idw – Informationsdienst Wissenschaft
Nachrichten, Termine, Experten
Nachrichten, Termine, Experten
idw - Informationsdienst
Wissenschaft
The Fraunhofer Institute for Nondestructive Testing IZFP carries out research and development activities in the field of nondestructive testing processes along the entire materials value chain. For customers in the automobile, aerospace, rail, energy, construction and agriculture industries, the institute offers a wide range of NDT expertise and technologies. From June 13 to 17, 2016, Fraunhofer IZFP will discuss and present the issue regarding corrosion and defect inspection of inaccessible components and construction parts with long range EMAT technique at the 19th World Conference on Non-Destructive Testing (WCNDT) in Munich.
As part of a condition-based maintenance, in the context of legal regulations and risk to public safety and the environment, periodic inspections are essential. Such inspections are time-consuming and pose a challenge for large structures, difficult accessible and inaccessible areas. Long-range and coupling-free ultrasonic inspection techniques can be used to detected defects in an early stage and consequential damages are averted.
Safety relevant infrastructure, such as pipelines in chemical and petrochemical plants, lines for gas and water, and supporting structures such as columns and posts can corrode in case of insufficient or faulty insulation. Due to the fact that visual inspection is not applicable and the corrosion areas are also often inaccessible for other methods, the detection and assessment of the defects are difficult. In addition, surface corrosion usually leads to very smooth wall tinning with complex geometry, so commercial measurement methods reach their limits and therefore can not make any satisfactory statements of the defect.
Inaccessible areas can be tested with long-range ultrasonic waves, so-called guided waves, under ideal conditions distances up to 50 m are capable, without an expensive exposure, remove of insulation and/ or dig out of the component.
Electro-magnetic acoustic transducer (EMAT) operates without direct contact (no couplant required) and is not influenced by non-conducting materials, so that even thin insulation layers must not removed.
The use of dispersive ultrasonic guided wave modes provides the possibility to detect very small wall thickness reductions in the sound path of an ultrasonic transmission and / or reflection measurement. Therefore they are suited to detect small corrosion-related damages. The measuring effect is based on that change of both the phase and group velocity of the dispersive ultrasonic wave mode with the wall thickness. Therefore quantitative information about the defects is accessible via the evaluation of the phase and / or time of flight of the receiving signal.
The described methods provide also quantitative information of relevant defects, so that a more accurate assessment is possible. The article gives an overview of the techniques used and presents diverse applications.
Merkmale dieser Pressemitteilung:
Journalisten, Wirtschaftsvertreter, Wissenschaftler
Werkstoffwissenschaften, Wirtschaft
überregional
Buntes aus der Wissenschaft, Wissenschaftliche Tagungen
Englisch
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