基于热力耦合模型的切削加工残余应力的模拟及试验研究

Finite Element Simulation and Experimental Research of Residual Stresses in the Cutting Based on the Coupled Thermo-mechanical Model

航空精密薄壁零件具有复杂的型腔结构,切削加工残余应力是薄壁零件精度稳定性的重要影响因素,因此必须对切削加工残余应力进行研究。根据热—弹塑性有限元理论,建立切削加工三维有限元模型,对航空铝合金材料Al2A12进行切削加工非线性弹塑性有限元模拟分析,对切削加工表面残余应力进行预测和计算。通过有限元分析,得到不同切削参数、刀具参数条件下的已加工表面残余应力的模拟结果,并对结果进行比较分析,得到各个因素对工件已加工表面残余应力的基本影响规律;进行不同加工工序条件下的切削加工残余应力的有限元模拟,在加工表面已有一次切削加工残余应力分布的情况下,进行二次切削加工有限元模拟,得到二次切削加工对工件已加工表面残余应力的影响规律;并且进行不同切削参数对残余应力影响的试验研究,验证有限元模型的正确性。

Aviation precision thin-walled parts have complex internal structures;and cutting induced residual stresses are important influencing factors for their precision stability.So,it is necessary to research on residual stresses in cutting.According to the thermal-elastic-plastic finite element theory,a 3D finite element model is established,the aviation material aluminum alloy Al2A12 is analyzed in a nonlinear elastic-plastic finite element simulation of orthogonal cutting,and residual stresses on the machined surface are predicted and calculated.By means of FEA,simulation results of residual stresses on the machined surface are obtained when different cutting speeds,tool angles,tool edge radiuses are used.By analyzing and comparing the results,the basic influence rules of various factors on residual stresses are found.Residual stresses induced by different cutting processes are simulated,the influence rules of a secondary cutting on residual stresses are obtained.At last,experiments are carried out to research the influences of different cutting parameters on residual stresses,and the validity of the 3D finite element model is proved.