The Experts below are selected from a list of 2340 Experts worldwide ranked by ideXlab platform
Sean B. Leen - One of the best experts on this subject based on the ideXlab platform.
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a strain gradient crystal plasticity model for microstructure sensitive Fretting crack initiation in ferritic pearlitic steel for flexible marine risers
International Journal of Fatigue, 2018Co-Authors: P.j. Ashton, Annette M. Harte, Sean B. LeenAbstract:Abstract A three-dimensional, strain-gradient, crystal plasticity methodology is presented for prediction of microstructure-sensitive length-scale effects in crack initiation, under fatigue and Fretting fatigue conditions, for a ferritic-pearlitic steel used in flexible marine risers. The methodology, comprising length-scale dependent constitutive model and scale-consistent fatigue indicator parameters, is calibrated and validated for representative (measured) dual-phase microstructures under strain-controlled low cycle fatigue conditions. Prediction of the effects of length-scale on Fretting crack initiation is based on a three-dimensional, crystal plasticity, frictional contact model to predict Fretting crack location and initial growth path, accounting for the effects of crystallographic orientation. The length-scale dependent fatigue and Fretting simulations predict (i) significant beneficial effect of reducing length-scale for low cycle fatigue life, (ii) complex cyclically- and spatially-varying effects and differences due to changing contact and grain length-scales, and (ii) that Fretting Damage generally decreases with decreasing (contact-grain) length-scale.
M. Kamaraj - One of the best experts on this subject based on the ideXlab platform.
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effect of surface treatments on Fretting fatigue Damage of biomedical titanium alloys
Tribology International, 2007Co-Authors: Aravind Vadiraj, M. KamarajAbstract:Abstract Fretting fatigue is an adhesive wear Damage caused by tangential micromotion under normal force at contact areas. It is observed along the contact points of hip implants and bone plates. Surface-modified biomedical titanium alloys offer better resistance against Fretting Damage. PVD TiN coatings and plasma nitriding have proved effective in minimizing friction and delaying the failure of materials. In the present study, attempt has been made to explain the Fretting fatigue failure mechanism sequence of PVD TiN-coated and plasma-nitrided Ti–6Al–4V and Ti–6Al–4V couple through friction measurement and microscopic examination.
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Characterization of Fretting fatigue Damage of PVD TiN coated biomedical titanium alloys
Surface & Coatings Technology, 2006Co-Authors: Aravind Vadiraj, M. KamarajAbstract:Abstract Fretting fatigue is a form of adhesive wear Damage due to small oscillatory movement between two contacting bodies under the action of uniform or non-uniform cyclic loads. Cyclic loads may be experienced due to vibration of one or both the bodies eventually leading to failure at the contact area. Fretting Damage is also experienced by load bearing implants within the body environment such as hip joints, knee joints, bone plates, etc. Damage characterization is important from the view of minimizing in-vivo failures. Titanium alloys are frequently used as bioimplants due to its excellent biocompatibility and low modulus of elasticity compared to stainless steel or Co–Cr–Mo alloys. Fretting wear Damage of load bearing implants can be minimized through suitable surface modification process. Ti–6Al–4V and Ti–6Al–7Nb are commonly used for biomedical applications and PVD TiN coated alloys are used for our Fretting fatigue studies. Fretting fatigue life of PVD TiN coated alloys improved compared to uncoated alloys.
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Damage characterization of unmodified and surface modified medical grade titanium alloys under Fretting fatigue condition
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2006Co-Authors: Aravind Vadiraj, M. KamarajAbstract:Abstract Fretting is a form of adhesive wear normally occurring at the contact points gradually leading to premature of load bearing medical implants made of titanium alloys. The aim of this work is to characterize the Fretting fatigue Damage features of PVD TiN coated, plasma nitrided and thermally oxidized Ti–6Al–4V and Ti–6Al–7Nb contact pairs. Fretting Damage is applied with calibrated proof ring and contact pad arrangement. The results are compared with Fretting Damage of uncoated alloys. The Damage progression during Fretting process is apparently explained with friction coefficient curves. Plasma nitrided pairs performed better in terms of Fretting fatigue lives with low friction coefficient of friction. PVD TiN coated pairs have experienced early failures due to third body mode of contact interaction with irregular friction coefficient pattern. Thermally oxidized pairs have experienced early failures due to high case thickness as well as irregular development of modified layer.
Minhao Zhu - One of the best experts on this subject based on the ideXlab platform.
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microstructure evolution and torsional Fretting fatigue Damage mechanism of 316l austenitic stainless steel at different torques
Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2018Co-Authors: Zhenbing Cai, Wulin Zhang, Jinfang Peng, Jianhua Liu, Xiyang Liu, Minhao ZhuAbstract:In this study, the torsional Fretting fatigue experiments are carried out on a multiaxis fatigue testing machine under a sinusoid torque to investigate the Fretting Damage mechanism of 316L austenitic stainless steel. The S-N curve of torsional Fretting fatigue displays different characteristics than that of the plain fatigue curve. After test, the Fretting Damage zones are analyzed in detail using scanning electron microscopy, electron probe microanalysis, and transmission electron microscopy. The transmission electron microscopic analyses show that there are two types of evolution in the dislocation structures: deformation twin system and cellular structure. With the increase in the torsional stress amplitudes, the dislocation structure changes from deformation twin system into walls-and-channel structures, finally evolving into cellular structures.
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an investigation on rotatory bending Fretting fatigue Damage of railway axles
Fatigue & Fracture of Engineering Materials & Structures, 2014Co-Authors: Chuan Song, Mingxue Shen, X F Lin, D W Liu, Minhao ZhuAbstract:ABSTRACT Fretting Damage failure analysis of a Chinese carbon railway axle RD 2 was carried out. ThewheelhubwasinsitucuttoexposetheDamagedsurfaceofthewheelseattoavoidadditionalDamage. A small-scale axle test rig was developed, and simulation tests were performed atdifferent rotator speeds of 1800 and 2100rpm. The wear mechanism of Fretting Damageareaswasacombinationofabrasivewear,oxidativewearanddelamination.Thefracturesur-faces exhibited characterization of multisource and step-profile. The Fretting fatigue crackinitiated at the subsurface and propagated along an inclined angle at the first stage. TheFrettingDamageatthehigherspeedwas moreseverecompared withthelowerspeed,whichlead to a relatively shorter fatigue life. The Damage morphologies of the axle in the simula-tion tests were in good agreement with that observed in the failure analysis on real axle. Keywords failure analysis; Fretting fatigue; press-fitted; railway axle; rotatory bending.NOMENCLATURE BE = binding energyE = Young's modulusFWHM = full width at half maximumHV
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torsional Fretting wear of a biomedical ti6al7nb alloy for nitrogen ion implantation in bovine serum
Tribology International, 2013Co-Authors: Zhenbing Cai, Mingxue Shen, Guangan Zhang, Yongkui Zhu, Liping Wang, Minhao ZhuAbstract:Abstract Ti6Al7Nb is a high-strength titanium alloy used in replacement hip joints that possesses the excellent biocompatibility necessary for surgical implants. Ti6Al7Nb treated with nitrogen gas (N 2 ) plasma immersion ion implantation–deposition (PIII–D) was investigated. Torsional Fretting wear tests of untreated and nitrogen-ion-implanted Ti6Al7Nb alloys against a Zr 2 O ball (diameter 25.2 mm) were carried out under simulated physiological conditions (serum solution) in a torsional Fretting wear test rig. Based on the analyses of the frictional kinetics behavior, the observation of 3D profiles, SEM morphologies and surface composition analyses, the Damage characteristics of the surface modification layer and its substrate are discussed in detail. The influence of nitrogen ion density on the implantation and torsional angular displacement amplitudes were investigated. The results indicated that ion implantation layering can improve resistance to torsional Fretting wear and thus has wide potential application for the prevention of torsional Fretting Damage in artificial implants. The Damage mechanism prevented by the ion implantation layer on the Ti6Al7Nb alloy is a combination of oxidative wear, delamination and abrasive wear. An increase in ion implantation concentration inhibited detachment by delamination.
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Fretting wear behaviors of a railway axle steel
Tribology International, 2010Co-Authors: J Zheng, Jinfang Peng, Xiao Jin, Minhao ZhuAbstract:Abstract Fretting Damage was one of the most important reasons for the failure of the railway axle. Fretting wear (tangential Fretting mode) tests of a railway axle steel (LZ50 steel) flats against 52 100 steel balls were carried out under different normal loads and displacement amplitudes on a hydraulic Fretting wear rig. Dynamic analyses in combination with microscopic examinations have been performed. The experimental results showed that the Fretting regimes of the LZ50 steel were strongly dependent upon the imposed normal loads and displacement amplitudes. The F t / F n curves exhibited different variation trends in different Fretting running regimes. The Fretting scars presented slight Damage in partial slip regime. In mixed Fretting regime, the trace of the plowing and plastic deformation flow can be observed on the Fretting scars. The wear mechanism during this regime was the combination of the abrasive wear, oxidative wear and delamination accompanied with obvious plastic deformation. The detachment of particles and plowing traces were the main phenomena in slip regime. And, thicker debris layer covered the contact zone of the scar. The severe degradation in slip regime presented the main wear mechanisms of abrasive wear, oxidative wear and delamination.
P.j. Ashton - One of the best experts on this subject based on the ideXlab platform.
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a strain gradient crystal plasticity model for microstructure sensitive Fretting crack initiation in ferritic pearlitic steel for flexible marine risers
International Journal of Fatigue, 2018Co-Authors: P.j. Ashton, Annette M. Harte, Sean B. LeenAbstract:Abstract A three-dimensional, strain-gradient, crystal plasticity methodology is presented for prediction of microstructure-sensitive length-scale effects in crack initiation, under fatigue and Fretting fatigue conditions, for a ferritic-pearlitic steel used in flexible marine risers. The methodology, comprising length-scale dependent constitutive model and scale-consistent fatigue indicator parameters, is calibrated and validated for representative (measured) dual-phase microstructures under strain-controlled low cycle fatigue conditions. Prediction of the effects of length-scale on Fretting crack initiation is based on a three-dimensional, crystal plasticity, frictional contact model to predict Fretting crack location and initial growth path, accounting for the effects of crystallographic orientation. The length-scale dependent fatigue and Fretting simulations predict (i) significant beneficial effect of reducing length-scale for low cycle fatigue life, (ii) complex cyclically- and spatially-varying effects and differences due to changing contact and grain length-scales, and (ii) that Fretting Damage generally decreases with decreasing (contact-grain) length-scale.
S Fouvry - One of the best experts on this subject based on the ideXlab platform.
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a fem Fretting map modeling effect of surface wear on crack nucleation
Wear, 2015Co-Authors: S Garcin, S Fouvry, S HerediaAbstract:Abstract Much research demonstrated that the Fretting sliding condition greatly influences Fretting Damage. Small displacement amplitudes, inducing partial slip, favor cracking, whereas large dissipative sliding gross slip amplitudes favor wear. Considering a Ti–6Al–4V/Ti–6Al–4V cylinder/plane contact, this typical evolution was quantified by plotting the evolution of maximum crack length versus displacement amplitude. Under partial slip, the crack nucleated above a critical tangential loading, related to a threshold δ CN_PS displacement amplitude. Above the sliding transition ( δ t ), although tangential loading remained high, crack length decreased to zero at the gross slip threshold δ CN_GS , due to surface wear extension which reduced contact stress and removed incipient nucleated cracks. This Fretting Damage evolution was simulated using an FEM code, enabling synergic modeling of wear and crack phenomena. The crack nucleation risk was quantified using an SWT parameter combined with a linear cumulative Damage law. Surface wear evolution was simulated by a local friction energy density wear approach. The three displacement values, δ t , δ CN_PS and δ CN_GS, were shown to be accurately predicted if, respectively, the FEM simulation takes account of the tangential accommodation of the test system, the Damage law is calibrated using reverse analysis of experimental partial slip crack nucleation results, and the energy wear rate is determined from the wear volume analysis in gross slip regions next to the sliding transition. This very good correlation enabled “Material Response Fretting Map” modeling and optimization of palliative coating strategy.
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1 Interface topography's effect on engineering reliability of junctions under Fretting conditions
2015Co-Authors: K. J. Kubiak, T G Mathia, S FouvryAbstract:This paper presents experimental results of different initial surface topography states influences on wide range of kinematic Fretting sliding conditions. Particularly the role of contact pressure and modes of manufacturing and therefore selected surface roughness parameters consequences in Fretting is elucidated. The impacts of various surfaces morphologies due to specific manufacturing processes (cutting and abrasive modes) are investigated. Damage mode observed and quantified under Fretting conditions (50mm radius sphere/plan contact submitted to different values of imposed contact pressure po=500-1000MPa and wide range of displacement amplitude δ*=2-50µm) is screening. Fretting Damage is usually a synergistic competition between two forms of Damage, i.e. wear and fatigue cracking. This paper attempts to bridge the gap between the Damage mode, kinematic (speed and forces) conditions and surface roughness. Here, the authors effort and provide a primary approach to evaluate the sliding under Fretting conditions as a factor of surface finishing roughness. Effect of surface 3D morphology parameters (i.e. amplitude, hybrid and orientation…), on Fretting sliding regime of AISI 1034 steel in contact with 52100 sphere is reported. Studied surface roughness include the wide surfaces range morphologies from the rough face plane milling cutter machining (Sq=4.3µm) up to optical abrasive polishing surface with Sq=113nm
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introduction of a new sliding regime criterion to quantify partial mixed and gross slip Fretting regimes correlation with wear and cracking processes
Wear, 2010Co-Authors: S Heredia, S FouvryAbstract:Abstract Fretting is associated to small displacement amplitudes between two contacting surfaces subjected to vibrations. Depending on the contact loading (normal force, displacement amplitude…), different sliding regimes may arise: partial slip, mixed slip and gross slip. In this paper, the Fretting behaviour of Ti-6Al-4V titanium alloy contact has been investigated. Sliding regimes are clearly defined through the analysis of the evolutions of an energy sliding ratio and the tangential force ratio. To accurately determine the sliding regime transition, a new criterion is introduced. It is defined as the proportion of gross slip cycles during the test (%GS). Fretting Damage is also investigated though the analysis of crack lengths and wear volumes, compared to the sliding regime. The results show the relevance of this new sliding criterion to quantify the transition between partial, mixed and gross slip regimes. By comparing the values of this criterion and Damage mechanisms, three steps have been defined in the competition between cracking and wear in the mixed slip regime. The first relates to a critical increase in cracks lengths, the second to a reduction of crack depths and the formation of a third body in the contact without ejection, and the last to the onset of wear by material removal.
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interface roughness effect on friction map under Fretting contact conditions
Tribology International, 2010Co-Authors: Krzysztof Kubiak, T G Mathia, S FouvryAbstract:In many industrial applications where Fretting Damage is observed in the contact (e.g. rotor/blade, electrical contacts, assembly joint, axe/wheel, clutch) the external loadings or geometry design cannot be changed. Therefore, the surface preparation and finishing process become essential to control and reduce the Damage caused by Fretting. In this paper, the authors present the experimental study of the initial surface roughness and machining process influence on Fretting conditions in both partial and full sliding regimes. Surfaces prepared by milling and smooth abrasive polishing processes have been analysed. The influence of roughness on sliding behaviour and analysis of friction have been reported. Also, the contact pressure influence and qualitative analysis of Fretting wear scar have been presented.
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finite element modelling of Fretting wear surface evolution application to a ti 6a1 4v contact
Wear, 2008Co-Authors: C Paulin, S Fouvry, C MeunierAbstract:Abstract Fretting is defined as a small displacement oscillatory motion between two solids in contact. Depending on the loading conditions (displacement amplitude, normal force, etc.) Fretting Damage can be induced by surface adhesion, abrasion, and fatigue with debris formation and ejection being the by products of wear. For the studied titanium alloy Ti–6A1–4V, Fretting conditions were reproduced through a simple cylinder on plane contact. By introducing an energy wear concept, the relative impact of pressure sliding amplitude and number of Fretting cycles can be rationalized through a single parameter. Predicting wear kinetics as well as geometrical changes of the wear scar under Fretting conditions appears to be of great interest for industrial applications, so a specific numerical method to model the progressive evolution of the wear scar is developed. This method, based on a finite element analysis combined with global experimental wear kinetics, allows the modification of nodal coordinates to simulate material removal. This approach is then validated by comparing numerical and experimental results. Finally, these results are discussed and further investigations are outlined.
