基于应变梯度理论的微切削毛刺仿真研究
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摘要
在微切削过程中,为了更准确地研究材料尺寸效应对毛刺高度和宽度产生的影响,基于应变梯度理论对传统的Johnson-Cook本构模型进行修正,然后通过用户子程序vumat将其导入ABAQUS有限元软件进行出口毛刺仿真。通过仿真结果可知:在考虑材料尺寸效应的条件下,随着切削厚度的增加,剪切变形区内最大应力值会减小,并向不考虑材料尺寸效应时的最大应力值靠近;在考虑材料尺寸效应的条件下,水平方向上的切削力会变大,进而导致出口毛刺的高度值和宽度值均大于不考虑材料尺寸效应时的对应值。
In the micro-cutting process,in order to more accurately study the effect of material size effect on the height and width of the burr,the traditional Johnson-Cook constitutive model is corrected based on the strain gradient theory,and then introduced it into the finite element software ABAQUS by using the subroutine vumat to simulate the exit burr.The simulation results show that taking material size effect into account,the maximum stress value in the shear deformation zone will decrease with the increase of the cutting thickness,and the maximum stress value will be approached when the material size effect is not considered.Taking the material size effect into account,the cutting force in the horizontal direction becomes larger,and the height value and the width value of the exit burr are both larger than the corresponding values when the material size effect is not considered.
In the micro-cutting process,in order to more accurately study the effect of material size effect on the height and width of the burr,the traditional Johnson-Cook constitutive model is corrected based on the strain gradient theory,and then introduced it into the finite element software ABAQUS by using the subroutine vumat to simulate the exit burr.The simulation results show that taking material size effect into account,the maximum stress value in the shear deformation zone will decrease with the increase of the cutting thickness,and the maximum stress value will be approached when the material size effect is not considered.Taking the material size effect into account,the cutting force in the horizontal direction becomes larger,and the height value and the width value of the exit burr are both larger than the corresponding values when the material size effect is not considered.
引文
[1]L K Gillespie,P T Blotter.The formation and properties of machining burrs[J].Journal of Manufacturing Science & Engineering,1976,98(1):66-74.
[2]Schueler G M,Engmann J,Marx T,et al.Burr formation and surface characteristics in micro-end milling of titanium alloys[C]//Burrs-Analysis,Control and Removal,2010:129-138.
[3]Deng W J,Xia W,Tang Y.Finite element simulation for burr formation near the exit of orthogonal cutting[J].International Journal of Advanced Manufacturing Technology,2009,43(9-10):1035.
[4]Guo Y B,Dornfeld D A.Finite element modeling of burr formation process in drilling 304 stainless steel[J].Journal of Manufacturing Science & Engineering,2000,122(4):612-619.
[5]?zel T,Thepsonthi T,Ulutan D,et al.Experiments and finite element simulations on micro-milling of Ti-6Al-4V alloy with uncoated and CBN coated micro-tools[J].CIRP AnnalsManufacturing Technology,2011,60(1):85-88.
[6]李红涛.介观尺度材料力学性能建模及微铣削工艺优化研究[D].上海:上海交通大学,2008.
[7]Shaw M C.The size effect in metal cutting[J].Sadhana,2003,28(5):875-896.
[2]Schueler G M,Engmann J,Marx T,et al.Burr formation and surface characteristics in micro-end milling of titanium alloys[C]//Burrs-Analysis,Control and Removal,2010:129-138.
[3]Deng W J,Xia W,Tang Y.Finite element simulation for burr formation near the exit of orthogonal cutting[J].International Journal of Advanced Manufacturing Technology,2009,43(9-10):1035.
[4]Guo Y B,Dornfeld D A.Finite element modeling of burr formation process in drilling 304 stainless steel[J].Journal of Manufacturing Science & Engineering,2000,122(4):612-619.
[5]?zel T,Thepsonthi T,Ulutan D,et al.Experiments and finite element simulations on micro-milling of Ti-6Al-4V alloy with uncoated and CBN coated micro-tools[J].CIRP AnnalsManufacturing Technology,2011,60(1):85-88.
[6]李红涛.介观尺度材料力学性能建模及微铣削工艺优化研究[D].上海:上海交通大学,2008.
[7]Shaw M C.The size effect in metal cutting[J].Sadhana,2003,28(5):875-896.