本文關鍵詞：鈦合金高速銑削力試驗與有限元數(shù)值分析，由筆耕文化傳播整理發(fā)布。

南京航空航天大學

碩士學位論文

鈦合金高速銑削力試驗與有限元數(shù)值分析

姓名：易俊杰

申請學位級別：碩士

專業(yè)：航空宇航制造工程

指導教師：劉長毅

20090101

南京航空航天大學碩士學位論文

摘 要

對鈦合金TC4、TC11的銑削力進行了銑削試驗研究，并進行二維切削與三維銑削有限元仿真，通過仿真得出銑削力、銑削溫度，與試驗數(shù)據(jù)進行對比分析。

1從切削熱、工件材料模型、切屑分離、摩擦類型四個方面進行切削有限元仿真，其中切屑分離是切削仿真中最重要的技術，本文以ALE、剪切失效、累進損傷失效三種技術，以不同的研究目的，分別應用于有限元切削仿真研究中。

2通過自適應和累進損傷失效技術建立了帶狀切屑二維切削有限元模型并進行了分析；以鈦合金鋸齒切屑形成機理為研究目的，利用累進損傷失效和網格重劃分技術分別實現(xiàn)了二維鋸齒切屑仿真；建立了超聲振動切削鈦合金二維有限元模型并進行了分析。

3建立了整體硬質合金銑刀銑削鈦合金三維銑削有限元模型，對銑削有限元模型、銑削機理、銑削過程進行了分析，，進行了銑削速度、每齒進給量、軸向切深三個銑削參數(shù)對銑削力的單因素影響分析。

4 對鈦合金TC4、TC11進行了三因素三水平正交銑削試驗，并得到了試驗銑削力結果的極差和非線性回歸經驗公式；為了與試驗進行對比，通過減小銑刀直徑、保持切削參數(shù)不變，建立了改進的三維銑削有限元模型并進行了分析。

二維切削仿真結果表明鈦合金鋸齒切屑的形成機理主要是熱塑性失穩(wěn)導致集中滑移；超聲振動切削能有效的降低切削力和切削溫度；三維銑削仿真結果與文獻結論基本相符。銑削試驗結果表明影響銑削力大小的三因素的重要性順序為：每齒進給量、徑向切深、切削速度；改進的銑削有限元仿真結果與實驗數(shù)據(jù)對比，表明變化趨勢是一致的。這些研究結果有利于更進一步研究鈦合金的切削機理，優(yōu)化加工參數(shù)。

關鍵詞：鈦合金，銑削力，有限元仿真，正交切削，三維銑削，切屑分離，網格重劃分

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Abstract

The milling force of titanium alloy TC4、TC11 milling experiments were investigated; And two-dimensional cutting and three-dimensional milling finite element method (FEM) were researched and simulated, milling force、milling temperature were obtained through the simulation, compared and analyzed with experiment data.

1 Titannium cutting FEM simulation was developed from four aspects :cutting heat、workpiece material model、chip separation、friction type. ALE、shear failure、progressive damage and failure three technologies, with different research purposes, were used to the chip separation in FEM.

2 Through adaptive mesh and progressive damage and failure technology ribbon chip of 2D FEM model was established and analyzed; with research purposes of serrated chip formation mechanism of titanium alloy, using progressive damage and failure and remesh technology to achieve 2D simulation of serrated chip.

3 3D milling FEM model with solid carbide milling cutter of titanium alloy was established. FEM model of milling、milling mechanism、milling process were analyzed, single factors effect of milling force of milling speed、feed per tooth、axial depth were respectively analyzed.

4 Three factors and three levels orthogonal milling experiments of titanium alloy TC4, TC11 were run，range and non-linear regression formula of milling force experiments results were obtained. In order to compare with the experiments, by reducing the cutter diameter, cutting parameters remain unchanged; an improved 3D FEM model of milling was established and analyzed.

2D simulation results show that the titanium alloy cutting serrated chip formation mechanism: thermoplastic instability lead to concentrated slip. Ultrasonic vibration cutting can effectively reduce the cutting force and cutting temperature. 3D milling simulation results are in line with the literature. Experimental results show that the order of importance of three factors affecting milling force: feed per tooth, radial depth of cut, cutting speed. Improved milling finite element simulation results, compared with the experimental data, the trend is the same. The findings of these investigations are in favor of further study on the cutting mechanism of titanium alloy, and optimize the processing parameters.

Key Words: titanium alloy, milling force, finite element simulation, orthogonal cutting,

three-dimensional milling, chip separation，remesh

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圖、表清單

圖2. 1網格掃描過程中節(jié)點的再分配...............................................................................................11

圖2. 2 幾何特征的檢測與失效..........................................................................................................11

圖2. 3累進損傷退化應力應變...........................................................................................................13

圖2. 4 線性損傷演化.........................................................................................................................14

圖3. 1二維正交切削有限元模型.......................................................................................................18

圖3. 2帶狀切屑的形成過程...............................................................................................................19

圖3. 3 0.004s切削應力云圖...............................................................................................................20

圖3. 4刀具溫度分布云圖...................................................................................................................20

圖3. 5切削力曲線..............................................................................................................................20

圖3. 6刀尖與前刀面節(jié)點溫度曲線圖...............................................................................................21

圖3. 7刀具溫度云圖..........................................................................................................................21

圖3. 8刀尖溫度曲線圖.......................................................................................................................21

圖3. 9切削溫度云圖..........................................................................................................................21

圖3. 10切削應力云圖.........................................................................................................................22

圖3. 11切削有限元模型.....................................................................................................................23

圖3. 12 第一塊鋸齒切屑的形成過程................................................................................................25

圖3. 13第一個切屑的形成.................................................................................................................25

圖3. 14鋸齒切屑的形成.....................................................................................................................26

圖3. 15切削力曲線圖.........................................................................................................................26

圖3. 16切削溫度云圖(v=180m/min)..................................................................................................26

圖3. 17切削應力云圖.........................................................................................................................27

圖3. 18切削溫度云圖(v=450m/min)..................................................................................................27

圖3. 19 切削速度v對切削的影響....................................................................................................28 圖3. 20 切削厚度對切削的影響........................................................................................................29

圖3. 21 摩擦系數(shù)對切削的影響........................................................................................................29

圖3. 22 刀具前角對切削的影響........................................................................................................30

圖3. 23 網格重劃分實現(xiàn)切屑分離....................................................................................................30

圖3. 24二維切削有限元模型.............................................................................................................31 vi

南京航空航天大學碩士學位論文

圖3. 25鈦合金正交切削有限元模擬結果.........................................................................................32

圖3. 26鋸齒狀切屑的一個節(jié)塊發(fā)展過程和等效塑性應變(Strain-Effective).................................33

圖3. 27形成鋸齒切屑時的切削力.....................................................................................................34

圖3. 28發(fā)生熱塑性失穩(wěn)時的切屑模擬結果.....................................................................................35

圖3. 29 振動切削模型........................................................................................................................37

圖3. 30 刀具切入工件之前................................................................................................................37

圖3. 31刀具切入工件.........................................................................................................................37

圖3. 32 刀具與工件分離....................................................................................................................38

圖3. 33振動切削切屑形狀.................................................................................................................38 圖3. 34普通切削與振動切削(摩擦系數(shù)μ=0.03)切削力................................................................39 圖3. 35 普通切削與振動切削(摩擦系數(shù)μ=0.3和μ=0.03)切削溫度............................................39

表3.1 TC4的化學成分.......................................................................................................................17

表3.2 TC4熱導率...............................................................................................................................17

表3.3 TC4比熱容...............................................................................................................................17

表3.4 TC4線膨脹系數(shù).......................................................................................................................17

表3.5 TC4彈性模量...........................................................................................................................17

表3.6 TC4泊松比...............................................................................................................................17

表3.7 TC4 J-C模型參數(shù).....................................................................................................................17

表3. 8 YG8刀具的物理和熱力學性能..............................................................................................18

圖4. 1斜角切削有限元模型...............................................................................................................42

圖4. 2斜角切削仿真過程切屑應力云圖...........................................................................................43

圖4. 3銑削有限元模型.......................................................................................................................44

圖4. 4銑削網格劃分..........................................................................................................................44

圖4. 5銑削仿真過程..........................................................................................................................46

圖4. 6銑削溫度圖..............................................................................................................................47

圖4. 7工件加工表面溫度云圖...........................................................................................................47

圖4. 8刀具刀尖三節(jié)點溫度曲線圖...................................................................................................47

圖4. 9銑削力曲線圖..........................................................................................................................48 圖4. 10銑削速度v對銑削力的影響(ap=5mm，ae=0.6mm，fz=0.075mm/z).................................48 圖4. 11每齒進給量fz對銑削力的影響(v=300m/min,ap=5mm,ae=0.6mm)......................................49

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  本文關鍵詞：鈦合金高速銑削力試驗與有限元數(shù)值分析，由筆耕文化傳播整理發(fā)布。