scholarly journals Service Life Assessment of Lead and its Alloy Anodes During Zinc Electrowinning

2019 ◽  
pp. 8720-8732
Author(s):  
Chang-jiang Yang ◽  
Keyword(s):  
Service Life ◽  
Life Assessment ◽  
Zinc Electrowinning

scholarly journals The thermal history and stress state of a fresh steam-pipeline influencing its remaining service life

2011 ◽  
Vol 15 (3) ◽  
pp. 691-704 ◽  
Author(s):  
Gordana Bakic ◽  
Vera Sijacki-Zeravcic ◽  
Milos Djukic ◽  
Stevan Maksimovic ◽  
Dusan Plesinac ◽  
...  
Keyword(s):  
Service Life ◽  
Elevated Temperatures ◽  
Operating Temperature ◽  
Life Assessment ◽  
Temperature History ◽  
Significant Variable ◽  
Remaining Life ◽  
Pipe Bend ◽  
Steam Pipeline ◽  
Remaining Life Assessment

The service life of thick-walled power plant components exposed to creep, as is the case with pipelines of fresh- and re-heated steam, depend on the exhaustion rate of the material. Plant operation at elevated temperatures and at temperatures below designed temperatures all relates to the material exhaustion rate, thus complicating remaining life assessment, whereas the operating temperature variation is a most common cause in the mismatching of real service- and design life. Apart from temperature, the tube wall stress is a significant variable for remaining life assessment, whose calculation depends on the selected procedure, due to the complex pipeline configuration. In this paper, a remaining life assessment is performed according to the Larson-Miller parametric relation for a ?324?36 pipe bend element of a fresh steam-pipeline, made of steel class 1Cr0.3Mo0.25V, after 160 000 hours of operation. The temperature history of the pipeline, altogether with the pipe bend, is determined based on continuous temperature monitoring records. Compared results of remaining life assessment are displayed for monitored temperature records and for designed operating temperature in the same time period. The stress calculation in the pipe bend wall is performed by three methods that are usually applied so to emphasize the differences in the obtained results of remaining life assessment.

scholarly journals Modeling the mechanical wear of the contact elements of pantograph during high-speed movement

2020 ◽  
Vol 157 ◽  
pp. 01022
Author(s):  
Victor Philippov ◽  
Alexandr Smerdin
Keyword(s):  
Service Life ◽  
High Speed ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Maximum Error ◽  
Life Assessment ◽  
Rolling Stock ◽  
Mechanical Wear ◽  
Wear Process ◽  
Mechanical Component

The use of contact elements with an extended service life is one of the most economical and least costly ways to ensure reliable, economical and environmentally friendly transmission of electricity to rolling stock. To evaluate the service life in OSTU, a methodology for conducting experimental studies of contact pairs of pantograph has been developed and successfully tested, involving bench tests for each pair of contact materials “contact insert - contact wire” in order to determine their optimal combination to reduce wear and increase service life. Assessment of the amount of wear and prediction of the life of the contact elements are made, including using mathematical modeling. The purpose of this article is to improve the mechanical component of the wear model of the contact elements of pantograph in high-speed conditions. The results of experimental studies and theoretical calculations of the mechanical wear of contact elements are presented. The analysis of the graphs allows us to conclude that it is possible to use an improved mathematical model for modeling the mechanical component of the wear process of the elements of contact pairs with a maximum error value of not more than 5%.

scholarly journals Service-Life Assessment of Existing Precast Concrete Structure Exposed to Severe Marine Conditions

2016 ◽  
Vol 30 (3) ◽  
pp. 04015036 ◽  
Author(s):  
I. Segura ◽  
S. Cavalaro ◽  
A. de la Fuente ◽  
A. Aguado ◽  
V. Alegre
Keyword(s):  
Service Life ◽  
Concrete Structure ◽  
Precast Concrete ◽  
Life Assessment

Prognostics Model for Predicting Aero-Engine Bearing Grade-Life

2009 ◽  
Author(s):  
Jie Hong ◽  
Xuewen Miao ◽  
Lei Han ◽  
Yanhong Ma
Keyword(s):  
Mathematical Model ◽  
Service Life ◽  
Critical Role ◽  
Operating Conditions ◽  
Life Assessment ◽  
Prognostic Models ◽  
Turbine Engine ◽  
Final Grade ◽  
Failure Data ◽  
Engine Bearing

Development of practical and verifiable prognostic approaches for service life of gas turbine engine bearings will play a critical role in improving the reliability and safety of aircraft engines. Upgrading current military aeroengine overhaul metrics based strictly on engine flight hours and total accumulated cycles with higher fidelity prognostic models will provide an opportunity to prevent failures caused by accelerated degradation due to operation in unusually harsh conditions, and will help avoid unnecessary maintenance caused by routine check on engines that operate under nominal operating conditions. Grade-life (GL) is used to describe the bearing’s service life, and a comprehensive engine bearing prognostic model comprised of a physics based mathematical model and a prognostic element is presented in this paper. The mathematical model utilizes information from the Sensed Data module to calculate the cumulative damage sustained by the bearing since it was first installed and the Prediction Grade-life (PGL) is captured. The prognostic estimate model is an empirical lifetime model, in which Empirical Grade-life (EGL) is assessed based on vibration signals intelligently. The final Grade-life of bearings is determined by fusion of analytic Grade-life (PGL) and Grade-life assessment value (EGL) based on Fuzzy Logic Inference, which reduces the uncertainty’s affection towards prediction results of the analytic model. Finally, bearing test stand run-to-failure data is used to verify the approach.

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