Dynamic Analysis And Structure Optimization For Beam Components Of High Bridge Type Gantry Machining Center

In China machinery industry, machine tool has its own special position, it Provide manufacturing equipment for manufacturing industry, plays an important role in development of nation economy,and enhances comprehensive national strength and state security. For decade, scale of machine tool industry in China had achieved great progress. Now, China has become the biggest producer and consumer country of machine tools. However domestic machine tools are still lack of ability of supply of high-grade machine and international competitiveness. China machine tool industry is large but not strong, which is due to lots of domestic enterprises are still using experience and static design method to design machine tools. With the development of finite element theory, designer generally recognized that the practical utility of using finite element method to design and optimize machine structure, nevertheless the problem that how to ensure the accuracy of machine tool dynamics model still could not be solved. This paper used SDF1016A Gantry Machining Center as research objective, studied with the beam components, and identified the slide guide dynamic stiffness. The purpose of which was to get accurate finite element model, and to provided the foundation for dynamic optimization designing. Mainly research contents of this paper included:(1). Summarized the parameters identification methods of equivalent dynamic model on mechanical joint surface. Indicated the availability of the method based on model updating, which is finite element modal analysis combining with experimental modal analysis.(2). Used Pro/E and ANSYS Workbench to perform collaborative simulation. Considering the guide joint surface parameters, constraints modal of beam components and spindle box was analyzed. The weak spot of the beam components and easy stimulated modal order numbers were find by analyzing the natural modal attributes and steady-state response.(3). According to the experimental conditions, LMS Applications for Noise and Vibration Testing was used in hammer modal test for spindle box. Four mode natural frequency and mode shapes can be get from result of test analysis. And the result can accurately match with finite element analysis. (4). Used ANSYS Workbench to correct dynamic stiffness parameters of the slide guide joint surface. The correction used the dynamic stiffness parameters of slid guide joint surface as the design variables points and four mode natural frequencies as the multiple targets. And it can update the dynamic stiffness parameters of slide guide equivalent dynamic model.(5). Put forward improvements for the spindle box weak parts by size optimization. Using five structure parameters as design variables, the improvements reduced the mass of the structure and increased the first natural frequency without any increment in first order amplitude. Comparing with previous structure, the dynamic performance of the improved structure is better.