预应力切削钛合金的有限元分析

Finite Element Analysis of Prestressed Cutting of Titanium Alloy

为揭示预应力切削对钛合金Ti6Al4V加工表面残余应力的调整机理,探讨切削时锯齿形切屑的形成过程,基于预应力切削原理建立了钛合金的预应力切削有限元模型,模拟了0、280 MPa和560 MPa这3种预应力下的锯齿形切屑形成过程以及已加工表面的残余应力分布。结果表明:采用预应力切削方法可以调整钛合金已加工表面的残余应力状态;预应力对锯齿形切屑的形成过程和切屑特征无明显影响;在材料弹性极限内施加越大的预应力,表面层残余压应力效果越显著,次表层最大残余压应力值越高,残余压应力层分布也越深。

In order to reveal the adjustment principle of prestressed cutting of the residual stress of titanium alloy Ti6A14V, and to explore the serrated chip forming process in cutting, a finite element model of prestressed cutting of titanium alloy was established based on the principle of prestressed cutting. The serrated chip forming process and distribution of residual stress to machined surface were simulated at the prestresses of 0,280 MPa and 560 MPa. The simulation results indicate that the status of residual stress on machined surface of titanium alloy can be adjusted in the cutting process by utilizing the prestressed cutting method. Prestress shows an indistinctive effect on the serrated chip forming process and characteristic. Within the elastic limit of titanium alloy, the higher the applied prestress is, the more prominent the compressive residual stress in surface layer is, and the higher the magnitude of compressive residual stress in subsurface layer is, the deeper the laver of comoressive residual stress distribution is.