scholarly journals A Model of Cylindrical Gear Failures Using the Criterion of the Working Surface Wear Resistance

2019 ◽  
pp. 3-9
Author(s):  
A.V. Antsupov ◽  
A.V. Antsupov ◽  
V.P. Antsupov ◽  
M.G. Slobodianskii
Keyword(s):  
Service Life ◽  
Wear Rate ◽  
Tooth Wear ◽  
Linear Wear ◽  
Calculation Algorithm ◽  
Limiting State ◽  
Cylindrical Gear ◽  
Kinetic Dependence ◽  
Friction Forces ◽  
Linear Wear Rate

Cylindrical gear failure due to tooth wear is one of the most common reasons for the decreased technical and economic indicators of various units resulting from the forced downtime for gear replacement or repair. Nowadays, the linear wear rate, an indicator that is found experimentally, is used to determine gear service life based on the statistical linear dependence of the wear on the friction forces. The determination of this indicator requires a large amount of data on the wear obtained with real transmissions or relevant laboratory samples that increases time and financial costs. Therefore, an analytical model of wear failures has been developed for project estimation of gear service life and the search for effective and lasting design solutions. The model represents a system of constitutive equations, which includes an energy equation describing the change in the current state of a pair of wear gear wheels and the conditions for their transition to the limiting state, a basic kinetic dependence of the energy-mechanical theory of stationary tribocoupling wear, and an equation for determining the transmission’s expected service life. The simultaneous solution of this system of equations taking into account the dependencies that describe the initial and boundary conditions of the gear element interaction resulted in the formulation of the algorithm for calculating their average expected service life. This allowed the authors to perform a comparative analysis of the effectiveness of various design options for improving gear durability and select the most appropriate ones. A distinctive feature of the proposed calculation algorithm is that it does not involve searching for experimental parameters similar to the linear wear rate.

scholarly journals Safety Evaluation of the Wear Life of High-Speed Railway Bridge Bearings by Monitoring Train-Induced Dynamic Displacements

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Gaoxin Wang ◽  
Youliang Ding ◽  
Hui Guo ◽  
Xinxin Zhao
Keyword(s):  
Service Life ◽  
Wear Rate ◽  
Small Amplitude ◽  
Safety Evaluation ◽  
Linear Wear ◽  
Railway Bridge ◽  
Linear Wear Rate ◽  
Wear Life ◽  
Short Period ◽  
Bridge Bearings

Bridge bearings experience numerous small-amplitude displacements under environmental loads. The continuous cyclic accumulations of these small-amplitude displacements will result in severe wear on the poly-tetra-fluoro-ethylene (PTFE) plates in the bridge bearings, which seriously endangers the service life of bearings. Traditional method directly uses the linear wear rate of cumulative displacements in a short period to evaluate the wearing life, but the linear wear rate only in a short period such as several days may not represent the characteristics in the whole bridge service life. Hence, this research takes the spherical steel bearings of the Nanjing Dashengguan Yangtze River Bridge as a study object. The cumulative dynamic displacement (CDD) under the action of a single train and the cumulative bearing travel (CBT) under the continual actions of many trains are studied using the monitored longitudinal displacement data from spherical steel bearings. Furthermore, the probability statistics and the Monte Carlo sampling simulation for CDD are studied, and the safety evaluation method for bearing wear life in the real environment is proposed using a reliability index regarding the failure probability of monitored CBT over the wear limit during service lifetime. In addition, safety evaluation on the bearing wear life was performed to assess the condition of spherical steel bearings in the real service environment. The results can provide an important reference for analysis on the bearing wear life of long-span railway bridge structures.

Analysis of the Factors that Predispose to Wear with a 32mm Femoral Head at 5–15 Year follow-up: Clinical and Radiographic Assessment of the Harris-Galante cup at 5–15 Year follow-up

2003 ◽  
Vol 13 (2) ◽  
pp. 65-73
Author(s):  
M. Katsimihas ◽  
G. Katsimihas ◽  
M.B Lee ◽  
I. D. Learmonth
Keyword(s):  
Wear Rate ◽  
Polyethylene Wear ◽  
Young Patients ◽  
Harris Hip Score ◽  
Linear Wear ◽  
Outer Diameter ◽  
Linear Wear Rate ◽  
Total Hip Replacements ◽  
Hip Replacements

The clinical and radiographic features of 109 consecutive hybrid total hip replacements performed between 1986 and 1992 in 96 patients were retrospectively reviewed. A cementless Harris-Galante (HGP1) cup and a 32mm monobloc straight Muller stem were used in all cases. At an average 10.11 (range 5 to 15) years following surgery, the excellent durability of fixation of the Harris-Galante cup has been demonstrated with only one cup (0.9%) revised for periacetabular osteolysis and aseptic loosening. The prevalence of polyethylene wear was 27.4%. The mean annual linear wear rate was 0.063mm (range 0.00–0.53mm). There was a significantly increased wear of polyethylene inserts with an outer diameter < 52mm (<10mm polyethylene thickness), (ANOVA Test). However, there was no association found between acetabular liner wear and the following factors: underlying diagnosis, Charnley grade, age, weight and sex of the patient. The Harris Hip Score ranged between 5 and 54 pre-operatively and the average HHS was more than 80 post-operatively with more than 70% of patients pain-free. A liner with a thickness of 10mm or greater may prove beneficial in the prevention and reduction of wear rate particularly in young patients. It is recommended that all patients with this cup design, in which a polyethylene insert that is less than 10mm thick is coupled with a 32mm head, should continue to be regularly followed up.

In vitro comparison of the two hard-hard articulations for total hip replacements

2001 ◽  
Vol 215 (2) ◽  
pp. 153-160 ◽  
Author(s):  
C Rieker ◽  
R Konrad ◽  
R Schoun
Keyword(s):  
Wear Rate ◽  
Abrasive Wear ◽  
Experimental Methodology ◽  
Wear Behaviour ◽  
Linear Wear ◽  
Linear Wear Rate ◽  
Total Hip ◽  
Metal On Metal ◽  
In Vitro Comparison

Polyethylene particle disease is one of the major causes of late aseptic loosening of total hip replacement. Two hard-hard articulations (alumina-on-alumina and metal-on-metal) have been developed in Europe as an alternative to the ultra-high molecular weight polyethylene (UHMWPE) articulations. Even though these hard-hard articulations are on the market and numerous reports have been published about them, only a very limited number of studies allowing a direct in vitro comparison of the two articulations have been published so far. This paper compares in vitro these two types of articulation (alumina-on-alumina and metal-on-metal), which have been tested with a hip simulator for their tribological behaviour using exactly the same experimental methodology. This comparison shows that these two types of hard-hard articulation have very similar abrasive wear behaviour with four main features: 1. A running-in wear period (1 × 106 cycles) gives a cumulative wear of about 20 μm with head diameters of 28 mm. 2. After the running-in wear, there is a stabilization of the linear wear behaviour with a low linear wear rate/106 cycles for both types of articulation. 3. The volumetric wear rate of both articulations (<2.0 mm3/year for head diameters of 28mm) is significantly lower than that observed for metal-on-polyethylene or ceramic-on-polyethylene articulations having the same head diameter. 4. Abrasive wear is readily apparent (indicating a mixed lubrication regime) with both types of articulation. The extremely low wear performance of these articulations is confirmed and they constitute a lowwear alternative to the UHMWPE articulations currently used.

Friction and Wear of Tire Tread Rubber

1996 ◽  
Vol 24 (3) ◽  
pp. 252-275 ◽  
Author(s):  
H. Sakai
Keyword(s):  
Wear Rate ◽  
Weight Reduction ◽  
Linear Wear ◽  
Test Machine ◽  
Unit Distance ◽  
Linear Wear Rate ◽  
Unit Energy ◽  
Short Time ◽  
Tread Rubber ◽  
Sticky Particles

Abstract Using a flat-belt tire test machine, this study investigated causal factors in the wear of tire tread. To ensure the success of the experiment, the accuracy of the testing device was improved and the trial conditions were kept under close control. As a measure against sticky particles of worn rubber clinging to the surfaces of the safety-walk and tires, a uniform amount of mica powder was electrostatically coated onto the tire tread surfaces. Surface whiteness was measured and controlled automatically to maintain a constant level. The amount of wear was calculated by weighing the tire on a precision six-order electrical balance sensitive down to 0.1 g. Consequently, in a relatively short time it was possible to ascertain measurable rates of wear, and the effects of main factors on the wear rate (the weight reduction per unit distance travelled) of car tires, the linear wear rate (the weight reduction per unit distance slid), the energetic wear rate (the weight reduction per unit energy lost), and friction coefficient were evident.

Wear Behavior of Polyester – Carbon Nanotubes Composites under Dry Sliding Ball-on-Flat Reciprocating Test

2015 ◽  
Vol 809-810 ◽  
pp. 1169-1174
Author(s):  
Adrian Cotet ◽  
Luminita Ciupagea ◽  
Dumitru Dima ◽  
Gabriel Andrei
Keyword(s):  
Carbon Nanotubes ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Abrasive Wear ◽  
Wear Behavior ◽  
Multiwall Carbon Nanotubes ◽  
Dry Sliding ◽  
Linear Wear ◽  
Linear Wear Rate ◽  
Multiwall Carbon

Friction coefficient and linear wear rate of polyester-carbon nanotubes composites were investigated through ball-on-flat reciprocating test, under dry sliding contact. Three types of nanoscopic fillers were used: multiwall carbon nanotubes (MWCNT), functionalized multiwall carbon nanotubes (MWCNT-COOH) and singlewall carbon nanotubes (SWCNT), with three values of weight content 0.1, 0.15 and 0.2 wt%. Comparative analysis was done for polyester and its composites tested over 14 m sliding distance, under three values of load, 30 N, 40 N and 50 N. Composites containing MWCNT underwent a decrease in friction coefficient and linear wear rate only in case of 50N loading. An improvement of wear behavior under 50N loading was obtained for the composite with 0.10 wt% functionalized carbon nanotubes. Generally, better values of wear rate at 50 N loading were recorded in case of composites with 0.15 wt% and 0.20 wt% MWCNT and SWCNT, respectively. Optical and electronic investigation of the worn surfaces revealed the occurrence of abrasive, adhesive and fatigue wear. Abrasive wear is due to the hard particles detached from the counterpart which produce scratches and furrows on sliding track. Adhesive wear results when soft particle of polymer are caught and blocked among the asperities of counterpart, and it develops over a local area, being influenced by temperature rise. Fatigue and abrasive wear are responsible for the formation of the 3rd body between contacting parts which affects the friction and wear behavior. Morphological analysis of worn surface showed the rise of transfer film that induces instability of wear parameters.

A STUDY ON THE IMPACT OF TEETH MESHING CONDITIONS AND PROFILE CORRECTION ON THE CARRYING CAPACITY, WEAR, AND LIFE OF A CYLINDRICAL GEAR

Tribologia ◽  
2016 ◽  
Vol 266 (2) ◽  
pp. 25-43
Author(s):  
Myron CHERNETS ◽  
Jerzy KIEŁBIŃSKI ◽  
Jurij CHERNETS
Keyword(s):  
Service Life ◽  
Gear Tooth ◽  
Tooth Wear ◽  
Allowable Limit ◽  
Cylindrical Gear ◽  
Angular Correction ◽  
Single Tooth ◽  
Profile Correction ◽  
Toothed Gears ◽  
The Impact

Using an innovative method for determining wear and life of toothed gears, the author investigates the effect of teeth meshing in a mixed (double-singledouble) tooth engagement of cylindrical helical gears on their contact strength, wear, and service life. The paper also presents a method for determining zones of double and single tooth engagement. It is found that gear profile correction leads to a reduction in maximum contact pressures by about 15–20%, depending on the applied type of correction. The distribution of pressures greatly depends on the conditions of tooth engagement. The wear of teeth is also significantly affected by their meshing conditions. Depending on the type of correction applied and its coefficients, the allowable limit of gear tooth wear will occur at different points of contact: at the beginning of double tooth engagement and at the beginning or end of single-tooth engagement. It is shown that the service life of gears can be considerably prolonged if optimum correction coefficients are applied. Specifically, height correction increases the gear life by 1.66 times while angular correction prolongs the service life of gears by up to two times.

Higher offset cross-linked polyethylene acetabular liners: is wear a significant clinical concern?

2018 ◽  
Vol 29 (6) ◽  
pp. 652-659 ◽  
Author(s):  
Ryan M Chapman ◽  
Douglas W Van Citters ◽  
Danielle Chapman ◽  
David F Dalury
Keyword(s):  
Wear Rate ◽  
Total Joint Replacement ◽  
The United States ◽  
Linear Wear ◽  
Volumetric Wear ◽  
Wear Rates ◽  
Linear Wear Rate ◽  
Joint Replacement Surgery ◽  
Replacement Surgery

Introduction:Total hip arthroplasty (THA) is the 2nd most common total joint replacement surgery in the United States. However, not all THA devices perform well and need revised for several reasons including dislocation. Higher offset acetabular liners reduce this problem by creating a more anatomically/biomechanically natural hip joint, increasing soft-tissue tension, and accommodating larger femoral heads in smaller acetabular cups via increased polyethylene thickness. To our knowledge, however, in vivo wear (another failure mode) performance of offset acetabular liners remains unknown.Methods:2 cohorts of 40 individuals (0-mm, 4-mm offset acetabular liners, respectively) from a single surgeon’s consecutive caseload were assessed. 6-week/5-year post-op radiographs were compared using a validated method using SolidWorks software to assess in vivo linear and volumetric wear rates. Resultant surgical offset was also quantified using this method.Results:Linear wear rate for 0-mm and 4-mm offset cohorts were 0.01 ± 0.09 mm/year and 0.08 ± 0.12 mm/year, respectively. Volumetric wear rate for 0-mm and 4-mm offset cohorts were 30.4 ± 20.4 mm3/year and 61.6 ± 42.1 mm3/year, respectively. Both of these were statistically significant. Neither linear nor volumetric wear rate was correlated with resultant surgical offset.Discussion:To our knowledge, this is the 1st study to compare in vivo wear performance of 0-mm and 4-mm offset acetabular liners. Although linear and volumetric wear rates were different between cohorts, neither reached previously established osteolysis thresholds. Moreover, wear rates were not correlated with resultant surgical offset. Finally, no patients in either cohort showed signs of osteolysis nor needed revision. As such, the clinical relevance of the wear rate differences is potentially less significant.

scholarly journals Long-term performance of oxidized zirconium on conventional and highly cross-linked polyethylene in total hip arthroplasty

SICOT-J ◽  
2020 ◽  
Vol 6 ◽  
pp. 10 ◽  
Author(s):  
Alberto V. Carli ◽  
Anay R. Patel ◽  
Michael B. Cross ◽  
David J. Mayman ◽  
Kaitlin M. Carroll ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Wear Rate ◽  
Hip Arthroplasty ◽  
Linear Wear ◽  
Wear Rates ◽  
Linear Wear Rate ◽  
Total Hip ◽  
Oxidized Zirconium

Introduction: Polyethylene wear and subsequent osteolysis remain obstacles to the long-term survivorship of total hip arthroplasty (THA). Highly cross-linked polyethylene (XLPE) with radical quenching represents a massive leap forward with dramatically improved wear rates compared to ultra-high molecular weight polyethylene (UHMWPE). In this study we evaluate the wear of UHMWPE and XLPE coupled with oxidized zirconium (OxZr) femoral heads. Methods: A longitudinal, retrospective analysis was performed identifying consecutive patients who received a 28-mm OxZr-on-polyethylene primary THA from 2003 to 2004 by a single, high-volume arthroplasty surgeon. Patients were divided into two groups: those that received (1) UHMWPE liner and (2) a highly XLPE liner. Patients were included if clinical follow-up was complete to 2014 or later. Radiographic analysis was performed by two blinded observers. Measures included cup position, annual linear wear rate, and presence of osteolysis. Pairwise comparisons, correlations, and inter-rater reliability were calculated. Results: Eighty patients were in the UHMWPE group with an average follow-up of 10 ± 1.23 years and 88 patients in the XLPE group with an average of 10 ± 1.03-year follow-up. Average age (68) was similar between groups (p = 0.288). Observer reliability was excellent for cup abduction (ICC = 0.940), anteversion (ICC = 0.942), and detection of osteolysis (ICC = 0.811). Annual linear wear rates were significantly higher (p = 1 × 10−19) with UHMWPE (0.21 ± 0.12 mm/year) compared to XLPE (0.05 ± 0.03 mm/year). Linear wear rate was significantly correlated to decreasing acetabular abduction (p = 0.035). Osteolysis was noted only in the UHMWPE group, with 17 patients (21.2%) exhibiting acetabular osteolysis and 37 (46.3%) patients exhibiting femoral osteolysis. Conclusions: OxZr coupled with XLPE showed minimal wear and no osteolysis at 10-year follow up. The yearly linear penetration rate is similar to that seen in other studies of XLPE THA. A careful longitudinal follow-up will be required to determine if advanced bearings such as OxZr or ceramic can show improved performance in the second decade of implantation.

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