Optimum Design Of Frame Structure Of Longmen CNC Machine

Gantry machining center has the processing large span, high efficiency, good stiffness, can obtain high machining accuracy and surface quality of components, which are widely used in the manufacture of large parts. To a large extent,static and dynamic performance of parts of the gantry machining center determines the processing performance of the gantry machining center. This paper takes the fixed beam gantry machining center as the research object and conducts the finite element analysis and optimization by the finite element analysis software ANSYS Workbench.The main content of this thesis is as following:1. By using the Workbench finite element analysis software, a new type of beam stiffened plate structure combining arch with vertical and horizontal ribs was designed based on the structural bionic of tortoiseshell. Firstly, the arrangement of the structure of stiffened plates was designed according to the stress distribution nephogram of beam without stiffened plates structures and the structural bionic of tortoiseshell. Then redundant quality of beam structure was removed by using the topology optimization technique. After the stiffened plate structure was determined, the critical dimensions of beam were optimized by using sensitivity analysis to achieve the purpose of the optimization of beam. All of these were based on the performance index such as deformation, weight and the inherent frequency of the beam. Compared with that of the prototype beam, the performance of the optimized beam with a new structure of stiffened plates had been improved obviously.2. By using the Workbench finite element analysis software, a new type of column stiffened plate structure was designed, the critical dimensions of beam were optimized by using sensitivity analysis to achieve the purpose of the optimization of beam.All of these were based on the performance index such as deformation, weight and the inherent frequency of the column.Compared with that of the prototype column, the performance of the optimized column with a new structure of stiffened plates had been improved obviously.3. Based on virtual material method, a layer of virtual material was added between beam and column, then the gantry framework was analysed with statics analysis and modal analysis. Through the comparison and analysis, the performances of gantry frame significantly had been improved obviously.4. For the beam with a new type of stiffened plate structure combining arch with vertical and horizontal ribs, two forms of the beam arrangement of rails were discussed. Firstly, two beams were modeled. Then the stress state of the two beams were determined respectively through the mechanical analysis of the beam. Finally, static analysis of the two beams was done by using the Workbench finite element analysis software.The results showed that matching the form of guide rails arrangement with parallel in the vertical direction up with the new structure of the inner ribs had a more excellent performance.