Analysis And Optimization Of Radiation And Scattering Characteristics Of Underwater Vehicle Based On FEM-IFEM Coupling Method

Underwater vehicle,as an important Marine structure to realize the exploration of Marine resources,Marine information survey,underwater detection and even ocean-water combat,plays a significant role in both civil and military applications.Due to special needs,its sound hidden performance is very important.With the development of sonar detection technology,the acoustic performance of underwater vehicle is more and more demanding.Therefore,it is of great theoretical and engineering significance to analyze the acoustic radiation/acoustic scattering characteristics of underwater vehicle vibration and optimize its acoustic design.This paper,aiming at analyzing and optimizing the acoustic performance of underwater vehicle,based on the finite element(FEM)and infinite element(IFEM)coupling method and the secondary development technology of ABAQUS,a commercial finite element software,respectively carry out the analysis and research of the characteristics of acoustic radiation of stern frame vibration of underwater vehicle and acoustic scattering of no appendage structure,and taking the conical shell and double spherical crown shell structure as objects,combined the ABAQUS software and ISIGHT optimization software,using the hybrid optimization algorithm,realizes the optimization design of acoustic radiation and acoustic scattering respectively.The main research ideas are as follows:From the problem of acoustic analysis and optimization in infinite domain,this paper firstly introduces the coupling method of finite element and infinite element,the secondary development technology of ABAQUS based on PYTHON language,and the relevant theories of optimization,laying a foundation for the research of acoustic analysis and optimization of the out-field.And then taking the cone-shell structure as object,this paper studied the acoustic radiation characteristics of typical stern structure of underwater vehicle,in which part realizes the program design of acoustic analysis of vibration of conical shell firstly based on the PYTHON language in the ABAQUS,and realizes the parametric analysis of the structural forms and material properties in the structure of longitudinal reinforcement,ring ribs,half cone Angle,shell thickness and so on,obtaining their influencing rules on the characteristics of vibration acoustic.Furthermore,the influence of composite materials on the stern vibration acoustic characteristics is also studied,including numerical analysis and experimental analysis of the vibration acoustic radiation of typical frame structure,and the vibration acoustic characteristic analysis of composite materials of stern structure.In addition,taking the spherical-cylindrical-cone shell composite structure is as the object,the acoustic scattering characteristics of underwater vehicle with typical no appendage structure are analyzed.The work includes that realizing the routinization of calculation analysis problem about the acoustic scattering of spherical-cylindrical-cone shell structure with no appendage structure based on the secondary development technology of ABAQUS.And build on that,the sound scattering characteristics of rigid and elastic,with or without sound absorbing layer structure with no appendage are compared and analyzed,and then analyses the variation rules of acoustic scattering characteristic of no appendage structure while adopting composite materials structure of different overlay laminate angles.Based on the characteristics analysis of acoustic radiation and acoustic scattering about the typical structures mentioned above,this paper finally takes the reinforced conical shell and double spherical crown cylindrical shell structure as research object,and takes the sound pressure at the far-field point of acoustic radiation and the target intensity of far-field sound as the optimization goal respectively,combined with ABAQUS and ISIGHT optimization software,using the hybrid optimization algorithm to separately carry out the study of the optimization design about the acoustic radiation of reinforced conical shell and acoustic scattering of double spherical crown cylindrical shell structure.The conclusion can be used to provide some reference and help for the improvement of sound hidden performance of new underwater vehicle.