OPT-ADD · Development of optical NDT techniques and automated defect detection
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2007-01-08 → 2009-01-07
- EU contribution
- €165,396
- Participants
- 1
- Scheme
- IIF
Lines connect the coordinator with its partners.
Results in brief
Final Activity Report Summary - OPT-ADD (Development of Optical NDT Techniques and Automated Defect Detection)
The main objective of this project was to develop optical techniques, namely moiré interferometry, speckle shearography and digital image processing, for non-destructive testing (NDT) and structural integrity assessment of engineering components and structures. During the two year period, extensive work was carried out on moiré interferometry, digital moiré system, speckle shearography, digital image correlation and thermography, with the following achievements: 1. Moiré interferometry (MI) was used to detect defects and measure stresses in materials and components including metal, composites, microelectronics and welded joints. To investigate the mechanical deformation of components on-site a specific technique, namely deformed specimen grating replication, was applied and its defect detection capability was evaluated. The quantitative evaluation of the mechanical behaviour of microelectronic elements, such as solder joints and packages, using MI was one of the major scientific achievements during this project. 2. A digital-optical moiré system was developed which could perform both digital moiré and computer aided shadow moiré. It automatically generated the gratings by software, thus allowing all data processing to be accomplished within a personal computer (PC). The system was used for shape measurement and three-dimensional reconstruction of various structures. 3. Shearography was used for defect detection in a host of materials. In order to further improve its capability, the shearography system was optimised through the use of a phase-shifting device and a variety of mathematical algorithms. 4. A novel digital image processing system was developed. Apart from the conventional image processing capabilities for fringe pattern interpretation, the system had an extra function for residual stress measurement based on an innovative method, consisting in a deformation pattern based digital image correlation (DPDIC). This was the most important scientific achievement of this project. With DPDIC, a portable optical residual stress measurement system would be developed, having the potential of on-site industrial applications without the need to use strain gauges. This would significantly reduce the labour and material costs associated with the bonding and disposal of strain gauges during the conventional approach. 5. Thermography was also used for defect detection in this project. Its capability to detect defects on a broad range of materials and structures was investigated. The optimised procedure was therefore formulated and discussed.
Data: CORDIS, © European Union
Project objective
This project aims to- Develop NDT optical methods far beyond existing capabilities, in particular, moiré interferometry and speckle shearography.- Develop automated defect recognition and auto-sentencing algorithms used in interpreting NDT images.High-density moiré has been used in characterising nano and micro scale mechanical behaviour of materials in previous work. This project seeks to build on and extensively develop this work so as to transport the method from optical laboratory and render it suitable for detecting flaws in engineering structure and materials during manufacture and in-service.Efforts will be focused on improving a technique--deformed specimen grating replication--for in-situ measurements and developing algorithms to enhance the fringe quality. Speckle shearography has been shown to detect successfully defects in composite materials but results can be very subjective and requires skill and experience to correctly characterise indications.Here the emphasis will be on optimising t he associated optical set-ups, developing new algorithms to improve defect detection and characterisation, and improving repeatability and ease of use.The project will also seek to develop algorithms for automated defect detection. Methods such as multi-variant analysis and neural networks etc will be used to automatically analyse NDT images to identify potential defects.The host organisation, TWI, has been working closely with SMEs across Europe to develop new NDT techniques for many years. Projects have successfully involved the whole supply chain including SMEs, RTDs and LE end users. TWI's 6500 membership base will ensure that the fellow will be exposed to a wide range of potential contributors and end users.This project will benefit end-users across a range of industries by developing new optical NDT methods, improving probability of detection (POD), increasing sensitivity to defects and reducing the likelihood of misinterpretation.
Original text from CORDIS.
Participants
- TWI LTD · CAMBRIDGECoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union