Examples of mathematical modelling used as a tool within NDT qualification
H. Wirdelius, SAQ Kontroll AB, Molndal, Sweden
ABSTRACT
New and stronger demands on reliability of used NDE/NDT procedures and methods have stimulated the development of simulation tools of NDT. To qualify the procedures extensive experimental work on test blocks is normally required. An infinite number of variables and possibilities has to be reduced into a limited group of statistically relevant NDT situations. In order to justify this, the concept of technical justification has been introduced. Despite the fact that the proposed qualification procedure with test pieces is very expensive it also tends to introduce a number of possible misalignments between the actual NDT situation that is to be performed and the proposed experimental simulation. Beside the problem of reconstructing the geometry and material the fabricated defects also has to be introduced with a verified prescription of its size and NDT characteristics. In the recent decade a number of mathematical models has been developed and used as tools within parts of the qualification process. A thorough validated model has the ability to be an alternative or a complement to the experimental work in order to reduce the extensive cost that is associated with the previous procedures. An interesting notation is though that these validations are often performed against very simplified and not thoroughly validated fabricated defects (e. g. EDM notches) with the echo dynamics used as the measurement of its credibility. The SUNDT program consists of a window based preprocessor and postprocessor together with a mathematical kernal (UTDefect) dealing with the actual mathematical modelling. The UTDefect computer code has been developed at the Division of Mechanics at Chalmers University of Technology and has been experimentally validated and verified ([1],[2],[3],[4]). In the present paper this software is briefly described together with some exemplifications of mathematical modelling used as a tool within NDT qualification.
Publication Source: First International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurised Components , 20 - 22 October 1998, Amsterdam, Netherlands. Held by the Joint Research Centre of the European Commission. Publisher:Woodhead Publishing Limited
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