Fatigue crack growth analysis of the low-pressure rotor of the steam turbine

Tento příspěvek shrnuje aplikovaný numericko-analytický přístup k predikci směru a rychlosti šíření trhlin v potenciálně kritických lokalitách hřídele nízkotlaké části parní turbíny. Primárním cílem bylo poskytnout hodnotící hledisko pro posouzení trojice kandidátních materiálů pro konstrukci hřídele v daných provozních podmínkách a s ohledem na předpokládaný charakter šíření trhlin. Výsledkem jsou predikované růstové křivky modelových trhlin, resp. diagramy mapující charakter šíření trhlin v podmínkách kombinovaného namáhání drážky závěsu lopatky turbíny.This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Grant Agreement 764545– TURBO-REFLEX.This paper summarizes the applied numerical-analytical approach for predicting the fatigue crack growth rate and direction of propagation in potentially critical localities of the shaft of the low-pressure part of the steam turbine. The primary objective was to develop a means of evaluation of a pair of candidate materials applicable to shaft design under given operating conditions and with respect to the expected mechanism of crack propagation. As a main result, predicted fatigue crack growth curves of model cracks and diagrams mapping the nature of crack propagation in the conditions of combined loading of the turbine blade groove were obtained

Comparison of J Integral Assessments for Cracked Plates and Pipes

The purpose of this article is to compare two predictive methods of J integral assessments for center-cracked plates, single-edge cracked plates and double-edge cracked plates produced from X52 and X70 steels, and a longitudinally cracked pipe produced from X70 steel. The two methods examined are: the GSM method and the Js procedure of the French RCC-MR construction code, designated here as the FC method. The accuracy of J integral predictions by these methods is visualized by comparing the results obtained with the “reference” values calculated by the EPRI method. The main results showed that both methods yielded similar J integral values, although in most cases, the GSM predictions were slightly more conservative than the FC predictions. In comparison with the “reference” values of the J integral, both methods provided conservative results for most crack configurations, although the estimates for cracks of a relative length smaller than 1/8 were not found to be so conservative. The prediction of burst pressures for external longitudinal semielliptical part-through cracks in X70 steel pipe showed that the magnitudes of predicted burst pressures came very close to each other, and were conservative compared to FEM (finite element method) calculations and experimentally determined burst pressures

Fatigue crack growth analysis of the low-pressure rotor of the steam turbine

Tento příspěvek shrnuje aplikovaný numericko-analytický přístup k predikci směru a rychlosti šíření trhlin v potenciálně kritických lokalitách hřídele nízkotlaké části parní turbíny. Primárním cílem bylo poskytnout hodnotící hledisko pro posouzení trojice kandidátních materiálů pro konstrukci hřídele v daných provozních podmínkách a s ohledem na předpokládaný charakter šíření trhlin. Výsledkem jsou predikované růstové křivky modelových trhlin, resp. diagramy mapující charakter šíření trhlin v podmínkách kombinovaného namáhání drážky závěsu lopatky turbíny.This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Grant Agreement 764545– TURBO-REFLEX.This paper summarizes the applied numerical-analytical approach for predicting the fatigue crack growth rate and direction of propagation in potentially critical localities of the shaft of the low-pressure part of the steam turbine. The primary objective was to develop a means of evaluation of a pair of candidate materials applicable to shaft design under given operating conditions and with respect to the expected mechanism of crack propagation. As a main result, predicted fatigue crack growth curves of model cracks and diagrams mapping the nature of crack propagation in the conditions of combined loading of the turbine blade groove were obtained

Metodika pro práci s přírodovědeckým typovým materiálem

The book deals with basic, really existing elements of nomenclature in natural sciences - types, which represent pillars for scientific names of organisms and minerals. It describes especially the managing of types governed by zoological and botanical codes (ICZN, ICN), both for their living and extinct representatives. The text covers the following aspects of managing types: their distinguishing, terminology, preparation, preventive conservation, packaging, labelling, documentation, publishing, studying, and loaning

An approximate method for calculating elastic-plastic stress and strain on notched specimens

The paper deals with an approximate method for calculating elastic-plastic stresses and strains on the surface of notched samples. The method is based on the Abdel-Karim-Ohno cyclic plasticity model. The plane stress condition is considered within the evaluation. The output of the approximation on several multiaxial axial-torsion load paths is compared to our own experimental results. Experiments were carried out on samples of two notch types manufactured from the 2124-T851 aluminum alloy. Strain distribution in the notch area was measured by digital image correlation. The comparison between computational solution and measured response shows that the new method allows for obtaining reasonably good approximation, even for relatively complicated multiaxial load cases.Web of Science154art. no. 143