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Erscheinungsjahr
- 2021 (2) (entfernen)
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- Beitrag zu einem Tagungsband (2) (entfernen)
Schlagworte
- Ablösungen (1)
- Additive manufacturing (1)
- Aktive Thermografie (1)
- Bauthermografie (1)
- Laser powderbed fusion (1)
- Metallanker (1)
- Micro-CT (1)
- Pores (1)
- Thermography (1)
Organisationseinheit der BAM
Die Thermografie beruht auf der bildlichen Darstellung von Temperaturunterschieden oder auch thermischen Kontrasten an der Oberfläche eines Untersuchungsobjektes. Diese bilden sich nur her-aus, wenn sich das Untersuchungsobjekt gerade erwärmt oder abkühlt. Der Beitrag erklärt mittels eines stark vereinfachten Modells die Entstehung solcher Kontraste als dynamischen Effekt verschiedener Abkühlgeschwindigkeiten. Neben Laborergebnissen werden beispielhaft einige Ergeb-nisse von einem mittelalterlichen Baudenkmal präsentiert, um das Verständnis für die thermografische Inspektion von Fassaden zu vertiefen.
Active thermography is a fast, contactless and non-destructive technique that can be used to detect internal defects in different types of material. Volumetric irregularities such as the presence of pores in materials produced by the Additive Manufacturing processes can strongly affect the thermophysical and the mechanical properties of the final component.
In this work, an experimental investigation aimed at detecting different pores in a sample made of stainless AISI 316L produced by Laser Powder Bed Fusion (L-PBF) was carried out using pulsed thermography in reflection mode. The capability of the technique and the adopted setups in terms of geometrical and thermal resolution, acquisition frequency and energy Density of the heating source were assessed to discern two contiguous pores as well as to detect a single pore. Moreover, a quantitative indication about the minimum resolvable pore size among the available and analysed defects was provided. A powerful tool to assess the Limits and the opportunities of the pulsed technique in terms of detectability and localizability was provided by comparing active thermography results to Computed Tomography as well as a related Finite Element Analysis (FEA) to simulate the pulsed heating transfer with Comsol.