Präsentation
Filtern
Dokumenttyp
- Vortrag (6)
Sprache
- Englisch (6)
Referierte Publikation
- nein (6)
Schlagworte
- Fire stability (6) (entfernen)
Organisationseinheit der BAM
Eingeladener Vortrag
- nein (6)
Composites in Fire and Flame
(2022)
Overview over the research results of the BAM in the field fire retardancy of composites. In different applications the flame retardancy of composites targets on different fire protection goals in the fire scenarios ignition, developing fire, and fully developed fire. Efficient solutions are tailored to pass a distinct fire test and to fit to a specific material. Flame inhibition as main flame retardancy mode of action combined with a minor mode of action in the condensed phase is general very efficient approach for composites. Alternatively residue design is demanded to achieve good results with only condensed phase mechanisms. Improving the fire stability asks for protective fire residues.
Carbon fibre (CF) and glass fibre (GF) reinforced polymers are used for diverse applications demaning flame and fire retardancy in the fire scenarios ignition, developing fire and fully developed fire. The fire behaviour of composites differs from polymers, since fibres behave often inert with respect to pyrolysis, change the melt flow / dripping behaviour, the heat absorption and transfer, the amount and properties of the fire residue. Concepts are needed suitable for the different fire protection goals, but also tailored for composites. The field is illuminated by examples carried out in the group of the author in the recent years. Approaches to halogen-free flame retardancy in GF reinforced thermoplastics and CF reinforced thermosets are presented as well as building up a bench and intermediate scale testing of composites in fire applying mechanical load and direct flame exposure simultaneously. The understanding of fire behaviour and flame retardancy modes of action in composites is a promising basis for target-oriented development.
The fire behaviour of carbon fibre (CF) reinforced polymers differs in comparison to polymers. Fibres behave often inert with respect to pyrolysis, they change the melt flow and dripping behaviour, the heat absorption and transfer, the amount and properties of the fire residue and so on. Flame and fire retardancy concepts are needed not only suitable for the different fire protection goals typical for each application, but also tailored for composites. This field is illuminated by examples taken from different projects carried out in the group of the author in the recent years. The examples target on different applications through achieving reduction in reaction to fire controlling the fire risks (flammability, heat release) in the beginning and development of a fire and investigating the fire stability, when a severe flame is directly applied (key property in fully developed fires). Approaches to halogen-free flame retardancy in CF reinforced thermosets are presented as well as building up a bench and an intermediate scale testing of composites in fire applying mechanical load (up to 1 MN compression) and direct flame exposure (180 kW/m2) simultaneously. Indeed, e.g. we have investigated the fire stability of stringer reinforced shell components taken out from the fuselage of an aircraft.
The understanding of fire behaviour, fire resistance, and fire retardant modes of action in composites is a promising basis for target-oriented development. The role of flame inhibition, charring, and protective layer formation is discussed. Successful concepts are presented for fire retardancy tailored for different application as well as general guidelines for future development. Different phosphorus flame retardants are proposed to achieve halogen-free flame retardancy with respect to ignition and developing fires. Different protective approaches are sketched for addressing the fire stability of composites that is the most important fire risk for the fire resistance in structural applications.
The fire resistance of load-bearing composite components, e.g. sandwich panels in transportation or stringer reinforced shells used for fuselages, differs in comparison to metal systems. Fibres behave rather inert with respect to pyrolysis reducing burn-through phenomena. The fire stability becomes the main task, because it already breaks down when reaching the softening temperature of the matrix. Fire protection concepts are needed based on efficient thermal insulation and tailored for composite structures.
The fire behaviour of fibre reinforced polymeric composites differs in comparison to polymers. Fibres behave often inert with respect to pyrolysis, they change dripping behaviour, the heat absorption and transfer, the amount and properties of the fire residue and so on. Their fire behaviour becomes somewhat singular. The fire resistance of load-bearing composite components, e.g. sandwich panels for transportation or stringer reinforced shells used for fuselages in aviation, differs in comparison to metal systems. Not burn-through, but the fire stability is typical critical mode of failure. The mechanical failure in fully developed fires can not be explained by the mechanical properties at room temperature, but are controlled by the decomposition and even more important by the softening of the matrix. Fire retardancy concepts are needed based on efficient thermal insulation and tailored for composites. This field is illuminated by examples taken from different projects carried out in the group of the presenting author in the recent years,[1-5] and still running unpublished activities as well. The fire stability is investigated for realistic compression loads, when a severe flame is directly applied (key property in fully developed fires). A bench scale specimen (specimen 150 mm x 150 mm, plates, sandwich, shells) and an intermediate scale (specimen 500 mm x 500 mm, plates, sandwich, shells) fire stability testing was performed. Indeed, e.g. we have investigated the fire stability of stringer reinforced shell components taken out from the fuselage of an aircraft. We applied mechanical load up to 233 kN and 1 MN in the bench-scale and intermediate-scale testing, respectively, and direct flame exposure using burners (180 kW/m2) simultaneously.
The understanding of the fire resistance and fire protection modes of action in composite and composite components is a promising basis for target-oriented development. The role of the fire residue, protective layer formation, and the design of the components is discussed. Successful concepts are presented for increasing the fire resistance of load-bearing composite components as well as general guidelines for future development.