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A B S T R A C T Rotors of turbines are exposed to high thermo-mechanical loads, especially during startup and shut-down procedures. Especially in the notched region of the blade-connection to the rotor a complex multiaxial elastic-plastic stress state is present. The reason is the multi-surface contact in combination with fatigue and creep-fatigue load. Within the scope of this work the blade-disc-connection of a gas turbine made of the nickel-based alloys IN792 (blades) and IN718 (disc) was investigated at typical local service temperature of 550 • C. The aim was the investigation of mutual influence of adjoining blades as well as the effect on cycles to failure by variation of friction behaviour due to different coatings on the surface of the blade root. An already existing life assessment method based on a local strain approach could be confirmed for this more complex loading situation. In contrast to this, a blade-shaft-connection of a steam turbine made of X12CrMoWVNbN10-1-1 was investigated at its typical service temperature of 600 • C. During cyclic loading, the martensitic 10Cr steel reacts with ongoing cyclic softening. The fundamental result of the work discussed here is the development of a new life assessment method based on a damage parameter, which is a function of accumulated plastic strain. This damage parameter is included in a complex material model considering static, cyclic and viscoplastic materials behaviour. Thus, the life assessment method could be verified with inelastic finite element calculations of the model specimens, which were especially designed for the low-cycle fatigue tests of blade-shaft-connection presented in this paper.

<p>Ultra high performance fibre reinforced concrete (UHPFRC) is a new construction material that enables the construction of slender and aesthetically appealing structures. First applications in structural engineering demonstrate the potential of this new building material. Most promising in that respect is the use of UHPFRC in combination with steel reinforcement. For this reason, the behaviour of UHPFRC tension chords reinforced with different types of steel has been experimentally investigated. In this paper an analytical model is presented which allows the calculation of the behaviour of reinforced UHPFRC tension chords. Based on a parametrical study failure modes and minimum reinforcement requirements are studied. Considering applications, significant benefits can be achieved with regard to the aesthetics by using filigree trusses. The possibilities are outlined with help of an example girder made of UHPFRC.</p>