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2005
Conference Paper
Titel
Semianalytical modeling applied to optimize the performance of ultrasonic inspections
Abstract
Due to the increasing use of new structural materials it can be foreseen that in-service inspections will be forced and new rules may be imposed for the certification of future critical components e.g. in automotive or aerospace industries. High sensitivity Non-Destructive Testing (NDT) methods used today are at their physical limitation, and to require more from them will lead to inspection time increases and unjustified reject rates with their commercial implications. This requires the use of new approaches to achieve efficient non-destructive testing with respect to economic constraints and more stringent safety objectives. An innovative approach includes modeling of NDT in the design and/or the maintenance processes. A significant risk reduction of NDT missing a defect which could lead to part failure can be achieved, without extra cost, by providing inspection conditions perfectly fitted to material and part geometry. With respect to ultrasonic NDT this can be obtained by using modeling which allows to design sensors optimized for the specific inspection problem. In view of defect detection, modeling and optimization allow for an elaboration of inspection parameters to ensure the reliability of the applied technique, thus optimizing the inspection performance. In this contribution, several examples are presented where a semi-analytical modeling approach has been applied accordingly. Focusing on inspection situations in aerospace industries, the optimization of single and multiple element transducers is exemplified where - depending on the specific inspection configuration under concern - the shape of the piezoelement is determined to ensure a proper focusing of the beam field in the range of interest. As another possibility to achieve such a focusing, specially designed mirrors have been modeled and successfully applied for the first time. This allows to use off-the-shelf standard probes and is particularly interesting for the inspection of parts with limited access.