The dovetail joint interfaces in aero-engine are susceptible to fretting wear, which can result in premature failure. Based on two-dimensional (2D) blade/disk contact finite element (FE) model and ...the energy model, an original substrate-debris-glaze conversion method is proposed and validated to predict the presence of a glaze layer at high temperatures in fretting wear. The present work investigates the effects of bottom angle, friction coefficient, centrifugal force and temperature on fretting wear of the dovetail joint. The results indicate that fretting wear predominantly occurs near the edges of the contact areas. Furthermore, the formation of glaze layer at high temperatures leads to a significant reduction in wear depth, ranging from 50% to 93%, compared to low temperatures without glaze layer.
Decreased fretting and corrosion damage at the taper interface of retrieved ceramic-on-polyethylene total hip arthroplasty (THA) implants has been consistently reported; however, resultant fretting ...corrosion as a function of femoral head size and taper geometry has not been definitively explained.
Eight cohorts were defined from 157 retrieved THA implants based on femoral head composition (n = 95, zirconia-toughened alumina, ZTA vs n = 62, cobalt-chromium alloy, CoCr), head size (n = 56, 32mm vs n = 101, 36mm), and taper geometry (n = 84, 12/14 vs n = 73, V40). THA implants were evaluated and graded for taper fretting and corrosion. Data were statistically analyzed, including via a 23 factorial modeling.
Factorial-based analysis indicated the significant factors related to both resultant (summed) fretting and corrosion damage were head material and taper geometry; head material–taper geometry interaction was also a significant factor in resultant corrosion damage. Lower rates of moderate-to-severe fretting and corrosion damage were exhibited on ZTA heads (ZTA = 13%, CoCr = 38%), smaller heads (32mm = 18%, 36mm = 26%), and 12/14 tapers (12/14 = 13%, V40 = 35%). ZTA+32mm heads demonstrated the lowest rates of moderate-to-severe fretting and corrosion damage (12/14 = 2%, V40 = 7%), whereas CoCr heads with V40 tapers demonstrated the greatest rates of moderate-to-severe damage (32mm = 47%, 36mm = 59%).
In this series, retrieved implants with ZTA, 32-mm heads paired with 12/14 tapers exhibited lower rates of moderate-to-severe damage. Factorial analysis showed head material, taper geometry, and their interactions were the most significant factors associated with resultant damage grades. Isolating implant features may provide additional information regarding factors leading to fretting and corrosion damage in THA.
IV (case series).
This paper presents two empirical parameters for the prediction of fretting. The first is a simple parameter,
D
fret
1, which is shown to correlate test data against fretting fatigue life in terms of ...the so-called running conditions of contact displacement and normal load. The second, more complex, parameter is shown to have the ability to capture: (i) the effect of relative slip on fretting fatigue life and (ii) a well-known fretting fatigue contact size effect in a more rational framework. This parameter combines a multiaxial fatigue parameter, the constants for which can be obtained from plain-fatigue testing, and a surface damage parameter
D
fret
2, which represents the surface damaging effect of fretting, the tribological constants for which can be obtained from fretting wear and fretting fatigue test data. A key benefit of
D
fret
2 is that it circumvents time-consuming incremental wear simulations.
This article presents an historical review of studies of the mechanics of fretting fatigue, concentrating on those carried out at the University of Oxford. It includes, particularly, the seminal ...initial studies conducted under the direction of Prof J.J.O’Connor in the early 1970s, and brings the picture up to date. It concludes with some consideration of what the next stage of challenges facing fundamental studies are.
•A detailed history of early studies of fretting fatigue is given.•The major advances in a systematic study of the subject, splitting the problem into fretting damage, crack nucleation and subsequent propagation are described.•Several methods of quantifying the nucleation phase, representing our current understanding, are given.
Grid-to-rod fretting (GTRF) is the main factor leading to the failures of fuel rods in reactor. The oxide layer formed on pre-wear stage has a significant impact on the wear resistance of zirconium ...(Zr) alloys fuel cladding. In this research, Zr alloy was immersed in high-temperature water conditions for 30 days,110 days,145 days, and 195 days. The characterization and fretting wear behavior of oxide layer on Zr alloy were investigated. Results show that the oxide layer consists of t-ZrO2, m-ZrO2, and metal Zr. The thickness and hardness of oxide layer increases with the corrosion time increase. The fretting running region and F-D curve are dependent on the oxide layer. Compared with Zr alloy, the wear volume of oxide layer on Zr alloy is significantly reduced because the structure of oxide layer is dense with a high hardness, leading to that the oxide layer is not easy to be destroyed during the fretting. The wear mechanism of Zr alloy is adhesive wear, and the wear mechanism of oxide layer is abrasive wear.
•The fretting wear behavior of pre-oxidized Zr alloy cladding was investigated.•The wear volume of oxide layer on Zr alloy decreases with the corrosion time increase.•The fretting running region and F-D curve are significantly dependent on the oxide layer.
Identification of the fatigue failure mode of the premium threaded connection for Oil Country Tubular Goods pipes was conducted via full-scale fatigue tests. A through-wall crack was found at the ...imperfect thread root of the male embodiment, but the crack initiation site depended on the stress level. At relatively higher stress amplitude region, the crack originated from the thread rounded corner by stress concentration. At relatively lower stress amplitude region, the crack originated at the middle of the thread root because of fretting fatigue. To investigate the fretting fatigue mechanism in the threaded connection, a fundamental fretting fatigue test was conducted. This test achieved the fretting fatigue failure at the middle of the contact surface under large gross slip condition.
•Fatigue failure mode of the premium threaded connection was identified.•Main crack originated at the middle of thread root because of fretting fatigue.•Fundamental fretting fatigue test reproduced the main crack at the middle.•Fretting fatigue on the thread root would be related to the large relative slip.
The objective of this study is to compare the performance of machine-learning strategy versus a physical friction-energy wear approach to predict the fretting wear volume of a low-alloyed steel ...contact by varying several loading parameters. Then, an artificial neural network (ANN) is used to predict the wear volume at each loading condition. These predictions were compared versus a physics-based friction energy wear modeling considering the third-body theory and the contact-oxygenation concept. A parametric study is performed to compare the prediction errors as a function of the proportion of the experiments involved in the modeling process. The results suggest that the physical modeling is more performant than ANN when a restricted number of experimental data is available for the calibration process.
•Comparison between ANN and physics-based energy wear model performance.•Physics-based energy wear model is highly performant even with small data base.•ANN is accurate when sufficient quantity of training data is used for calibration.
The effects of applying a bonded MoS
2
solid lubricant to a 1050 steel substrate were investigated using a torsional fretting wear apparatus. Tests were conducted under a normal load of 50 N with ...angular displacement amplitudes ranging from 0.1 to 5°. Wear scars were examined using scanning electron microscopy, energy-dispersive X-ray spectrometry, optical microscopy, and surface profilometry. The MoS
2
coating exhibited different torsional fretting regimes than those of the substrate. Fretting regimes of the coating were primarily in the partial slip regime (PSR) and the slip regime (SR) with no mixed fretting regime. The width of the PSR narrowed. Due to the lubricating effects of the coating, the friction torque was consistently lower than that of the substrate. The damage to the coating in the PSR was very slight, and its granular structure remained even after 1,000 cycles. The damage mechanism to the SR coating was a combination of abrasive wear, oxidative wear, and delamination. The MoS
2
coating had potential to alleviate torsional fretting wear.
Electrical contacts, which are used in aerospace engineering with high reliability requirements, are usually plated in order to prevent corrosion. The wear and fretting corrosion behavior of gold ...plated copper contacts is studied at different current loads. The degradation of contacts is explained with reference to current to melt metal and breakdown oxide films. The contacts with higher current delay the time before reaching failure. The comparison between the cases with and without current load revealed metal melting as a result of current heating. The observed surface morphology reveals five typical regions within the fretted zone.
•The wear and fretting corrosion behavior of gold plated copper contacts is studied at various current loads.•A higher current load delays the time before reaching failure and corresponds to a relatively low contact resistance.•Contacts with higher current load suffer a severe fluctuation in contact resistance.•The five typical regions shared by the worn scars are identified.•The dual role of the current joule heating on fretting contact material is analyzed explicitly.
•Differences between tribocorrosion, fretting corrosion and MACC has been clarified.•Apparatus simulating rotational micro-motion of modular tapers has been designed.•Circumstances other than ...biomedical application regarding MACC have been discussed.•Surface modification technology regarding MACC mitigation has been emphasized.
Mechanically-assisted crevice corrosion (MACC) is a synergistic combination of wear and crevice corrosion. The major differences between tribocorrosion, fretting corrosion and MACC relate to the relative scale of motion and contact area, are clarified in this work. Experimental testing methods for MACC and design of simulation apparatuses are compared and discussed. MACC associated with biomedical alloys used as orthopedic implants, screws, and dental implants has been the subject of most recent research regarding this corrosion mechanism. However, there are also many engineering structures where the pre-requisite conditions for MACC are met but have to date received less scientific scrutiny. Examples are tubes and supportive bars/plates constructions, bolt-type structures and rail track foot covered by fastening systems. Reasonable selection of fretting-resistant materials, proper mounting methods and development of lubricating coating and oil/grease would be effective for mitigating MACC, and it is proposed that surface modification regarding contact geometries and surface compliances may have future promise.
