基于多应力耦合的航空框类零件加工变形仿真分析及其控制技术

Simulation and Control of the Machining Deformation of Aeronautic Frame Shaped Workpiece under Muti-Stress Coupling

针对航空铝合金7050-T7451材料框类零件数控加工变形问题,采用三维有限元方法分析了耦合应力对加工变形的影响机理。首先,利用单元生死技术、动态载荷步分别模拟铣削加工过程中材料去除和走刀过程,分析了初始残余应力、装夹应力和铣削机械应力耦合状态下走刀路径对加工变形大小及其分布状况的影响规律。其次,以不同的装夹方案为边界条件,分析了耦合应力对加工变形的影响规律,可为航空结构件加工的尺寸稳定性提供理论指导和工艺策略。

According to the machining deformation of the aeronautic aluminum-alloy （7050-T7451） frame shaped workpiece, the effect rule of machining deformation caused by stress coupling is studied with three-dimension FEM. First, use ＂birth and death＂ element and dynamic load step technique to simulate the material removal and tool path respectively, analyzed the machining deformation and effect rule caused by the tool route under the coupling of initial residual stress, fixturing stress and milling residual stress. Second, analyzed the machining deformation and the effect rule which caused by stress coupling under the different fixturing scheme as the boundary condition. With this model, the research result can be used to support the selection of practical technology for guaranteeing the dimension stability of the aeronautic structure in theory.