Design Theory Analysis Of Converter Trunnion Ring And Torque Bar

Modern converters are heavy equipments of large volume, large tonnage and complicated spatial structural shapes. They are running under impact heavy loading and in high temperature environment. The existing structural design theory is incapable of analyzing of the spatial stress and deformation of converters. The three-dimensional nonlinear finite element technique with full size and full-shape of converters is required to calculate the thermo-mechanical coupled stress and deformation, in which the computational modeling is heavy workload and long computing cycles by professional computing staff. It is too hard to an ordinary design engineer. Such a situation has severely restricted the independent innovation of large-scale converter design.This dissertation presents new design theories for two key equipments of converter, the torque bar with variable cross-sections and the water-cooled trunnion ring with single box and dual-chamber cross-sections. They are suitable for ordinary design engineers.A theoretical modeling of the torque bar with variable cross-sections is established on the basis of the elementary elasticity theory and the torsional vibration theory. The analytical expressions of stress, strain and vibration are derived. The comparisons with the numerical solutions obtained by the full-size three-dimensional finite element method illustrates that the theoretical solutions have relatively high accuracy and can be applied to the design calculation of bar strength, stiffness and vibration property.A bending and twisting mechanical modeling of the water-cooled trunnion ring with a single box and dual-chamber cross-section is established based on the closed thin-walled bar constraint torsion theory. The analytical expressions of internal force, mechanical stress, axis deflection, rotation angle as well as torsion angle in any section of the trunnion ring are derived under different mechanical loads, such as concentrated force, distributed force, bending moment and torque. The comparisons with the numerical solutions obtained by the full-size three-dimensional finite element modeling illustrate that the theoretical solutions are the correct expression of the complex variation of the stress and deformation and have relatively high accuracy. It can be applied to structural design of the water-cooled trunnion ring based on the mechanical loading.The double-linear theory is presented to obtain the theoretical three-dimensional temperature field of the water-cooled trunnion ring in radial, axial and circumferential directions according the heat radiation characteristics of the large volume converter on the relatively small trunnion ring. The analytical expressions of spatial temperature distribution are derived. The comparisons with the numerical solutions obtained by the full-size three-dimensional finite element modeling illustrate that the theoretical solutions have relatively high accuracy and are the correct expressions of the complex variation of spatial temperature.A thermo-stress and thermo-deformation modeling of the water-cooled trunnion ring with a single box and dual-chamber cross-section is established based on thermoelsticity and the force method of structural analysis. The analytical expressions of spatial thermo-stress and thermo-deformation distribution are derived. The comparisons with the numerical solutions obtained by the full-size three-dimensional finite element modeling illustrate that the theoretical solutions have relatively high accuracy to meet engineering requirements and are the correct expressions of the complex variations of spatial thermo-stress and thermo-deformation.By the applications of the bending and twisting mechanical modeling, the double-linear theory, and the thermo-stress and thermo-deformation modeling of the water-cooled trunnion ring with a single box and dual-chamber cross-section, the theoretical solution method of the thermo-mechanical coupled stress and deformation is established by the sum of the corresponding stress and deformation components of mechanical loadings and thermo-loadings. The comparisons of the theoretical solutions with the numerical solutions obtained by the full-size three-dimensional finite element modeling show that the theoretical solutions have relatively high accuracy to meet engineering requirements and are the correct expressions of the complex variations of spatial thermo-mechanical coupled stress and deformation. Kspecially, the theoretical distributions of spatial thermo-mechanical coupled deformation are in high calculation accuracy.The stress and deformation expressions presented in the dissertation are all the analytical expressions. They are simply to calculate hy the designed computer programming, and easy to be applied by ordinary design engineers. Hence, the calculation and design cycles should been shorten greatly.