Papers by Keyword: Fretting Wear

Abstract: LGJ150/25 steel core aluminum stranded wires were selected as the test wires, and the aeolian vibrations which work in different cycle times of wire that is under the conditions of dry and acidic corrosion were simulated by the self-made test bed. The electronic number of corona discharge of each pre-set conductor was measured, when applying AC high voltage on the wearing wires step by step,so that the corona inception voltages of the conductors could be confirmed. And the effect of the vibration cycle times and environmental conditions on the corona discharge was researched. Taking the sum of all aluminium stands wear area of a pre-set wire as the fretting wearing capacity, the relationship between the wire wearing capacity and the corona discharge was studied. The results indicate that the corona inception voltages of the conductors decrease with the increase of the cycle times and the wires wear capacity. In general, the wear capacity of the acidic corrosion conductors is larger, and its corona inception voltage is lower. Therefore the decrease of the conductor fretting wear can effectively reduce the corona loss of transmission lines and other hazards.

Abstract: The effect of surface modification due to fretting wear behaviour of coated SCMV (High Strength Alloy Steel) with interlayer is investigated by simulation using ABAQUS Software on a cylinder on flat contact configuration under gross sliding conditions. The effect of interlayer stiffness and the surface modification are analysed with the focus on the interlayer stress failures and its associated stresses behaviour. Tangential stress and shear stress are predicted to reduce with the increase of numbers of wear cycles due to the effect of contact conforming. Stresses in the interlayer are predicted to increase with the interlayer stiffness due to the function of the interlayer as the load bearer.

Abstract: 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 6000^th cycle model and onwards. Overall the relationship of fretting wear and plasticity has been defined qualitatively.

Abstract: 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 (6000^th, 60000^th, 150000^th and 300000^th) 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].

Abstract: Fretting induced cracking is commonly observed in industrial components that are in contact and are subjected to small oscillatory movements between them. Fretting causes a considerable reduction in fatigue strength. In this paper, finite element modeling is used in conjunction with Smith Watson Topper (SWT) criterion to estimate crack initiation in fretting. The predictions from the analysis are compared with the experimental results. It is concluded that the analysis must include the effect of residual stress and wear profile with debris effect for better predictions.

Abstract: Finite element method to analyze the fretting wear characteristics based on Hertz theory, Coulomb friction law and a modified Archard wear equation, has been applied to a cylinder-on-flat configuration for typical steam generator tube material Inconel 690 alloy and typical anti-vibration bar material Inconel 600 alloy (Cr plating) in the nuclear power plant, under gross slip and partial slip conditions. The evolutions of contact profile, surface contact variables with increase in wear cycles are predicted. The slip regime is predicted to have significant effects on the fretting wear behavior. Under the gross slip regime, it is found that the peak contact pressure occurs at the center of the contact scar, and the actual relative slip is slightly smaller than the applied value. The contact width increases, and the peak pressure decreases gradually with increase in wear cycles. Whereas under the partial slip regime, the peak contact pressure occurs at the stick-slip boundary, the actual relative slip is much smaller than the applied value, and no relative slip occurs in the stick zone. The contact width increases gradually, and the peak pressure increases rapidly with increase in wear cycles.

Abstract: Finite element analysis of a coated SCMV (high-strength alloy steel) substrate with interlayer has been studied with the emphasized of stresses behaviour predicted in the substrate region due to the fretting wear surface profiles modification. The analysis is simulated using a simple cylinder-on-flat contact geometry under gross sliding condition for a given surface profile on a specific number of fretting cycles. The effect of interlayer stiffness on the stresses predicted in the substrate region is studied. It is found that the stresses in the substrate region are generally predicted to reduce with the increase of interlayer stiffness and with the advancement of wear.

Abstract: The fretting wear behavior of Ti-6Al-4V is studied with the focus on cyclic plasticity effect under gross sliding condition. The analysis is simulated using finite element based method with a new surface profile model represently a given number of cycles using a cylinder-on-flat geometry. The effect of cyclic plasticity on the stresses and plastic strain distribution is studied. The maximum tangential stress is predicted at the trailing edge while the maximum compressive tangential stress is predicted at the leading edge of contact area. Plasticity in shear component is significant compare to tangential component and predicted at 0^th and 3000^th cycles only. It is found that important to include plasticity that remains from previous cycle for better prediction of fretting wear.

Abstract: The fretting wear of coated SCMV (high-strength alloy steel) substrate with interlayer is studied with the focus on stresses associated with the coating failure under gross sliding condition. The analysis is simulated using finite element based method for a given number of cycles of worn half cylinder-on-flat geometry. The effect of interlayer stiffness on the stress distributions in the coating is studied. The maximum tensile stress at the trailing edge and the maximum compressive stress at the leading edge are reducing with increasing interlayer stiffness. The maximum shear stress at the coating-interlayer interface is predicted to have negligible effect with the change of interlayer stiffness. All the stresses are generally predicted to reduce with cycle. In general, stiffer interlayer will reduce the risk of coating failure.

Abstract: Methodological aspects of fretting and fretting-corrosion research of metallic biomaterials are presented in this article. At the Faculty of Mechanical Engineering Technical University of Bialystok tribometer device was constructed to test the fretting phenomenon with flat-on-flat contact configuration [. Based on the results of published research the fretting regimes were established. Values of the amplitude of reversible movement were 80-120 µm, the frequency was 1 Hz [2] and the value of the pressure was 20 MPa. Fretting-corrosion tests in simulated biological fluids should be performed in the three-electrode system in presence of the reference electrode and counter electrode along with the working electrode to the potentiostat. It is important to leave the system loaded and immersed for about 30 minutes prior to testing the potential of the system. During that time system potentials are stabilized. After that, acquiring data for fretting corrosion should be started with measurement potential/time changes [. A better understanding of the fretting processes will largely eliminate its effects at the construction design stage.