scholarly journals INVESTIGATIONS ON WEAR AND FRICTION IN THE SI ENGINE VALVETRAIN

2021 ◽  
Vol 10 (4) ◽  
pp. 12-23
Author(s):  
Marek WOŹNIAK ◽  
Cristina Florena BANICA ◽  
Mihai DIACONU ◽  
Gustavo OZUNA ◽  
Piotr JÓŹWIAK ◽  
...  
Keyword(s):  
Wear Rate ◽  
Wear Intensity ◽  
Lubrication System ◽  
Oil Lubrication ◽  
Volumetric Wear ◽  
Si Engine ◽  
Valve Spring ◽  
Wear And Friction ◽  
Bearing Loads ◽  
System Operating

The engine valvetrain system operating under conditions of insufficient oil lubrication, caused by incorrect installation of the gasket between the block and the head, was tested. The aim of the analysis was to determine the wear intensity and resistance to motion in camshaft bearings. A model was developed that includes a camshaft, bearings, tappet-valve-spring subassemblies and a part of the lubrication system. It was used to determine the bearing loads and the amount of oil supplied. The volumetric wear of the camshaft journals and bearing covers was measured. For the estimated engine run, the wear rate and resistance to motion were compared for the cases of the engine with correct and incorrect lubrication.

scholarly journals Investigations on wear and friction in the SI engine valvetrain

2018 ◽  
Vol 175 (4) ◽  
pp. 53-64
Author(s):  
Marek WOŹNIAK ◽  
Cristina Florena BANICA ◽  
Mihai DIACONU ◽  
Gustavo OZUNA ◽  
Piotr JÓŹWIAK ◽  
...  
Keyword(s):  
Wear Rate ◽  
Wear Intensity ◽  
Lubrication System ◽  
Oil Lubrication ◽  
Volumetric Wear ◽  
Si Engine ◽  
Wear And Friction ◽  
Bearing Loads ◽  
System Operating ◽  
Lubrication Conditions

The engine valvetrain system operating under insufficient oil lubrication conditions, caused by an incorrect installation of the gasket between the block and the head, was tested. The aim of the analysis was to determine the wear intensity and resistance to motion in camshaft bearings. A model including a camshaft, bearings, tappet-valve-spring subassemblies and a part of the lubrication system was developed. It was used to determine the bearing loads and the amount of oil supplied. The volumetric wear of the camshaft journals and bearing covers was measured. For the estimated engine run, the wear rate and resistance to motion were compared for the cases of the engine with correct and incorrect lubrication.

Effect of abrasive particle size on tribological behavior of elastomers

2019 ◽  
Vol 234 (3) ◽  
pp. 373-385 ◽  
Author(s):  
F Hakami ◽  
A Pramanik ◽  
AK Basak ◽  
N Ridgway ◽  
MN Islam
Keyword(s):  
Particle Size ◽  
Tensile Strength ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Abrasive Particle ◽  
Tribological Behaviour ◽  
Elongation At Break ◽  
Tear Strength ◽  
Wear And Friction ◽  
Abrasive Size

Effect of abrasive particle size on tribological behaviour of different elastomers was investigated experimentally in this study. The size of abrasive particle size was varied from coarse (425 µm) to fine (82 µm). Wear rate and coefficient of friction were calculated and analyzed accordingly followed by the examination of worn surfaces by a scanning electron microscope to unravel the wear mechanism. Experimental results showed that abrasive size had a significant effect on wear and friction behaviour of the elastomers. As the abrasive particle size increased, wear rate and coefficient of friction also increased at different rates and exhibited different wear mechanisms that changed from friction to fatigue and roll formation. Mechanical properties of elastomers such as hardness, tensile strength, tear strength, and elongation at break also contributed to wear and friction. The effect of elongation at break and tensile strength on wear rate is more pronounced at lower abrasive particle size, whereas hardness and tear strength play a pivotal role at the higher abrasive size.

Wear and osteolysis outcomes for highly cross-linked polyethylene in primary total hip arthroplasty compared with conventional polyethylene: a 15- to 18-year single-centre follow-up study

2020 ◽  
pp. 112070001989697 ◽  
Author(s):  
Nam Hoon Moon ◽  
Won Chul Shin ◽  
Min Uk Do ◽  
Suk-Woong Kang ◽  
Sang-Min Lee ◽  
...  
Keyword(s):  
Wear Rate ◽  
Survival Rates ◽  
Reoperation Rate ◽  
Volumetric Wear ◽  
Wear Rates ◽  
Total Hip ◽  
Kaplan Meier ◽  
Long Term Result ◽  
Wear Reduction

Background: Although highly positive results for wear reduction of highly cross-linked polyethylene (HXLPE) have been reported around the 10-year follow-up, the long-term result related to reoperation and wear-related survival is still an issue. Therefore, this study aimed to compare the follow-up results of a single manufacture’s polyethylene liner for >15 years in terms of survival and wear rate. Methods: This retrospective cohort study included 134 primary total hip arthroplasties (THAs) who were followed up for at least 15 years. The mean age at the time of surgery was 50.7 years (conventional polyethylene [CPE] group = 22; HXLPE group = 112). Linear and volumetric wear rates of polyethylene were measured, and the reoperation rate and radiographic osteolysis were evaluated and Kaplan-Meier survival analysis was performed in both groups. Implant-related complications were also examined. Results: HXLPE group showed a significantly lower wear rate in both linear and volumetric wear. None of the hip radiographs showed evidence of loosening or osteolysis in the HXLPE group. The survival rates at 15- to 18-year follow-up were 90.9% and 95.5% in the CPE and HXLPE groups when all-cause reoperation was the endpoint, and 90.9% and 100.0% when the wear-related reoperation was the endpoint, respectively. Implant-related complications were not different between the 2 groups. Conclusions: Wear reduction and osteolysis showed a great advantage in HXLPE after a 15-year follow-up. Although the CPE and HXLPE showed excellent survival, wear and osteolysis were more frequent in the CPE; therefore, the high risk of reoperation in the future should be considered.

Investigation of Vapor-Phase Lubrication in a Gas Turbine Engine

1997 ◽  
Author(s):  
Kenneth W. Van Treuren ◽  
D. Neal Barlow ◽  
William H. Heiser ◽  
Matthew J. Wagner ◽  
Nelson H. Forster
Keyword(s):  
Gas Turbine ◽  
Vapor Phase ◽  
Gas Turbine Engine ◽  
Rolling Contact ◽  
Phosphate Ester ◽  
Lubrication System ◽  
Oil Lubrication ◽  
Vapor Phase Lubrication ◽  
Engine Operation ◽  
Turbine Engine

The liquid oil lubrication system of current aircraft jet engines accounts for approximately 10–15% of the total weight of the engine. It has long been a goal of the aircraft gas turbine industry to reduce this weight. Vapor-Phase Lubrication (VPL) is a promising technology to eliminate liquid oil lubrication. The current investigation resulted in the first gas turbine to operate in the absence of conventional liquid lubrication. A phosphate ester, commercially known as DURAD 620B, was chosen for the test. Extensive research at Wright Laboratory demonstrated that this lubricant could reliably lubricate railing element bearings in the gas turbine engine environment. The Allison T63 engine was selected as the test vehicle because of its small size and bearing configuration. Specifically, VPL was evaluated in the number eight bearing because it is located in a relatively hot environment, in line with the combustor discharge, and it can be isolated from the other bearings and the liquid lubrication system. The bearing was fully instrumented and its performance with standard oil lubrication was documented. Results of this baseline study were used to develop a thermodynamic model to predict the bearing temperature with VPL. The engine was then operated at a ground idle condition with VPL with the lubricant misted into the #8 bearing at 13 ml/hr. The bearing temperature stabilized at 283°C within 10 minutes. Engine operation was continued successfully for a total of one hour. No abnormal wear of the rolling contact surfaces was found when the bearing was later examined. Bearing temperatures after engine shutdown indicated the bearing had reached thermodynamic equilibrium with its surroundings during the test. After shutdown bearing temperatures steadily decreased without the soakback effect seen after shutdown in standard lubricated bearings. In contrast, the oil lubricated bearing ran at a considerably lower operating temperature (83°C) and was significantly heated by its surroundings after engine shutdown. In the baseline tests, the final bearing temperatures never reached that of the operating VPL system.

Correlation of the Volumetric Tool Wear Rate of Carbide Milling Inserts With the Material Removal Rate of Ti–6Al–4V

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Mathew Kuttolamadom ◽  
Parikshit Mehta ◽  
Laine Mears ◽  
Thomas Kurfess
Keyword(s):  
Wear Rate ◽  
Tool Wear ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Tool Material ◽  
Feed Speed ◽  
Volumetric Wear ◽  
Machining Economics ◽  
Material Volume

The objective of this paper is to assess the correlation of volumetric tool wear (VTW) and wear rate of carbide tools on the material removal rate (MRR) of titanium alloys. A previously developed methodology for assessing the worn tool material volume is utilized for quantifying the VTW of carbide tools when machining Ti–6Al–4V. To capture the tool response, controlled milling experiments are conducted at suitable corner points of the recommended feed-speed design space, for constant stock material removal volumes. For each case, the tool material volume worn away, as well as the corresponding volumetric wear profile evolution in terms of a set of geometric coefficients, is quantified—these are then related to the MRR. Further, the volumetric wear rate and the M-ratio (volume of stock removed to VTW) which is a measure of the cutting tool efficiency, are related to the MRR—these provide a tool-life based optimal MRR for profitability. This work not only elevates tool wear from a 1D to 3D concept, but helps in assessing machining economics from a stock material-removal-efficiency perspective as well.

Influence of heat treatment on the volumetric wear rate of Al-25Mg 2 Si2Cu4Mn alloy

2017 ◽  
Vol 4 (10) ◽  
pp. 10921-10926
Author(s):  
Neeta S. Mathapati ◽  
Virupaxi Auradi ◽  
D.G. Mallapur
Keyword(s):  
Heat Treatment ◽  
Wear Rate ◽  
Volumetric Wear

scholarly journals Al/Graphene/CNT hybrid composites: Hardness and sliding wear studies

2021 ◽  
Vol 49 (2) ◽  
pp. 414-421
Author(s):  
Manjunath Naik ◽  
L.H. Manjunath ◽  
Vishwanath Koti ◽  
Avinash Lakshmikanthan ◽  
Praveennath Koppad ◽  
...  
Keyword(s):  
Wear Rate ◽  
Sliding Wear ◽  
Hybrid Composites ◽  
Wear Behavior ◽  
Lubricating Layer ◽  
Wear And Friction ◽  
Bulk Hardness ◽  
Graphene Content ◽  
Worn Surface ◽  
Sliding Distance

Graphene and carbon nanotubes are two carbon based materials known for their unique wear and friction properties. It would be quite interesting to understand the wear behavior of aluminium hybrid composites when these two nanosize reinforcements are incorporated into it. The hybrid composites with varying weight fractions of graphene (1, 2, 3 and 5 wt.%) and fixed CNT content of 2 wt.% were produced using powder metallurgy technique. The effect of varying graphene content on hardness and sliding wear of hybrid composites was studied. The wear tests were done as per ASTM G-99 standard with fixed sliding velocity (2 m/s) and sliding distance (1200 m) but varying applied load (10 - 30 N). Worn surface analysis was conducted using scanning electron microscope to arrive at wear mechanisms responsible for wear of aluminium and its hybrid composites. Increase in graphene content led to increase in bulk hardness with highest value of 61 RHN for hybrid composite with 3 wt.% graphene content. The wear rate of hybrid composites was found to be decreasing with enhancement in graphene content. Lower wear rate in hybrid composites was due to the formation of lubricating layer on the worn surface.

ASSESSMENT OF ABRASIVE WEAR RATE FOR PTFE-BASED COMPOSITES IN COMBINATION WITH STEEL

Tribologia ◽  
2021 ◽  
Vol 296 (2) ◽  
pp. 29-35
Author(s):  
Magdalena Lemecha ◽  
Krzysztof Ligier ◽  
Jerzy Napiórkowski
Keyword(s):  
Wear Rate ◽  
Carbon Fibre ◽  
Abrasive Wear ◽  
Polymer Film ◽  
Contact Area ◽  
Glass Fibre ◽  
Volumetric Wear ◽  
Ptfe Composite ◽  
Test Materials ◽  
Ptfe Composites

This paper presents a study of the tribological wear rate for PTFE-based composites in combination with C45 steel. PTFE composites with the addition of glass fibre, bronze, carbon fibre, and graphite were selected for the study. Tribological tests were conducted in a roller-block combination over an expanded contact area with no lubrication, using an SMC-2 machine. The study assessed the mass and volumetric wear for the test materials and the wear rate index. The highest wear values were noted for the PTFE composite with the addition of bronze, while the lowest was for the PTFE composite with the addition of glass fibre. For all the test materials, the formation of a polymer film on the steel counter specimen was noted.

Tribological assessment of a flexible carbon-fibre-reinforced poly(ether—ether—ketone) acetabular cup articulating against an alumina femoral head

2008 ◽  
Vol 222 (3) ◽  
pp. 273-283 ◽  
Author(s):  
S C Scholes ◽  
I A Inman ◽  
A Unsworth ◽  
E Jones
Keyword(s):  
Wear Rate ◽  
Carbon Fibre ◽  
Acetabular Component ◽  
Volumetric Wear ◽  
Wear Rates ◽  
Lubrication Regime ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Ether Ketone ◽  
Low Wear

New material combinations have been introduced as the bearing surfaces of hip prostheses in an attempt to prolong their life by overcoming the problems of failure due to wear-particle-induced osteolysis. This will hopefully reduce the need for revision surgery. The study detailed here used a hip simulator to assess the volumetric wear rates of large-diameter carbon-fibre-reinforced pitch-based poly(ether—ether—ketone) (CFR-PEEK) acetabular cups articulating against alumina femoral heads. The joints were tested for 25×106 cycles. Friction tests were also performed on these joints to determine the lubrication regime under which they operate. The average volumetric wear rate of the CFR-PEEK acetabular component of 54 mm diameter was 1.16 mm3/106 cycles, compared with 38.6 mm3/106 cycles for an ultra-high-molecular-weight polyethylene acetabular component of 28 mm diameter worn against a ceramic head. This extremely low wear rate was sustained over 25×106 cycles (the equivalent of up to approximately 25 years in vivo). The frictional studies showed that the joints worked under the mixed—boundary lubrication regime. The low wear produced by these joints showed that this novel joint couple offers low wear rates and therefore may be an alternative material choice for the reduction of osteolysis.

Paper Machine Bearing’s Temperature and Air-Velocity Optimization under Air-Oil Lubrication

2012 ◽  
Vol 550-553 ◽  
pp. 3054-3058
Author(s):  
Feng Zhang ◽  
Gong Bo Han ◽  
Su Xia Duan
Keyword(s):  
Temperature Field ◽  
Velocity Field ◽  
High Speed ◽  
Paper Machine ◽  
Lubrication System ◽  
Oil Lubrication ◽  
Air Velocity ◽  
Temperature Field Distribution ◽  
Temperature And Pressure ◽  
Lubrication Effect

The purpose of this resarch was investigated the air-oil temperature field distribution under air-oil lubrication and oil lublubrication, meanwhile also study the air-oil lubrication effect under different air velocity inlet the bearing cavities of the high-speed paper machine dryer section. Base on the CFD theory, the temperature field of CARB bearing outer ring and the velocity field of the bearing cavities were simulated by the FLUENT software.Result show that air-oil lubricatin can reach the same cooling effect is contras with oil lubrication in the same heat production by roller; the best air-velocity value of air-oil lubrication system is obtain for the change of temperature and pressure in bearing cavities. It is confirm that the air-oil lubrication is viable in the high-speed paper machine dryer section.

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