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Erscheinungsjahr
- 2016 (2) (entfernen)
Dokumenttyp
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- Englisch (2)
Schlagworte
- Constitutive equation (1)
- Creep (1)
- Fire engineering (1)
- composite (1)
- fire resistance (1)
- fire stability (1)
- intermediate-scale testing (1)
- sandwich panels (1)
- shells (1)
The phenomenon of creep of structural steel in fire engineering is gaining more and more interest. Due to shortcomings of the EC3 constitutive model and other approaches based on classical creep theory an alternative approach mainly based on the ideas of Krempl is proposed. Due to this so-called operator approach the material as well as the constitutive model is looked upon as an operator. The application of this view serves as a guide through the analysis of the relationship between experimental facts and constitutive theory especially in the context of transient creep.
Intermediate-scale testing is indispensable when investigating the fire resistance under simultaneous compressive load of components made of glass- and carbon-fibre-reinforced composites (GFRP and CFRP). BAM is successfully operating an intermediate-scale test stand, developed for a specimen size of 500 mm x 500 mm (1000 mm). The fire resistance in terms of fire stability of CFRP and GFRP sandwiches are investigated, e.g. at 20 % of their compressive failure load at room temperature. Times to failure increase by up to a factor of 4 due to intumescent coatings. For GFRP sandwiches, different core structures with and without additional flame retardants show an astonishing impact on time to failure. CFRP shell structures are investigated on the intermediate scale with and without stringer reinforcements, resulting in completely different mechanical failure behaviour in the ultimate load test as opposed to the fire resistance test. The stringers become the only load-carrying part, while the shell acts as a protective layer. Thus the design exploiting this self-protection potential, i.e. the residue of the front skin protecting the load-bearing structure, is highlighted as a most promising route to enhance the fire resistance of lightweight materials.