Filtern
Dokumenttyp
- Zeitschriftenartikel (12)
- Vortrag (9)
- Posterpräsentation (3)
- Beitrag zu einem Tagungsband (1)
- Forschungsdatensatz (1)
Schlagworte
- Computed tomography (9)
- X-ray computed tomography (9)
- Additive manufacturing (6)
- Data processing (4)
- Porosity (4)
- 3D printing (2)
- ANFO (2)
- Ammonium nitrate (2)
- Chaboche model (2)
- Computertomographie (2)
- Explosives (2)
- GTN model (2)
- Implants (2)
- Metrology (2)
- Non-destructive characterisation (2)
- Prill (2)
- Specific surface area (2)
- Surface area (2)
- X-ray refraction (2)
- XCT (2)
- 3D printing Polyamide 12 (1)
- Additive Fertigung (AM) (1)
- Anisotropy (1)
- Autocorrelation function (1)
- Beam hardening (1)
- CT (1)
- Calcium phosphate (1)
- Ceramics (1)
- Coating (1)
- Composite panel (1)
- Correlation map (1)
- Damage (1)
- Damage analysis (1)
- Damage correlation map (1)
- Damage histogram (1)
- Defect detection (1)
- Delamination (1)
- Diesel particulates filter (1)
- Digital Volume Correlation (1)
- Electron beam melting (1)
- FEM (1)
- High Strength Concrete (1)
- Impact damage (1)
- Implant (1)
- In-situ Computed Tomography (1)
- Industry 4.0 (1)
- Laser beam melting (1)
- Lattice structure (1)
- Lattice structures (1)
- Maskinteknik (1)
- Material and damage behaviour (1)
- Mechanical Engineering (1)
- Mechanical properties (1)
- Medical implants (1)
- Microstructural analysis (1)
- Multiple-layered scaffold (1)
- Neutron diffraction (1)
- Normung (1)
- Numerische Simulation (1)
- Panels (1)
- Parabolic flight (1)
- Part geometry (1)
- Part material (1)
- Partial volume effect (1)
- Permeability tensor (1)
- Polyamid 12 (1)
- Polyamide 12 (1)
- Polycaprolactone (1)
- Refraction (1)
- Röntgen-Refraktion (1)
- Röntgenrefraktion (1)
- SLS (1)
- Schadensanalyse (1)
- Time-lapse X-ray computed tomography (1)
- Viscoplastic (1)
- X-Ray refraction (1)
- aRTist (1)
- composites (1)
- standardization (1)
- µ-gravity (1)
Organisationseinheit der BAM
- 8 Zerstörungsfreie Prüfung (26) (entfernen)
Eingeladener Vortrag
- nein (9)
Ammonium nitrate (AN) prills are commonly used as an ingredient in industrial explosives and in fertilisers. Conventional techniques (such as BET or mercury intrusion porosimetry) can measure the open porosity and specific surface area of AN prill, but the closed porosity is not obtainable. This work was focused on evaluating X-ray computed tomography (XCT) as a non-destructive technique for the assessment of porosity in AN prills. An advanced data processing workflow was developed so that the segmentation and quantification of the CT data could be performed on the entire 3D volume, yet allowing the measurements (e.g.; volume, area, shape factor…) to be extracted for each individual phase (prill, open porosity, closed porosity) of each individual prill, in order to obtain statistically relevant data. Clear morphological and structural differences were seen and quantified between fertiliser and explosive products. Overall, CT can provide a very wide range of parameters that are not accessible to other techniques, destructive or non-destructive, and thus offers new insights and complementary information.
Ammonium nitrate (AN) prills are commonly used as an ingredient in industrial explosives and in fertilisers. Conventional techniques (such as BET or mercury intrusion porosimetry) can measure the open porosity and specific surface area of AN prill, but the closed porosity is not obtainable. This work was focused on evaluating X-ray computed tomography (XCT) as a non-destructive technique for the assessment of porosity in AN prills. An advanced data processing workflow was developed so that the segmentation and quantification of the CT data could be performed on the entire 3D volume, yet allowing the measurements (e.g.; volume, area, shape factor…) to be extracted for each individual phase (prill, open porosity, closed porosity) of each individual prill, in order to obtain statistically relevant data. Clear morphological and structural differences were seen and quantified between fertiliser and explosive products. Overall, CT can provide a very wide range of parameters that are not accessible to other techniques, destructive or non-destructive, and thus offers new insights and complementary information.
The characterisation of AM structures is an important aspect of the AM process, required in order to:
1. optimise the AM printing process
2. assess the quality of produced parts
A wide range of characterisation techniques are available, and the selection can be complex, based on multiple factors.
One output from the MetAMMi project is a good practice guide on the correct choice of characterisation technique.
The quantification of experimental and data analysis errors is most of the times jeopardised by the presence of surface roughness, waviness, as well as by typical measurement artefacts of the XCT technique (for instance refraction at sharp edges). One way to at least estimate the influence of those factors on dimensional measurements and on tolerances is to simulate them using Monte-Carlo method. An alternative strategy is to use independent knowledge (e.g. CMM data) to smoothen/calibrate/correct XCT data.
Durch den großflächigen Einsatz der Computertomographie (CT) in unterschiedlichen Industriebereichen steigen auch die Anforderungen an die quantitative Bildanalyse. Subjektive Bildwahrnehmung muss durch objektive Algorithmen ersetzt werden. In diesem Artikel stellt die Bundesanstalt für Materialforschung und -prüfung (BAM), die seit den 1980er Jahren an der Entwicklung der industriellen CT beteiligt ist, anhand ausgewählter Beispiele den aktuellen Stand ihrer Analysemethoden an verschiedenen Anwendungsbeispielen der CT vor.
We show how the combination of the spatial autocorrelation function and permeability calculations, applied to 3D X-ray computed tomography data, can yield quantitative information on the anisotropy of both meso-structure and fluid flow in Diesel Particulate Filter (DPF) materials, such as Cordierite and SiC. It was found that both the degree of anisotropy, and the orientation of the permeability and meso-structure are similar, but not identical. We confirm that the morphological anisotropy of cordierite materials is weak, and clearly influenced by the extrusion process that determines the main direction of anisotropy. Properties of the autocorrelation function are discussed and it is shown why estimating the characteristic length of real meso-structures (grain or ?pore? size) is not possible. Finally, we show that the autocorrelation function applied on grey-level images can give a good estimate of the degree of anisotropy even with limited resolution.
During their life cycle, composite structures used in aircraft structures can be subjected to high- and low-velocity impact loading. High velocity impact damage is usually easy to detect as it creates visible external damage. Low-velocity impacts are more complex to assess because, although significant damage can be generated internally, there can be little indication of external damage on the impacted surface, leading to the term BVID. Impact damage, especially barely visible impact damage, is therefore of primary concern for design and maintenance of modern aircraft composite structures. As a result there is a concerted research effort to improve the damage resistance and tolerance of these materials.
One of the great strengths of X-ray computed tomography over conventional inspection methods (ultrasound, thermography, radiography) is that it can image damage in 3D. or inter-ply interfaces. An X-ray computed tomography (CT) data processing methodology is developed to extract the through-thickness distribution of damage in curved or deformed composite panels. The method is applied to [(0°/90°)2]s carbon fibre reinforced polymer (CFRP) panels subjected to low velocity impact damage (5 J up to 20 J) providing 3D ply-by-ply damage visualisation and analysis. Our distance transform approach allows slices to be taken that approximately follow the composite curvature allowing the impact damage to be separated, visualised and quantified in 3D on a ply-by-ply basis. In this way the interply delaminations have been mapped, showing characteristic peanut shaped delaminations with the major axis oriented with the fibres in the ply below the interface. This registry to the profile of the panel constitutes a significant improvement in our ability to characterise impact damage in composite laminates and extract relevant measurements from X-ray CT datasets.
In this paper we report on the characterization by X-ray computed tomography of calcium phosphate (CaP) and polycaprolactone (PCL) coatings on Ti-6Al-4V alloy scaffolds used as a material for medical implants. The cylindrical scaffold has greater porosity of the inner part than the external part, thus, mimicking trabecular and cortical bone, respectively. The prismatic scaffolds have uniform porosity. Surface of the scaffolds was modified with calcium phosphate (CaP) and polycaprolactone (PCL) by dip-coating to improve biocompatibility and mechanical properties. Computed tomography performed with X-ray and synchrotron radiation revealed the defects of structure and morphology of CaP and PCL coatings showing small platelet-like and spider-web-like structures, respectively.