D.H. Lammlein PhD Dissertation - Vanderbilt University

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conventional tooling and it must therefore be concluded that the conical tool geometry exacerbates XY plane tool deflection and induces force oscillations. The lack of the stabilizing influence of a horizontal shoulder on the material surface is believed to contribute to this deflection. In addition, as compared to conventional tooling, the dynamometer data showed axial (Z) forces (Figure 68) that were lower in magnitude relative to the XY plane forces (Figure 69). The result of this periodic tool deflection was a coarse surface banding as opposed to a fine surface finish. The problem is alleviated at a 4° spindle head angle. Figure 67: XY plane force oscillations were typically present at low spindle head angles with conical welds, presumably due to the lack a horizontal, stabilizing shoulder. The experiment was therefore performed at a 4° angle where this problem did not exist. 84
Figure 68: Typical axial(Z-axis) force data. Figure 69: Typical in plane force data. Conical Inclusive Angle Tests The 80º and 90º conical tools were selected for the experimental weld matrix because they produced the highest quality welds based on surface appearance. Conical welds typically produced advancing side flash and a trough-like surface defect on the 85
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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
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Figure 157: A thermal camera image
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ottom sample is a tungsten inert ga
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N - newton (force unit) n - visco-p
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INTRODUCTION Friction Stir Welding,
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educed conduction lengths. In small
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CHAPTER I LITERATURE REVIEW: COMPUT
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frictional condition at the interfa
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contact. The contact area can inclu
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For horizontal sections, a heat inp
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(1.11) where r p is the probe (pin)
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This efficiency term, η pd , is kn
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The heat input on the tool surface
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The added complication of these met
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Figure 5: Lateral cross sections of
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Flow stress in aluminum alloys is d
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Figure 8: Three flow fields a) rota
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and post-weld cool-down. This model
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Williams et al. [60] use a 2D-axisy
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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 and 70: [41] Heinz B., Skrotzki B., Eggler
Page 71 and 72: CHAPTER II COMPUTATIONAL ANALYSIS O
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: Figure 66: A shoulder-less, conical
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
Page 121 and 122: The Eulerian, finite volume, CFD so
Page 123 and 124: Figure 92 shows the increasing elem
Page 125 and 126: Figure 91: CFD model geometry consi
Page 127 and 128: Figure 95: Lateral cross-section of
Page 129 and 130: Figure 96: Attempts a probe tapered
Page 131 and 132: CHAPTER IV THE FRICTION STIR WELDIN
Page 133 and 134: applications for its high strength
Page 135 and 136: Figure 97: Experimental weld sample
Page 137 and 138: Figure 99: Split protrusion type de
Page 139 and 140: with a cupped recess. It is however
Page 141 and 142: of tapered retraction (i.e. move th
Page 143 and 144: The adjustments in vertical positio
Page 145 and 146: manners the assigned depth was main
Page 147 and 148: Figure 108: Lateral macrosections f
Page 149 and 150: Figure 110: (Supported, cupped tool
Page 155 and 156: apparent strength of 26% parent whi
Page 157 and 158: 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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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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