Numerical Analysis of Serrated Chip Formation Mechanism of Titanium Alloy in Ultrasonic Vibration Assisted Machining
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摘要: 超声振动辅助切削(UVAM)作为一种新颖而有效的加工技术,可有效提高工件的切削加工性能,被广泛应用于钛合金切削加工领域。建立热-力耦合模型仿真超声振动切削钛合金Ti6Al4V的瞬态切削过程,研究不同振幅对钛合金锯齿切屑的影响。数值研究结果表明:超声振动与切削速度的耦合作用导致材料出现大塑性变形,且高温是形成锯齿形切屑的主要原因。随着振动振幅的增大,切屑的弯曲半径、锯齿齿距和锯齿化系数均随之增大。本文结论为钛合金超声振动辅助切削的锯齿形切屑形成机理研究提供了参考。Abstract: As a new and effective machining technology, ultrasonic vibration assisted machining (UVAM) can effectively improve the machining performance of workpieces, which has been widely used in the field of titanium alloy machining. A thermo-mechanical coupled model is established to simulate the transient cutting process of titanium alloy Ti6Al4V in ultrasonic vibration assisted machining. The influence of different vibration amplitudes on the serrated chips of titanium alloy is studied. The simulation results show that the coupling effect of ultrasonic vibration and cutting speed leads to large plastic deformation, and high temperature is the main reason for the formation of serrated chips. The bending radius, serration pitch and serration coefficient of chip all increase with the increase of amplitude. The conclusion can provide a guidance for the research of serrated chips formation mechanism of titanium alloy in ultrasonic vibration assisted machining.
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表 1 Ti6Al4V的物理和热力学性能参数[14]
参数 数值 线膨胀系数a/(m·(m·℃)-1) 9.6×10-6 比热容c/(J·(kg·℃)-1) 526.3 密度ρ/(kg·m-3) 4.43×103 弹性模量E/MPa 1.14×105 泊松比v 0.342 热导率η/(W·(m·℃)-1) 6.785 表 2 仿真工艺参数[17]
参数 取值 切削速度V/(m·min-1) 40, 80, 120, 160 进给量f/(mm·r-1) 0.1 工件切削厚度d/mm 2 刀具前角α/(°) 0 刀具后角β/(°) 7 刀尖半径r/μm 25 -
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