Filtern
Erscheinungsjahr
Dokumenttyp
- Beitrag zu einem Tagungsband (80)
- Zeitschriftenartikel (51)
- Posterpräsentation (46)
- Vortrag (33)
- Beitrag zu einem Sammelband (8)
- Forschungsbericht (4)
- Sonstiges (2)
- Dissertation (1)
Sprache
- Englisch (152)
- Deutsch (70)
- Mehrsprachig (2)
- Polnisch (1)
Schlagworte
- Structural health monitoring (17)
- RFID sensors (14)
- Gas storage areas (12)
- Membrane-based gas sensing (12)
- Subsurface monitoring (12)
- Monitoring (11)
- Mobile Robot Olfaction (10)
- Nano aerial robot (10)
- Smart structures (10)
- Drop test (9)
Organisationseinheit der BAM
- 8 Zerstörungsfreie Prüfung (68)
- 8.1 Sensorik, mess- und prüftechnische Verfahren (68)
- 1 Analytische Chemie; Referenzmaterialien (9)
- 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen (9)
- 1.9 Chemische und optische Sensorik (7)
- 2 Prozess- und Anlagensicherheit (4)
- 2.1 Sicherheit von Energieträgern (4)
- 3 Gefahrgutumschließungen; Energiespeicher (2)
- 6 Materialchemie (2)
- 6.7 Materialsynthese und Design (2)
Paper des Monats
- ja (1)
Eingeladener Vortrag
- nein (33)
Barrier formation and increasing the melt viscosity are addressed as the two main general fire retardancy mechanisms of polymer nanocomposites. They result in specific impacts on fire properties that consequentially cause varying flame retardancy efficiency in different fire tests. The barrier formation retards mainly flame spread (peak of heat release rate) in developing fires, but does not reduce fire load (total heat evolved), ignitability or flammability (limiting oxygen index, UL 94). Furthermore, this flame retardancy effect increases with increasing irradiation and vanishes with decreasing irradiation. The increased melt viscosity prevents dripping, which is beneficial or disadvantageous depending on the fire test used. In some test, it become the dominant influence, transforming self-extinguishing samples into flammable materials or causing wicking. Advantages and the limits are sketched comprehensively for exploiting the main general fire retardancy mechanisms of polymer nanocomposites. It is concluded that barrier formation and changing the melt viscosity in nanocomposites are not sufficient for most applications, but must be accompanied by additional mechanisms in special systems or in combination with other flame retardants.
A method was developed to assess the heat insulation performance of intumescent coatings. The method consists of temperature measurements using the bench-scaled experimental set-up of a cone calorimeter and finite difference simulation to calculate the effective thermal conductivity dependent on time/temperature. This simulation procedure was also adapted to the small scale test furnace, in which the standard time-temperature curve is applied to a larger sample and thus which provides results relevant for approval. Investigations on temperature and calculated effective thermal conduction were performed on intumescent coatings in both experimental set-ups using various coating thicknesses. The results correspond to each other as well as showing the limits of transferability between both fire tests. It is shown that bench-scaled cone calorimeter tests are a valuable tool for assessing and predicting the performance of intumescent coatings in larger tests relevant for approval. The correlation fails for processes at surface temperatures above 750°C, which are not reached in the cone calorimeter, but are attained in the small scale furnace set-up.
Structural Health Monitoring (SHM) is an important part of buildings surveillance and maintenance to detect material failure as early as possible and to contribute in protection of structures and their users.
The implementation of Radio Frequency Identification (RFID) sensor systems without cable connection and battery into building components offers innovative possibilities to enable long-term in-situ SHM of addressed structures, bridges. The objectives of the presented study are complete embedding of RFID sensors systems in concrete, full passive communication with the systems, at best for the whole life span of structures. One challenge for this task is the highly alkaline environment in concrete, which requires non-degrading and robust encapsulation. Further Requirements are passive communication and energy supply, appropriate antenna design, placement and fixation in concrete, and the selection and implementation of sensors and connections. The concept is to develop and optimize a simple and robust system, which meets the requirements, as well as comprehensive validation in concrete specimen and real world applications. Two different systems were developed (HF and UHF RFID, respectively).
First tasks were the implementation of analog sensors using the superposition principle for the signal adaption. Investigation of suitable materials for robust encapsulation and sensor protection against basic environments.
Four materials were investigated in pH 13 solution for 14 days
- 3D-Printer-Polymer was completely resolved
- PVC has no noticeable decrease in weight
- (VitaPro) glass filter for the sensor protector, has weight loss 2.7 %
- The epoxy resin has increased by 1.8 % due to moisture expansion
Different concrete samples were prepared for the validation of the systems.
RFID sensors were embedded in different integration depths. Investigate the energy- and data transfer through concrete, also with varying moisture content. Additionally, signal strength data was used to optimize and validate the antenna characteristics in concrete. Next steps are to guarantee a sufficient energy supply for UHF RFID systems embedded in different concrete mixtures and further embedding the HF and UHF RFID systems in real bridges and buildings to validate the long term monitoring.