The Submarine Structural-acoustic Radiation Optimization Analysis Based On Multidisciplinary Design Optimization Theory

The multidisciplinary design optimization (MDO) is a new technology of late years. The general design principle of MDO can be described as followings: in the total design process, the complicated system can be decomposed into a lot of subsystems which are accordant with the current engineering design organization by decomposition and accordance, and different kinds of disciplinary or subsystems can be integrated by distributed computer net technology, so the optimism for complicated engineering systems can be solved integrally by global optimum.In this paper, the structural-acoustic radiation optimization of a submarine as example, the MDO technology is introduced to analysis the structural-acoustic optimization problem, and using the result to improve the submarine structural-acoustic performance.In this paper, based on the structural dynamic response function and acoustic radiation function, there have discussed the acoustic power sensitivity and structure-acoustic optimization problem. There have built the flow chart of structural-acoustic optimization, by integrating FEM code and BEM code, and the genetic algorithm is used as the strategy in MDO platform. In the optimization function, the acoustic radiation power is defined as objective function. In order to build the relational expression of pressure objective function and power objective function, the sphere enveloping surface model is introduced, with it to evaluate the pressure in acoustic domain.In the numerical example, there have deal with the sizing optimization, stiffeners layout optimization and topology optimization. In the sizing optimization, the stiffened plate in air and finite stiffened double cylindrical shell in water be analyzed. There have analyzed the double cylindrical shell by combining sensitivity information and Taylor formula. In the layout optimization, the stiffeners position is defined as design variable. In addition, there have a trial of applying the modification evolutionary structural optimization method in structural-acoustic topology optimization analysis.In the end, there have deal with the structural-acoustic optimization problem of submarine stern structure using MDO platform and power sensitivity information. After optimization, the acoustic performance is improved. The numerical analysis shows that use the acoustic radiation power as objective function is feasible and efficient.In this paper, some works have been done as fellow:(1) Using conformal transformation theory to analyze the acoustic radiation in a three-dimensional right-angle space, there have analyzed the influence of acoustic power and direction by the boundary property. The result has extended the space of acoustic boundary property.(2) Using the structural dynamic response function and acoustic radiation function, the sensitivity of acoustic radiation power is deduced. In addition, the sensitivity information is used to optimize the structural-acoustic radiation of stiffened double cylindrical shell and submarine structure.(3) Building the mathematical model of acoustic radiation optimization, using the MDO theory, there has analyzed the structural-acoustic optimization process and optimization platform.(4) Integrating FEM code and BEM code, the genetic algorithm is used as optimization strategy in sizing optimization, stiffeners layout optimization and topology optimization.