scholarly journals Fatigue Reliability Analysis Method of Reactor Structure Considering Cumulative Effect of Irradiation

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 801
Author(s):  
Bo Sun ◽  
Junlin Pan ◽  
Zili Wang ◽  
Yi Ren ◽  
Dariusz Mazurkiewicz ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Reliability Analysis ◽  
Life Prediction ◽  
Cumulative Effect ◽  
Neutron Dose ◽  
Design Parameters ◽  
Performance Parameters ◽  
Analysis Method ◽  
Fatigue Reliability ◽  
Rate Of Increase

The influence of irradiation should be considered in fatigue reliability analyses of reactor structures under irradiation conditions. In this study, the effects of irradiation hardening and irradiation embrittlement on fatigue performance parameters were quantified and a fatigue life prediction model was developed. Based on this model, which takes into account the cumulative effect of a neutron dose, the total fatigue damage was calculated according to Miner’s linear cumulative damage law, and the reliability analysis was carried out using the Monte Carlo simulation method. The case results show that the fatigue life acquired by taking into account the cumulative effect of irradiation was reduced by 24.3% compared with that acquired without considering the irradiation effect. Irradiation led to the increase of the fatigue life at low strains and its decrease at high strains, which is in accordance with the findings of an irradiation fatigue test. The rate of increase in the fatigue life decreased gradually with the increase of the neutron dose. The irradiation performance parameters had a small influence on fatigue reliability, while the fatigue strength coefficient and the elastic modulus had a great influence on the fatigue reliability. Compared with the current method, which uses a high safety factor to determine design parameters, a fatigue reliability analysis method taking into account the cumulative effect of irradiation could be more accurate in the reliability analysis and life prediction of reactor structures.

Fatigue Reliability Analysis Including Super Long Life Regime

2010 ◽  
Vol 118-120 ◽  
pp. 17-26 ◽  
Author(s):  
Yong Xiang Zhao
Keyword(s):  
Fatigue Life ◽  
Reliability Analysis ◽  
Life Prediction ◽  
Reliability Assessment ◽  
Cyclic Stress ◽  
Fatigue Life Prediction ◽  
Fatigue Reliability ◽  
Stress Strain ◽  
Structural Fatigue ◽  
Long Life

For an engineering structure with an actual fatigue life over that corresponding to a so-called fatigue limit, appropriate reliability assessment and fatigue life prediction are essential for developing the structure and sustaining its high quality in service. Basic clues are explored. A competition fatigue initial mechanism is shown to provide a requirement of material primary quality management. Affordable deduced material and structural probabilistic S-N curves are presented by fitting into material mid-and-long life S-N data and fatigue limits and, then, comparing to structural fatigue limits. Random cyclic stress-strain relations are depicted for constructing random stressing history of structures. Reliability assessment and fatigue life prediction are established to synthetically consider the interference of applied stresses deduced from the random cyclic stress-strain relations and capacity strengths derived from the structural S-N relations with an expected life. Affordable and appropriate method has been then developed to realize the reliability assessment and fatigue life prediction including the super long life regime. Availability of the present method has been indicated through a reliability analysis to the velocity related reliabilities and fatigue lives of a railway axle.

An Efficient Methodology for Fatigue Reliability Analysis of Mechanical Components Based on the Stress-Life Prediction Approach

2003 ◽  
Author(s):  
Jun Tang ◽  
Young Ho Park
Keyword(s):  
Fatigue Life ◽  
Reliability Analysis ◽  
Life Prediction ◽  
Failure Modes ◽  
Theoretical Background ◽  
Fatigue Reliability ◽  
Integrated Method ◽  
Reliability Method ◽  
Mechanical Components ◽  
Prediction Approach

An efficient methodology for fatigue reliability assessment and its corresponding fatigue life prediction of mechanical components using the First-Order Reliability Method (FORM) is developed in this paper. Using the proposed method, a family of reliability defined S-N curves, called R-S-N curves, can be constructed. In exploring the ability to predict spectral fatigue life and assessing the corresponding reliability under a specified dynamics environment, the theoretical background and the algorithm of a simple approach for reliability analysis will first be introduced based on fatigue failure modes of mechanical components. It will then be explained how this integrated method will carry out the spectral fatigue damage and failure reliability analysis. By using this proposed methodology, mechanical component fatigue reliability can be predicted according to different mission requirements.

Modification optimization-based fatigue life analysis and improvement of EMU gear

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yong-Hua Li ◽  
Chi Zhang ◽  
Hao Yin ◽  
Yang Cao ◽  
Xiaoning Bai
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Engineering Practice ◽  
Analysis Method ◽  
Intelligent Algorithm ◽  
Transient Dynamic Analysis ◽  
Content Type ◽  
Gear Modification ◽  
Life Analysis ◽  
Fatigue Life Analysis

PurposeThis paper proposes an improved fatigue life analysis method for optimal design of electric multiple units (EMU) gear, which aims at defects of traditional Miner fatigue cumulative damage theory.Design/methodology/approachA fatigue life analysis method by modifying S–N curve and considering material difference is presented, which improves the fatigue life of EMU gear based on shape modification optimization. A corrected method for stress amplitude, average stress and S–N curve is proposed, which considers low stress cycle, material difference and other factors. The fatigue life prediction of EMU gear is carried out by corrected S–N curve and transient dynamic analysis. Moreover, the gear modification technology combined with intelligent optimization method is adopted to investigate the approach of fatigue life analysis and improvement.FindingsThe results show that it is more corresponded to engineering practice by using the improved fatigue life analysis method than the traditional method. The function of stress and modification amount established by response surface method meets the requirement of precision. The fatigue life of EMU gear based on the intelligent algorithm for seeking the optimal modification amount is significantly improved compared with that before the modification.Originality/valueThe traditional fatigue life analysis method does not consider the influence of working condition and material. The life prediction results by using the method proposed in this paper are more accurate and ensure the safety of the people in the EMU. At the same time, the combination of intelligent algorithm and gear modification can improve the fatigue life of gear on the basis of accurate prediction, which is of great significance to the portability of EMU maintenance.

A Dynamic Simulation Approach to Machine Component Life Prediction

1988 ◽  
Author(s):  
T. S. Liu ◽  
E. J. Haug ◽  
B. Dopker
Keyword(s):  
Fatigue Life ◽  
Stress Analysis ◽  
Elastic Deformation ◽  
Life Prediction ◽  
Dynamic Stress ◽  
Subsequent Paper ◽  
Simulation Approach ◽  
Analysis Method ◽  
Deformation Method ◽  
Dynamic Stress Analysis

Abstract A system simulation approach is presented for dynamic stress analysis and life prediction of components of machines that undergo nonsteady gross motion and elastic deformation. The method employs finite element structural analysis, coupled gross motion-elastic deformation dynamics, and computer-based fatigue analysis, A computer aided engineering methodology is developed for life prediction by linking together software from dynamics, structures, and fatigue life estimation; to compliment conventional fatigue experiments. Dynamic stress analysis is carried out using either an uncoupled gross motion-elastic deformation method or a more accurate approach that takes into account the coupling between large displacements and elastic deformation. With the aid of vehicle operational scenarios, stress/strain histories at critical regions in vehicle components during a projected service life are simulated. A local strain approach is used to calculate cumulative fatigue damage at notches, which is used in assessing fatigue life of components during the design phase; i.e., prior to availability of experimental data A vehicle example is presented, using a simplified dynamic-stress analysis method. The more general and accurate fully coupled dynamic-stress analysis method will be illustrated in a subsequent paper.

A Multiaxial Fatigue Reliability Analysis Method of Casing Drilling in Casing String

2011 ◽  
Vol 347-353 ◽  
pp. 1749-1753
Author(s):  
Ping Wang ◽  
Zhan Qu ◽  
Jiong Zhang ◽  
Jian Bing Zhang ◽  
Liang Wang
Keyword(s):  
Fatigue Life ◽  
Equivalent Stress ◽  
Multiaxial Fatigue ◽  
Analysis Method ◽  
Fatigue Reliability ◽  
Combined Stress ◽  
Biaxial Fatigue ◽  
Von Mises Equivalent Stress ◽  
Von Mises ◽  
Stress Criteria

The Von Mises equivalent stress criteria is used to equivalent convert and correct the uniaxial and biaxial fatigue reliability experimental study of the casing material. And the probabilistic fatigue P–S–N curve of the casing is gained. The fatigue limit and fatigue life in test is equivalent convert to actual casing by combined stress correction factor. A multiaxial fatigue life calculation formula is proposed by correcting the probabilistic fatigue P–S–N curve.

The Reliability Analysis of Cylindrical Helical Compression Spring of Various Design Parameters

2012 ◽  
Vol 479-481 ◽  
pp. 2050-2054
Author(s):  
Jun Shi ◽  
Ya Yu Huang ◽  
Bin Xing Hu ◽  
Xiang Ping Hu
Keyword(s):  
Fatigue Life ◽  
Reliability Analysis ◽  
Economic Benefit ◽  
High Strength ◽  
Interference Model ◽  
Design Parameters ◽  
Matlab Software ◽  
Compression Spring ◽  
Controlling Variables ◽  
The Way

When designing the cylindrical helical compression spring, many designers use high- strength materials or various strengthening technology approaches in order to improve the reliability of spring. These approaches increase the costs and reduce economy. With the help of MATLAB software, this paper analyzes how the chosen design parameters of the cylindrical helical compression spring influence its reliability based on stress-strength interference model with the way of controlling variables method when the fatigue life of spring is longer than one million cycles. It is shown that changing the spring design parameters, instead of using valuable or rare materials, can achieve high reliable level especially when the reliability of spring can't reach the requirement and hence can get a better economic benefit.

Durability analysis using Markov chain modeling under random loading for automobile crankshaft

2019 ◽  
Vol 10 (4) ◽  
pp. 454-468 ◽  
Author(s):  
Salvinder Singh ◽  
Shahrum Abdullah
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Fatigue Life ◽  
Automotive Industry ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Fatigue Reliability ◽  
Load History ◽  
Content Type ◽  
Durability Analysis

Purpose The purpose of this paper is to present the durability analysis in predicting the reliability life cycle for an automobile crankshaft under random stress load using the stochastic process. Due to the limitations associated with the actual loading history obtained from the experimental analysis or due to the sensitivity of the strain gauge, the fatigue reliability life cycle assessment has lower accuracy and efficiency for fatigue life prediction. Design/methodology/approach The proposed Markov process embeds the actual maximum and minimum stresses by a continuous updating process for stress load history data. This is to reduce the large credible intervals and missing loading points used for fatigue life prediction. With the reduction and missing loading intervals, the accuracy of fatigue life prediction for the crankshaft was validated using the statistical correlation properties. Findings It was observed that fatigue reliability corresponded well by reporting the accuracy of 95–98 per cent with a mean squared error of 1.5–3 per cent for durability and mean cycle to failure. Hence, the proposed fatigue reliability assessment provides an accurate, efficient, fast and cost-effective durability analysis in contrast to costly and lengthy experimental techniques. Research limitations/implications An important implication of this study is durability-based life cycle assessment by developing the reliability and hazard rate index under random stress loading using the stochastic technique in modeling for improving the sensitivity of the strain gauge. Practical implications The durability analysis is one of the fundamental attributes for the safe operation of any component, especially in the automotive industry. Focusing on safety, structural health monitoring aims at the quantification of the probability of failure under mixed mode loading. In practice, diverse types of protective barriers are placed as safeguards from the hazard posed by the system operation. Social implications Durability analysis has the ability to deal with the longevity and dependability of parts, products and systems in any industry. More poignantly, it is about controlling risk whereby engineering incorporates a wide variety of analytical techniques designed to help engineers understand the failure modes and patterns of these parts, products and systems. This would enable the automotive industry to improve design and increase the life cycle with the durability assessment field focussing on product reliability and sustainability assurance. Originality/value The accuracy of the simulated fatigue life was statistically correlated with a 95 per cent boundary condition towards the actual fatigue through the validation process using finite element analysis. Furthermore, the embedded Markov process has high accuracy in generating synthetic load history for the fatigue life cycle assessment. More importantly, the fatigue reliability life cycle assessment can be performed with high accuracy and efficiency in assessing the integrity of the component regarding structural integrity.

Probabilistic fatigue life prediction for concrete bridges using Bayesian inference

2018 ◽  
Vol 22 (3) ◽  
pp. 765-778 ◽  
Author(s):  
Ming Yuan ◽  
Yun Liu ◽  
Donghuang Yan ◽  
Yongming Liu
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Concrete Bridges ◽  
Fatigue Life Prediction ◽  
Analysis Method ◽  
Analysis Framework ◽  
Box Girder ◽  
Material Life ◽  
Comparison With Experimental Data ◽  
Life Prediction Model

A probabilistic fatigue life prediction framework for concrete bridges is proposed in this study that considers the stress history from the construction stage to the operation stage. The proposed fatigue analysis framework combines the fatigue crack growth-based material life prediction model and a nonlinear structural analysis method. A reliability analysis is proposed using the developed probabilistic model to consider various uncertainties associated with the fatigue damage. A Bayesian network is established to predict the fatigue life of a concrete bridge according to the proposed framework. The proposed methodology is demonstrated using an experimental example for fatigue life prediction of a concrete box-girder. Comparison with experimental data of fatigue life shows a satisfactory accuracy using the proposed methodology, and the ratio of the posterior predicted mean (updating time n = 8) to the test value decreases to 33%–1% in the current investigation.

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