scholarly journals Creep Analysis of High Temperature Components Under Multi-Axial Loading

1998 ◽  
Author(s):  
Abbas A. Moftakhar ◽  
Grzegorz Glinka
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Solution Method ◽  
Efficient Estimation ◽  
Computational Time ◽  
Strain History ◽  
Linear Elastic ◽  
Creep Analysis ◽  
High Temperature Components ◽  
Simplified Solution

A simplified solution method that enables the estimation of stresses and strains in high temperature components under creep conditions is presented. The solution is derived based on strain energy density considerations and is applicable to both uniaxial and multiaxial stress states. In particular, this simplified method is developed for an efficient estimation of the cyclic stress-strain history at critical locations which needed for fatigue analysis of hot sections under creep conditions where conventional finite element creep analysis becomes extremely time consuming. The input data necessary to perform this simplified solution are the stresses and strains obtained from a linear elastic analyses. If the finite element method (FEM) is used for the linear elastic analysis of components, then the simplified solution method can be programmed as a post processor file. The file uses the linear elastic FEM results and generates an approximate time-dependent analysis. Presented results illustrates the accuracy of the method by comparing with finite element creep analysis results for several hot sections under creep conditions. Also, it is shown that the computational time needed to perform this solution is far less than the conventional finite element creep analysis.

Creative Design-by-Analysis Solutions Applied to High-Temperature Components

1993 ◽  
Vol 115 (3) ◽  
pp. 221-227
Author(s):  
A. K. Dhalla
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Detailed Analysis ◽  
Structural Response ◽  
Cost Effective ◽  
Element Analysis ◽  
Finite Element Software ◽  
Division 1 ◽  
High Temperature Components ◽  
Elevated Temperature Design

Elevated temperature design has evolved over the last two decades from design-by-formula philosophy of the ASME Boiler and Pressure Vessel Code, Sections I and VIII (Division 1), to the design-by-analysis philosophy of Section III, Code Case N-47. The benefits of design-by-analysis procedures, which were developed under a US-DOE-sponsored high-temperature structural design (HTSD) program, are illustrated in the paper through five design examples taken from two U.S. liquid metal reactor (LMR) plants. Emphasis in the paper is placed upon the use of a detailed, nonlinear finite element analysis method to understand the structural response and to suggest design optimization so as to comply with Code Case N-47 criteria. A detailed analysis is cost-effective, if selectively used, to qualify an LMR component for service when long-lead-time structural forgings, procured based upon simplified preliminary analysis, do not meet the design criteria, or the operational loads are increased after the components have been fabricated. In the future, the overall costs of a detailed analysis will be reduced even further with the availability of finite element software used on workstations or PCs.

A Hybrid Mobility Solution Method for Dynamically Loaded Misaligned Journal Bearings

2012 ◽  
Author(s):  
S. Boedo
Keyword(s):  
Finite Element ◽  
Reynolds Equation ◽  
Solution Method ◽  
Hybrid Approach ◽  
Journal Bearings ◽  
Finite Element Solution ◽  
Computational Time ◽  
Element Solution ◽  
Dynamically Loaded ◽  
Mobility Solution

This paper presents a hybrid mobility solution approach to the analysis of dynamically loaded misaligned journal bearings. Mobility data obtained for misaligned bearings (calculated from a finite element representation of the Reynolds equation) are compared with existing curve-fitted mobility maps representative of a perfectly aligned bearing. A relative error analysis of mobility magnitude and direction provides a set of misaligned journal bearing configurations (midplane eccentricity ratio and normalized misalignment angle) where existing curve-fitted mobility map components based on aligned bearings can be used to calculate the resulting journal motion. For bearing configurations where these mobility maps are not applicable, the numerical simulation process proceeds using a complete finite element solution of the Reynolds equation. A set of numerical examples representing misaligned main and connecting rod bearings in a four-stroke automotive engine illustrate the hybrid solution method. Substantial savings in computational time are obtained using the hybrid approach over the complete finite element solution method without loss of computational accuracy.

A Hybrid Mobility Solution Approach for Dynamically Loaded Misaligned Journal Bearings

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
S. Boedo
Keyword(s):  
Finite Element ◽  
Reynolds Equation ◽  
Solution Method ◽  
Journal Bearings ◽  
Finite Element Solution ◽  
Computational Time ◽  
Element Solution ◽  
Solution Approach ◽  
Dynamically Loaded ◽  
Mobility Solution

This paper presents a hybrid mobility solution approach to the analysis of dynamically loaded misaligned journal bearings. Mobility data obtained for misaligned bearings (calculated from a finite element representation of the Reynolds equation) are compared with existing curve-fitted mobility maps representative of a perfectly aligned bearing. A relative error analysis of mobility magnitude and direction provides a set of misaligned journal bearing configurations (midplane eccentricity ratio and normalized misalignment angle), where existing curve-fitted mobility map components based on aligned bearings can be used to calculate the resulting journal motion. For bearing configurations where these mobility maps are not applicable, the numerical simulation process proceeds using a complete finite element solution of the Reynolds equation. A numerical example representing a misaligned main bearing in a four-stroke automotive engine illustrates the hybrid solution method. Substantial savings in computational time are obtained using the hybrid approach over the complete finite element solution method without loss of computational accuracy.

The Support of Horizontal Vessels Containing High-Temperature Fluids—A Design Study

1998 ◽  
Vol 120 (3) ◽  
pp. 232-237 ◽  
Author(s):  
A. S. Tooth ◽  
J. S. T. Cheung ◽  
L. S. Ong ◽  
H. W. Ng ◽  
C. Nadarajah
Keyword(s):  
Finite Element ◽  
High Temperature ◽  
Thermal Loading ◽  
Maximum Stress ◽  
Small Displacement ◽  
Finite Element Approach ◽  
Supporting Structure ◽  
Linear Elastic ◽  
Design Charts ◽  
Element Approach

This paper investigates the behavior of horizontal cylindrical vessels, subjected to thermal loading by high-temperature fluid, where the saddles are fixed to the supporting structure. In order to determine an optimum saddle design, three widely used saddle configurations, with differing saddle heights and top saddle plate extensions, are explored. Thereafter, one of the saddle designs is selected to illustrate a decoupling procedure, for the radial and axial expansions, whereby design charts are obtained to derive the maximum stress values for a range of vessel geometries. The finite element approach, using linear elastic, small displacement analysis, is used throughout.

Some Fundamental Aspects of Redesign and Remanufacture of High Temperature Components

2008 ◽  
Vol 44-46 ◽  
pp. 25-32 ◽  
Author(s):  
Shan Tung Tu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Temperature ◽  
Creep Damage ◽  
Time Dependent ◽  
Life Extension ◽  
Process Industries ◽  
Conservation Of Energy ◽  
High Temperature Components ◽  
The Impact

The impact of remanufacturing on the conservation of energy and resources has been well recognized during the last decade. When the relevant technologies are applied for high temperature components in power and process industries, a redesign of the component life should be required due to the time-dependent feature of high temperature failure. In order to provide some fundamentals for redesign and remanufacture of high temperature components, mechanical behavior of a two-bar structure with one bar being remanufactured is analyzed. An optimal repairing time is given. From the viewpoint of creep damage, various high temperature structures are analyzed by using damage coupled finite element method. Suggestions for life extension remanufacture are proposed for typical high temperature components.

scholarly journals How to Increase the Accuracy of Analysis and Reduce the Computational Time in ANSYS in the Case of Deformation Study of Orthopedic Bone Plates

2013 ◽  
Vol 834-836 ◽  
pp. 1592-1600 ◽  
Author(s):  
Javad Malekani ◽  
Prasad K.D.V. Yarlagadda ◽  
Beat Schmutz ◽  
Yuan Tong Gu ◽  
Michael Schuetz
Keyword(s):  
Finite Element ◽  
Solution Method ◽  
Geometric Model ◽  
Material Model ◽  
Bone Plates ◽  
Computational Time ◽  
Not Given ◽  
Finite Element Analyses ◽  
Effective Parameters ◽  
Ansys Workbench

Currently, finite element analyses are usually done by means of commercial software tools. Accuracy of analysis and computational time are two important factors in efficiency of these tools. This paper studies the effective parameters in computational time and accuracy of finite element analyses performed by ANSYS and provides the guidelines for the users of this software whenever they us this software for study on deformation of orthopedic bone plates or study on similar cases. It is not a fundamental scientific study and only shares the findings of the authors about structural analysis by means of ANSYS workbench. It gives an idea to the readers about improving the performance of the software and avoiding the traps. The solutions provided in this paper are not the only possible solutions of the problems and in similar cases there are other solutions which are not given in this paper. The parameters of solution method, material model, geometric model, mesh configuration, number of the analysis steps, program controlled parameters and computer settings are discussed through thoroughly in this paper.

Numerical Simulation of Welding Residual Stress and its Creep Strain for Cr5Mo Steel Welded Joint

2011 ◽  
Vol 55-57 ◽  
pp. 41-46
Author(s):  
Ling Cheng ◽  
Zheng Nan Chen ◽  
Jian Gao
Keyword(s):  
Residual Stress ◽  
High Temperature ◽  
Welded Joint ◽  
Great Influence ◽  
Welding Residual Stress ◽  
Element Analysis ◽  
Creep Analysis ◽  
The Finite Element Analysis ◽  
Sequential Coupling ◽  
High Temperature Components

By the finite element analysis codes ABAQUS and the function of RESTART, a sequential coupling calculating program for creep based on welding residual stress has been developed by establishing the model of temperature field, residual field and creep analysis. The welding residual stress and creep of welded joint for Cr5Mo furnace tubes was simulated by the program. This method established the basis for calculating the effects of welding residual stress on the creep of welded joint. A creep comparison between the welded joint tubes with welding residual stress and with internal pressure was made in the paper. The results show that although the residual stress is greatly decreased due to the creep relaxation behavior at high temperature, the initial welding residual stress has a great influence on the tube creep. The research results provide a reference for strength design of high temperature components.

Creep Analysis of Steel Structures in High Temperature Using Finite Element Method

2012 ◽  
Vol 204-208 ◽  
pp. 1267-1270
Author(s):  
Yue Song Liu ◽  
Yu Ching Wu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Temperature ◽  
Nonlinear Behavior ◽  
Steel Structure ◽  
Steel Structures ◽  
Creep Analysis ◽  
Fire Effect ◽  
In Fire ◽  
Element Method

To predict the behavior of steel structure under fire effect, the material property is very important in the analysis of steel structure at high temperature. This paper adopted finite element method to investigate the nonlinear behavior of steel structures under high temperature and creep conditions. We studied the creep strains with different models of creep. Differences between these models are highlighted. Furthermore, the importance of creep effect in fire is discussed.

scholarly journals Fatigue Crack Growth Analysis with Extended Finite Element for 3D Linear Elastic Material

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 397
Author(s):  
Yahya Ali Fageehi
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Propagation ◽  
Crack Growth ◽  
Mixed Mode ◽  
Propagation Path ◽  
Loading Conditions ◽  
Extended Finite Element ◽  
Linear Elastic

This paper presents computational modeling of a crack growth path under mixed-mode loadings in linear elastic materials and investigates the influence of a hole on both fatigue crack propagation and fatigue life when subjected to constant amplitude loading conditions. Though the crack propagation is inevitable, the simulation specified the crack propagation path such that the critical structure domain was not exceeded. ANSYS Mechanical APDL 19.2 was introduced with the aid of a new feature in ANSYS: Smart Crack growth technology. It predicts the propagation direction and subsequent fatigue life for structural components using the extended finite element method (XFEM). The Paris law model was used to evaluate the mixed-mode fatigue life for both a modified four-point bending beam and a cracked plate with three holes under the linear elastic fracture mechanics (LEFM) assumption. Precise estimates of the stress intensity factors (SIFs), the trajectory of crack growth, and the fatigue life by an incremental crack propagation analysis were recorded. The findings of this analysis are confirmed in published works in terms of crack propagation trajectories under mixed-mode loading conditions.

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