Dynamic Response Spectroscopy (DRS) is an innovative ultrasonic inspection technique for corrosion mapping through challenging coatings, such as Technowrap™, where existing ultrasonic techniques are ineffective. This technique has been designed to look through Technowrap™ composite repairs to measure the remaining wall thickness of the underlying metallic pipe.
A custom DRS probe excites the steel with a range of low ultrasonic frequencies, which pass easily through Technowrap™.
Using advanced algorithms, these frequencies are extracted from the returning signal at each location and used to determine the steel thickness.
The DRS probe travels over the Technowrap™ constructing a map of steel thickness.
Integrity Assessment of Technowrap™ Composite Repairs
Inspection of pipework using the DRS system, through a Technowrap™ composite repair will provide the client with accurate data i.e. the current area and depth of the defect. Measurement of the actual defect size will enable in service integrity assessment of the repaired pipework, especially beneficial for long lifetime repairs where internal corrosion is present.
Comparing the measured size of defect with that assumed in the engineered design will ensure that the repaired pipework can still be considered fit for purpose.
The graph demonstrates the accuracy of the DRS technique in measuring the remaining wall thickness (differentiating between a 5 and 6 mm wall thickness) underlying an 8 mm thick Technowrap™ composite repair.