摘要
基于等效热—力载荷建立了Ti6Al4V合金超声振动车削三维有限元模型,将切削过程等效为机械效应和热效应对工件表面的循环作用,通过数值计算确定了力—热载荷分布形状、强度及其在超声振动切削中的变化规律。通过试验获取了Ti6Al4V合金超声振动车削表面的残余应力,验证了等效热—力载荷模型的可靠性。基于上述模型,通过控制变量分析了微量润滑与液氮冷却方式下,冷却与润滑效应对超声振动车削表面三维残余应力分布的影响规律及机理,结果表明,不同冷却润滑方式下,钛合金超声振动切削表面均可以产生残余压应力场,其中,切削力是影响残余压应力及作用深度的主要因素。切削液润滑效应会降低刀具与工件表面的摩擦和切应力,导致残余压应力减小,而冷却效应主要通过改变工件材料的变形抗力,进而改变切削力,对工件表面残余应力产生间接影响。以液氮为代表的强力冷却介质可以显著降低切削温度,进而提升切削过程中工件材料的变形抗力和切削力,从而导致切削表面残余压应力增大。
The article presents a 3D finite element model of Ti6Al4V alloy ultrasonic vibration turning based on an equivalent thermal-mechanical load.The cutting process involves the cyclic interaction between mechanical and thermal effects on the workpiece surface.Numerical calculations determine the shape,intensity,and variation of force-thermal load distribution in ultrasonic vibration cutting.Experimental verification is conducted to obtain residual stresses on the surface of Ti6Al4V alloy during ultrasonic vibration turning.Based on this model,this study analyzes the influence mechanism of cooling and lubrication effects on three-dimensional residual stress distribution on surfaces during ultrasonic vibration turning under controlled variables such as minimal lubrication and liquid nitrogen cooling methods.The results indicate that different cooling-lubrication methods can generate residual compressive stress fields on titanium alloy surfaces,with cutting force being a major factor affecting both the magnitude and depth of residual compressive stress.The lubricating effect reduces friction between the tool and workpiece surface,decreasing cutting forces and resulting in reduced residual compressive stress.The cooling effect primarily affects the workpiece′s deformation resistance by changing its material properties which indirectly influences cutting forces.Strong cooling media like liquid nitrogen significantly lowers cutting temperature,enhances deformation resistance during machining processes leading to increased cutting forces thus causing higher residual compressive stresses on machined surfaces.
作者
王进
刘国梁
郑金滔
王德祥
刘富豪
Wang Jin;Liu Guoliang;Zheng Jintao;Wang Dexiang;Liu Fuhao
出处
《工具技术》
北大核心
2024年第11期49-56,共8页
Tool Engineering
基金
国家自然科学基金(52375446,52005281)
山东省自然科学基金(ZR2020QE181)。
关键词
等效热—力载荷
超声振动车削
三维残余应力
equivalent thermal-mechanical loading
ultrasonic vibration turning
three-dimensional residual stress
