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.

Cracking Induced by Fretting of Aluminium Alloys

1997 ◽  
Vol 119 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Z. R. Zhou ◽  
L. Vincent
Keyword(s):  
Aluminium Alloys ◽  
Small Amplitude ◽  
Crack Nucleation ◽  
Normal Load ◽  
Fatigue Cracking ◽  
Fretting Fatigue ◽  
Fretting Wear ◽  
Partial Slip ◽  
Material Loss ◽  
Main Effects

Fretting-wear and fretting-fatigue loadings can both result in wear (material loss) and in crack nucleation and propagation (fatigue process). This paper deals with cracking induced by small amplitude displacements in the case of aeronautic aluminium alloys. The two sets of fretting maps are introduced: running condition fretting map is composed of partial slip (sticking), mixed fretting and gross sliding regime; material response fretting map is associated with two macro-degradation modes. Crack nucleation and propagation are analysed for every fretting regime. The mixed fretting regime appeared most detrimental with regards to fatigue cracking. Slip amplitude and normal load main effects discussed for fretting wear can be used to justify the fatigue limit decrease often obtained for fretting fatigue experiments.

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.

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.

Crystal Plasticity Modeling of Laser Peening Effects on Tensile and High Cycle Fatigue Properties of 2024-T351 Aluminum Alloy

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Maziar Toursangsaraki ◽  
Huamiao Wang ◽  
Yongxiang Hu ◽  
Dhandapanik Karthik
Keyword(s):  
Residual Stresses ◽  
Crystal Plasticity ◽  
High Cycle Fatigue ◽  
Driving Forces ◽  
Crack Nucleation ◽  
Fatigue Properties ◽  
Laser Peening ◽  
Cycle Fatigue ◽  
Fatigue Crack Nucleation ◽  
Near Surface

Abstract This study aims to model the effects of multiple laser peening (LP) on the mechanical properties of AA2024-T351 by including the material microstructure and residual stresses using the crystal plasticity finite element method (CPFEM). In this approach, the LP-induced compressive residual stress distribution is modeled through the insertion of the Eigenstrains as a function of depth, which is calibrated by the X-ray measured residual stresses. The simulated enhancement in the tensile properties after LP, caused by the formation of a near-surface work-hardened layer, fits the experimentally obtained tensile curves. The model calculated fatigue indicator parameters (FIPs) under the following cyclic loading application show a decrease in the near-surface driving forces for the crystal slip deformation after the insertion of the Eigenstrains. This leads to a higher high cycle fatigue (HCF) resistance and the possible transformation of sensitive locations for fatigue failure further to the depth after LP. Experimental observations on the enhancement in the HCF life, along with the relocation of fatigue crack nucleation sites further to the depth, reveal the improvement in the HCF properties due to the LP process and validate the numerical approach.

scholarly journals Tangential Loading of General Three-Dimensional Contacts

1998 ◽  
Vol 65 (4) ◽  
pp. 998-1003 ◽  
Author(s):  
M. Ciavarella
Keyword(s):  
Pressure Distribution ◽  
Poisson’S Ratio ◽  
Normal Load ◽  
Complete Solution ◽  
Tangential Force ◽  
Three Dimensional ◽  
Poisson's Ratio ◽  
Partial Slip ◽  
Normal Contact ◽  
Slip Regime

A general three-dimensional contact, between elastically similar half-spaces, is considered. With a fixed normal load, we consider a pure relative tangential translation between the two bodies. We show that, for the case of negligible Poisson’s ratio, an exact solution is given by a single component of shearing traction, in the direction of loading. It is well known that, for full sliding conditions, the tangential force must be applied through the center of the pressure distribution. Instead, for a full stick case the tangential force must be applied through the center of the pressure distribution under a rigid flat indenter whose planform is the contact area of the problem under consideration. Finally, for finite friction a partial slip regime has to be introduced. It is shown that this problem corresponds to a difference between the actual normal contact problem, and a corrective problem corresponding to a lower load, but with same rotation of the actual normal indentation. Therefore for a pure translation to occur in the partial slip regime, the point of application of the tangential load must follow the center of the “difference” pressure. The latter also provides a complete solution of the partial slip problem. In particular, the general solution in quadrature is given for the axisymmetric case, where it is also possible to take into account of the effect of Poisson’s ratio, as shown in the Appendix.

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.

Multiscale Modelling of Stick-Slip Transition of Rough (Fractal) Surfaces

2007 ◽  
Vol 539-543 ◽  
pp. 2594-2600
Author(s):  
Bernardino Chiaia ◽  
Mauro Borri-Brunetto
Keyword(s):  
Tangential Force ◽  
Numerical Algorithms ◽  
Critical Force ◽  
Contact Forces ◽  
Smooth Transition ◽  
Partial Slip ◽  
Small Scale ◽  
Stick Slip ◽  
The One ◽  
Slip Transition

The apparent shear strength of rock discontinuities is lower than that of small scale samples. At the same time, the sliding behavior is characterized, in situ, by marked instabilities. Numerical algorithms permit to calculate contact forces at any point, and to describe the stick-slip transition. On the other hand, the critical aspects are not captured by classical theories. Multiscale simulations show that the contact domain between rough surfaces is a lacunar set. This explains the size-dependence of the apparent friction coefficient. By applying an increasing tangential force, the regime of partial-slip comes into play. However, the continuous and smooth transition to fullsliding predicted by the Cattaneo-Mindlin theory is not occurring in real situations. We implement a numerical renormalization group technique, taking into account the redistribution of stress consequent to partial-slip. This permits the critical value of the tangential force to be found. The critical force is less than the one predicted by Coulomb’s theory, and depends on the specimen size and on the topology of the interface.

Sign in / Sign up

Export Citation Format

Share Document