Cyclic plasticity models and fatigue criteria for exhaust manifold life assessment in the context of limited material data available

2021 ◽  
pp. 1-18
Author(s):  
Josef Košťál ◽  
František Šebek ◽  
Jindřich Petruška ◽  
Thomas Seifert
Keyword(s):  
Life Assessment ◽  
Cyclic Plasticity ◽  
Exhaust Manifold ◽  
Material Data

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 Fatigue and Corrosion Fatigue Life Assessment With Application to Autofrettaged Parts

2018 ◽  
Author(s):  
Volodymyr Okorokov ◽  
Donald MacKenzie ◽  
Yevgen Gorash
Keyword(s):  
Fatigue Life ◽  
Crack Initiation ◽  
Corrosion Fatigue ◽  
Local Stress ◽  
Life Time ◽  
Life Assessment ◽  
Cyclic Plasticity ◽  
Theoretical Modelling ◽  
Experimental Program ◽  
Low Carbon

This study investigates an effect of autofrettage on the fatigue and corrosion fatigue life of high pressure parts made from low carbon structural steel. To estimate the beneficial effect of autofrettage application, an extensive experimental program and advanced theoretical modelling are conducted and analyzed in this study. Accurate calculation of compressive residual stresses is achieved by application of a cyclic plasticity model which can precisely simulate a cyclic plasticity response of material. In terms of a fatigue life prediction methodology, a non-local stress based approach with a modified critical distance theory is used for prediction of the crack initiation stage providing conservative fatigue assessment. Because of the fact that the crack propagation stage can take a considerable part of the total life for autofrettaged parts, more accurate fatigue life calculation is performed by the use of a fracture mechanics approach. The total fatigue life time of autofrettaged parts is then calculated as a sum of the crack initiation and propagation stages.

Fatigue-Life Assessment

2021 ◽  
pp. 98-133
Author(s):  
Phillip E. Prueter
Keyword(s):  
Fatigue Life ◽  
Damage Tolerance ◽  
Pressure Vessels ◽  
Life Assessment ◽  
Cyclic Plasticity ◽  
Fatigue Assessment ◽  
Fatigue Life Assessment ◽  
Component Design ◽  
Engineering Mechanics ◽  
Growth Approach

Abstract This article offers an overview of fatigue fundamentals, common fatigue terminology, and examples of damage morphology. It presents a summary of relevant engineering mechanics, cyclic plasticity principles, and perspective on the modern design by analysis (DBA) techniques. The article reviews fatigue assessment methods incorporated in international design and post construction codes and standards, with special emphasis on evaluating welds. Specifically, the stress-life approach, the strain-life approach, and the fracture mechanics (crack growth) approach are described. An overview of high-cycle welded fatigue methods, cycle-counting techniques, and a discussion on ratcheting are also offered. A historical synopsis of fatigue technology advancements and commentary on component design and fabrication strategies to mitigate fatigue damage and improve damage tolerance are provided. Finally, the article presents practical fatigue assessment case studies of in-service equipment (pressure vessels) that employ DBA methods.

Creep-Cyclic Plasticity and Damage Assessment of an SS304 Weldolet

2021 ◽  
Author(s):  
Manu Puliyaneth ◽  
Haofeng Chen
Keyword(s):  
Thermal Load ◽  
Damage Assessment ◽  
Creep Behaviour ◽  
Life Assessment ◽  
Cyclic Plasticity ◽  
Matching Method ◽  
Damage Mechanisms ◽  
Creep Fatigue ◽  
Dwell Period ◽  
Linear Matching Method

Abstract Creep-fatigue and creep-ratcheting life assessment of an SS304 weldolet considering full creep-cyclic plasticity interaction is investigated using the extended Direct Steady Cycle Analysis (eDSCA) within the Linear Matching Method Framework (LMMF). The creep behaviour is modelled using the Norton relationship, which is modified by the Arrhenius rule to account for the temperature variation within the weldolet. The introduction of a creep dwell increases the reverse plasticity resulting from the creep relaxation. This leads to both creep-fatigue and creep-ratcheting damage mechanisms at different regions within the weldment. For thermal load dominated loading combinations, creep ratcheting due to both cyclically enhanced creep and creep enhanced plasticity are observed based on the dwell period. The effect of dwell period, load and temperature on the creep-fatigue and creep-ratcheting interaction of a weldolet are presented. The simultaneous presence of various damage mechanisms at different locations within the weldment highlights the importance and requirement of the proposed creep-cyclic plasticity investigations at weld locations.

scholarly journals Cyclic Plasticity Behavior of 90° Back-to-Back Pipe Bends Under Cyclic Bending and Steady Pressure

2018 ◽  
Author(s):  
Nak-Kyun Cho ◽  
Haofeng Chen
Keyword(s):  
Cyclic Loading ◽  
Life Assessment ◽  
Cyclic Plasticity ◽  
Piping System ◽  
Cyclic Bending ◽  
Out Of Plane ◽  
Parametric Studies ◽  
Structural Responses ◽  
Plane Bending ◽  
Internal Pressures

Back-to-back pipe bends are widely adopted applications in many industries including nuclear sectors. Evaluation of their load bearing capability under complex cyclic loading is very important. Recently, a couple of research reported shakedown boundary of a 90° back-to-back pipe bends by adopting a conservative approach but no comprehensive post yield structural behaviors have been dealt with. In this research the concerning pipe bends subjected to cyclic opening in-plane (IP)/out-of-plane (OP) bending and steady internal pressures are analyzed to construct shakedown and ratchet limit boundary by means of the Linear Matching Method. Analyzed results present that the concerning pipe bends under out-of-plane bending has higher resistance to cyclic bending than under in-plane bending. In additions, the out-of-plane bending causes very small alternating plasticity areas, unlike the in-plane bending. Full cyclic incremental analyses known as step-by-step analysis are performed to verify the structural responses either side of each boundary and confirm correct responses. Parametric studies are carried out with respect to changes in geometry of the concerning pipe bends subjected to the same loading, and semi-empirical equations are derived from relationships of the reverse plasticity limit and the limit pressure with the bend characteristic. This paper offers broad understandings of structural responses of the 90° back-to-back pipe bends under the complex cyclic loading as well as providing key points to be considered for the life assessment of the piping system.

On Constitutive Models for Ratcheting of a High Strength Rail Steel

2014 ◽  
Vol 891-892 ◽  
pp. 1146-1151 ◽  
Author(s):  
Chung Lun Pun ◽  
Qian Hua Kan ◽  
Peter J. Mutton ◽  
Guo Zheng Kang ◽  
Wen Yi Yan
Keyword(s):  
Experimental Data ◽  
Rail Steel ◽  
Kinematic Hardening ◽  
High Strength ◽  
Cyclic Plasticity ◽  
Plasticity Model ◽  
Loading Test ◽  
Material Data ◽  
Chaboche Model ◽  
Cyclic Plasticity Model

The ratcheting behaviour of a hypereutectoid high strength rail steel with carbon content of 0.85% was experimentally studied under both uniaxial and bi-axial cyclic loadings recently by the authors. To numerically simulate the multiaxial ratcheting behaviour of the rail steel, the Abaqus built-in Lemaitre-Chaboche model was applied first in current study. Following Abaqus documentation, the material data for the Lemaitre-Chaboche model were calibrated from the uniaxial loading test results. Comparing with experimental data, the Lemaitre-Chaboche model with the calibrated data provides overpredictions for the ratcheting responses of the rail steel under both uniaxial and bi-axial loadings. After that, a modified cyclic plasticity model with a coupling multiaxial parameter in the isotropic and kinematic hardening rules was applied for the material. The material data for this modified model were calibrated from both uniaxial and bi-axial loading tests. Comparison between the simulated results and the experimental data show that this modified cyclic plasticity model has the capacity to simulate both uniaxial and multiaxial ratcheting behaviour of the hypereutectoid rail steel with an acceptable accuracy.

Intelligence and Personality

2020 ◽  
Vol 41 (3) ◽  
pp. 124-132
Author(s):  
Marc-André Bédard ◽  
Yann Le Corff
Keyword(s):  
Personality Traits ◽  
Big Five ◽  
Real Life ◽  
Big Five Personality Traits ◽  
Original Study ◽  
Life Assessment ◽  
Big Five Personality ◽  
Verbal Intelligence ◽  
Nonverbal Intelligence ◽  
French Canadian

Abstract. This replication and extension of DeYoung, Quilty, Peterson, and Gray’s (2014) study aimed to assess the unique variance of each of the 10 aspects of the Big Five personality traits ( DeYoung, Quilty, & Peterson, 2007 ) associated with intelligence and its dimensions. Personality aspects and intelligence were assessed in a sample of French-Canadian adults from real-life assessment settings ( n = 213). Results showed that the Intellect aspect was independently associated with g, verbal, and nonverbal intelligence while its counterpart Openness was independently related to verbal intelligence only, thus replicating the results of the original study. Independent associations were also found between Withdrawal, Industriousness and Assertiveness aspects and verbal intelligence, as well as between Withdrawal and Politeness aspects and nonverbal intelligence. Possible explanations for these associations are discussed.

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