超声辅助钛合金切削的表面残余应力数值仿真

Numerical Simulation on Residual Stress of Titanium Alloy Surface Aided with Ultrasonic Vibration Cutting

针对钛合金加工后表面残余应力严重影响其使用性能的问题,采用Johnson-Cook失效准则,通过施加边界条件,以非线性有限元技术Abaqus/Explicit建立了钛合金TC4二维正交切削热力耦合切削仿真模型,分析了超声切削和普通切削在不同切削速度下钛合金的切削过程,获得了不同工况下的表面残余应力分布规律。结论表明:钛合金TC4已加工表面层的残余应力是拉应力,沿深度方向由拉应力逐渐过渡到压应力;在相同的切削参数下,超声切削后工件表面的残余拉应力较普通切削时小,最大残余压应力较普通切削时大,且最大残余压应力出现的位置相对较浅。

For the serious influence of machined surface residual stress on titanium alloy performances,with the failure criterion of Johnson-Cook and by the boundary conditions,the two-dimensional finite element cutting simulation model of thermal coupling is established on orthogonal angles of titanium alloy TC4 in virtue of the nonlinear finite element technology Abaqus/Explicit.The cutting process of titanium alloy with different cutting speed through ultrasonic and common cutting is analyzed.And different distribution rules of surface residual stress are obtained under different working conditions.Results show that the tensile stress exists on the surface of TC4 workpiece,and is gradually transformed to the compressive stress along the depth direction.Besides,under the same cutting parameters,compared to that of common cutting,tensile residual stress on the workpiece surface decreases but the maximum compressive residual stress increases,and its position is relatively shallow in the process of ultrasonic cutting.