scholarly journals Damage Localization of Conventional Creep Damage Models and Proposition of a New Model for Creep Damage Analysis.

1998 ◽  
Vol 41 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Yan LIU ◽  
Sumio MURAKAMI
Keyword(s):  
Creep Damage ◽  
Damage Localization ◽  
Damage Analysis ◽  
New Model ◽  
Damage Models

New model for creep damage analysis and its application to creep crack growth simulations

2013 ◽  
Vol 30 (1) ◽  
pp. 32-37 ◽  
Author(s):  
J.-F. Wen ◽  
S.-T. Tu ◽  
X.-L. Gao ◽  
J. N. Reddy
Keyword(s):  
Crack Growth ◽  
Creep Crack Growth ◽  
Creep Damage ◽  
Damage Analysis ◽  
New Model ◽  
Creep Crack

A Damage Evaluation Model of Turbine Blade for Gas Turbine

2016 ◽  
Author(s):  
Dengji Zhou ◽  
Meishan Chen ◽  
Huisheng Zhang ◽  
Shilie Weng
Keyword(s):  
High Temperature ◽  
Real Time ◽  
Gas Turbine ◽  
Evaluation Model ◽  
Creep Damage ◽  
Operating Conditions ◽  
Damage Analysis ◽  
Damage Evaluation ◽  
Analysis Model ◽  
Estimation Model

Current maintenance, having a great impact on the safety, reliability and economics of gas turbine, becomes the major obstacle of the application of gas turbine in energy field. An effective solution is to process Condition based Maintenance (CBM) thoroughly for gas turbine. Maintenance of high temperature blade, accounting for most of the maintenance cost and time, is the crucial section of gas turbine maintenance. The suggested life of high temperature blade by Original Equipment Manufacturer (OEM) is based on several certain operating conditions, which is used for Time based Maintenance (TBM). Thus, for the requirement of gas turbine CBM, a damage evaluation model is demanded to estimate the life consumption in real time. A physics-based model is built, consisting of thermodynamic performance simulation model, mechanical stress estimation model, thermal estimation model, creep damage analysis model and fatigue damage analysis model. Unmeasured parameters are simulated by the thermodynamic performance simulation model, as the input of the mechanical stress estimation model and the thermal estimation model. Then the stress and temperature distribution of blades will be got as the input of the creep damage analysis model and the fatigue damage analysis model. The real-time damage of blades will be evaluated based on the creep and fatigue analysis results. To validate this physics-based model, it is used to calculate the lifes of high temperature blade under several certain operating conditions. And the results are compared to the suggestion value of OEM. An application case is designed to evaluate the application effect of this model. The result shows that the relative error of this model is less than 10.4% in selected cases. And it can cut overhaul costs and increase the availability of gas turbine significantly. Therefore, the physical-based damage evaluation model proposed in this paper, is found to be a useful tool to tracing the real-time life consumption of high temperature blade, to support the implementation of CBM for gas turbine, and to guarantee the reliability of gas turbine with lowest maintenance costs.

Creep-Damage Analysis: Comparison Between Coupled and Uncoupled Models

2000 ◽  
Vol 122 (4) ◽  
pp. 408-412 ◽  
Author(s):  
S. Bhandari ◽  
X. Feral ◽  
J.-M. Bergheau ◽  
G. Mottet ◽  
P. Dupas ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Internal Pressure ◽  
Validation Study ◽  
Pressure Vessel ◽  
Creep Damage ◽  
Damage Analysis ◽  
Hypothetical Accident ◽  
Computer Codes ◽  
Damage Theory ◽  
Reactor Pressure

Numerical simulation of creep rupture of a reactor pressure vessel in a severe hypothetical accident needs to perfectly take account of interactions between creep phenomena and damage. The continuous damage theory enables to formulate models strongly coupling elasto-visco-plasticity and damage. Such models have been implemented in various computer codes and, in particular, in ASTER at Electricite´ de France, CASTEM 2000 at Commissariat a` l’Energie Atomique and SYSTUS+® at SYSTUS International. The objective of this paper is to present briefly a validation study of the three different numerical implementations and to compare the coupled approach to an uncoupled one on an example of a cylinder of the program “RUPTHER,” under internal pressure and heated to a temperature of 700°C. [S0094-9930(00)01004-0]

Literature Review on the Development of Computational Software System for Creep Damage Analysis for Weldment

2012 ◽  
Vol 510 ◽  
pp. 490-494 ◽  
Author(s):  
Feng Tan ◽  
Qiang Xu ◽  
Zhong Yu Lu ◽  
Dong Lai Xu
Keyword(s):  
Constitutive Equation ◽  
Literature Review ◽  
Creep Damage ◽  
Computational Approach ◽  
Software System ◽  
Damage Analysis ◽  
Computational System

This paper reports a literature review on the development of computational software system for creep damage analysis for weldment. It starts with a brief review on the creep damage problem in weldment and the computational approach; identifies the need for computational approach and the un-availability of such computational system; further details on the preliminary development progress of a transfer programme and constitutive equation subroutines. This paper contributes to knowledge to the development of computational system for creep damage analysis.

Findings on Creep-Fatigue Damage in Pressure Parts of Long-Term Service-Exposed Thermal Power Plants

1985 ◽  
Vol 107 (3) ◽  
pp. 260-270 ◽  
Author(s):  
F. Masuyama ◽  
K. Setoguchi ◽  
H. Haneda ◽  
F. Nanjo
Keyword(s):  
Fatigue Damage ◽  
Power Plants ◽  
Thermal Power ◽  
Field Experiences ◽  
Creep Damage ◽  
Thermal Power Plants ◽  
Damage Analysis ◽  
Creep Fatigue ◽  
Fatigue Damage Analysis

The increase of long-term service exposure to thermal power plants, the tendency toward intermediate and cyclic operation to meet the change in electric power demand and supply situation, and the requirement to develop higher-temperature and higher-pressure plants have led to increasing attention towards the reliability improvement. This paper presents findings from field experiences of cracking or failure and two types of damage analyses—(1) creep-fatigue damage analysis based on the life fraction rule and (2) metallurgical damage analysis—of boiler pressure parts that have been exposed to long-term elevated temperature service. The field experiences are (1) cracking or failure of thick-walled Type 316 stainless steel pressure parts in the main steam line of an ultra-supercritical thermal power plant and (2) dissimilar metal weld joints for boiler tubing. The creep-fatigue damage analysis of these pressure parts showed a reasonable correspondence with the field experience. According to the creep-fatigue damage analysis and the metallurgical damage analysis, most of damage was restrained creep mode phenomenon without deformation. The creep damage was composed of metallurgical damage and mechanical damage such as microvoids and structural defects. One method of simulating field experienced creep damage was proposed and performed. As a result, the process of creep voids being generated and growing into cracks without deformation was successfully observed. Also a review of the current status of nondestructive detecting methods of creep damage suggests that detecting the creep voids metallurgically is more practical at the present time than doing so analyzing the changes in physical properties of the material. It is also suggested that, in the metallurgical approach, detecting the creep voids and cracks by replica method and anlayzing precipitates for evaluation of material deterioration by precipitate extraction method will make it possible to successfully address the problem of plant equipment creep damage evaluation and life prediction.

Notch Behavior of Components Under the Stress-Controlled Creep–Fatigue Condition: Weakening or Strengthening?

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Jian-Guo Gong ◽  
Fu-Zhen Xuan
Keyword(s):  
Stress Ratio ◽  
Maximum Stress ◽  
Strain Range ◽  
Creep Damage ◽  
Equivalent Strain ◽  
Holding Time ◽  
Damage Analysis ◽  
Strengthening Effect ◽  
Creep Fatigue ◽  
The Difference

Notch-related weakening and strengthening behavior under creep–fatigue conditions was studied in terms of the elastic–viscoplasticity finite-element method (FEM). A coupled damage analysis, i.e., the skeletal point method for creep damage evaluation coupled with the equivalent strain range method for fatigue damage, was employed in the notch effect evaluation. The results revealed that, under the short holding time condition, a weakening behavior was observed for the notch, while a strengthening effect was detected with the increase of holding time. The difference could be ascribed to the creep damage contribution in the holding stage. The influence of stress concentration factor (SCF), stress ratio, and the maximum stress was strongly dependent on the competition of creep and fatigue mechanism.

scholarly journals Creep Damage Analysis of Mod.9Cr-1Mo Steel Welds Considering Void Mechanics Modeling

2019 ◽  
Vol 2019 (0) ◽  
pp. 1009B1030
Author(s):  
Takashi Honda ◽  
Takuya Fukahori ◽  
Takumi Tokiyoshi ◽  
Yasuharu Chuman ◽  
Toshihide Igari ◽  
...  
Keyword(s):  
Creep Damage ◽  
Damage Analysis ◽  
Steel Welds
Sign in / Sign up

Export Citation Format

Share Document