Thermal Stress and Fatigue Analysis of Exhaust Manifold

2004 ◽  
Vol 261-263 ◽  
pp. 1203-1208 ◽  
Author(s):  
Sam Son Yoon ◽  
Keum Oh Lee ◽  
Soon Bok Lee ◽  
K.H. Park
Keyword(s):  
Elastic Limit ◽  
Damage Model ◽  
Isothermal Condition ◽  
Strain Range ◽  
Operating Conditions ◽  
Cyclic Plasticity ◽  
Exhaust Manifold ◽  
Element Analysis ◽  
Cyclic Plasticity Model ◽  
Overlay Model

In this study, we investigated the reliability assessment of exhaust manifold used in thermomechanical condition. Overlay model proposed by Besseling[1] was modified to consider the strain range dependence on elastic limit. By combining geometrical relation in hysteresis loop and temperature dependence of elastic limit with isothermal overlay model, temperature dependent cyclic plasticity model was proposed. Continuous damage model based on isothermal fatigue data was generalized for non-isothermal condition. Finite element analysis and life prediction of exhaust manifold were performed under severe operating conditions.

scholarly journals On Creep Fatigue Interaction of Components at Elevated Temperature

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Daniele Barbera ◽  
Haofeng Chen ◽  
Yinghua Liu
Keyword(s):  
High Temperature ◽  
Mechanical Load ◽  
Direct Method ◽  
Bending Moment ◽  
Strain Range ◽  
Cyclic Plasticity ◽  
Element Analysis ◽  
Total Strain Range ◽  
Creep Fatigue ◽  
A Direct Method

The accurate assessment of creep–fatigue interaction is an important issue for industrial components operating with large cyclic thermal and mechanical loads. An extensive review of different aspects of creep fatigue interaction is proposed in this paper. The introduction of a high temperature creep dwell within the loading cycle has relevant impact on the structural behavior. Different mechanisms can occur, including the cyclically enhanced creep, the creep enhanced plasticity and creep ratchetting due to the creep fatigue interaction. A series of crucial parameters for crack initiation assessment can be identified, such as the start of dwell stress, the creep strain, and the total strain range. A comparison between the ASME NH and R5 is proposed, and the principal differences in calculating the aforementioned parameters are outlined. The linear matching method (LMM) framework is also presented and reviewed, as a direct method capable of calculating these parameters and assessing also the steady state cycle response due to creep and cyclic plasticity interaction. Two numerical examples are presented, the first one is a cruciform weldment subjected to cyclic bending moment and uniform high temperature with different dwell times. The second numerical example considers creep fatigue response on a long fiber reinforced metal matrix composite (MMC), which is subjected to a cycling uniform thermal field and a constant transverse mechanical load. All the results demonstrate that the LMM is capable of providing accurate solutions, and also relaxing the conservatisms of the design codes. Furthermore, as a direct method, it is more efficient than standard inelastic incremental finite element analysis.

scholarly journals An R5 Based Creep-Fatigue Critical Flaw Assessment of an In-Service Reformer Piping Tee Using Finite Element Analysis

2014 ◽  
Author(s):  
Phillip E. Prueter ◽  
David J. Dewees ◽  
Robert G. Brown
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Operating Conditions ◽  
Cyclic Plasticity ◽  
Assessment Procedure ◽  
Element Analysis ◽  
Thermal Transients ◽  
Non Linear ◽  
Creep Fatigue ◽  
Critical Flaw

This study employs three dimensional (3D) non-linear, finite element analysis (FEA) to supplement a critical flaw sizing assessment of an in-service reformer piping tee. The analysis is guided by the EDF (Électricité de France) Assessment Procedure R5 (formerly from British Energy Generation LTD. or BEGL) as well as Part 10 of API 579-1/ASME FFS-1. Specifically, Volume 4/5 of R5, which addresses crack growth, is used to determine the largest permissible flaw as a function of operational cycles and time at temperature. Required stresses are generated using FEA as well as the simplified reference stress techniques of R5 as appropriate. The analysis explicitly considers thermal transients, as well as cyclic plasticity. Furthermore, modeling of steady state operating conditions considers creep in the FEA material model. Additionally, creep-fatigue flaw growth is considered for a range of initial defect sizes. The targeted inelastic, non-linear FEA is leveraged to remove significant uncertainty and conservatism, and the simplified techniques of R5 are employed wherever reasonable to give the most efficient analysis possible. This investigation provides estimates of flaw propagation rates based on historical cyclic operation and permits determination of reasonable inspection intervals for the reformer tee in question. Paper published with permission.

A Study of Early Stage Self-Loosening of Bolted Joints

2001 ◽  
Author(s):  
Yanyao Jiang ◽  
Bin Huang ◽  
Hua Zhao ◽  
Chu-Hwa Lee
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Early Stage ◽  
Three Dimensional ◽  
Cyclic Strain ◽  
Bolted Joints ◽  
Cyclic Plasticity ◽  
Clamping Force ◽  
Element Analysis ◽  
Cyclic Plasticity Model

Abstract Both experimental investigation and finite element analysis were conducted to explore the mechanisms of the early stage self-loosening of bolted joints under transverse cyclic loading. The nuts were glued to the bolts using a strong thread locker in the self-loosening experiments to ensure that no backing-off of the nut occurred. Depending on the loading magnitude, the clamping force reduction ranged from 10% to more than 40% of the initial preload after 200 loading cycles. Three-dimensional elastic-plastic finite element analysis was conducted with the implementation of an advanced cyclic plasticity model. The finite element results revealed that the local cyclic plasticity occurring near the roots of the engaged threads resulted in cyclic strain ratchetting. The localized cyclic plastic deformation caused the stresses to redistribute in the bolt, and the result was the gradual loss of clamping force with loading cycles. The finite element results agreed with the experimental observations quantitatively. Both experiments and finite element simulations suggested that the friction between the clamped plates has an insignificant influence on self-loosening.

Thermo-Mechanical Analysis of the Exhaust Manifold of a High Performance Turbocharged Engine

2018 ◽  
Vol 774 ◽  
pp. 307-312 ◽  
Author(s):  
Mariano Lorenzini ◽  
Matteo Giacopini ◽  
Saverio Giulio Barbieri
Keyword(s):  
Finite Element ◽  
Thermal Fatigue ◽  
Thermal Loading ◽  
Complex Geometry ◽  
Combustion Engine ◽  
Equivalent Plastic Strain ◽  
Operating Conditions ◽  
Exhaust Manifold ◽  
Element Analysis ◽  
Damage Criterion

This contribution presents a methodology for the structural analysis of the exhaust manifold of an internal combustion engine. In particular, the thermal loading and the related thermal fatigue damage mechanism are addressed. The component investigated is a melted exhaust manifold which includes the turbine involute. The complex geometry of the component derives from the project constrains in terms of engine performance and sound targets. Finite Element simulations are performed to obtain a virtual approval of the component geometry, in advance with respect to the component manufacturing. The Finite Element analysis accurately follow the experimental approval procedure which considers different warming and rapid cooling cycles to mimic typical engine operating conditions. Two particular aspects of the developed numerical methodology are described in details: a) the elasto-plastic behaviour of the material at high temperatures; b) a damage criterion for thermal fatigue. Following the Ferrari expertise derived by previous experimental and numerical analysis of other exhaust manifolds, the increase of the equivalent plastic strain registered for a single thermal cycle (delta PEEQ) is firstly adopted as a damage criterion. The methodology reveals itself to be well correlated with the experimental evidences thus limiting the number of tests necessary for the component approval.

Fatigue Analysis in Pressure Vessel Design by Local Strain Approach: Methods and Software Requirements

2005 ◽  
Vol 128 (1) ◽  
pp. 2-7 ◽  
Author(s):  
Arturs Kalnins
Keyword(s):  
Pressure Vessel ◽  
Kinematic Hardening ◽  
Strain Range ◽  
Local Strain ◽  
Equivalent Strain ◽  
Software Requirements ◽  
Cyclic Plasticity ◽  
Half Cycle ◽  
Fatigue Evaluation ◽  
Cyclic Plasticity Model

The purpose, methods for the analysis, software requirements, and meaning of the results of the local strain approach are discussed for fatigue evaluation of a pressure vessel or its component designed for cyclic service. Three methods that are consistent with the approach are evaluated: the cycle-by-cycle method and two half-cycle methods, twice-yield and Seeger’s. For the cycle-by-cycle method, the linear kinematic hardening model is identified as the cyclic plasticity model that produces results consistent with the local strain approach. A total equivalent strain range, which is entered on a material strain-life curve to read cycles, is defined for multiaxial stress situations

scholarly journals Modelling the Strain Range Dependent Cyclic Hardening of SS304 and 08Ch18N10T Stainless Steel with a Memory Surface

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 832 ◽  
Author(s):  
Radim Halama ◽  
Jaromír Fumfera ◽  
Petr Gál ◽  
Tadbhagya Kumar ◽  
Alexandros Markopoulos
Keyword(s):  
Experimental Data ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Back Stress ◽  
Internal Variable ◽  
Austenitic Steels ◽  
Cyclic Plasticity ◽  
Isotropic Hardening ◽  
Plasticity Model ◽  
Cyclic Plasticity Model

This paper deals with the development of a cyclic plasticity model suitable for predicting the strain range dependent behavior of austenitic steels. The proposed cyclic plasticity model uses the virtual back-stress variable corresponding to a cyclically stable material under strain control. This new internal variable is defined by means of a memory surface introduced in the stress space. The linear isotropic hardening rule is also superposed. First, the proposed model was validated on experimental data published for the SS304 material (Kang et al. Constitutive modeling of strain range dependent cyclic hardening. Int J Plast 19 (2003) 1801–1819). Subsequently, the proposed cyclic plasticity model was applied to own experimental data from uniaxial tests realized on 08Ch18N10T at room temperature. The new cyclic plasticity model can be calibrated by the relatively simple fitting procedure that is described in the paper. A comparison between the results of a numerical simulation and the results of real experiments demonstrates the robustness of the proposed approach.

A Study of Early Stage Self-Loosening of Bolted Joints

2003 ◽  
Vol 125 (3) ◽  
pp. 518-526 ◽  
Author(s):  
Yanyao Jiang ◽  
Ming Zhang ◽  
Chu-Hwa Lee
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Early Stage ◽  
Three Dimensional ◽  
Cyclic Strain ◽  
Bolted Joints ◽  
Cyclic Plasticity ◽  
Clamping Force ◽  
Element Analysis ◽  
Cyclic Plasticity Model

Both experimental investigation and finite element analysis were conducted to explore the mechanisms for the early stage self-loosening of bolted joints under transverse cyclic loading. The nuts were glued to the bolts using a strong thread locker in the self-loosening experiments to ensure that no backing-off of the nut occurred. Depending on the loading magnitude, the clamping force reduction ranged from 10% to more than 40% of the initial preload after 200 loading cycles. Three-dimensional elastic-plastic finite element analysis was conducted with the implementation of an advanced cyclic plasticity model. The finite element results revealed that the local cyclic plasticity occurring near the roots of the engaged threads resulted in cyclic strain ratcheting. The localized cyclic plastic deformation caused the stresses to redistribute in the bolt, and the result was the gradual loss of clamping force with loading cycles. The finite element results agreed with the experimental observations quantitatively. When the two clamped plates started to slip and the slip displacement was controlled, both experiments and finite element simulations suggested that the friction between the clamped plates has an insignificant influence on the early stage self-loosening.

scholarly journals Strain Range Dependent Cyclic Hardening of 08Ch18N10T Stainless Steel—Experiments and Simulations

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4243 ◽  
Author(s):  
Jaromír Fumfera ◽  
Radim Halama ◽  
Radek Procházka ◽  
Petr Gál ◽  
Miroslav Španiel
Keyword(s):  
Stainless Steel ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Austenitic Steels ◽  
Cyclic Plasticity ◽  
Experimental Program ◽  
Isotropic Hardening ◽  
Plasticity Model ◽  
Cyclic Plasticity Model

This paper describes and presents an experimental program of low-cycle fatigue tests of austenitic stainless steel 08Ch18N10T at room temperature. The low-cycle tests include uniaxial and torsional tests for various specimen geometries and for a vast range of strain amplitude. The experimental data was used to validate the proposed cyclic plasticity model for predicting the strain-range dependent behavior of austenitic steels. The proposed model uses a virtual back-stress variable corresponding to a cyclically stable material under strain control. This internal variable is defined by means of a memory surface introduced in the stress space. The linear isotropic hardening rule is also superposed. A modification is presented that enables the cyclic hardening response of 08Ch18N10T to be simulated correctly under torsional loading conditions. A comparison is made between the real experimental results and the numerical simulation results, demonstrating the robustness of the proposed cyclic plasticity model.

Finite Element Modeling of Damage Formation in Rubber-Toughened Polymer

2005 ◽  
Vol 297-300 ◽  
pp. 1019-1024
Author(s):  
Mitsugu Todo ◽  
Yoshihiro Fukuya ◽  
Seiya Hagihara ◽  
Kazuo Arakawa
Keyword(s):  
Finite Element ◽  
Damage Zone ◽  
Damage Model ◽  
Crack Tip ◽  
Optical Microscope ◽  
Toughening Mechanism ◽  
Element Analysis ◽  
Zone Formation ◽  
Macro Scale ◽  
Rubber Toughened

Microscopic studies on the toughening mechanism of rubber-toughened PMMA (RTPMMA) were carried out using a polarizing optical microscope (POM) and a transmission electron microscope (TEM). POM result showed that in a typical RT-PMMA, a damage zone was developed in the vicinity of crack-tip, and therefore, it was considered that energy dissipation due to the damage zone development was the primary toughening mechanism. TEM result exhibited that the damage zone was a crowd of micro-crazes generated around rubber particles in the vicinity of notch-tip. Finite element analysis was then performed to simulate such damage formations in crack-tip region. Macro-scale and micro-scale models were developed to simulate damage zone formation and micro-crazing, respectively, with use of a damage model. It was shown that the damage model introduced was successfully applied to predict such kind of macro-damage and micro-craze formations.

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