Vibration Analysis Of Cylindrical Shells With Bases And Internal Raft Isolation System

Low-speed submarine voyage, the submarine noise generated by the machine running, about the overall sound level of 70% of the radiation。These noise which is made by vibration from raft isolation system to pass through to the cylinder. As the real raft isolation system in the submarine is complexed, testing is difficult. We need a convenient estimate method which included with the base isolation system, including the vibration characteristics of cylindrical shell . Around this purpose, this completed the following tasks:1,derived based on the high-order Rayleigh-Ritz principle of shell element and finite strip shell element , compared these elements with the flat, folded plates and shells by the vibration analysis of the performance of numerical examples, and it shows that higher-order element and finite strip element with high accuracy and convergence speed.2,obtained analytic trial function based on the generalized conforming quadrilateral membrane element and plate element, and use the above-mentioned two element based on the assembled of analytical trial function of the generalized conforming quadrilateral flat-type shell element, with the two-parameter method to prove analytic trial function based on the generalized quadrilateral plate element for coordination of the fourth-order plate solution for solving the problem of uniqueness and convergence. The numerical example shows that the present quadrilateral shell element is better than other similar shell elements with higher accuracy and computational efficiency.3,BLZPACK, FEAST, and PARDISO packages, based on the Fortran language, each has developed block-Lanczos method and the use of quantum mechanics, density matrix based on the tube line integral method of calculating the finite element eigenvalue parallel programs. The numerical examples show that these two methods with the accurate and efficient characteristics. At the same time, the finite element program for parallel programs to compare the calculation time of the initial validation of the computational efficiency of parallel programs.4,the use of frequency response function synthesis method with a typical internal floating raft isolation system with a base of cylindrical shell structure of the model, and a two-unit floating raft isolation system calculated on the cylindrical shell structure of base connection points of the displacement and entered into force on the base of comparison, results showed that the frequency response function is integrated with good accuracy.5,in order to verify frequency response function synthesis method for the experimental frequency response function of the correctness of data integration on a single-layer vibration isolation system with internal cylindrical shell structure with a base of experimental study, in which the internal single-layer vibration isolation system the source for the stiffened plate structure, and its frequency response function is measured by the experiment, with the base of the cylindrical structure used in the preceding chapters of the finite element model unit available, experimental results show that the use of experimental data containing noise pollution in a comprehensive, the frequency response function synthesis still has a certain degree of accuracy. This shows that the frequency response function synthesis method can easily deal with experimental data and theoretical frequency response function, frequency response function data, integrated with a wide range of engineering application prospects.