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| 2. |
- 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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| 3. |
- 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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| 4. |
- Grahn, Karin, et al.
(författare)
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Occupational noise exposure and acute effects on pulse rate and blood pressure
- 2022
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Ingår i: Proceedings of the International Congress on Acoustics.
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Konferensbidrag (refereegranskat)abstract
- Environmental exposure to noise and particle matter (PM) are risk factors for cardiovascular disease (CVD). Although there are often higher levels in occupational settings, little is known about noise and particle exposures at work and CVD risks. We investigated occupational noise and particle exposures and acute effects on pulse rate and blood pressure. 46 active, non-smoking, male construction workers were included in the study. Continuously logged personal exposure measurements of noise (LAmax, LCpeak) and dust of PM 0.1-10, continuously logged pulse rate and blood pressure measurements were performed for one working day on each participant. Significant associations were seen between these three exposures and acute changes in pulse rate. The effects were seen below the Swedish occupational exposure limits for LAmax and LCpeak, indicating that these limits may not protect from adverse cardiovascular effects. Also, an additive effect on pulse rate was seen if simultaneously exposed to noise and dust. No association were found between these exposures and blood pressure.
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| 5. |
- 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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| 6. |
- 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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