Based on thermo-elastic-plastic finite element equation for simulating the metal orthogonal cutting process, a coupled thermo-mechanical model with regard to plain strain orthogonal metal cutting is constructed under some assumptions. In addition, several special finite element techniques, such as the chip separation criteria and friction model, have been implemented to improve the accuracy and efficiency of the finite element simulation. A chip separation criterion based on stress failure is adopted to realize the separation of twin nodes. In the end, the machining process of material AISI4340 is simulated, and some results of simulation are analyzed and discussed. This coupled thermo-mechanical model is proved to be right by comparing the simulated results with the experimental data.

The residual stress field of the stress-free aeronautic aluminum-alloy(7050-T7451) in the milling is studied with three-dimension FEM, and four typical tool-routes are simulated and analyzed respectively. According to the optimization goal of NC milling machining, a reasonable route is selected. In the course of this work, the cutting process is simulated using the dynamic loading step, and the removal of material is realized with the “birth and death” element technique. With this calculating model, the accuracy of simulation is improved greatly, and the research result can be used to support the selection of practical technology for guaranteeing the dimension stability of the workpiece during it in NC milling.

基于理论分析与实际模拟计算中所遇到的问题,研究、讨论了切屑分离标准、表面接触、自适应网格等与金属切削加工模型的计算精度、效率密切相关的各项技术,并针对大型工程项目中的有限元计算问题,分析了采用并行结构和网络计算技术的可行性和必要性.在通用商业有限元软件的基础上,运用以上各项技术对航空铝合金材料7050T7451进行了加工模拟.

采用多因素回归正交实验法进行铣削实验,在给出四因素、四水平实验模型中常系数和指数数学推导公式的基础上,建立了特种材料7050-T7451的铣削力模型,为进一步研究航空铝合金数控加工变形提供了可靠的边界条件.