Community Research and Development Information Service - CORDIS

Verification and application of ultrasonic NDT for marine bonded structures

The objectives of this task were: to extend existing ultrasonic NDT techniques for inspection of adhesively bonded joints during production (QA) and in-service testing for shipbuilding.

Results summary:
- Acceptance and qualification of joints:
During the materials selection NDT was used to characterise the ultrasonic properties of the adhesive materials in order to investigate the inspectability of joints formed with these materials. The difference in ultrasonic properties between rigid and flexible adhesive was investigated and this information was used to assess the testability of new joint designs.

- Inpsection of prototype structures:
During this task NDT was used to inspect the completed prototype and to assess the quality of the bonding. New inspection techniques such as phased array ultrasound and standard NDT equipment was used to inspect a range of bonded structures developed by the BONDSHIP partners.

For example, production butt strap joints for bonded steel and aluminium structures were inspected during manufacture and delaminations in the joint were detected. This is a signficant result since the delaminated areas could act as corrosion sites leading to degradation of the joint performance during the service life of the structure.

The principle results and findings from sections 1 and 2 of this programme of work were:
-- Characterisation of adhesives used for shipbuilding
-- Development of simulation tools to predict ultrasonic testability of bonded structures
-- Application of current and state-of-the-art ultrasonic NDT for the inspection of production prototypes
-- Experience in the development and deployment of new inspection methods (low frequency techniques, and large area rapid scanning) for large bonded structures

- Ultrasonic NDT to assess performance of joints and critical defects
NDT Solutions worked with the University of Southampton and Vosper Thornycroft to support their work on joint performance and crictical defects. This included pre-screening of coupons before mechanical testing and monitoring of joint during testing. NDT was also used to investigate test joints with known defects to assess detection levels. For example, ultrasound was used to measure the change in thickness (displacement) of the adhesive bondload in a joint under load.

Vosper Thornycroft manufactured a test joint with a range of defects that could be encountered during production or in-service. They aim of this work was to assess the sensitivity of the ultrasound inspection techniques to these types of defects. This joint was successfully scanned demonstrating that ultrasonic images of the joint could be obtained:

The principle results and findings from this section of work were:
-- Demonstrated use of NDT for pre-screening of test coupons
-- Successful detection of displacement stresses in adhesive joints during mechanical testing
-- Use of novel ultrasound imaging technology for the detection of simulated production and in-service defects

- Use and exploitation of results
Synergy between BONDSHIP and a UK DTI project (UWASI) led by NDT Solutions was developed. The BONDSHIP project provided many test assemblies for a new inspection system developed by NDT Solutions. The BONDSHIP results has helped NDT Solutions successfully market new ultrasonic equipment and test techniques for the inspection of bonded composite components in the marine and power (wind turbine) industries. This has given NDT Solutions a competitive edge in the inspection of marine components enabling it to further explore the marine and related markets.

Experience gained in the BONDSHIP project has enabled NDT Solutions to successfully approach UK materials suppliers, manufacturers and operators for high performance carbon fibre composite marine structures to demonstrate NDT technologies for production QA and in-service testing.

Related information

Reported by

Dunston Innovation Centre, Dunston Road
United Kingdom
Follow us on: RSS Facebook Twitter YouTube Managed by the EU Publications Office Top