Masters Theses


Detection of discontinuities in friction stir welded components.


"This work looks into the detection of two major types of flaws occurring in friction stir welds - advancing side wormholes and root side kissing bonds. The latter being a laminar type of defect, located towards the root of the weld, is more difficult to detect using nondestructive methods. Butt weld samples from a design of experiment matrix with imposed skin-to-skin gaps of known width at the joint were destructively examined and the discontinuities found in them were catalogued. A relationship defining the process parameter limit for wormhole-free welds is established. Further, samples from another design of experiment matrix of wormhole-free welds were nondestructively examined for root side kissing bonds using relatively low frequency eddy current. A statistically significant correlation is established between height of kissing bond and corresponding normalized reactive voltage. Finally, the detection capability of the eddy current method is quantified using two methods - Monte Carlo simulation and probability density functions of normalized reactive voltage for zero and non-zero flaw conditions. The latter approach provides a relationship between flaw size and detection capability"--Abstract, page iii.


Richards, Von

Committee Member(s)

Liou, Frank W.
Krishnamurthy, K.


Mechanical and Aerospace Engineering

Degree Name

M.S. in Manufacturing Engineering


Boeing Company
U.S. Air Force Research Laboratory (Wright-Patterson Air Force Base, Ohio)


University of Missouri--Rolla

Publication Date

Summer 2006


xiii, 72 pages


© 2006 Harsha Jyoti Phukan, All rights reserved.

Document Type

Thesis - Citation

File Type




Subject Headings

Eddy currents (Electric)
Friction welding
Nondestructive testing
Welded joints -- Testing

Thesis Number

T 9037

Print OCLC #


Link to Catalog Record

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