| Description |
xiii, 72 leaves : illustrations ; 28 cm. |
| Summary |
"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, leaf iii. |
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