D.H. Lammlein PhD Dissertation - Vanderbilt University
D.H. Lammlein PhD Dissertation - Vanderbilt University
D.H. Lammlein PhD Dissertation - Vanderbilt University
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
CHAPTER II<br />
COMPUTATIONAL ANALYSIS OF FRICTION STIR WELDED T-JOINTS<br />
Computational Analysis of Friction Stir Welded T-Joints; D. H. <strong>Lammlein</strong>, P. A.<br />
Fleming, D. M. Wilkes, George E. Cook, A. M. Strauss, D. R. DeLapp, and D. A.<br />
Hartman; Inter-Institutional Report, <strong>Vanderbilt</strong> <strong>University</strong> and Los Alamos National<br />
Lab, 2008<br />
Misalignment Detection and Enabling of Seam Tracking for Friction Stir Welding; P. A.<br />
Fleming, D. H. <strong>Lammlein</strong>, D. M. Wilkes, G. E. Cook, A. M. Strauss, D. R. DeLapp, and<br />
D. A. Hartman; Science and Technology of Welding and Joining, Vol. 14, #1, 2008.<br />
Note: This chapter presents the entirety of the former document. Additionally, the<br />
portions of the latter relevant to the chapter title are presented.<br />
FEA assessment of FSW Process Geometry for Seam Misalignment Detection<br />
In friction stir welding (FSW), it is commonly know that the process forces<br />
transmitted through the tool are dependent on process parameters and process geometries.<br />
A threshold level of variation in one or more of these process factors during a given weld<br />
will produce a discernible change in the weld process forces. Fleming et al. [1,2] have<br />
demonstrated that, for certain process geometries, weld process force feedback can be<br />
utilized for online weld seam misalignment detection. Seam misalignment detection in<br />
FSW is the estimation, based on some feedback signal, of the lateral tool position with<br />
respect to the weld jointline. It is the belief of the authors that weld process forces differ<br />
based on lateral tool position wherever the conditions beneath the tool vary with lateral<br />
tool position. In the case of the blind type T-joint setup depicted in Figure 30, the<br />
geometry of the welded material and fixturing beneath the tool change drastically with<br />
lateral tool position and these changes are readily detectable in process force data. This<br />
work presents finite element analysis (FEA) as a tool for determining the viability of a<br />
given weld process geometry for seam misalignment detection. Using a simple finite<br />
47