The burst of a disc in rotating machinery can cause catas- trophic damage of the equipment and, more importantly, it can represent a mortal threat to anyone in the sphere of influence of the event. In order to minimize the danger associated to a rotating component failure, burst testing is required by the au- thorities in order to set safety margins to the normal operating speeds. Moreover more accurate predicting tools are required for designing the components. This paper presents the results of a numerical and analytical study on the assessment of the crack driving force for discs containing surface flaws. The aim is to provide a simple, though reliable, tool in order to be able to calculate the possible dangerous in-service speed for a rotating component and, therefore, to set burst margins above the nor- mal operating conditions of the equipment. An R6-like flaw as- sessment procedure is adopted considering different assumptions in the definition of the critical speed and the analytical predic- tions are compared with the results of elastic-plastic finite ele- ment analysis of disc. In particular, the validity and potentiality of the method is proved for surface flaws in different positions in the disc.

CRITICAL SPEED OF FLAWED ROTORS: GLOBAL VS. LOCAL APPROACH

SCOLAVINO, LUIGI;BERETTA, STEFANO;
2014-01-01

Abstract

The burst of a disc in rotating machinery can cause catas- trophic damage of the equipment and, more importantly, it can represent a mortal threat to anyone in the sphere of influence of the event. In order to minimize the danger associated to a rotating component failure, burst testing is required by the au- thorities in order to set safety margins to the normal operating speeds. Moreover more accurate predicting tools are required for designing the components. This paper presents the results of a numerical and analytical study on the assessment of the crack driving force for discs containing surface flaws. The aim is to provide a simple, though reliable, tool in order to be able to calculate the possible dangerous in-service speed for a rotating component and, therefore, to set burst margins above the nor- mal operating conditions of the equipment. An R6-like flaw as- sessment procedure is adopted considering different assumptions in the definition of the critical speed and the analytical predic- tions are compared with the results of elastic-plastic finite ele- ment analysis of disc. In particular, the validity and potentiality of the method is proved for surface flaws in different positions in the disc.
2014
Proceedings of ASME Turbo Expo 2014
fracture, turbine, disc rotor
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11311/965640
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