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1 – 10 of over 8000Bearings in electric machines often work in high speed, light load and vibration load conditions. The purpose of this paper is to find a new fatigue damage accumulation rating life…
Abstract
Purpose
Bearings in electric machines often work in high speed, light load and vibration load conditions. The purpose of this paper is to find a new fatigue damage accumulation rating life model of ball bearings, which is expected for calculating fatigue life of ball bearings more accurately under vibration load, especially in high speed and light load conditions.
Design/methodology/approach
A new fatigue damage accumulation rating life model of ball bearings considering time-varying vibration load is proposed. Vibration equations of rotor-bearing system are constructed and solved by Runge–Kutta method. The modified rating life and modified reference rating life model under vibration load is also proposed. Contrast of the three fatigue life models and the influence of dynamic balance level, rotating speed, preload of ball bearings on bearing’s fatigue life are analyzed.
Findings
To calculate fatigue rating life of ball bearings more accurately under vibration load, especially in high speed and light load conditions, the fatigue damage accumulation rating life model should be considered. The optimum preload has an obvious influence on fatigue rating life.
Originality/value
This paper used analytical method and model that is helpful for design of steel ball bearing in high speed, light load and vibration load conditions.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2019-0180/
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Xingyang Chen, Linlin Ma, Haoping Xie, Fengting Zhao, Yufeng Ye and Lin Zhang
The purpose of this paper is to present a crack initiation mechanism of the external hydrogen effect on type 304 stainless steel, as well as on fatigue crack propagation in the…
Abstract
Purpose
The purpose of this paper is to present a crack initiation mechanism of the external hydrogen effect on type 304 stainless steel, as well as on fatigue crack propagation in the presence of hydrogen gas.
Design/methodology/approach
The effects of external hydrogen on hydrogen-assisted crack initiation in type 304 stainless steel were discussed by performing fatigue crack growth rate and fatigue life tests in 5 MPa argon and hydrogen.
Findings
Hydrogen can reduce the incubation period of fatigue crack initiation of smooth fatigue specimens and greatly promote the fatigue crack growth rate during the subsequent fatigue cycle. During the fatigue cycle, hydrogen invades into matrix through the intrusion and extrusion and segregates at the boundaries of α′ martensite and austenite. As the fatigue cycle increased, hydrogen-induced cracks would initiate along the slip bands. The crack initiation progress would greatly accelerate in the presence of hydrogen.
Originality/value
To the best of the authors’ knowledge, this paper is an original work carried out by the authors on the hydrogen environment embrittlement of type 304 stainless steel. The effects of external hydrogen and argon were compared to provide understanding on the hydrogen-assisted crack initiation behaviors during cycle loading.
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Airee Afiq Abd Rahim, Shahrum Abdullah, Salvinder Singh Karam Singh and Mohd. Zaki Nuawi
The purpose of this paper is to focus on the reliability assessment on the basis of automobile suspension fatigue life using wavelet decomposition method.
Abstract
Purpose
The purpose of this paper is to focus on the reliability assessment on the basis of automobile suspension fatigue life using wavelet decomposition method.
Design/methodology/approach
The discrete wavelet transform (DWT) of automobile coil spring signal is implemented as a response to different road surfaces. A reliability analysis is applied to determine the potential of the wavelet implementation in fatigue life analysis. The signals used in this study are highway and rural road.
Findings
On the basis of the implementation of wavelet decomposition method, low-level decomposition replicates the original signals in comparison with high-level decomposition. The fatigue life of low-level decomposition lies in the 2:1 and 1:2 correlation graph. The percentage difference for mean cycle to failure presents low values for low-level decomposition, with 44.31 per cent for highway and 44.20 per cent for rural road. The percentage of difference for high-level decomposition is high.
Originality/value
The determination of fatigue life analysis by using the DWT method is suitable for low-level decomposition. High-level decomposition is considered noise that cannot be eliminated and does not contribute to the failure of the structure.
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Yue Zhou, El Mehdi Abbara, Dayue Jiang, Arad Azizi, Mark D. Poliks and Fuda Ning
This study aims to uncover the multiscale relations among geometry, surface finish, microstructure and fatigue properties of curved-surface AlSi10Mg parts fabricated by powder bed…
Abstract
Purpose
This study aims to uncover the multiscale relations among geometry, surface finish, microstructure and fatigue properties of curved-surface AlSi10Mg parts fabricated by powder bed fusion (PBF) additive manufacturing.
Design/methodology/approach
This paper investigated the high-cycle tensile and bending fatigue behaviors of PBF-built AlSi10Mg parts with curved surfaces. Besides, the surface finish, porosity and microstructure around various curvatures were characterized. Meanwhile, the stress distributions of the fatigue specimens with curved surfaces under the dynamic tensile/bending loading were analyzed via theoretical analysis and ANSYS simulation.
Findings
The results showed that the as-built specimens with the smallest curvature exhibited the best surface quality, smallest grain sizes and thinnest grain boundaries. In addition, the tensile fatigue fracture occurred around the largest curvature position of fatigue specimens, which was consistent with the simulated fatigue safety factor results. Moreover, the bending fatigue specimens with the largest curvature presented the shortest fatigue life due to the highest bending and shear stresses along the loading direction.
Originality/value
So far, most studies have focused on the fatigue behavior of as-built AlSi10Mg parts with planar structures only. The investigation on fatigue properties of as-built AlSi10Mg parts with curved surfaces remains unexplored. This study provides new insights into the characterization and quantification of the fatigue performance of PBF-built metal parts with complex geometries, the knowledge of which can promote their adoption in real industries.
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Hongchun Sun, Tianlu Wang and Xindong Zhang
Fatigue damage of internal threads has gradually become the main failure mode of force sensor. To make the internal thread structure of force sensor meet the fatigue performance…
Abstract
Purpose
Fatigue damage of internal threads has gradually become the main failure mode of force sensor. To make the internal thread structure of force sensor meet the fatigue performance requirements, the design criteria of static strength and fatigue life are comprehensively considered in this paper.
Design/methodology/approach
The variation of static stress and fatigue life with the size of the main structure is obtained by simulation. By changing the number of thread turns, the hub height and outer diameter of the hub, the optimized design of the spoke force sensor is determined.
Findings
The experiment was carried out based on the determined optimized structure, and the results showed that the fatigue life meets the design requirements.
Originality/value
This research has certain guiding significance for the design and developments of high-cycle fatigue force sensors.
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D.W. Lloyd, C.D. Price, C. Wild and D.B. Brook
The method of measuring strain fields in fabrics, described earlier, is applied to an example of heavy industrial fabrics. The example chosen is that of heavy woven conveyor…
Abstract
The method of measuring strain fields in fabrics, described earlier, is applied to an example of heavy industrial fabrics. The example chosen is that of heavy woven conveyor belts. Conveyor belts are limited in their load rating and fatigue life by the means used to join them together. Two forms of joint are used, mechanical joints and spliced joints. Experimentally determined strain fields are used to explain the mechanisms of failure of each type of joint, and to assess the effectiveness of a modified joint. Measurements of strains through the thickness of spliced joints are used to contribute to the understanding of failure mechanisms in such joints.
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ATTENTION has been focussed on aspects of helicopter airworthiness by the publication of the HARP Report. In this document, existing requirements for public transport helicopters…
Abstract
ATTENTION has been focussed on aspects of helicopter airworthiness by the publication of the HARP Report. In this document, existing requirements for public transport helicopters were reviewed and recommendations made for improved safety standards and it has been stated that a series of accidents in recent years, some of them related to North Sea operations, are believed to be reason for the request to the ARB which led to the setting up of the Panel. A contributory factor was the realisation that these kind of public transport operations were in their infancy and enormous expansion can be expected.
Pedro G.P. Leite and Gilberto Gomes
The purpose of this paper is to present the application of the boundary element method (BEM) in linear elastic fracture mechanics for analysis of fatigue crack propagation…
Abstract
Purpose
The purpose of this paper is to present the application of the boundary element method (BEM) in linear elastic fracture mechanics for analysis of fatigue crack propagation problems in mixed-mode (I+II) using a robust academic software named BemCracker2D and its graphical interface BemLab2D.
Design/methodology/approach
The methodology consists in calculating elastic stress by conventional BEM and to carry out an incremental analysis of the crack extension employing the dual BEM (DBEM). For each increment of the analysis, the stress intensity factors (SIFs) are computed by the J-Integral technique, the crack growth direction is evaluated by the maximum circumferential stress criterion and the crack growth rate is computed by a modified Paris equation, which takes into account an equivalent SIF to obtain the fracture Modes I and II. The numerical results are compared with the experimental and/or BEM values extracted from the open literature, aiming to demonstrate the accuracy and efficiency of the adopted methodology, as well as to validate the robustness of the programs.
Findings
The paper addresses the numerical simulation of fatigue crack growth. The main contribution of the paper is the introduction of a software for simulating two-dimensional fatigue crack growth problems in mixed-mode (I+II) via the DBEM. The software BemCracker2D coupled to the BemLab2D graphical user interface (GUI), for pre/post-processing, are very complete, efficient and versatile and its does make relevant contributions in the field of fracture mechanics.
Originality/value
The main contribution of the manuscript is the development of a GUI for pre/post-processing of 2D fracture mechanics problems, as well as the object oriented programming implementation. Finally, the main merit is of educational nature.
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David J. Sherwin and Patrik Jonsson
Modern production management systems are being increasinglycomputerized in the pursuit of higher quality, the faster development ofnew products and lower unit costs. But the…
Abstract
Modern production management systems are being increasingly computerized in the pursuit of higher quality, the faster development of new products and lower unit costs. But the present generation of methods and software, e.g. JIT, MRP II, CIM, omit to integrate the maintenance function and do not properly consider plant availability and renewal. Considers how these can be included in the next CIM generation, the advantages and costs of doing so, and the quality and market‐share consequences of failure to do it. Total productive maintenance (TPM) and reliability‐centred maintenance (RCM) are considered inadequate in themselves, but each has features which can be used within an integrated management information system to implement TQM and optimize life cycle profit (LCP), provided that the need to collect and analyse failure, repair and maintenance data in respect of increasingly expensive plant is fully recognized.
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In his introduction to this paper the author likened the function of the tribology centres to that of a two‐way bridge—for the drawing in of information about industry's…
Abstract
In his introduction to this paper the author likened the function of the tribology centres to that of a two‐way bridge—for the drawing in of information about industry's tribological problems and for the outflow of remedial advice and help.