Wissenschaftliche Artikel der BAM
Filtern
Erscheinungsjahr
Dokumenttyp
- Beitrag zu einem Tagungsband (209) (entfernen)
Sprache
- Englisch (209) (entfernen)
Schlagworte
- NDT (15)
- Reliability (11)
- Concrete (10)
- Simulation (10)
- Computed tomography (8)
- Non-destructive testing (8)
- Ultrasound (8)
- Active thermography (6)
- Ferroelectret (6)
- Thermography (6)
- Acoustic emission (5)
- Additive manufacturing (5)
- Air-coupled ultrasonic testing (5)
- Cellular polypropylene (5)
- Fatigue (5)
- Hydrogen (5)
- Structural health monitoring (5)
- Welding (5)
- CFRP (4)
- Composites (4)
- Monte Carlo methods (4)
- Nondestructive testing (4)
- POD (4)
- Transducer (4)
- Ultrasonic (4)
- Ultrasonics (4)
- Africa (3)
- Air-coupled (3)
- Online NMR Spectroscopy (3)
- Railway (3)
- Sustainability (3)
- Ultrasonic testing (3)
- Additive Manufacturing (2)
- Alkali-activated materials (2)
- Atmospheric pressure plasma (2)
- CCS (2)
- CFD simulation (2)
- CONSENS (2)
- Composite (2)
- Corrosion (2)
- Crack detection (2)
- Damage detection (2)
- Dust explosions (2)
- Embedded sensors (2)
- Emission (2)
- Energetic materials (2)
- Existing structures (2)
- Experimental testing (2)
- Fiber optic sensors (2)
- GFRP (2)
- GMR (2)
- Geruch (2)
- Glass fiber reinforced polymers (2)
- Human factors (2)
- Hybrid mixtures (2)
- Hydrogen storage (2)
- Imaging ellipsometry (2)
- Laser Thermography (2)
- Laser metal deposition (2)
- Laser thermography (2)
- Lock-in Thermography (2)
- Machine learning (2)
- Material moisture (2)
- Materials (2)
- Measurement uncertainty (2)
- Measurements (2)
- Monitoring (2)
- NDT-CE (2)
- Optical fiber sensor (2)
- Organic peroxide (2)
- Passive thermography (2)
- Phase grating (2)
- Photon counting detectors (2)
- Pressure tanks (2)
- Process Analytical Technology (2)
- Process Monitoring (2)
- Process industries (2)
- Radiographie (2)
- Reverse time migration (2)
- SAFT (2)
- Smart Sensors (2)
- Structural Health Monitoring (2)
- Super resolution (2)
- Talbot- Lau interferometry (2)
- Thermoacoustic (2)
- Validation (2)
- Wind turbine blades (2)
- X-Ray Diffraction (2)
- Zerstörungsfreie Prüfung (2)
- 2-D Welding Simulation (1)
- 3D concrete printing (1)
- 3D inspection (1)
- 3D-Rekonstruktion (1)
- AAM (1)
- Acoustic-Structure Interaction (1)
- Additive manufacturing of concrete (1)
- Adhesive joint (1)
- Admixtures (1)
- Aeroacoustics (1)
- Aerospace (1)
- AgBB Bewertung (1)
- Air-coupled ultrasound (1)
- Airborne ultrasonic testing (1)
- Akustische Emission (1)
- Analysis of variance (1)
- Analytical approach (1)
- Analytics (1)
- Artificial and natural defects (1)
- Artificial defect (1)
- Artificial neural networks (1)
- Artificial weathering (1)
- Atomic force microscopy (1)
- Automated arc welding (1)
- Axle (1)
- Axles (1)
- BLDC (1)
- Back-scatter techniques (1)
- Backlight (1)
- Barriere (1)
- Bauprodukte (1)
- Bayesian updating of measurement uncertainties (1)
- Bias (1)
- Bingham fluid (1)
- Bistable amplifier (1)
- Bodenbelag (1)
- Borehole probe (1)
- Box-Behnken (1)
- Bridge (1)
- Bridge Monitoring (1)
- Bridge monitoring (1)
- Bridge reassessment (1)
- Bridge structures (1)
- Bridges (1)
- Broadband (1)
- Building material (1)
- CO2 corrosion (1)
- CO2-storage (1)
- CT (1)
- Capillary conductivity (1)
- Carbon arc-air gouging (1)
- Carbon emissions (1)
- Carbon-fibre-reinforced plastic (1)
- Carbonation (1)
- Cement (1)
- Characterisation (1)
- Chemisoprtion (1)
- Chloride extraction (1)
- Circular economy (1)
- Civil Engineering (1)
- Civil engineering (1)
- Click Chemistry (1)
- Co-planar translational laminography (1)
- Coda Wave Interferometry (1)
- Coherent Fourier scatterometry (1)
- Coherent Heterodyne (1)
- Cohesive granular media (1)
- Competencies (1)
- Component Testing (1)
- Composite pressure vessel (1)
- Composite structures (1)
- Computed Tomography (1)
- Computed tomographie (1)
- Computer-Simulation (1)
- Computersimulation (1)
- Computertomographie (1)
- Concrete Bridge (1)
- Concrete filled tube (CFT) column (1)
- Concrete mesoscale (1)
- Concrete structures (1)
- Construction (1)
- Control Chart (1)
- Copper (1)
- Corrosion fatigue (1)
- Crack depth (1)
- Crack formation (1)
- Crack growth (1)
- Crack pattern (1)
- Creep-resistant steel (1)
- Cross linking (1)
- Cure process (1)
- Curriculum (1)
- Cusum (1)
- Cycle-by-cycle (1)
- Cyclic load (1)
- Cylinder (1)
- Cytop (1)
- DLP (1)
- DMD (1)
- Damage evolution (1)
- Damage location (1)
- Dangerous goods (1)
- Data fusion (1)
- Data visualization (1)
- Data-informed reliability analysis (1)
- Ddistributed strain sensing (1)
- Deconvolution (1)
- Defect Detection (1)
- Defect detection (1)
- Defect sizing (1)
- Defects (1)
- Degree of purity (1)
- Di-tert-butyl peroxide (DTBP) (1)
- Di-tert-butylperoxide (DTBP) (1)
- Dichtheit (1)
- Diffusion (1)
- Digital I-OFDR (1)
- Digital Twin (1)
- Digital radiography (1)
- Digitalisation (1)
- Distributed Fiber Optic Sensor (1)
- Distributed acoustic sensor (DAS) (1)
- Distributed fiber optic radiation sensors (1)
- Distributed fiber optic sensing (1)
- Distributed fibre optic sensors (1)
- Distributed polymer optical fiber sensor (1)
- Distributed strain sensing (1)
- Doctoral School (1)
- Domain decomposition methods (1)
- Drone (1)
- Dual-energy imaging (1)
- Duplex stainless steel (1)
- Dynamic mechanical analysis (DMA) (1)
- Dynamical theory (1)
- EDM (1)
- Earth masonry (1)
- Ecodesign (1)
- Eddy current testing (ET) (1)
- Education (1)
- Electric discharge machining (1)
- Electric impedance (1)
- Electro-Magneto-Mechanical (1)
- Electrochemistry (1)
- Electromagnetic Force (1)
- Electron backscatter diffraction (1)
- Electron tomography (1)
- Electron transport (1)
- Electronic nose (1)
- Emission test chamber (1)
- Emissionen (1)
- Endlager (1)
- Energy Labelling (1)
- Engineered Barrier System (EBS) (1)
- Engineered barrier; (1)
- Epitaxially grown 4H-SiC layers (1)
- Epoxy (1)
- Erosion onset (1)
- Erosion phenomena (1)
- Experiments (1)
- Exploding Wire (1)
- FEM (1)
- FETI (1)
- FFT (1)
- FMEA (1)
- FSW (1)
- Failure Modes and Effects Analysis (1)
- Fatigue damage (1)
- Fatigue of sandwich shell structures (1)
- Fatigue tests (1)
- Fault detectionchanging (1)
- Ferroelectrets (1)
- Fiber Bragg grating (1)
- Fiber optic sensor (1)
- Fiber reinforced polymer (1)
- Fiber resisted polymers (1)
- Fiber-reinforced plastics (1)
- Fibre pull-out (1)
- Filler material distribution (1)
- Finit Element Method (1)
- Finite Element Modelling (1)
- Finite element model (1)
- Fire after earthquake (1)
- Fire performance (1)
- Flame propagation (1)
- Flash excitation (1)
- Fluidics (1)
- Fluorescence screen (1)
- Focused sound fields (1)
- Focused transducers (1)
- Fracture (1)
- Fracture mechanics problems (1)
- Freeform shaped workpieces (1)
- GMAW (1)
- GTR 13 (1)
- Galvanic corrosion (1)
- Gamma radiation (1)
- Gamma radiation monitoring (1)
- Gas discharges (1)
- Gas explosions (1)
- Gas sensors (1)
- Gefahrgutverpackungen (1)
- Geometric Phase (1)
- Glass scanning (1)
- Glass-fibre-reinforced (1)
- Granular cohesion (1)
- Green Deal (1)
- Grout (1)
- Grouted connection (1)
- Grouting (1)
- Guided Waves (1)
- Gypsum dehydration (1)
- HSLA steel (1)
- Harmonisation (1)
- Hazardous substances (1)
- Health monitoring (1)
- Helium (1)
- High entropy alloy (1)
- High resolution ultrasonic testing (1)
- High-Order Methods (1)
- High-Strength Steel (1)
- High-Throughput Fire Tests (1)
- High-entropy alloy (1)
- High-fired medieval gypsum mortars (1)
- High-power Laserbeam Welding (1)
- Historic facades (1)
- Hot Cracks (1)
- Human Factors (1)
- Hydrogen assisted cracking (1)
- ISO 11119 (1)
- Ignition source (1)
- Imaging (1)
- Imaging condition (1)
- Immersion tank testing (1)
- Impact (1)
- Impulse response function (1)
- In-situ compression (1)
- Incoherent optical frequency domain reflectometry (1)
- Inconel 718 (1)
- Incorrect classification (1)
- Indirect Hard Modeling (1)
- Industrial reference standard (1)
- Inherent Strain (1)
- Inspection (1)
- Inspection planning (1)
- Insulation material (1)
- Interlaboratory test (1)
- Internal defects (1)
- Interoperability (1)
- Interpass temperature (1)
- Intumescent coatings (1)
- Inverse problem (1)
- Istzustandserfassung (1)
- JLH (1)
- Jet erosion (1)
- Jet flame (1)
- Kinematic theory (1)
- Knudsen effect (1)
- Kunststoffbehälter (1)
- LBM-DEM (1)
- LBM-DEM numerical simulation (1)
- LCA (1)
- LIBS (1)
- LTT (1)
- LTT Weld Filler Materials (1)
- Laminography (1)
- Large-scale test (1)
- Laser Powder Bed Fusion (1)
- Laser beam welding (1)
- Laser metal deposition (LMD) (1)
- Laser powder bed fusion (1)
- Laser powderbed fusion (1)
- Laser-metal-deposition (1)
- Laser-plasma hybrid (1)
- Leaching (1)
- Levelized cost of energy (1)
- Levitation Device (1)
- Lightweight materials (1)
- Limited angle tomography (1)
- Linear parameter varying systems (1)
- Load Experiment (1)
- Load cycles (1)
- Local fatigue approaches (1)
- Long term monitoring (1)
- Low field NMR spectroscopy (1)
- Lower explosion limit (1)
- Machining (1)
- Macroscopic (1)
- Magnetic field (1)
- Magneto-optical sensor (1)
- Magnetostriction (1)
- Maintenance (1)
- Maritime Atmosphäre (1)
- Maritime atmosphere (1)
- Material behavior (1)
- Material characterisation (1)
- Material characterization (1)
- Material classification (1)
- Material inspection (1)
- Materialeigenschaft (1)
- Mesoscale (1)
- Mesoscopic (1)
- Metal magnetic memory (1)
- Micro-CT (1)
- Microfine Cement (1)
- Micromechanical modelling (1)
- Mineralogie (1)
- Mini-plant (1)
- Minimum ignition temperature (1)
- Modal Analysis (1)
- Model calibration (1)
- Model interpolation (1)
- Modellierung (1)
- Modelling (1)
- Modular model (1)
- Modular production units (1)
- Molecular diffusion (1)
- Motor control (1)
- Moving vehicles (1)
- Mukuru (1)
- Multi-attribute decision method (1)
- Multi-criteria decision support (1)
- Multidisciplinary (1)
- Multiscale (1)
- Muon tomography (1)
- NDT Reliability (1)
- Nanomaterial (1)
- Natural gas (1)
- Non-Destructive Testing (NDT) (1)
- Non-destrucive testing (1)
- Nondestructive Testing (1)
- Nuclear magnetic resonance (1)
- Numerical simulation (1)
- Odour (1)
- Offshore (1)
- Offshore foundations (1)
- Offshore wind turbines (1)
- Online NMR spectroscopy (1)
- Onset of jet erosion (1)
- Optical backscatter reflectometry (1)
- Optical fibre (1)
- Optical incremental encoder (1)
- Optical methods (1)
- Optical microphone (1)
- Optical time domain reflectometry (1)
- Osteoporosis (1)
- PLIF-RIM optical techniques (1)
- PMSM (1)
- Passive RFID (1)
- Pattern recognition methods (1)
- Penetration depth (1)
- Perceived Intensity (1)
- Perceived intensity (1)
- Perfluorinated polymer optical fibers (1)
- Phase transformation (1)
- Phase-contrast X-ray imaging (1)
- Phased array technique (1)
- Phasenzusammensetzung (1)
- Photon counting detector (1)
- Photon-electron transport (1)
- Physisorption (1)
- Piezoelectric (1)
- Pile integrity (1)
- Pipeline (1)
- Plasma acoustics (1)
- Plasma-transferred-arc (1)
- Plasticity-based Analysis (1)
- Polymer (1)
- Polymer optical fibers (1)
- Pore-size distribution (1)
- Pores (1)
- Post Weld Heat Treatment (PWHT) (1)
- Potential method (1)
- Practicality measurement (1)
- Pressure vessels (1)
- Prestressed concrete (1)
- ProMoAM (1)
- Probabilistic (1)
- Probabilistic reassessment (1)
- Probability of detection (1)
- Process Control (1)
- Process control (1)
- Process monitoring (1)
- Process noise (1)
- Proficiency Testing (1)
- Prozess-Spektroskopie (1)
- Purity grade (1)
- Quality Infrastructure (1)
- Quality assurance (1)
- Quantification (1)
- RIM-PLIF techniques (1)
- RT (1)
- Radar (1)
- Radiation induced attenuation (1)
- Radiation-induced attenuation (1)
- Radiography (1)
- Radiology (1)
- Raman band width (1)
- Raman microspectroscopy (1)
- Rayleigh scattering (1)
- Re-assessment of exiting bridges (1)
- Reaction Stress (1)
- Reconstruction (1)
- Reconstruction algorithms (1)
- Reconstruction of stress resultants (1)
- Recycling (1)
- Reference defect (1)
- Reflection seismics (1)
- Regulations (1)
- Release (1)
- Reliability assessment (1)
- Repair (1)
- Repair and overhaul (1)
- Repair patch (1)
- Repair welding (1)
- Research (1)
- Residual Stress (1)
- Residual Stresses (1)
- Residual stress (1)
- Residual stresses (1)
- Restoration and conservation (1)
- Reverse Time Migration (1)
- Rheology (1)
- Risk (1)
- Robot (1)
- Robustness (1)
- Rotor blade (1)
- Round robin test (1)
- SEP 1927 (1)
- SHM (1)
- SLM printed plasma torch (1)
- Safety (1)
- Safety characteristics determination (1)
- Salinization (1)
- Sandwich (1)
- Scaled Boundary Finite Element Method (1)
- Scanning kelvin probe force microscopy (1)
- Scarf repairs (1)
- Science (1)
- Sciences (1)
- Screed (1)
- SealWasteSafe (1)
- Sectioning Method (1)
- Seismic measurement (1)
- Seismically damaged column (1)
- Selective Laser Melting (1)
- Self-healing (1)
- Sensitivity (1)
- Sensitivity analysis (1)
- Sensor array (1)
- Sensors (1)
- Servo drive (1)
- Shark profile (1)
- Shell Buckling (1)
- Shrinkage Reducing Admixture (1)
- Silicon carbide (1)
- Sine sweep excitation (1)
- Slice theoreme (1)
- Smart geosynthetics (1)
- Smart structures (1)
- Soil-Structure-Interaction (1)
- Soil-structure interaction (1)
- Solar heating (1)
- Spent nuclear fuel (1)
- Stability Design (1)
- Stained glass (1)
- Standardisation (1)
- Static load (1)
- Static load monitoring (1)
- Statistical analysis (1)
- Steel (1)
- Steel corrosion (1)
- Steel fibres (1)
- Steel structures (1)
- Strain (1)
- Strain measurements (1)
- Stress (1)
- Stress Relief Cracking (SRC) (1)
- Structural build-up (1)
- Structural health monitoring (SHM) (1)
- Structural integrity management (1)
- Structured light scanning (1)
- Subcritical debonding (1)
- Subspace-based residual (1)
- Super somputing (1)
- Superplasticizer (1)
- Supplementary Cementitious Materials (1)
- Supplementary cementitious materials (1)
- Suppressing vibrations (1)
- Surface cracks (1)
- Swept wavelength interferometry (SWI) (1)
- Synchrotron radiation (1)
- Synchrotron radiography (1)
- Synthetic Aperture Focusing Technique (1)
- THz SAFT Optical layer reconstruction (1)
- TMR (1)
- TW-COTDR (1)
- Technical crack detection (1)
- Tendon duct (1)
- Tensile strength (1)
- Test method (1)
- Thermal anhydrite (1)
- Thermal contrast (1)
- Thermal radiation (1)
- Thermal wave (1)
- Thermoacoustics (1)
- Thermodynamik (1)
- Thermographic inspection (1)
- Thermographic testing (1)
- Thermomechanical (1)
- Thermomechanical Fatigue (TMF); High Cycle Fatigue (HCF); Cast iron; Fatigue assessment (1)
- Thermoplastic (1)
- Thermoset polymers (1)
- Thixotropy (1)
- Time reversal (1)
- Time-resolved thermogram (1)
- Transducers (1)
- Tribology (1)
- Tubular X-joints (1)
- Tunnel Inspection (1)
- UHPFRC (1)
- UT (1)
- Ultraschall (1)
- Ultrasonic Echo Technique (1)
- Ultrasonic Testing (1)
- Ultrasonic echo (1)
- Ultrasonic guided waves (1)
- Ultrasonic immersion tank testing (1)
- Ultrasonic machining (1)
- Ultrasonic material determination (1)
- Ultrasonic tests (1)
- Ultrasonic transducer (1)
- Ultrasound Emission (1)
- University (1)
- Urban planning (1)
- Urbanisation (1)
- VOC (1)
- VOC Emissionen (1)
- Vacuum (1)
- Versalzung (1)
- Vertical earthquakes (1)
- Vibration (1)
- Visibility (1)
- Water layer thickness (1)
- Wave propagation (1)
- Weathering (1)
- Weld residual stress (1)
- Welded (1)
- Welding costs (1)
- Welding process selection (1)
- Welding residual stress (1)
- White light interference microscopy (1)
- Wide bandgap compound semiconductor (1)
- Wind (1)
- Wind Energy (1)
- Wind Turbines (1)
- Wind energy (1)
- Wind turbine (1)
- Wind turbine rotor blade (1)
- X-ray (1)
- X-ray computed tomography (1)
- X-ray detector (1)
- X-ray diffraction (1)
- X-ray imaging (1)
- X-ray laminography (1)
- X-ray refraction (1)
- X-ray spectra (1)
- X-ray tomography (1)
- Zement (1)
- aluminum (1)
- cold neutrons (1)
- composite (1)
- dXCT (1)
- distributed sensor (1)
- dual-energy (1)
- failure prevention (1)
- fiber optic sensor (1)
- grating (1)
- i-TRIBOMAT (1)
- inspection (1)
- iron embrittlement (1)
- laminography (1)
- neutron diffraction (1)
- neutron imaging (1)
- neutron instrumentation (1)
- poultry odorous air monitoring (1)
- railway embankment (1)
- refraction (1)
- residual stress (1)
- smart geotextile (1)
- synchrotron CT (1)
- thermal treatment (1)
- topography (1)
- µCT-analysis (1)
- Überdruckverfahren (1)
Organisationseinheit der BAM
- 8 Zerstörungsfreie Prüfung (69)
- 7 Bauwerkssicherheit (31)
- 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen (28)
- 8.3 Thermografische Verfahren (13)
- 8.4 Akustische und elektromagnetische Verfahren (13)
- 7.2 Ingenieurbau (11)
- 7.4 Baustofftechnologie (11)
- 5 Werkstofftechnik (10)
- 9 Komponentensicherheit (10)
- 8.6 Faseroptische Sensorik (9)
Sustainability means meeting the needs of today without compromising the needs of the next generations. How can we meet the needs of the next generations, if we do not even know what these needs are? If we do not listen to the next generation and learn from them? Do we even meet the needs of today for everyone on earth?
Alkali-activated fly ash mortars were studied with regard to durability-relevant transport coefficients and the electrochemical behaviour of embedded carbon steel bars on exposure of the mortars to leaching, carbonation and chloride penetration environments. The transport coefficients differed considerably between different formulations, being lowest for a mortar with BFS addition, but still acceptable for one of the purely fly ash-based mortars. Leaching over a period of ~300 days in de-ionized water did not lead to observable corrosion of the embedded steel, as shown by the electrochemical data and visual inspection of the steel. Exposure to 100 % CO2 atmosphere caused steel depassivation within approx. two weeks; in addition, indications of a deterioration of the mortar were observed. The results are discussed in the context of the different reaction products expected in high- and low-Ca alkali-activated binders, and the alterations caused by leaching and carbonation.
Laser-Metal-Deposition (LMD) and Plasma-Transferred-Arc (PTA) are well known Technologies which can be used for cladding purposes. The prime objective in combining LMD and PTA as a Hybrid Metal Deposition-Technology (HMD) is to achieve high Deposition rates at low thermal Impact. Possible applications are coatings for wear protection or repair welding for components made of steel. The two energy sources (laser and Plasma arc) build a Joint process Zone and are configurated to constitute a stable process at laser powers between 0.4-1 kW (defocused) and Plasma currents between 75-200 A. Stainless steel 316L serves as filler material. For this HMD process, a Plasma Cu-nozzle is designed and produced by powder bed based Selective Laser Melting. The potential of the HMD Technology is investigated and discussed considering existing process. This paper demonstrates how the interaction of the two energy sources effects the following application-relevant properties: Deposition rate, powder Efficiency and energy Input.
Maintenance, repair and overhaul of components are of increasing interest for parts of high complexity and expensive manufacturing costs. In this paper a production process for laser metal deposition is presented, and used to repair a gas turbine burner of Inconel 718. Different parameters for defined track geometries were determined to attain a near net shape deposition with consistent build-up rate for changing wall thicknesses over the manufacturing process. Spot diameter, powder feed rate, welding velocity and laser power were changed as main parameters for a different track size. An optimal overlap rate for a constant layer height was used to calculate the best track size for a fitting layer width similar to the part dimension. Deviations in width and height over the whole build-up process were detected and customized build-up strategies for the 3D sequences were designed. The results show the possibility of a near net shape repair by using different track geometries with laser metal deposition.
Energy efficient products often have a higher purchase price than less efficient alternatives. However, the life cycle costs are often lower due to the lower operating costs. From a purely economic point of view, efficient appliances are not only more ecological but often also more economical and, accordingly, should be purchased more frequently than less efficient appliances. However, this is not always the case. Information deficits are one of the major reasons of this discrepancy: the purchase price is visible during the purchasing process, but the follow-up costs are not, at least not in their exact amount. The EU Energy Label can be considered as a solution to close this gap. During the past decades, there has been a discussion on whether it would be better to communicate the monetary costs associated with energy consumption, since their calculation by the consumer is difficult or needs a high level of cognitive effort.
In this study, experiments and field studies on a total of 19 product groups were evaluated with regard to the question of whether the indication of costs instead of physical units affects the decision-making process of the consumer. It has been assessed under which circumstances it might positively influence the purchase decision of the customer, i.e. helping him or her to arrive at a more “energy efficient” decision. Overall, the results indicate that monetary claims possibly exceed the effect of claims on a physical basis when the costs or the differences between the alternatives available seem “relevant” to the consumer.
Currently at Deutsche Bahn (DB) ultrasonic inspections in maintenance procedures for wheelset axles with a bore hole are, to the greatest possible extent, carried out using automated ultrasonic inspection system. Although the acceptance levels are in accordance with DIN 27201 part 7, the testing results have shown in recent years that in the case of true indications, the effective defect sizes were far below the level of acceptance. Due to this experience it can be assumed that the automated ultrasonic inspection systems are testing substantially more sensitively than required. This increased sensitivity leads to an increase in false indications, generally resulting in the unnecessary demounting of wheelsets. In Research cooperation between Federal Institute for Materials Research and Testing (BAM) and DB the effective flaw detection sensitivity of existing automated ultrasonic inspection system will be determined and the true/false indication ratio optimised. Through systematic investigations with the Probability of Detection method on the existing automated ultrasonic inspection system the results could be directly applied to the optimisation of existing ultrasonic inspections of wheelset axles with a bore hole in maintenance procedures and the level of reliability can be considerably increased.
For industrial applications dealing with hydrogen, the definition of safety distances and the assessment of possible hazards emanating from releases is mandatory. Since hydrogen is usually stored and transported under pressure, one scenario to be considered is the momentum driven release of hydrogen from a leakage with subsequent ignition. In this scenario, the emitted heat radiation from the resulting jet flame to the surroundings has to be determined to define adequate safety distances. For hydrocarbon flames, different jet flame models are available to assess the hazards resulting from an ignited jet release. Since hydrogen flames differ from hydrocarbon flames in their combustion behavior, it has to be checked if these models are also applicable for hydrogen. To evaluate the accuracy of these models for hydrogen jet flames, tests at real-scale are carried out at the BAM Test Site for Technical Safety (BAM-TTS). Herein, the flame geometry and the heat radiation at defined locations in the surroundings are recorded for varying release parameters such as leakage diameter (currently up to 30 mm), release pressure (currently up to max. 250 bar) and mass flow (up to max. 0.5 kg/s). The challenge here is the characterization of the flame geometry in an open environment and its impact on the thermal radiation. Existing heat radiation data from the literature are mostly based on unsteady outflow conditions. For a better comparability with the steady state jet flame models, the experiments presented here are focused on ensuring a constant mass flow over the release duration to obtain a (quasi) stationary jet flame. In addition, stationary outflow tests with hydrocarbons (methane) were also carried out, which are intended to serve as reference tests for checking flame models based on hydrocarbon data.
Investigation of the salinization in marine and offshore environment - test methods and challenges
(2019)
Salinization and contamination of metal surfaces by chloride-containing aerosols is of great importance with regard to corrosion phenomena in the maritime sector and in offshore applications. Especially Offshore Wind Turbines are exposed to extreme corrosive conditions due to high chloride concentrations in the atmosphere and the resulting high chloride deposition rates. It is of great importance to evaluate to what extent salinization of the surface influences the corrosion protection of coatings and pitting occurrence on stainless steels under atmospheric conditions to evaluate the durability of metallic building structures in offshore and marine environments. The evaluation of the scientific literature and regulatory guidelines has shown that there are still many open questions regarding the contamination of metal surfaces by chlorides. This contribution will discuss how salinization of metal surfaces is evaluated and monitored according to current standards and guidelines. Future challenges concerning test methods and the application of evaluated salinization values and deposition rates will be discussed.
The lack of traceability to meter of X-ray Computed Tomography (CT) measurements still hinders a more extensive acceptance of CT in coordinate metrology and industry. To ensure traceable, reliable, and accurate measurements, the determination of the task-specific measurement uncertainty is necessary. The German guideline VDI/VDE 2630 part 2.1 describes a procedure to determine the measurement uncertainty for CT experimentally by conducting several repeated measurements with a calibrated test specimen. However, this experimental procedure is cost and effort intensive. Therefore, the simulation of dimensional measurement tasks conducted with X-ray computed tomography can close these drawbacks. Additionally, recent developments towards a resource and cost-efficient production (“smart factory”) motivate the need for a corresponding numerical model of a CT system (“digital twin”) as well. As there is no standardized procedure to determine the measurement uncertainty of a CT system by simulation at the moment, the project series CTSimU was initiated, aiming at this gap. Concretely, the goal is the development of a procedure to determine the measurement uncertainty numerically by radiographic simulation. The first project (2019-2022), "Radiographic Computed Tomography Simulation for Measurement Uncertainty Evaluation - CTSimU" developed a framework to qualify a radiographic simulation software concerning the correct simulation of physical laws and functionalities. The most important outcome was a draft for a new guideline VDI/VDE 2630 part 2.2, which is currently under discussion in the VDI/VDE committee. The follow-up project CTSimU2 "Realistic Simulation of real CT systems with a basic-qualified Simulation Software" will deal with building and characterizing a digital replica of a specific real-world CT system. The two main targets of this project will be a toolbox including methods and procedures to configure a realistic CT system simulation and to develop tests to check if this replica is sufficient enough. The result will be a draft for a follow-up VDI/VDE guideline proposing standardized procedures to determine a CT system's corresponding characteristics and test the simulation (copy) of a real-world CT system which we call a "digital twin".
Recently, non-destructive testing in civil engineering (NDT-CE), in particular of concrete components, has successfully mastered the leap from research to practice. Several methods have been established for field inspections to determine the concrete cover of reinforcement or to estimate the compressive strength as well as other parameters related to the concrete material. In addition, the application of nondestructive testing is indispensable, if information about the inner structure - such as the location of rebars and tendon ducts or the damage-related condition assessment to detect grouting defects, honeycombs, delamination, or corrosion - is required. Besides the selection of a suitable NDT method and an appropriate inspection system, the reliability of the results depends largely on the person who applies the non-destructive inspection technique and evaluates the inspection results. To ensure a high quality of non-destructive concrete evaluation as well as to keep the uncertainty caused by the inspection personnel to a minimum, structured, consistent and regulated theoretical as well as practical training of inspection personnel is essential. To close this gap, the subcommittee of education (UA-A) within the committee for NDT-CE of the German Society for Nondestructive Testing (DGZfP) has been reactivated in 2018 to establish uniform training standards for nondestructive concrete inspections in the long term. The subcommittee consists of scientists, practitioners, authorities, and clients. So far, the national standard DIN 4871 “Non-destructive testing - Qualification and Certification of NDT personnel in Civil Engineering (NDT-CE)” was developed and is currently under review. This standard considers the civil-industry-specifics, for example, that standards for NDT of concrete, as well as related product standards with a few exceptions, still do not exist at the moment. Within this presentation, the concept, the connection to ISO 9712 and other standards as well as an overview of the developed German standard DIN 4871 will be presented.
Introduction of a monitoring system for Bingham fluids in additive manufacturing with concrete
(2022)
Freeform additive manufacturing of concrete structures is a rising technology in civil engineering with several fascinating advantages. Nonetheless, to ensure reliability and structural integrity, standards and quality control are required in the future to bring this technology into the market. As the concrete is manufactured continuously, continuous quality control of the printing process is also required, i.e. comprehensive process monitoring. At BAM, a test rig will be installed, enabling the printing of concrete structures with a maximum size of 2 m x 1 m x 1 m (l x w x h). Here, process monitoring is the focus of the test rig. In this study, we show the results of the first pump tests, including the measurement of several parameters such as temperature and pressure along the supply system, i.e. from the concrete pump to the printer head.
Maintenance and renewal costs of a typical railway, track and substructure represents 50–60% of the total costs of such infrastructure over its entire service life. Innovations in track and substructure are therefore fundamental to achieve a significant
impact on the overall cost reduction for the railways. Therefore new solutions for track improvements that are effective and that can minimize the interruption of traffic are needed. Moreover, failures of railway embankments happened recently in different regions of the world. Such events, such as the one happened in UK in February 2013 (http://www.bbc.co.uk/news/uk-england-south-yorkshire-21441070), are showing the importance of monitoring track and infrastructure coupled with the use of numerical models for the localization of the critical areas and the design of appropriate countermeasures. Indeed embankment failures, landslides and uneven settlements and similar events are becoming much more common than in the past due to climate changes, and this requires the infrastructure managers to look from a different perspective infrastructure maintenance issues. What was previously consider as “extreme” is now “common” and thus actions need to be taken to be ready when such events will happen. The aim is to mitigate their effects on the infrastructure and to minimize disruptions to train services and reduce maintenance costs to restore the normal service conditions. If this mental change happens, then the need for solutions and techniques for global asset monitoring and ground stabilization will probably increase. Among the others, geotextiles and geogrids for soil reinforcement used in combination with condition monitoring techniques have the potential for minimizing catastrophic events, whilst at the same time providing a good balance among costs and benefits (i.e. sustainability).
The paper describe a case study where the use of multifunctional geotextiles, able to provide both strengthening and monitoring functions, has been tested along a railroad near the city of Chemnitz (Germany). The results are here reported to show the potential use and the innovative aspect of this solution.
The Infrastar training school provides lectures and hands-on training to Master and PhD students, early-stage researchers and (young) professionals on all aspects of asset management of civil infrastructures with respect to fatigue of materials. It is organized yearly since 2019 and up to 20 profiles are selected to attend the 3.5-day training.
A team of 7 teachers provides insight in multi-disciplinary and intersectoral basic concepts in three core fields, ranging from the design to the dismantling of the structures (bridges and wind turbines):
1. Monitoring and auscultation,
2. Structural and action models,
3. Reliability, risk and decision analyses.
Each year, a recognized expert is invited to deliver a keynote lecture to raise interest in a specific aspect of one of the fields covered. The presentation is recorded and published on the training school website.
Classical film radiography is a well-established NDT technique and it is most commonly used for testing weld seams and corroded pipes e.g. in oil and gas industry or in nuclear power plants. In the course of digitization, digital detector arrays (DDA) are finding their way into industrial applications and are replacing film radiography step by step. This study deals with the latest generation of DDAs, the photon counting and energy resolving detectors (PCD), and their characteristics compared to charge integrating detectors (CID). No matter which technology to use, radiography still lacks a general issue: A three-dimensional object is projected onto a two dimensional image. Of course, advanced computed tomography (CT) algorithms exist since many years, but if the object to investigate is too large to fit into the manipulation system or its shape is not appropriate, CT is not feasible or sensible to be applied. To overcome this limitation, numerous laminographic algorithms have been developed in the past. In this study, photon counting detectors are used in combination with co-planar translational laminography to gain reconstructed three-dimensional volumes. Both laminographic testing and PCDs require a serious knowledge of many parameters that can influence the image quality in the resulting datasets. These are e.g. the detector efficiency and calibration procedure, setting of energy thresholds, exposure data, number of projections, beam length correction and spatial resolution. The use of PCDs yields more variables to be considered compared to CIDs. The most important parameters in laminographic testing and in the use of PCDs are described in this study and limits are discussed.
Carbon arc-air gouging is a common technology when repairing defects in welded structures. Often this technique is applied in repeated cycles even on the same location of the joint. Due to the multiple heat input by gouging and subsequent re-welding, the residual stresses are strongly influenced. This can become crucial when microstructure and mechanical properties are adversely affected by multiple weld reparations. Knowledge about the relation of gouging and residual stresses is scarce but important when high strength steels, which are sensitive to residual stresses, are processed. The present study shows the effect of repair welding on a high strength steel structural element. The weld and the heat affected zone were subjected to multiple thermal cycles by gouging and subsequent repair welding. The residual stresses were determined by X-ray diffraction at different positions along the joint. The results showed that the residual stress level has increased by the repair cycles. This is most pronounced for the heat affected zone. Adapted welding procedures may prevent detrimental residual stress distributions.
The levelized cost of energy (LCoE) is an important measure to quantify the macro-economic efficiency of an offshore wind farm and to enable a quantitative comparison with other types of energy production. The costs of the structural integrity management - which is required to ensure an adequate lifetime reliability of the turbine support structures - are part of the operational expenditures of an offshore wind farm. An optimization of the structural integrity management may reduce the operational expenditures and consequently the LCoE. However, the effect of the structural integrity management on the LCoE is hardly known. To investigate this effect, this paper presents a sensitivity analysis of the LCoE of a generic offshore wind farm. The probabilistic models of the parameters influencing the LCoE are based on a literature study including an explicit model for the structural integrity management.
The analysis reveals that LCoE may potentially be reduced if an optimization of the structural integrity management enables a service life extension.
In this contribution, we discuss the influence of scattered radiation on materials’ effective attenuation coefficients at higher X-ray energies. The selected X-ray spectra for the dual-energy experiments correspond to 3 MV and 7.5 MV acceleration potential of the used betatron. Experiments were performed on a test phantom containing step wedges of different low- and high-Z materials. We evaluated the ratio between low- and high-energy X-ray attenuation coefficients quantitatively based on simulated poly-energetic high-energy X-ray source spectra and the detector sensitivity using the “analytical Radiographic Testing inspection simulation tool” (aRTist) developed at BAM. Furthermore, the influence of scattered radiation is evaluated using an efficient Monte-Carlo simulation. The simulation results are compared quantitatively with experimental investigations. Finally, important applications of the proposed technique in the context of aviation security are discussed.
High Entropy Alloys (HEAs) are a recent class of materials. In contrast to conventional alloys, HEAs consist of five alloying elements in equiatomic equilibrium. The high entropy effect is due, among other things, to the increased configuration entropy, which promotes solid solution formation. Many HEAs have enormous application potential due to excellent structural property combinations from very low to high temperatures. For the introduction of HEAs in real components, however, the question of the applicability of machining production technologies for component manufacture is of central importance. This has so far received Little attention in global materials research. Reliable and safe processing is essential for the demand of economical component production for potential areas of application, e.g. in power plant technology.
For metals, milling is the standard machining process. This article presents the results of machining analyses. It focuses on the surface integrity resulting from the milling process on a Co20Cr20Fe20Mn20Ni20-HEA. For this purpose, investigations were carried out using ball nose end milling tools for conventional milling process in comparison to an innovative hybrid process available at BAM Berlin, Ultrasonic-Assisted Milling (USAM). USAM promises a lower Degradation of the surface properties due to lower loads on the workpiece surface during machining.
For this purpose, basic milling parameters (cutting speed and tooth feed) were systematically varied and cutting forces were measured during the milling experiments. The subsequent Analysis of these forces allows an understanding of the mechanical loads acting on the tool and component surface. These loads cause topographical, mechanical and microstructural influences on the surface and consequently on the surface integrity. For their characterization, light and scanning electron microscopy were used, and the roughness and residual stresses via X-ray diffraction were measured. The results indicate significant advantages using USAM, especially due to reduced cutting forces compared to the conventional milling process. This causes lower mechanical loads on the tool and surface, combined with lower tensile residual stresses on and below the surface, and ultimately results in a significantly enhanced surface integrity.
The current paper presents residual stress analyses of large scale LTT (Low Transformation Temperature) welds. LTT filler materials are specially designed for residual stress engineering by means of an adjusted martensite phase transformation. Controlling the level of mostly detrimental residual stresses already during the welding process would be highly attractive as time and cost consuming post processing may be prevented. In large scale welds the residual stress state is influenced by the heat control (e.g. interpass temperature) during welding. Therefore, welding residual stresses are studied here putting the focus on the influence of welding process parameters while joining heavy steel sections with a thickness of 25 mm. The residual stress state was determined at the top surface using X-ray diffraction as well as in the bulk by neutron diffraction. The results show that control of the interpass temperature is vital for the residual stresses present in the joints. This accounts for the top surface but is most pronounced for the bulk of the welds. While high interpass temperatures are appropriate to induce compressive residual stresses in the weld metal, low interpass temperatures favor unwanted tensile residual stresses instead.
Carbon Fibre Reinforced Plastics (CFRP) are more and more used in modern civil aircrafts. These days the whole fuselage is made of this material (B787; A350). Due to strict certification standards the normal in-service loading gives a low stress level compared to the static and even the fatigue strength of the material. Hence CFRP are assumed to have an infinite life. To evaluate this assumption, fatigue tests on CFRP-specimens were performed up to 108 load cycles and the first inter-fibre failure was evaluated non-destructively by accompanying Xray-refraction topography. A tensile testing machine was integrated in a small angle X-ray scattering (SAXS) setup. X-ray refraction topography was performed while the CFRP samples were tensile loaded. This non-destructive technique enables the detection of micro-cracking and inter-fibre failure especially for CFRP. For Glass Fibre Reinforced Plastic (GFRP) X-ray refraction and in-situ loading has already been successfully used. The increase of inner surfaces due to inter fibre failure was measured as a function of the stress state. Fatigue tests were performed at and below the limit of inter-fibre failure strength. State of the art is to assume the failure of the samples under cyclic loading as the fatigue life. Accompanying non-destructive X-ray refraction measurements reflects the damage state and enables to trace its evolution even if the total failure of the specimens does not occur. This investigation technique is of high interest to give the engineer a design value of infinite life which is practically often reached due to knock down factors of certification standards. Finally the infinite life was found for cyclic fatigue loaded CFRP-samples even under high inter fibre transverse and shear loading investigated up to 108 load cycles.