弱刚度结构件切削加工残余应力的研究

Research on Cutting Induced Residual Stress of Weak-rigidity Parts

弱刚度结构件具有刚度差和材料去除量大等特点,加工过程中产生的残余应力容易导致其加工变形,尤其对于精度要求高且厚度不均匀的弱刚度结构件,更有必要研究切削加工残余应力的影响因素,从而为控制弱刚度结构件的加工变形提供基础。根据正交切削理论和热弹塑性有限元理论建立了切削加工的三维有限元模型,对材料为40CrNiMo的变厚度弱刚度结构件进行了切削加工模拟,对切削过程中的残余应力进行了有限元计算。通过对比不同切削参数情况下残余应力的分布,得到了残余应力随切削参数的变化规律;将变厚度弱刚度结构件的加工分为二次等厚度的切削加工,通过与一次加工得到的残余应力进行对比,得到了2种不同加工工序对变厚度弱刚度结构件的残余应力影响规律。

The cutting induced residual stress of weak rigidity parts has great influence on part distortion, especially those parts that have high precision and uniform thickness. It is necessary that studying the influence factor on residual stress imparted by machining to provide methods to control the weak rigidity parts distortion. The finite element model （FEM） of cutting process was established based on orthogonal cutting theory and thermal elastic-plastic finite element theo- ry. The cutting process of the weak rigidity part of uneven thickness whose material is 40CrNiMo was simulated and the cutting induced residual stress was computed. The influence rules of cutting parameters on residual stress were obtained by comparing the different residual stress distribution coming from different cutting parameters. The weak-rigidity part with uneven thickness was simulated by twice even cutting depth, so the different cutting process influence rules on the part were obtained by comparing the one cutting process.