Stable and unstable friction in fretting contacts

Hintikka, Jouko; Mäntylä, Antti; Vaara, Joona; Frondelius, Tero; Lehtovaara, Arto

doi:10.1016/j.triboint.2018.10.014

Cited by 32 publications

(30 citation statements)

References 32 publications

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“…If the largest outlier is excluded (marked with a red circle) R 2 raises to 0.99. Linear increase of wear volume with accumulated energy for identical contacts is frequently reported in the literature (see Fouvry and Merhej, 9 Hintikka et al, 15 Hintikka et al 18 and Heredia and Fouvry and Pearson and Shipway 20 ). However, in this case, the linearity exists between contacts of different sizes.…”

Section: Resultsmentioning

confidence: 59%

“…However, it should be noted that there is a small degree of inherent non-uniformity due to elastic deformation of the samples under load. 18 During the experimental series, it was noted that normal load excursions of up to 50% of the set value were occurring, mainly during reversal of the torsion direction. A stiff spring was inserted into the load path in an attempt to mitigate this.…”

Section: Experimental Strategy and Setupmentioning

confidence: 97%

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Experimental investigation of debris entrapment in annular contacts

Aleksejev

Clark

Huber

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part J:

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In wearing contacts, a part of the wear debris is trapped between the surfaces, creating a wear debris bed. Many researchers report such beds providing a degree of protection against further wear. It was hypothesized, that in an annular contact, the level of debris entrapment increases with the width of the annulus resulting in decrease in wear. To test this hypothesis, two series of experiments using EN1A steel and 6082T6 aluminium alloy annuli, measuring 1, 2 and 4 mm wide were carried out. When steel was used, there was no clear correlation between ring width and total mass loss or steady-state wear rate. When aluminium was used, wear decreased with the ring width according to both metrics. This behaviour appears to correlate with worn surface roughness, suggesting worn surface roughness to be a parameter controlling debris entrapment.

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Section: Resultsmentioning

confidence: 59%

Section: Experimental Strategy and Setupmentioning

confidence: 97%

Experimental investigation of debris entrapment in annular contacts

Aleksejev

Clark

Huber

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…where ∆γ eq is an equivalent slip increment, τ eq is an equivalent frictional shear stress and k is a constant regulating the rate of change. Friction coefficient is also limited by its maximum allowed value of 0.8, that is based on the stabilized friction measurements in [9,6].…”

Section: Methodsmentioning

confidence: 99%

FEM-based wear simulation for fretting contacts

Mäntylä

Juoksukangas

Hintikka

et al. 2020

RakMek

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This article presents a robust Finite-Element-Method-based wear simulation method, particularly suitable for fretting contacts. This method utilizes the contact subroutine in a commercial finite element solver Abaqus. It is based on a user-defined contact formulation for both normal and tangential directions. For the normal contact direction, a nodal gap field is calculated by using a simple Archard's wear equation to describe the depth of material removal due to wear. The wear field is included in the contact pressure calculation to allow simulation of wear and contact stress evolution during the loading cycles. The main advantage of this approach is that all contact variables are accessible inside the routine, which allows full coupling between normal and tangential contact variables. Also, there is no need for mesh modifications during the solution. This makes the implementation flexible, robust and particularly suitable for fretting cases where friction and tangential contact stiffness play an essential role. The method is applied to the bolted joint type fretting test case. The methodology is also fully applicable to complex real component simulations.

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“…Friction generates a loss of energy and useful power as it is a force contrary to movement [7], this is affected by various factors such as the finish of the surfaces in contact, the composition of the materials, the dimensional tolerances between friction pairs, the operating temperature of the tribological system, the hardness of the materials and the lubrication used, whether solid or liquid. All these parameters are those that define the coefficient of friction which is different for each class of friction force that occurs [6]. It is presented by the interaction between the two surfaces in contact, so its value depends both on the weight of the object and the dynamic forces that occur in relative movement, as on the finish of the surfaces and the type of material found in contact [8].…”

Section: III Frictionmentioning

confidence: 99%

“…The measurements of the friction coefficients depend on various mechanical factors such as the type of movement, the value of the applied load, the speed at which the test is run, its duration and, in addition to this, the environmental factors such as the humidity and temperature, which must be controlled in order to achieve a more realistic approach to the model studied. From the tests, the coefficient of friction [6] and the diameter of the wear scar of the element are generally determined, to declare the contact conditions. Additionally, the tribometer used may contain sensors that in turn allow the measurement of vibrations, noise and operating temperature.…”

Section: Introductionmentioning

confidence: 99%