise ship is studied.The wet mode of the whole ship is analyzed,and the structural vibration of the whole ship was measured.Meanwhile,the vibration response of the whole ship is predicted based on the finite element model and backward deduced excitation load.The predicted value and measured value of vibration response are compared,it is found that the trends of frequency response curves of two vibration responses are basically the same,the error of the effective value of vibration response is within 22%,but only 0.24mm/s difference,from the perspective of comfort,this error can be ignored,the validity of finite element model and excitation load is verified.The contribution of these two kinds of excitation to each compartment response is analyzed based on the vibration response simulation of whole ship,it is found that the contribution of the main engine excitation to the cabin response is greater when the cabin is located adjacent or directly above the main engine room,the largest proportion was 81.9%,when the cabin is far from the two excitation sources,the propeller excitation contribution is larger,the largest proportion was 88.9%,it provides reference for the later vibration control of similar ships.The underwater sound field of the X-BOW polar cruise liner was established based on direct boundary method,the low frequency underwater noise of X-BOW polar exploration cruise liner is analyzed,the contribution of two excitation sources to underwater noise is analyzed by the principle of superposition,where,for near-field water noise,at the stern position,the near-field noise is dominated by the acoustic radiation generated by propeller excitation,accounted for 90.3%,at bow position,54.7%of the acoustic radiation was generated by propeller excitation,the acoustic radiation generated by the host excitation accounted for 45.3%,for the far field underwater noise,the contribution of propeller excitation to underwater noise is much greater than that of main engine excitation,the maximum can account for 87.3%.It provides a reference for underwater acoustic radiation control of similar ships.Then,TMD is used to control the loca0 vibration of the whole ship.The local control area is identified as the 7th floor sun deck and the 8th floor viewing platform using modal research.A method for solving local modal equivalent mass is proposed and the local equivalent mass of the two regions is solved,the optimal mass ratio of TMD in the two regions was determined to be 0.05 through frequency response analysis.After the TMD is installed on the model loaded with excitation source,the response at the main vibration frequency decreased from 0.8mm/s to 0.13mm/s at the seventh sun deck area and the response decreased from 0.87mm/s to 0.085mm/s at the viewing platform(back)area on the eighth floor,and the result has certain robustness,it provides a reference method for TMD control of local vibration of structures.The SEA model of 100m X-BOW polar adventure cruise ship is established,the cabin noise of whole ship is predicted by using simulation,the predicted results are compared with the actual ship test results,the error of cabin sound pressure level is less than 10.5%,which meets the engineering error requirements.Room P434 and ROOM X310 are selected as cabin noise control objects,the loss factor digraphs of these two rooms at 1000Hz were established.K path analysis is taken from main engine room to P434 and main engine room to X310,the first 300 transmission paths are analyzed,and the first 50 paths contribute most of the transfer energy.The control theory of front J key transfer edge is proposed based on K path theory,using this theory,the top 5 transfer edges with the largest contribution are selected,by increasing the loss factor of the main transfer edge,cabin noise control effect is achieved,the sound pressure level of P434 at 1000Hz is reduced by 9.2dBA and the sound pressure level of the X310 at 1000Hz is reduced by 10.5dBA,it provides a reference method for optimal noise control of ship cabin.