Research On Vibration Prediction And Local Structure Optimization Of Tuna Longline Fishing Vessels

With the continuous development of ship structure research,ship operators and national inspection agencies have continuously improved the ship's vibration performance requirements,and the state's close attention to ship vibration problems.As a result,the performance requirements of various fishing vessels are increasingly advanced.A 33.45-meter tuna longline fishing vessel of a shipyard is used as the target ship type in the paper,and the overall vibration prediction and local structure optimization of the tuna longline fishing boat are carried out in combination with the latest ship vibration standard.The dissertation is divided into three aspects: establishing a three-dimensional finite element model of the tuna longline fishing boat;Establishing an overall modal analysis of the different conditions of the tuna longline fishing vessel,and optimizing the local vibration by changing the local structure of the tuna longline fishing vessel.The selection requirements based on the vibration of the new standard tuna longline fishing boat are proposed,and the response value is quickly processed by programming.The main research contents are as follows.Firstly,the research methods of the overall vibration of the ship and the research methods of local vibration are briefly introduced.Secondly,according to the general layout map,basic structure diagram,rib profile diagram,typical cross-section diagram of the tuna longline fishing boat,the first structure diagram and the tail structure diagram are used to establish tuna longline fishing using MSC.PATRAN/NASTRAN pre-processing modeling software.The three-dimensional finite element model of the ship,through the addition of mass points,makes the three-dimensional finite element model of the tuna longline fishing boat closer to the full-load catch,the fishery,the full-loaded fish to the fishery,the full load to the port,the empty port,and the empty port.The load conditions of the five real ships.After that,through the overall vibration prediction of the target ship,the upper deck of the target ship is found to be too large,and the local vibration is too large.For the problem of excessive local vibration of the target ship,the local structure is strengthened,the cabin partition is increased,and the column is reasonably added.The harmful vibrations of the upper deck of the target ship's main engine,and comparing the results,get the best solution.Finally,when calculating the ship's response,it is found that the response calculation result is a huge amount of data,and manual screening is prone to errors.After the results of the response calculation are obtained,the paper is programmed by VB,and based on the requirements of the new standard,the rapid processing of the value of the response calculation result is completed,including the fast extraction of the response value and the automatic calculation of the weighted value.