Filtern
Erscheinungsjahr
Dokumenttyp
- Beitrag zu einem Tagungsband (18)
- Zeitschriftenartikel (12)
- Beitrag zu einem Sammelband (6)
- Vortrag (5)
- Buchkapitel (3)
- Handbuch (1)
Sprache
- Englisch (45) (entfernen)
Schlagworte
- Monitoring (4)
- Messtechnik (3)
- Sensorik (3)
- Structural health monitoring (3)
- Application (2)
- Characterisation (2)
- Digital image correlation (DIC) (2)
- Digitale Bildkorrelation (DIC) (2)
- Drop test (2)
- Dynamic testing (2)
- Dynamische Tests (2)
- Polymer optical fiber (2)
- Spannungs-Dehnungs-Kurve (2)
- Split Hopkinson pressure bar (SHPB) (2)
- Standard (2)
- Strain (2)
- Stress-strain curve (2)
- Temperature (2)
- Accelerometer (1)
- Additive Manufacturing (1)
- Ageing (1)
- Aging (1)
- Air-based (1)
- Berlin Main Station (1)
- Bridges (1)
- Brillouin scattering (1)
- Brillouin-Streuung (1)
- Chemiluminescence (1)
- Chemiluminescence (CL) (1)
- Condition monitoring (1)
- Damage detection of bridges (1)
- Data processing (1)
- Data-fusion (1)
- Defect evaluation (1)
- Degradation (1)
- Dehnungssensor (1)
- Differential displacements (1)
- Digital image correlation (1)
- Distributed sensor (1)
- Environment (1)
- Experimental-analytical symbiosis (1)
- FBG sensors (1)
- Faseroptischer Sensor (1)
- Fatigue (1)
- Fiber bragg grating (1)
- Fiber optic sensor (1)
- Fiber-optic sensor (1)
- Fibre-optic sensor (1)
- Hazardous scenarios (1)
- High speed stereo photogrammetry (1)
- Hydraulic levelling system (1)
- In-situ Process Monitoring (1)
- Intelligentes Geotextil (1)
- Lagrange multiplier test (1)
- Lagrangian Multipliers (1)
- Laser-based displacement measuring system (1)
- Localization (1)
- Long-term monitoring (1)
- Magnetic field (1)
- Magnetostrictive metal coating (1)
- Materials evaluation (1)
- Measurement Methods for Composition and Structure (1)
- Measurement Methods for Material Performance, Modelling and Simulation Methods (1)
- Measurement Methods for Material Properties (1)
- Measurement reliability (1)
- Mesh routing (1)
- Multi-hop (1)
- Multi-sensor system (1)
- Non-destructive Materials (1)
- Non-destructive testing (1)
- Numerical simulation (1)
- Optical Fibres (1)
- Optical digitization (1)
- Optical transmission stability (1)
- Plastic optical fibres (1)
- Polymer optical fibers (POFs) (1)
- Polymeroptische Faser (1)
- Process development (1)
- Reliability (1)
- Safety (1)
- Safety management (1)
- Self-diagnostic fiber optical sensor (1)
- Sensing (1)
- Sensors (1)
- Smart geotextiles (1)
- Specification (1)
- Standardisation (1)
- Standardization (1)
- Standards (1)
- Steel sheet container (1)
- Strain measurements (1)
- Strain sensor (1)
- Structural health (1)
- Structural modelling (1)
- Structured light scanning (SLS) (1)
- Temperature behavior (1)
- Testing (1)
- Textile-reinforced composites (1)
- Thermo-oxidative stability (1)
- Transparency (1)
- Verteilter Sensor (1)
- WSN (1)
Organisationseinheit der BAM
- 8 Zerstörungsfreie Prüfung (2)
- 4 Material und Umwelt (1)
- 4.2 Material-Mikrobiom Wechselwirkungen (1)
- 5 Werkstofftechnik (1)
- 5.1 Mikrostruktur Design und Degradation (1)
- 5.2 Metallische Hochtemperaturwerkstoffe (1)
- 5.4 Multimateriale Fertigungsprozesse (1)
- 8.0 Abteilungsleitung und andere (1)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (1)
- 8.3 Thermografische Verfahren (1)
Eingeladener Vortrag
- nein (5)
High quality tubular products are essential to the oil and gas industry. Quality control during their production focuses on the non-destructive detection of surface defects. The structured light technique is a candidate for the challenge to detect, monitor and evaluate such defects in real-time.
In the present study the automatic processing of structured light measurements is performed and validated. The algorithm for the automatic Analysis of inspection data has an advantage over current data evaluation methods based on individual assessments of operators.
With more than 180.000 engineers and scientists VDI Association of German Engineers and VDE Association for Electrical, Electronic & Information Technologies are belonging to the major technical and scientific associations in Europe. Both organizations promote the advancement of technology and among other things by developing recognized technical regulations as national and international standards. Since 2011 Technical Committee 2.15 Optical Measuring Methods for Structure Analysis and Monitoring as a common committee of both organizations is working among other things on the development of standards for optical measuring and testing methods. The committee consists of 27 members representing industrial users, system manufacturers, research institutes and universities. Currently the committee is drafting the new standard VDI/VDE 2626 Part 1 - Optical measuring procedures – Image correlation methods – Basics and equipment, which will be introduced in this presentation.
Draft VDI/VDE 2626 Part 1 describes practical acceptance and reverification procedures for the evaluation of the accuracy of optical measuring systems based on digital image correlation (DIC) methods. The document applies to DIC measurement systems used a) for full-field determination of two- or three-dimensional displacement of surfaces, and b) for
full-field determination of the elongation or strain of surfaces. The standard describes quality parameters as well as methods and reference objects for their determination. The quality parameters serve to specify DIC systems, and to compare different systems. They are equally suitable a) for acceptance tests as well as b) for reverification of DIC systems within the framework of a quality management system.
The acceptance test is used to determine whether the DIC system complies with the quality parameter limits specified by the manufacturer, or with contractually agreed limits by the manufacturer and user, respectively. For this test the quality parameters zero-displacement error, zero-strain error, and displacement error are defined and used. Zero-displacement error and zero-strain error describe minimum measurement uncertainties of the DIC system a user has to reckon with. They are influenced by different uncertainty contributions. The quality parameter displacement error is used to check the ability of the DIC system to determine absolute displacements within the measurement volume and to confirm the traceability of this measurement to the SI system.
Reverification of DIC systems serves to ensure long-term compliance with specified limits for the quality parameters. By comparing the results of successive reverification measurements of the quality parameters used for the acceptance test, it is possible to analyze trends with respect to changes in DIC system characteristics.
Piezoresistive accelerometers use a strain-sensing element, generally made of semiconductor material, e.g., silicon to convert the mechanical motion into an electrical signal. This element is usually designed in form of a cantilever beam loaded with a mass. Acceleration causes bending of the beam, which produces a change of electrical resistance proportional to the applied acceleration.
Main advantages of piezoresistive accelerometers in comparison to other types, e.g., piezoelectric and capacitive, is their robust and highly dynamic behavior, which qualifies them for application in high impact shock applications. Mechanical damping is typically implemented with silicon oil in a way that the output signal is undistorted over a wide frequency range. These characteristics principally qualify them for the application in drop tests carried out at BAM, for which they are calibrated over the frequency range from 1 to 4 kHz. However, using silicon oil for damping, has the drawback of temperature dependent change of its viscosity, leading to temperature dependent deviation of the accelerometer’s sensitivity.
This study presents experimental results of the temperature behavior of a piezoresistive accelerometer with a dynamic range up to ±5000 g.
This type of accelerometer is applied for drop tests which are partially performed at temperatures of -40 or +100 °C.
Fiber optic sensors have gained increasing importance in recent years and are well established in many areas of industrial applications. In this paper, we introduce a concept of a self-diagnostic fiber optic sensor. The presented sensor is to resolve the problems of embedded fiber optic sensors in complex structures and to enable the validation under operational conditions. For this purpose, different magnetostrictive coated fiber optic sensors were developed and various experiments were performed to verify their mode of Operation and to determine the respective reproducibility. The measuring principle is illustrated by obtained experimental results, which showed a change in wavelength from 1 pm at a magnetic field strength change of 0.25 mT.
In addition, the temperature characteristics of the implemented magnetostrictive sensor were analyzed and an experimental factor of 1.5 compared to a reference fiber optic sensor was determined.
Measurement and data recording systems are important parts of a holistic Structural Health Monitoring (SHM) system.
New sensor technologies such as fiber-optic sensors are often used; however, standards (or at least guidelines) are not yet available or internationally approved. This lack in standardization makes the acceptance of FOS technologies in complex SHM systems substantially difficult. A standard family for different FOS technologies is therefore being developed that should help to design SHM systems in an optimal way. International standardization activities take place in several standardization bodies such as IEC and ASTM, and within SHM societies such as ISHMII.
The paper reports on activities in standardization of fiber-optic sensors, on results already achieved, and on newly started projects. Combined activities of fiber sensor experts and SHM experts from Civil Engineering are presented. These contributions should help owners of structures as well as developers of sensors and monitoring systems to select effective and validated sensing technologies. Using these standards, both parties find recommendations how to proceed in development of SHM systems to evaluate the structural behavior based on e.g. standardized fiber optic sensors, and to derive necessary measures, e.g. the optimal maintenance strategy.
Berlin Main Station is the largest multi-level station in Europe. Its daily passenger number amounts to over 300.000. Structures built for such a large number of people require a high-level safety standard. The station was built on the inner city site of the historic Lehrter Bahnhof. The conditions for building and start of operation were challenging by several reasons. The typical sandy ground with a high level of groundwater makes the permanent static stability of such a complex structure difficult. Several completed, ongoing, and planned construction activities in the immediate vicinity of the station influence the ground settlement of the whole area. On basis of the structural design an impact prediction was calculated, which expected certain vertical displacements particularly between the single columns of the outer concrete bridges of the building. These columns support the glass roof construction, which only allows a defined limit of displacement. In order to avoid damage, a concept for monitoring and adjusting potentially occurring displacements was developed for installation at the outer bridges of the station.
The stress vs. strain curve of materials is affected the rate of imposed straining. Among the methods for dynamic testing the technique known as 'split Hopkinson pressure bar' (SHPB) has evolved into the most widely used one to exert high-speed straining. The theory behind it comprises simple equations to compute stress and strain. The reliability of the strain analysis can be assessed by digital image correlation (DIC). The present results indicate that the visually observed strain is smaller than predicted by theory.
Innovative structural damage detection of bridges by least squares adjustment with constraints
(2016)
Long-term monitoring of bridges requires the early detection of spreading damage because very often the damage is not really visible. For many decades engineers and scientists relayed on dynamic methods especially modal ones. However, after fundamental tests by the U.S. FHWA in 1993, it became evident that more successful methods should be developed, but no innovation really happened. A substantial innovative detection method started four years ago from Lagrange Multiplier Testing which eventually resulted in experimental verification based on measurement of deflection and curvature of the bridge beam and together the methodological combination of both.
The stress vs. strain curve of materials is affected the rate of imposed straining. Among the methods for dynamic testing the technique known as 'split Hopkinson pressure bar' (SHPB) has evolved into the most widely used one to exert high-speed straining. The theory behind it comprises simple equations to compute stress and strain. The reliability of the strain analysis can be assessed by digital image correlation (DIC). The present results indicate that the visually observed strain is smaller than predicted by theory.