考虑铣削残余应力的压弯成形仿真计算方法

Simulation Method for Press Bending Considering Residual Stresses in Milling

针对铣削加工引起的残余应力影响工件压弯成形过程中弹塑性应力分布并最终影响成形工件形状精度的问题,提出考虑铣削残余应力的压弯成形仿真计算方法。首先基于弹塑性理论推导了压弯成形应力计算公式,然后建立了考虑铣削残余应力的压弯成形有限元模型,研究了铣削残余应力对压弯成形应力应变分布及回弹的影响规律,采用数值方法建立了考虑铣削残余应力的压弯成形应力计算公式。结果表明:该有限元模型可以用于研究压弯成形应力应变变化规律,低速铣削产生的残余压应力对压弯成形卸载前的应力分布和压弯卸载后上下表面的切向应变影响最大,高速铣削引起的铣削残余应力使得试件压弯卸载后弯曲角度最小,变形程度最大。

Aiming at the effect of the shape accuracy of the formed workpiece and the residual stresses induced by milling on the elastoplastic stress distribution in the press bending process of the workpiece,a simulation method for press bending considering residual stresses in milling was proposed.Firstly,the analytical formulas of the bending stress were derived.Then,the finite element model for the bending considering the induced residual stress in milling was established.The influences of the residual stresses caused by milling operation on the press bending were investigated,and the analytical formula of the bending stress considering the residual stress in milling was established via numerical method.Results indicate that the present finite element model can be used to study the change in the stress-strain distribution in bending.The residual stress generated by low speed milling has the greatest influence on the stress distribution before unloading and the tangential strain on the upper and lower surfaces after unloading.The residual stresses induced by the high-speed milling minimize the bending angle and maximize the deformation of the specimen after unloading.