| 1. |
- Fuente, Raquel, et al.
(författare)
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Development and demonstration of an automated system for limited access weld inspection by using infrared active thermography
- 2015
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Ingår i: Proceedings 7th International Symposium on NDT in Aerospace. - Berlin. ; , s. 1-8
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Konferensbidrag (refereegranskat)abstract
- Weld inspection for surface breaking defects detection has been traditionally performed by using NDT methods such as Fluorescent PenetrantInspection (FPI), Visual Inspection (VI) or Eddy Currents (EC). All those well known techniques have as common drawback the need of skilled operator intervention in order to analyse obtained results. In the specific case of inspection of welds with limited access, the application of those traditional methods is even more complex, thus increasing inspection time and reducing the defect detection capability. Therefore, the development of a fully automated non-contact method overcoming these limitations is desired. Active thermography (IRT) represents one of the most promising techniques for replacing traditional techniques for surface breaking defect detection in welds.This technique makes use of an excitation source in order to heat the sample undertest and an infrared camera for thermal evolution monitoring. With the combination of these excitation-monitoring techniques, heterogeneities in the heat flow caused bysurface breaking cracks can be detected. In this work, a robotic solution was developed and demonstrated for the inspection of welds with real cracks in a representative environment with limited access. The system consists of a continuous laser-line excitation source together with a FLIR SC 655 micro bolometer thermographic camera. In order to access limited areas, two different aluminium polished mirrors have been used for bothinfrared radiation monitoring and laser excitation respectively. The inspection results, analysis and comparison with traditional methods will be shown.
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| 2. |
- Runnemalm, Anna, 1970-, et al.
(författare)
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Automated inspection of welds with limited access by use of active thermography with laser line excitation
- 2016
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Konferensbidrag (refereegranskat)abstract
- Inspection of welds for detecting surface breaking defects is traditionally performed by using NDT methods such as Fluorescent Penetrant Inspection, Visual Inspection or Eddy Current. All those well-known techniques have drawbacks, as they need access to the surface, either for preparation with e.g. liquids or for using contact probes. Traditional methods also require a skilled operator to carry out the inspection, and moreover to analyse the obtained results. Furthermore, for the inspection of welds with limited access, the use of those traditional methods is even more complex, resulting in increased inspection time and reduced detection capability or in worst case, areas impossible to inspect. Therefore, the development of a fully automated non-contact method overcoming these limitations is desired. ;Active thermography is a novel NDT technique for weld inspection. The method has shown promising results for replacing traditional techniques when it comes to detection of surface breaking defects in metals. The method make use of an excitation source in order to heat the sample in a controlled manner during the test, and an infrared thermal camera for recordings of the thermal evolution. ;In this work, an automated solution developed and demonstrated for inspection of welds in a jet-engine component with limited access is presented. The NDT system is mounted on an industrial robot, making it possible to automatic scan the inspected area. The system consists of a, continuous laser-line excitation source together with a FLIR SC 655 microbolometer thermographic camera. In order to access limited areas, two polished aluminium mirrors have been used for both infrared radiation monitoring and laser excitation respectively. A solution for automatic analysing, defect detection and sizing is also included and presented.
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| 3. |
- Runnemalm, Anna, 1970-, et al.
(författare)
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Ultraviolet excitation for thermography inspection of surface cracks in welded joints
- 2014
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Ingår i: Nondestructive Testing and Evaluation. - : Informa UK Limited. - 1058-9759 .- 1477-2671. ; 29:4, s. 332-344
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Tidskriftsartikel (refereegranskat)abstract
- Infrared thermography is a non-contact and full field inspection method which has proven to be suitable for automatic surface crack detection. For automatic analysis of the inspection results, a high signal-to-noise ratio (SNR) is required. In this paper an alternative excitation method, using ultraviolet (UV) illumination, is presented and evaluated. Artificial surface defects, so-called notches, in a titanium plate are detected both in the weld seam and in the heat affected zone. Notches with a size from 80 mm in width and 250 mm in length are detected. The SNR using UV illumination is compared with that using flash lamp excitation. The results show that UV illumination using a mercury lamp is a good alternative as excitation source for thermography when detecting surface cracks. To validate the excitation method, results from real surface cracks are included.
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| 4. |
- Larsson, Martin, et al.
(författare)
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Innovativa energieffektiva växthus - designade för lågtempererade energikällor och värmeåtervinning
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Lågtempererad restvärme är i dag en underutnyttjad resurs i samhället trots stor tillgång. I den här förstudien har växthus studerats, dvs system med stort behov av värmeenergi under delar av året. Projektet studerade teoretiskt ett växthuskoncept som använder lågvärdiga (30 – 40 °C) externa och interna värmekällor för uppvärmning, samt nyttjandet av frikyla (daggpunkt ca 25–10 °C) via termiskt lager för avfuktning. Syftet med förstudien är att skapa förutsättningar för hållbar och konkurrenskraftig växthusodling i Sverige genom synergier mellan olika branscher och tekniker. Som möjliggörare föreslås ett nytt koncept, som utvecklas för växthusodling, där energi- och odlingseffektivitet samspelar. Genom att utvärdera konceptet avser förstudien besvara frågeställningar om hur energieffektiv teknik dels kan minska energibehovet för växthus, dels använda sig av lågtempererade värmekällor, i kombination med värmeåtervinning, samtidigt som klimatet i växthuset styrs så odlingskapaciteten och CO2-gödsling förbättras. Resultatet visar att potentialen är mycket årstidsberoende och mycket beroende av hur stor värmekällan från växtbelysning är. Värmeåtervinning av växthusets interna värme kan minska värmeenergibehovet med ca 85% och växthuset kan använda lågtempererad värmekälla på ca 30–40 °C. Ytterligare resultat är att produktionen även kan ökas med ca 30–50% (beroende på årstid) med effektiv CO2-gödning och bättre klimat för växterna.
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| 5. |
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| 6. |
- Garcia de la Yedra, Aitor, et al.
(författare)
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Defect strategies in Nickel Superalloys weld using active thermography
- 2014
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Ingår i: 12th International Conference on Quantitative InfraRed Thermography, 7-11/7 Bordeaux. ; , s. 1-9
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Konferensbidrag (refereegranskat)abstract
- As a result of extreme operation conditions in gas turbines, high resistance materials with excellent behaviour at high temperature are required. Alloys, such as MarM-247 nickel based superalloy, with excellent mechanical properties at very high temperature (even at 85 % of their melting point) are being used in these applications. This extraordinary behaviour is mainly due to the presence of a strengthening phase (γ’) with the following chemical composition: Ni3(Al, Ti). However, during welding these materials are susceptible to cracking and this is why weld inspections become crucial. In this work different strategies for defect detection in welds are introduced, all of them based on active thermography. The work covers aspects such as different excitation and data evaluation strategies.
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| 7. |
- Runnemalm, Anna, 1970-, et al.
(författare)
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Automatic thermography inspection of welded components with limited access
- 2014
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Ingår i: Proceedings of 6th International Symposium on NDT in Aerospace, 12-14th November 2014, Madrid, Spain. ; , s. 1-10
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Konferensbidrag (refereegranskat)abstract
- Inspection of welds with limited access puts specific requirement on the NDT-method to be used. A non-contact method without the need for special surface preparation is preferable for fast and cost efficient inspection and with the possibility of automation. Infrared thermography has been known for quite a long time and is today mainly used for NDT inspection of composite structures. The technique is based on registering the heat conduction of the material of the surface of the structure. The method requires some kind of excitation resulting in a change of heat locally in the inspected area. In the study presented in this paper, different excitation methods are evaluated, such as continuous laser, flash lamp and induction. The study also includes conditions for miniaturization andautomation of the inspection methods. For welds difficult to access, thermography is a suggested as a possible inspection method.
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