拉伸装夹对航空框类零件加工变形影响的有限元分析

拉伸装夹可以改变已加工零件表面的残余应力分布状态,使其向残余压应力的方向转化,这对于提高航空零件的疲劳性能非常有益。但是,对于航空薄壁件来说,由于其结构刚性差,装夹方式不当易引起较大的加工变形,从而影响到其加工精度。本文采用有限元分析方法,模拟分析了拉伸装夹方案对薄壁件加工变形的影响。在保证已加工表面产生所需残余压应力的前提下,从控制薄壁件加工变形的角度出发,对拉伸装夹方案进行了优化。结果表明,采用拉伸装夹对于框类零件加工同样适用,为减小加工变形,拉具和拉撑间距应尽量大,拉伸力尽可能小,拉伸位置尽量放在刚性较强的面上。

Finite Element Analysis of Stretched Fixation Effect on Machining Deformation of Frame-Shaped Components

The stretched fixation(SF) can change the residual stress distribution on the machined work surface and improve the fatigue performance of the work,so it has a practical value in machining aero components.However,for frame-shaped components with thin walls(FSCTW),SF has a great effect on the machining deformation because of the poor rigidity.As a result,it is important to make clear its effect when SF is used to machine FSCTW.Finite element models are established to show the effect of SF on machining deformation of FSCTW.Simulation results show that SF can be used to machine FSCTW.To decrease the machining deformation,it has to decrease the fixtation force,to lengthen the distance between stretching supports and to locate the sttetching supports on the wall with high rigidity.