Research On Structural Stress And Anti-vibration Analysis Of Spherical Tank

Compared with other storage vessels, the spherical tank has smaller area surface, lighter weight etc. It is popular in petrochemistry, construction&communication, aviation&seafaring and nuclear industry etc. Construction of spherical tank in China started much late. In spite of fast development, there exists great difference compared with the advanced level of the world, such as design, manufacture, assembly and materials etc.The FEM (finite element method) is popularly used in stress analysis of spherical tank. Due to the complexity of the structure and loads, e.g. the earthquake and wind load, how to deal with the finite element meshing of the model and the load boundary condition to increase the efficiency of design by analysis remains a valuable research subject. In this paper, the methods of dealing with the finite element meshing and earthquake load were investigated by theoretical analysis, numerical simulation and experimental study. The ANSYS secondary development of finite element analysis of nozzle-shell connections of spherical tank was carried out on ANSYS8.1 developing platform. The main work and conclusions are as follows:1) To improve the meshing at the connection of support to shell of spherical tank, HyperMesh6.0, a more efficient FEA (finite element analysis) pre-processing and post-processing software, was applied to mesh the model in this paper. By comparing the FEA results with the stress-strain measurements, it is shown that better meshing can be obtained by applying HyperMesh6.0 to mesh the model. And as a result, better calculation precision can be achieved and calculation time can be shortened.Through finite element analysis and stress-strain measurements of a 2500m~3 spherical tank under hydrostatic test, it is shown that the maximum stress locates at the lowest point of the connection of support to shell which is demonstrated by GB12337-1998, Steel Spherical Vessel, is not always tenable. Through finite element analysis of spherical tanks of various dimensions and under various load conditions, it is shown that the location and value of maximal stress will change with the dimension of structure and load condition. By finite element analysis, the location and the value of the maximum stress can be exactly obtained.2) As the method of calculating natural vibration period of spherical tank in...