Study on Optimal Calculation Model for High Piers of Rigid Frame Bridge Under Pile-Soil Effect
Issue:
Volume 3, Issue 6, December 2018
Pages:
134-144
Received:
19 November 2018
Accepted:
4 December 2018
Published:
2 January 2019
DOI:
10.11648/j.eas.20180306.11
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Abstract: The relative deformation value measured at the stage of closing and pushing of continuous rigid frame bridge appears difference from the model theoretical calculated values in most cases, because most models ignore the pile-soil effect and simplified consider the bottom of the pier as consolidation. At the same time, most literatures use single pile-soil effect model to analyze the stress influence on bridge structures, however, there are few researches on the difference and simulation accuracy of the different pile-soil effect model. Therefore, this paper discusses the advantages and disadvantages of six different pile-soil effect calculation models, and determining high pier optimal calculation model of rigid frame bridge by comparing and analyzing the relative displacement of the top closure. Last, this article gets the conclusion that the three-spring model is the optimal calculation model of high pier under pile-soil effect.
Abstract: The relative deformation value measured at the stage of closing and pushing of continuous rigid frame bridge appears difference from the model theoretical calculated values in most cases, because most models ignore the pile-soil effect and simplified consider the bottom of the pier as consolidation. At the same time, most literatures use single pil...
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Effects of Ambient Temperature and Shaft Power Variations and Compressor Degradation on Creep-Fatigue Interaction Life Consumption of Industrial Gas Turbine Blades
Ebigenibo Genuine Saturday,
Thank-God Isaiah
Issue:
Volume 3, Issue 6, December 2018
Pages:
145-152
Received:
9 December 2018
Accepted:
25 December 2018
Published:
16 January 2019
DOI:
10.11648/j.eas.20180306.12
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Views:
Abstract: This work centres on the investigation of the effects of ambient temperature, shaft power level and compressor degradation (in the form of reduction of health parameter indices including flow capacity index, isentropic efficiency index, and the pressure ratio index) on the creep-fatigue interaction life consumption of the high pressure turbine blades of LM2500+ engine. The aim is to ascertain how the different effects affect engine creep-fatigue interaction life consumption so that engine operators will be properly guided. The Larson-Miller parameter method was used for creep life tracking while the modified universal slopes method was used for the fatigue life analysis. Creep and fatigue damage parameters were obtained at each engine operation point and the linear damage accumulation model was used for the creep-fatigue interaction life analysis. The life analysis models were implemented in PYTHIA, Cranfield university’s in-house gas turbine performance and diagnostics software where an engine model was developed and creep-fatigue interaction life was investigated at different ambient temperatures and shaft power levels. In the compressor degradation, 1% and 2% reduction in the health parameter indices were implanted in the developed engine model and the effects of the degradations were investigated at different shaft power levels and ambient temperatures. It was observed that at a given shaft power level, creep-fatigue life expressed in terms of creep-fatigue factor decreases with increase in ambient temperature while at a given ambient temperature, creep-fatigue life decreases with increase in shaft power. For the degraded engine, the percentage decrease in creep-fatigue factors increases with both shaft power increase and ambient temperature increase. Doubling the compressor health parameter indices reduction nearly doubles the impact on creep-fatigue life consumption. For instance, at 70% power level, the 1% and 2% degradation cases gave percentage reductions in creep-fatigue interaction life as 10.84% and 21.16% respectively while the respective results at 90% power level are 16.05% and 30.10%. The methodologies developed could be applied to other engine types and the results will serve as useful guides to engine operators.
Abstract: This work centres on the investigation of the effects of ambient temperature, shaft power level and compressor degradation (in the form of reduction of health parameter indices including flow capacity index, isentropic efficiency index, and the pressure ratio index) on the creep-fatigue interaction life consumption of the high pressure turbine blad...
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