D.H. Lammlein PhD Dissertation - Vanderbilt University

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[58] Schnieder JA, Beshears R, Nunes AC; Interfacial sticking and slipping in the friction stir welding process, Mater. Sci. Eng. A, Vol 435-436 (2006) 297-304. [59] Arbegast WJ; Modeling friction stir joining as a metal working process: Hot Deformation of Aluminum Alloys, (editor Z. Jin), TMS (2003). [60] Williams SW, Colegrove PA, Shercliff H, Prangell P; Intergrated modeling of the friction stir welding process: Proc. of the 6 th International Symposium on Friction Stir Welding, 2007. [61] Schmidt H, Hattel J; Analysis of the velocity field in the shear layer: Proc. of the 6 th International Symposium on Friction Stir Welding, 2007. [62] Sato T, Otsuka D, Watanabe Y; Designing of friction stir weld parameters with finite element flow simulation: Proc. of the 6 th International Symposium on Friction Stir Welding, 2007. [63] St-Georges L, Dasylva-Raymond V, Kiss LI, Perron AL; Prediction of optimal parameters of friction stir welding: Proc. of the 6 th International Symposium on Friction Stir Welding, 2007. [64] Song M, Kovacevic R; Thermal modeling of friction stir welding in a moving coordinate system and its validation: Materials Science Forum 2002, (346-402) 1537- 1542. [65] De Vuyst T, Magotte O, Robineau A, Goussian J-C, Alvise LD; Multi-physics simulation of the material flow and temperature field around FSW tool: Proc. of the 6 th International Symposium on Friction Stir Welding, 2007. [66] Chen ZW, Pasang T, Qi R, Perris R; Tool-workpiece interface and shear layer formed during friction stir welding: Proc. of the 6 th International Symposium on Friction Stir Welding, 2007. [67] Atharifar H, Lin DC, Kovacevic R; Studying tunnel-like defect in friction stir welding process using computational fluid dynamics: Mat. Sci. Tech. 2007, Detroit MI. [68] Shinoda T, Kondo Y; Friction stir welding of aluminum plate: Welding Int., 11(3) (1997), p179-184. [69] Sheppard T, Jackson A; Constitutive equations for use in prediction of flow stress during extrusion of aluminum alloys: Mat. Sci. Tech. 13(3) (1997), p203-209. 46
CHAPTER II COMPUTATIONAL ANALYSIS OF FRICTION STIR WELDED T-JOINTS Computational Analysis of Friction Stir Welded T-Joints; D. H. Lammlein, P. A. Fleming, D. M. Wilkes, George E. Cook, A. M. Strauss, D. R. DeLapp, and D. A. Hartman; Inter-Institutional Report, Vanderbilt University and Los Alamos National Lab, 2008 Misalignment Detection and Enabling of Seam Tracking for Friction Stir Welding; P. A. Fleming, D. H. Lammlein, D. M. Wilkes, G. E. Cook, A. M. Strauss, D. R. DeLapp, and D. A. Hartman; Science and Technology of Welding and Joining, Vol. 14, #1, 2008. Note: This chapter presents the entirety of the former document. Additionally, the portions of the latter relevant to the chapter title are presented. FEA assessment of FSW Process Geometry for Seam Misalignment Detection In friction stir welding (FSW), it is commonly know that the process forces transmitted through the tool are dependent on process parameters and process geometries. A threshold level of variation in one or more of these process factors during a given weld will produce a discernible change in the weld process forces. Fleming et al. [1,2] have demonstrated that, for certain process geometries, weld process force feedback can be utilized for online weld seam misalignment detection. Seam misalignment detection in FSW is the estimation, based on some feedback signal, of the lateral tool position with respect to the weld jointline. It is the belief of the authors that weld process forces differ based on lateral tool position wherever the conditions beneath the tool vary with lateral tool position. In the case of the blind type T-joint setup depicted in Figure 30, the geometry of the welded material and fixturing beneath the tool change drastically with lateral tool position and these changes are readily detectable in process force data. This work presents finite element analysis (FEA) as a tool for determining the viability of a given weld process geometry for seam misalignment detection. Using a simple finite 47
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FRICTION STIR WELDING OF SPHERES, C
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TABLE OF CONTENTS TABLE OF FIGURES
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Appendix ..........................
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Figure 16: Left(FE streamline), Mid
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Figure 51: A thermal camera image t
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for a similar conventional weld (3/
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Figure 102: Tapered retraction proc
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setting are indicated. Note that st
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Unsupported welds of this kind with
Page 19 and 20: Figure 157: A thermal camera image
Page 21 and 22: ottom sample is a tungsten inert ga
Page 23 and 24: N - newton (force unit) n - visco-p
Page 25 and 26: INTRODUCTION Friction Stir Welding,
Page 27 and 28: educed conduction lengths. In small
Page 29 and 30: CHAPTER I LITERATURE REVIEW: COMPUT
Page 31 and 32: frictional condition at the interfa
Page 33 and 34: contact. The contact area can inclu
Page 35 and 36: For horizontal sections, a heat inp
Page 37 and 38: (1.11) where r p is the probe (pin)
Page 39 and 40: This efficiency term, η pd , is kn
Page 41 and 42: The heat input on the tool surface
Page 43 and 44: The added complication of these met
Page 45 and 46: Figure 5: Lateral cross sections of
Page 47 and 48: Flow stress in aluminum alloys is d
Page 49 and 50: Figure 8: Three flow fields a) rota
Page 51 and 52: and post-weld cool-down. This model
Page 53 and 54: Williams et al. [60] use a 2D-axisy
Page 55 and 56: Figure 16: Left(FE streamline), Mid
Page 57 and 58: Figure 18: Temperature contour over
Page 59 and 60: Figure 22: Temperature distribution
Page 61 and 62: Figure 24: Lateral velocity contour
Page 63 and 64: Figure 26: Experimental(white) vers
Page 65 and 66: Figure 28: Top view schematic of tu
Page 67 and 68: [5] Taylor RE, Groot H, Goerz T, Fe
Page 69: [41] Heinz B., Skrotzki B., Eggler
Page 73 and 74: Figure 30: Blind t-joint setup with
Page 75 and 76: Figure 33: Process forces and later
Page 77 and 78: Figure 35: Experimental Welds, Axia
Page 79 and 80: Figure 37: FEA boundary conditions
Page 81 and 82: A 4500 N axial force is applied eve
Page 83 and 84: axial force with lateral offset dur
Page 85 and 86: Figure 42: Contour plot of von Mise
Page 87 and 88: Figure 44: Deformation contour for
Page 89 and 90: Figure 46: Quarter-plate model for
Page 91 and 92: Figure 49: Contour plot of deflecti
Page 93 and 94: where P is the weld power (W), Q is
Page 95 and 96: Figure 52: Fluent CFD model zones.
Page 97 and 98: Figure 55: Thermal contour of weld
Page 99 and 100: Figure 59: Thermal contour of weld
Page 101 and 102: Figure 61: Velocity vectors for 0.0
Page 103 and 104: Figure 65: Contour of velocity magn
Page 105 and 106: CHAPTER III THE APPLICATION OF SHOU
Page 107 and 108: Figure 66: A shoulder-less, conical
Page 109 and 110: Figure 68: Typical axial(Z-axis) fo
Page 111 and 112: Figure 71: 90° conical tool macros
Page 113 and 114: Figure 75: Run 3, 80° conical tool
Page 115 and 116: Figure 79: (90º tool) Ultimate ten
Page 117 and 118: Figure 83: (90º tool) Lateral forc
Page 119 and 120: Figure 87: (80º tool) Lateral forc
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The Eulerian, finite volume, CFD so
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Figure 92 shows the increasing elem
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Figure 91: CFD model geometry consi
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Figure 95: Lateral cross-section of
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Figure 96: Attempts a probe tapered
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CHAPTER IV THE FRICTION STIR WELDIN
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applications for its high strength
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Figure 97: Experimental weld sample
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Figure 99: Split protrusion type de
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with a cupped recess. It is however
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of tapered retraction (i.e. move th
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The adjustments in vertical positio
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manners the assigned depth was main
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Figure 108: Lateral macrosections f
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Figure 110: (Supported, cupped tool
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apparent strength of 26% parent whi
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with a 100º conical tool (0.025”
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Figure 119: Macrosection view of an
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and tooling. Torque is highly depen
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locally in proportion to the local
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Figure 126: (threaded tool) Contour
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Figure 128: (conical tool) Geometry
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Figure 131: (threaded tool) Lateral
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The results presented here show tha
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Figure 136:(from left: Tapered retr
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[8] Metallurgical analysis of ablat
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CHAPTER V FRICTION STIR WELDING OF
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Collaboration between Advanced Meta
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eccentricity, the method of interio
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gas tungsten arc welding of small d
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Full penetration welds of 4.2” (1
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Figure 143: The curvature of the pi
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Figure 144: Experimental axial forc
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Together, a fine wall thickness tol
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Figure 147: Axial force history for
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The weld macrosections show complet
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Figure 154: Macrosections of welds
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Figure 157: A thermal camera image
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Figure 159: Average tool shank temp
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471,146 faces. The meshes are fine
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Figure 162: A closeup view of mesh
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4 2 3 4 5 16 " 1.745 2 0.24
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applied heat locally in proportion
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Figure 164: Modeled temperature con
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Page 215 and 216:
Page 217 and 218:
Figure 172: Model pathlines for the
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Figure 174: Model pathlines for the
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later speed setting, the tool welds
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Figure 178: Zoom view of a macro ta
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Figure 180: The superficial appeara
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Figure 182: The rotary welding appa
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Figure 185: A diagram illustrating
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CONCLUSION AND FUTURE WORK Conclusi
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new FSW process environment is reso
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D.H. Lammlein PhD Dissertation - Vanderbilt University

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