scholarly journals A Numerical Study on the Effect of Variable Wear Coefficient on Fretting Wear Characteristics

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1840
Author(s):  
Shengjie Wang ◽  
Magd Abdel Wahab
Keyword(s):  
Plastic Strain ◽  
Numerical Study ◽  
Equivalent Plastic Strain ◽  
Fretting Wear ◽  
Partial Slip ◽  
The Finite Element Method ◽  
Wear Coefficient ◽  
Wear Characteristics ◽  
Slip Regime ◽  
The Difference

Fretting wear is a common phenomenon that happens between contact parts when there is an oscillatory relative movement. To investigate wear characteristics history in the fretting process, the finite element method (FEM) is commonly applied to simulate the fretting by considering the wear in the model. In most literature publications, the wear coefficient is considered as a constant, which is not a real case based on the experimental results. To consider the variation of wear coefficient, a double-linear model is applied in this paper, and the tribologically transformed structure (TTS) phase is considered in the study of the wear coefficient variation model. By using these models for variable wear coefficient for both flat and cylinder, the difference of wear characteristics, plastic strain, and stress between variable wear coefficient model (VWCM) and constant wear coefficient model (CWCM) are analyzed. The results show that the variable wear coefficient has no significant effect on the wear characteristic at the end of the process in the gross sliding regime. However, in the partial slip regime, the effect of variable wear coefficient on wear characteristics is significant. Due to the difference in contact geometry in the fretting process between VWCM and CWCM, the tangential and shear stress and equivalent plastic strain also show differences during the fretting process.

Modelling of Fretting Wear under Partial Slip Conditions Using Combined Isotropic-Kinematic Hardening Plasticity Model

2014 ◽  
Vol 1025-1026 ◽  
pp. 50-55
Author(s):  
Abdul Latif Mohd Tobi ◽  
M.Y. Ali ◽  
M.H. Zainulabidin ◽  
A.A. Saad
Keyword(s):  
Plastic Strain ◽  
Kinematic Hardening ◽  
Equivalent Plastic Strain ◽  
Fretting Wear ◽  
Cyclic Plasticity ◽  
Partial Slip ◽  
Plasticity Model ◽  
Slip Conditions ◽  
Contact Configuration ◽  
Specific Number

This paper presents finite element modelling of fretting wear under partial slip conditions using combined isotropic-kinematic hardening plasticity model with the emphasized to investigate the cyclic-plasticity behaviour predicted under fretting condition. The model is based on two-dimensional (2D) cylinder-on-flat contact configuration of titanium alloy, Ti-6Al-4V. A number of wear profiles at specific number of wear cycle (6000th, 60000th, 150000th and 300000th) are simulated. Contact pressure, tangential stress, shear stress, equivalent plastic strain, tangential plastic strain and also shear plastic strain are gathered and analysed. It is found that the plastic strain response of the combined isotropic-kinematic hardening plasticity model is slightly higher compare to linear kinematic hardening plasticity model [1].

Fretting wear behavior of thermal-oxidation on titanium alloy in air and vacuum atmosphere

2021 ◽  
pp. 2150135
Author(s):  
Liangliang Sheng ◽  
Xiangtao Deng ◽  
Hao Li ◽  
Yuxuan Ren ◽  
Guoqing Gou ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Thermal Oxidation ◽  
Wear Behavior ◽  
Fretting Wear ◽  
Partial Slip ◽  
Ti6al4v Titanium Alloy ◽  
Slip Regime ◽  
Air Atmosphere ◽  
Vacuum Atmosphere

In this work, an in-situ XPS analysis test combined self-designed high precision fretting wear tester was carried out to study the fretting wear behavior and the resulting tribo-oxidation of thermal-oxidation film on Ti6Al4V titanium alloy under the varied working atmosphere. The fretting-induced tribo-oxidation under the air and vacuum ([Formula: see text] Pa) environment was analyzed and its response on the resulting fretting wear resistance and damage mechanism was discussed. Results show that the working environment plays a significant role in the formation of tribo-oxidation and then determining the fretting wear resistance. Thermal-oxidation film in the vacuum atmosphere shows a better fretting wear resistance than that in the air atmosphere for all fretting regimes, except for partial slip regime (PSR) where there is an equivalent fretting wear resistance. Compared with the substrate Ti6Al4V titanium alloy, the thermal-oxidation film in the vacuum atmosphere performs a good protection for titanium alloy, especially for slip regime (SR), but not applied for air atmosphere.

Effect of Crystallographic Texture on Deformation Fields in Fretting Contacts

2005 ◽  
Author(s):  
J. R. Mayeur ◽  
D. L. McDowell ◽  
R. W. Neu
Keyword(s):  
Plastic Strain ◽  
Half Space ◽  
Crystallographic Texture ◽  
Element Model ◽  
Partial Slip ◽  
Slip Regime ◽  
Microstructural Heterogeneity ◽  
Alpha Beta ◽  
Cyclic Plastic Strain ◽  
Elastic Shakedown

Fretting contacts in the partial slip regime are simulated by a finite element model of a rigid cylinder on an elastic-crystal viscoplastic half-space. The half-space is modeled as duplex Ti-6Al-4V, a polycrystalline metal alloy consisting of equiaxed primary alpha grains and secondary lamellar alpha+beta grains. Various realistic 3-D crystallographic textures are considered. The deformation fields generated by fretting are quantified in terms of cumulative effective plastic strain distributions and plastic strain maps. The results clearly demonstrate the importance of the various sources of microstructural heterogeneity in the surface layers. The main sources of microstructural heterogeneity include the distribution of phases, slip system strength anisotropy, and crystallographic texture. In basal textured materials with fretting on the edge, the plastic strain is more evenly distributed in the subsurface regions than in other textured cases. This is explained by the greater number of grains able to deform by soft slip modes and the symmetry of this type of texture relative to the fretting orientation. Transverse and basal/transverse textures result in more heterogeneously-distributed plastic strain with strain often concentrated in narrow vein-like structures with maximum accumulation near alpha/alpha+beta grain boundaries. Elastic shakedown is more difficult to achieve in the later case. Ratcheting is the primary mechanism for cyclic plastic strain accumulation.

An Experimental and Numerical Study on Forming Force, Fracture Behavior, and Strain States in Two Point Incremental Forming Process

2016 ◽  
Vol 725 ◽  
pp. 586-591
Author(s):  
Chen Hao Wang ◽  
William J.T. Daniel ◽  
Hai Bo Lu ◽  
Sheng Liu ◽  
Paul Anthony Meehan
Keyword(s):  
Plastic Strain ◽  
Fracture Behavior ◽  
Numerical Study ◽  
Equivalent Plastic Strain ◽  
Fem Simulation ◽  
Forming Force ◽  
Forming Process ◽  
Approaches To Study ◽  
Tool Diameter ◽  
Numerical Approaches

Two-point incremental sheet forming process (TPIF) is an emerging and promising manufacturing process for the production of complex geometries or customized functional sheet components. In this study, the single-pass TPIF process is investigated using experimental and numerical approaches to study the forming force evolution, fracture behavior and strain states with a varied wall angle hemisphere shape. It can be concluded that both the peak force and fracture depth increases with tool diameter and incremental depth in TPIF process. It seems the deformation mechanism or the failure mechanism is strongly dependent on particular forming conditions based on a failure parts morphology observation. FEM simulation results indicated that the major plastic strain is positive while the minor plastic strain is negative in the TPIF process on a hemiphere shape. it can be concluded that the strain increment and total equivalent plastic strain is affected by both tool diameter and incremental depth.

Investigation on the Interaction between Plasticity Response and Fretting Wear under Partial Slip Condition

2014 ◽  
Vol 699 ◽  
pp. 378-383
Author(s):  
M.A. Harimon ◽  
Abdul Latif Mohd Tobi ◽  
Abdullah Aziz Saad ◽  
M.N. Che Seman
Keyword(s):  
Plastic Strain ◽  
Wear Behavior ◽  
Surface Profile ◽  
Slip Condition ◽  
Fretting Wear ◽  
Cyclic Plasticity ◽  
Partial Slip ◽  
Number Of Cycles ◽  
Relationship Of ◽  
Worn Surface

The fretting wear behavior of Ti-6Al-4V is studied with the focus on cyclic plasticity effect under partial slip condition. The analysis is simulated using finite element based method with a new worn surface profile model represent a given number of cycles using a cylinder-on-flat geometry. The effect of surface modification on the stresses and plastic strain distribution is studied. As the profiles become deeper and wider, the contact pressure and shear stress increase at the stick zone. Due to this increment, the accumulation of plastic strain will become more significant. This may lead to material’s ductility exhaustion that could initiate the nucleation of crack. Plastic deformation is predicted to occur in the 6000th cycle model and onwards. Overall the relationship of fretting wear and plasticity has been defined qualitatively.

Transition in the Fretting Phenomenon Based on the Variabile Coefficient of Friction

2012 ◽  
Vol 463-464 ◽  
pp. 343-346
Author(s):  
Stefan Ghimişi ◽  
Liliana Luca ◽  
Gheorghe Popescu
Keyword(s):  
Small Amplitude ◽  
Crack Nucleation ◽  
Tangential Force ◽  
Fretting Wear ◽  
Partial Slip ◽  
Fatigue Properties ◽  
Fatigue Crack Nucleation ◽  
Slip Regime ◽  
Mixed Regime ◽  
Slip Transition

Fretting is now fully identified as a small amplitude oscillatory motion which induces a harmonic tangential force between two surfaces in contact. It is related to three main loadings, i.e. fretting-wear, fretting-fatigue and fretting corrosion. Fretting regimes were first mapped by Vingsbo. In a similar way, three fretting regimes will be considered: stick regime, slip regime and mixed regime. The mixed regime was made up of initial gross slip followed by partial slip condition after a few hundred cycles. Obviously the partial slip transition develops the highest stress levels which can induce fatigue crack nucleation depending on the fatigue properties of the two contacting first bodies. Therefore prediction of the frontier between partial slip and gross slip is required.

scholarly journals The Effect of Displacement Amplitude on Fretting Wear Behavior and Damage Mechanism of Alloy 690 in Different Gaseous Atmospheres

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5778
Author(s):  
Long Xin ◽  
Lanzheng Kang ◽  
Weiwei Bian ◽  
Mengyang Zhang ◽  
Qinglei Jiang ◽  
...  
Keyword(s):  
Wear Behavior ◽  
Displacement Amplitude ◽  
Fretting Wear ◽  
Partial Slip ◽  
Wear Volume ◽  
Stick Slip ◽  
Slip Regime ◽  
Mixed Regime ◽  
Alloy 690 ◽  
Strong Adhesion

The effect of displacement amplitude on fretting wear behavior and damage mechanisms of alloy 690 in air and nitrogen atmospheres was investigated in detail. The results showed that in air, the friction coefficient gradually increased with the increase in displacement amplitude which conformed to the universal law. In nitrogen, however, it had the highest point at the displacement amplitude of 60 μm due to very strong adhesion. Whether in air or nitrogen, the wear volume gradually increased with the increase in displacement amplitude. The wear volume in air was larger than that in nitrogen except at 30 μm. At 30 μm, the wear volume in air was slightly smaller. With an increase in displacement amplitude, a transformation of fretting running status between partial slip, mixed stick-slip, and final gross slip occurred along with the change of Ft-D curves from linear, to elliptic, to, finally, parallelogrammical. Correspondingly, the fretting regime changed from a partial slip regime to a mixed regime to a gross slip regime. With the increase in displacement amplitude, the transition from partial slip to gross slip in nitrogen was delayed as compared with in air due to the strong adhesion actuated by low oxygen content in a reducing environment. Whether in air or nitrogen, the competitive relation between fretting-induced fatigue and fretting-induced wear was prominent. The cracking velocity was more rapid than the wear. Fretting-induced fatigue dominated at 30 μm in air but at 30–60 μm in nitrogen. Fretting-induced wear won the competition at 45–90 μm in air but at 75–90 μm in nitrogen.

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