Detection of friction stir welding defects using specific damping capacity
AssigneeKing Abdulaziz University
InventorsWaheed Sami Abushanab, Essam B. Moustafa
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Abstract
A method for determining a quality of a friction stir welded seam is described. The method involves applying an impact to a welded plate and comparing its damping capacity with the damping capacity of a geometrically equivalent defect-free plate. Damping capacities that differ by a small percent difference indicate that the welded plate is also defect-free. This method is particularly advantageous when dealing with small defects, which produce miniscule changes in natural frequency which may not be measureable.
Claims17
A method for determining a quality of a friction stir welded seam on a welded plate, the method comprising:
- subjecting the welded plate and a geometrically-equivalent defect-free plate to a physical impact to generate a vibration;
- measuring a specific damping capacity of the vibration of the welded plate and the geometrically-equivalent defect-free plate using an accelerometer;
- comparing the specific damping capacity of the welded plate to the geometrically-equivalent defect-free plate;
- and
- determining the quality of the welded seam by the similarity between the specific damping capacity of the welded plate and the defect-free plate,
- wherein the method is non-destructive, and
- wherein the welded plate and the defect-free plate each comprise at least 95 wt % aluminum relative to a respective total weight.
A method for predicting the quality of a friction stir welded seam of a welded plate, comprising:
- calculating a specific damping capacity (ψ) of the welded plate according to the formula
- ψ
- =
- 1
- a
- +
- (
- b
- ×
- ω
- )
- wherein a is −0.0077, b is 5.9×10−5, and ω is the rotation rate in rpm;
- and
- wherein the friction stir welded seam is formed with a constant welding speed in a range of 10-50 mm/min.
Dependencies are inferred from the claim text.