The inspection of engineering structures using long-range guided waves is attractive because it is possible to investigate the integrity of a structure up to 100m away from the point of measurement. Because effective inspections require a good understanding of the different vibration modes, finite element modelling is a powerful tool for assessing the feasibility and interpreting the results of guided wave inspections.
- Faster inspection of structures (eg rail).
- Characterisation of flaws using guided waves. Estimation of the depth, circumferential extent and axial extent of flaws.
- Inspection of pipes containing features which distort the signal such as branch connections or pipe bends
TWI pioneered the use of guided waves for industrial pipeline inspection in the late 1980s. The technology offers:
- No need to remove coatings - time/cost saving
- Ability to access 'difficult' areas, eg underground pipes, rail level crossings, etc
- Full volume evaluation
- Large coverage from a single position
Benefits of a combined modelling and experimental approach include:
- New techniques for quantifying flaws.
- Optimised location of probes for defect detection.
- Evaluation of difficult situations, eg branches, joints.
- Development of the technology for new applications such as: rails, storage tanks, bridge suspension cables, bridge pre-stressing tendons
Flaw sizing in pipelines has been an important technical breakthrough, arising from a new technique developed internally at TWI. Using a combination of modelling and experimental validation, the guided wave inspection procedure was improved by enhancing signal processing and inspection procedures to enable estimates of the through wall extent of a flaw (amongst other characteristics) to be determined from guided wave inspections. This has increased the cost-effectiveness of guided waves inspection since flaws can be prioritised and ultimately, fitness-for-service assessments can be made based directly on the inspection results.
For more information, please contact us.
