ESR: A Large Expert System Application in the Domain of Life Assessment of High Temperature Power Plant Components

1992 ◽  
Author(s):  
A. Jovanovlc ◽  
K. Malle ◽  
H. Kautz
Keyword(s):  
High Temperature ◽  
Expert System ◽  
Power Plant ◽  
System Application ◽  
Life Assessment ◽  
Plant Components

scholarly journals Accelerated Creep Life Assessment of In-Service Power Plant Components

2019 ◽  
Vol 293 ◽  
pp. 03001
Author(s):  
Saud Hamad Aldajah ◽  
Mohammad Mazedul Kabir ◽  
Mohammad Y. Al-Haik
Keyword(s):  
High Temperature ◽  
Power Plant ◽  
Structural Integrity ◽  
Elevated Temperatures ◽  
Sem Analysis ◽  
Life Assessment ◽  
High Temperature Creep ◽  
Creep Life ◽  
Temperature Creep ◽  
Plant Components

Structural metals used in plant components are subject to aging from a combination of fatigue, creep, and corrosion. Exposure to elevated temperatures promotes creep. Aged metals lose toughness, or the ability to absorb energy at stress above the yield point and cannot endure an occasional high load without fracturing. Creep is one of the most critical factors for determining the structural integrity of components. The main objective of the current study is to assess the remaining creep life of various 20-year old power plant engineering components such as the high temperature fasteners. Due to time constraints, the approach followed in this study was to utilize the accelerated high temperature creep testing in addition to Scanning Electron Microscopy (SEM) analysis to assess the remaining life of 4 different samples. The accelerated high temperature creep tests were conducted at a stress level of 61 MPa and at a temperature of 1000°C for samples Sample 1 (original), Sample 2, Sample 3 and Sample 4; these samples were collected from different parts of the power plant. SEM analysis was carried out for all the samples. The results of the accelerated high temperature tests were compared to similar materials’ theoretical creep data using Larson Miller curve. The Larson Miller actual creep lives of the tested samples were much higher than the experimental ones, which suggest that the samples are critically aged. SEM analysis on the other hand, showed that all samples have high percentage of creep voids

Robust Methods for Creep Fatigue Analysis of Power Plant Components Under Cyclic Transient Thermal Loading

2013 ◽  
Author(s):  
Yevgen Kostenko ◽  
Henning Almstedt ◽  
Konstantin Naumenko ◽  
Stefan Linn ◽  
Alfred Scholz
Keyword(s):  
High Temperature ◽  
Power Plant ◽  
Constitutive Model ◽  
Thermal Loading ◽  
Hold Time ◽  
Local Stress ◽  
Life Assessment ◽  
Heat Transfer Analysis ◽  
Turbine Component ◽  
Plant Components

The aim of this paper is to apply robust mechanisms-based material laws to the analysis of typical high-temperature power plant components during an idealized start-up, hold time and shut-down sequence under a moderate temperature gradient. Among others a robust constitutive model is discussed, which is able to reflect inelastic deformation, hardening/recovery, softening and damage processes at high temperature. The model is applied for a creep analysis of advanced 9–12%CrMoV heat resistant steels and calibrated in particular case against experimental data for 10%CrMoV steel type. For a steam temperature profile transient heat transfer analysis of an idealized steam turbine component is performed providing the temperature field. From the subsequent structural analysis with the inelastic constitutive model local stress and strain state variations are obtained. As an outcome a multi-axial thermo-mechanical fatigue (TMF) loading loop for one or several loading cycles can be generated. They serve as input for a fatigue life assessment based on the generalized damage accumulation rule, whose results come close to reality. In addition, the accuracy of a simplified method which allows a rapid estimation of notch stresses and strains using a notch assessment rule (NAR) [1] based on Neuber approach is examined.

Online Creep-Fatigue Monitoring of Cyclic Operation in a Coal-Fired Power Plant

2017 ◽  
Author(s):  
Stan T. Rosinski ◽  
Kent Coleman ◽  
Mario Berasi ◽  
Curt Carney ◽  
Ulrich Woerz ◽  
...  
Keyword(s):  
High Temperature ◽  
Power Plant ◽  
Fatigue Damage ◽  
Power Plants ◽  
Transfer Functions ◽  
Stress Transfer ◽  
Operating Conditions ◽  
Element Analysis ◽  
Thermal Transients ◽  
Plant Components

Coal-fired power plants are often required to cycle extensively and operate relatively infrequently due to power market conditions and an increasingly broad deployment of renewable energy. This cyclic (start-stop and/or fast ramp rate) operation can result in accumulation of fatigue damage, particularly in thick-walled components such as high temperature headers that experience the greatest thermal transients. In addition, components exposed to high temperature and pressure experience creep damage over time. Tracking the accumulation of creep and fatigue damage can aid in life management of these components. EPRI developed the Creep-FatiguePro™ system to monitor the accumulation of creep and fatigue damage in plant components while considering component geometry and the ongoing changes in operating conditions (temperatures, pressures and flow rates). The software requires a configuration process to define stress transfer functions for damage analysis and often involves performing a finite element analysis for each component geometry. Although accurate, this process can be time-consuming, especially if a large number of components are to be monitored. In a recent application of this system at the As Pontes power plant in Spain, a simple closed form analytical solution was used in the configuration process in order to more rapidly obtain the stress transfer functions. For direct interaction with the plant’s data historian, the software was also modified to support connection to the plant data system. Results using the two configuration approaches will be compared and recommendations made for future use in monitoring creep and fatigue damage in power plant components.

Multi-axial thermo-mechanical analysis of power plant components from 9–12% Cr steels at high temperature

2011 ◽  
Vol 78 (8) ◽  
pp. 1657-1668 ◽  
Author(s):  
Konstantin Naumenko ◽  
Andreas Kutschke ◽  
Yevgen Kostenko ◽  
Thorsten Rudolf
Keyword(s):  
High Temperature ◽  
Power Plant ◽  
Mechanical Analysis ◽  
Cr Steels ◽  
Plant Components

Probabilistic Life Assessment Method of Low Cycle Fatigue for Power Plant Components

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1704-1710
Author(s):  
Myung Soo Kang
Keyword(s):  
Power Plant ◽  
Low Cycle Fatigue ◽  
Operating Time ◽  
Assessment Method ◽  
Life Assessment ◽  
Assessment Procedure ◽  
Cycle Fatigue ◽  
Inspection Planning ◽  
Structural Failure ◽  
Plant Components

This study focuses on the probabilistic analysis method to the determination of low cycle fatigue life for power plant components. The analysis incorporates standard life assessment modeling techniques used in the determination analysis of the low cycle fatigue. The probabilistic life assessment is developed to increase the reliability of life assessment. A probabilistic life assessment procedure can provide the engineer with the probability of structural failure as a function of operating time given the uncertainties in the input data. The probabilistic life assessment involves some uncertainties, for example, initial crack size, aspect ratio, crack initiation time, crack location, structural geometry, material properties, and loading condition, and a triangle distribution function is used for random variable generation. The resulting information provides the engineer with an assessment of the probability of structural failure. This information can form the basis of inspection planning and retirement-for-cause decisions. This study forms basis of the probabilistic life assessment technique and will be extended to other damage mechanisms.

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