Approximate Analysis And Optimization Design Methods Of Ship Acoustics

SWATH ship has superior performance and has been used by military units in recent years.Our country has built dozens of SWATHs and put them into use,whose displacement ranges from 200? 3000 tons.They have been used for transportation,supervision,survey and research tasks.However,the design and construction techniques of special purpose of large tonnage small waterline catamaran is not consummate,the related technology need to be consummated.This paper studies the basic principle of the boundary element theory and the application in ship acoustic analysis,comes up with the usage of finite element and boundary element method to fulfill ship acoustic design and gives a complete numerical forecast process of catamaran ship's mechanical noise.For the underwater sound radiation analysis of catamaran or multi-hull ship,determining the acoustic near and far field must take the multi-body spacing dimension into account.For the theoretical study of near-field far-field,ship acoustic calculating evaluation standard is proposed and has been taken into a main index in the evaluation of ship radiated noise.Because of the complexity of the catamaran structure,it is difficult to directly put the numerical calculation model into design optimization.This paper puts forward the surrogate model method,in order to be used for optimization design of acoustic structure.This paper selected the underwater cylindrical shell to approximately replace ship compartment.By research and summary of various kinds of approximate model technology,selecting three kinds of agent model to carry on the numerical fitting.Then through the program operation,completed the acoustic structure optimization.For catamaran,size optimization method is proposed in this paper.Through the analysis of the hull structure and cabin with high water tank noise contribution radiation,the paper find the variables with high sensitivity and take them into size optimization.The research use the finite element calculation of the frequency response and acoustic calculation of boundary element,combine the size optimization method,efficiently solved the problem of acoustic structure optimization of the catamaran and provides a set of complete process and methods of catamaran noise prediction and acoustic optimization design.