Figure 3 Work Flow
WP-1 This work package will include writing a system specification and procuring samples and a mock-up for procedure development and performance trials. The partner responsible for this is TWI.
Following on from the successful completion of WP- 1, WP’s 2, 3 and 4 will involve the development of sub-sea NDT equipment and techniques and will take place in parallel.
WP-2 Development of sub-sea marinised ACFM system and transducer arrays to operate from a robotic manipulator, accurately deployed by an ROV for the required test component weld configurations
ACFM is a sensitive electromagnetic surface inspection technique that can identify and evaluate surface cracks on ‘as welded’ components. The ACFM transducer (or an array of such transducers) is moved over the component surface in order to detect surface breaking fatigue cracks. In service fatigue cracking represents the greatest threat to offshore structures operating in adverse weather conditions and the cracks are prone to develop and propagate from surface stress raisers such as at the toe (edge) of a weld. The ACFM technique compliments the PA-AUT , because whereas ACFM is a good technique for detecting cracks on uneven (as welded) surfaces, Ultrasonic Testing is a volumetric inspection technique and surface breaking cracks in the weld cap area can be difficult to detect because of the reduced signal to noise ratio.
TSC Ltd is the original developer of the technology together with University College, London. The company will be supported by TWI and the Technical University of Szczecin (PSZ), both of which have strong electromagnetic NDT Sections. Dacon will provide support and input for equipment marinisation.
WP-3 Development of a sub-sea marinised PAUT system to operate from a robotic manipulator accurately deployed by an ROV for the required test component configurations.
Although fatigue cracks often emanate from surface stress raisers (i.e. surface notch), buried defects can also often act as stress raisers and therefore potentially give rise to fatigue cracks when cyclic loading is applied by sea movement, as in the case of an offshore structure. PAUT provides a good solution for sub-sea weld volumetric inspection because the PA probe sweeps an ultrasonic beam through the weld metal over a range of angles thus ensuring that the full weld volume is insonified.
SME Vermon, who are specialists in phased array systems and technique development, TWI, who are a major research organisation in this field and SME Dacon, who will provide input for equipment marinisation will be involved in this work-package.
WP-4 Development of sub-sea marinised LRUT system that can be accurately deployed and set to work from an ROV.
LRUT offers the possibility of inspecting more than one weld from an inspection point, using a ring of ultrasound transducers that is able to orbit a point of energy around the weld circumference. The technique can is sensitive to flaws on both the internal and external surfaces as well a internal flaws. Moreover the welds could be inspected under coatings. The technique could be adopted for continuous monitoring with permanently mounted sensors.
This work package will involve I&T Nardoni, who are an experienced service inspection provider of LRUT to industry and TWI, who invented and continue to developed the technology, equipment, transducers and techniques for a range of industrial applications.
The three NDT technique development work packages will precede the following:
WP-5 Development of marinised robotic manipulators to scan the ACFM and PA-AUT inspection heads on the designated weld test configurations, with vision system for control and visual inspection of welds.
This is a vital WP and the success of the whole project depends on its successful outcome as the specific NDT tests will not be possible unless the manipulators can be deployed (by the ROV) to an exact location on the component and the manipulators function (scan) in their intended manner. However the WP objectives are realistically achievable and the robotic manipulators must be able to be easily deployed from a standard work ROV.
Dacon, which is a diving company with a track record in developing sub-sea manipulators will be responsible for this work-package along with, TSC and TWI who are experienced in designing manipulators for NDT applications.
A work-package for demonstrating the system and the complete SubCTest system will accompany the work:
WP-6 Laboratory & Field trials
The validation of the development activities undertaken by the research organisations in WPs 1, 2, 3, 4 and 5 will be through a number of laboratory and field trials using a set of samples procured in WP- 1 but not used for the development work. Validation procedures for each of the developed NDT technologies will be written by the responsible research organisation in consultation and agreement with the relevant SME responsible for the field trials.
The laboratory trials will be carried out by the research organisations responsible for the specific WP developments and will be witnessed by the relevant SME organisation carrying out the field trials. The SME service companies, I&T Nardoni for the PA-AUT and LRUT, and Dacon for ACFM will conduct the initial field trials at a venue yet to be agreed, although TWI North located in the North East of England has an NDT Diver test and examination tank facility that is ideal for the purpose and could be made available. The TWI Validation Centre based in South Wales and that is independent of the TWI NDT Technology Group will over see the validation trials. The HSE and PSA will (subject to weather and operational conditions and ROV availability) arrange access for the deployment and sub-sea testing of one of the developed manipulators on a production platform. However, if it is not feasible to access a production platform the contingency position will be to use the Diver Tank facility at TWI North.
This work package will also include training activities. The relevant research organisations (i.e. TSC for ACFM and TWI for PA-AUT and LRUT) will train the technical staff of the performing service inspection companies in the project, i.e. Dacon for ACFM and I&T Nardoni for LRUT and PA-AUT field trials. The technical staff from the service inspection companies will therefore be in a position to acquire technology transfer of knowledge through the project research organisations.
The work-package for bringing the results of the project to a wide audience while ensuring that the results benefit the SMEs properly is defined within:
WP-7 Dissemination & Exploitation and contribution to standards. A high level of dissemination will take place particularly during the final 3 to 6 months of the project. The aim will be to maximise the economic benefit to the SMEs as quickly as possible. Following an industry targeted market research, a ‘Plan for the use and dissemination of knowledge (PUDK) will be prepared by TSC and the project coordinator for submission and comment/approval by the project steering committee (PSC). The business plan will detail the most appropriate route for dissemination to benefit the SME participants and will include the publishing of technical papers in appropriate technical and industry journals.
WP-8 Project and Consortium Management. TWI Ltd will act as project coordinator and provide the project management and administration services. Mr Graham Edwards, an experienced and qualified project manager from within the NDT Technology Group of TWI at Abington, Cambridge will be appointed as the dedicated project manager and coordinator on behalf of the SMEs.