The principal objectives of the project are as follows.

(1) To produce and validate four new, novel and unique non-destructive evaluation (NDE) techniques that are specifically targeted at the inspection of GRP pipes, as used in the Oil and Gas industry after installation and throughout their in-service life. The techniques are:

• In plane shearography inspection techniques (OT)
• Sonically stressed thermography inspection techniques (IRT)
• Dry coupled phased array ultrasonic test techniques (PAUT)
• Low energy digital radiography inspection techniques (DRT)

Current techniques are well developed for the inspection of metal pipes. The new NDE techniques will be developed to a similar level of performance on GRP pipe as on metal pipe.

(2) To develop prototype equipment with associated automated systems required for their application, for the 4 NDE techniques:

• A prototype Low energy digital radiography test (DRT) system
• A prototype dual illuminated optical shearography (OT) system
• A prototype sonically stressed infra-red thermography (IRT) system
• A prototype dry coupled phased array ultrasonic test (PAUT) system

The performance of these systems will be validated in field trials. The development of NDE techniques and sensors are specifically targeted at the inspection of GRP pipes as used in the Oil and Gas industry after installation and throughout their in-service life. There are 4 new novel and unique NDE techniques together with associated automated systems required for their application (see table below). The innovations required for each individual discipline and associated items are:

SME	NDE Techniques	Defect type to be detected	Application of NDE technique
AJAT	Real Time Digital Low Energy Radioscopy (DRT)	Cracks, porosity, voids, fibre volume fraction and low volume un-bonds	Post assembly process
LOE In-Plane	Shearography (OT)	BVID, fibre breakage, cracks, porosity and voids Kissing Bonds	At completion of installation process and in-service if practicable
Lot Oriel	Active Thermography (IRT)	Detection of Kissing Bond, BVID, cracks, porosity and voids	In-service and during manufacture if applicable
NDT Solutions	Phased Arrays UTs (PAUT)	Characterisation Of Kissing Bond, BVID, cracks, porosity and voids	In-service and during manufacture if applicable
MIKRON	Automation of NDE with remote scanner system(s)	All of above items	In-service including offshore, during and immediately after installation

Low Energy Radioscopy. Main innovations mean that the current film based radiography will be replaced by real time digital radioscopy, reducing the ionising radiation affected zone hence diminishing the workplace intrusion and level of personnel exposure to ionising radiation. New and novel Low Energy X-ray techniques will be developed that are capable of detecting low volume defects in GRP components that include sub-structure. Current digital systems do not have sufficient resolution to detect this type of defect. This will be facilitated by the high-risk development of a new and novel technique using the radioscopic effect of additives to the adhesive. The effect of such additives on the strength of the bond will be investigated, the use of the additive will increase the variation in X-ray attenuation between the pipe material and adhesive. Optimisation of this detection capability will involve research into the levels of filtering (hardware and software), shot geometry, Low Energy X-ray quantity and quality levels together with digital image processing (DSP) development. The findings of this project will contribute towards the production of the initial European governing standard, given the consent of the consortium.

Shearography. Main innovations include development of a shearographic system and data sheets quantifying the boundary conditions for the full range of GRP materials, structures, sub-structures, defects and loading mechanisms (such as heat or vacuum) within the scope of the project. An optimal instrument will be designed and developed with a unique layout that will allow mapping of the strain pattern 'in plane' which will ease the examination of the pipes. This will be achieved by the introduction of a second illumination source that will provide a novel system that can determine the proportions of in-plane and out of plane components. This in-plane data enables the complete range of faults to be determined, such as fibre breakage, which is difficult to quantify with traditional out of plane systems. Correlation of this data will also facilitate the extraction of the true in-plane component from which mathematical (FE) models can be compared to allow true mapping of the structure's strain field. Examination of the strain field will deliver information as to the presence of full range of defects and disbonds. The developed sensor will be incorporated into a unique head design that will facilitate the application of the technology to a variety of small diameter pipes. This novel high-risk development gives a quantifiable method of assessing the performance of a GRP pipe in real world operation. As a consequence, although the use of shearography is normally in the manufacturing environment, any opportunity to transfer the technology into the field-servicing environment will be fully exploited if advantageous and practicable.

Thermography. The use of lamb waves to detect discontinuities in GRP Pipes will be considered. The potential benefits of such a system are: (1) large area detection from one location. (2) detection under coatings or along buried pipes with limited exposure to the outer surface. The research will review the various Lamb wave modes and identify those most suited to damage detection as well as for the excitation of heating mechanisms deep into the GRP structure. As considered for the Shearography system, data sheets quantifying the boundary conditions for the full range of GRP materials, structures, sub-structures, defects and loading mechanisms will be required. Although the range of energies used will be different, it is recognised that there is considerable overlap here therefore the resource requirement will be split over the two tasks. These stressing mediums will only be researched and used as a fall back position for the high risk main innovation that is the widespread use of an entirely new medium using lamb waves to impart standing or pulsed resonant waves into the pipe. The particle movement within these waves will cause a frictional interaction between un-bonded interfaces particularly when there is little clearance between the faces. Theoretically this will be an ideal system to detect the currently undetectable KB's phenomenon. Brief research by the author on a small sample set, indicated that traditional systems used for measuring the area of delamination after impact, tends to be reported at up to 30% less than the area indicated by a sonically excited Thermographic inspection. The fall back position will be to use high-energy ultra-low frequency transducers or traditional heating mechanisms such as flash lamps to impart heat into the structure.

Ultrasonic NDE methods Main innovations will include the use of array beam forming for spatial averaging to reduce structural noise and to increase the Probability of Detection (POD). Optimisation of a phased array system transducer design, matrix design, degree of damping together with the focal laws, filters and driving equipment software to be used in a dry contact probe will also be researched. Further experimentation will involve developing differing focussing and software routines to produce the level of sensitivity normally reserved for higher frequency systems whilst working at the low-range required to inspect porous GRP Pipe material. Unique circuitry will need to be developed for the control and processing of the low frequency data. A prototype wheel probe sensor, housing the phased array transducer, will be developed to be optimised for the inspection of GRP and with a view to interfacing the unit with the in situ scanner for the inspection of in-service pipes.

Man Machine Interface. This will include the development of an exclusive user-friendly operator interface and suite of analysis tools, which being reliable and intuitive, allow rapid visualisation and enhanced sentencing of components via the displayed NDE data received from the data acquisition systems. The aim is to perfect operator comfort and data interpretation by ergonomically improving the user interface; this will automatically have a favourable affect on the technique POD. The result will be a complete system incorporating advanced data processing and data display features by the use of multitasking computer technology to provide versatile and repeatable real time defect detection and characterisation.