scholarly journals Friction Behavior of Pre-Damaged Wet-Running Multi-Plate Clutches in an Endurance Test

Lubricants ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 68
Author(s):  
Thomas Schneider ◽  
Katharina Voelkel ◽  
Hermann Pflaum ◽  
Karsten Stahl
Keyword(s):  
Coefficient Of Friction ◽  
Later Life ◽  
Second Step ◽  
Experimental Investigations ◽  
Endurance Test ◽  
Friction Behavior ◽  
Speed Range ◽  
The Coefficient Of Friction ◽  
Endurance Tests

Wet-running multi-plate clutches should be prevented from failing due to the often safety-relevant functions they fulfill in the drive train. In addition to long-term damage, spontaneous damage is of particular relevance for failures. This paper focuses on the influence of spontaneous damage on frictional behavior in the later life cycle. The aim of the experimental investigations is to initially cause spontaneous damage in wet-running multi-plate clutches with sintered friction linings. For this purpose, three clutches are first pre-damaged in stage tests with different intensities, so that the first spontaneous damage (local discoloration, sinter transfer) occurs. In the second step, an endurance test is carried out with the pre-damaged clutch packs and a non-pre-damaged reference clutch. The friction behavior of the clutches during the endurance test is compared and evaluated. It shows that local discoloration and sinter transfer are no longer visible after the endurance tests. At the beginning of the endurance test, the values of coefficient of friction are higher over the entire speed range of the heavily pre-damaged clutches than with the slightly pre-damaged clutch and the non-pre-damaged reference clutch. At the end of the endurance test, it can be observed that the greater the pre-damage to the clutches is, the greater the coefficient of friction increases with decreasing sliding speed.

Investigation of the friction behavior of plasma spray Mo/NiCrBSi coated brake discs

2021 ◽  
Vol 63 (3) ◽  
pp. 259-265
Author(s):  
Halil Kılıç ◽  
Cenk Mısırlı ◽  
İbrahim Mutlu
Keyword(s):  
Coefficient Of Friction ◽  
Plasma Spray ◽  
Wear Behavior ◽  
Atmospheric Plasma ◽  
Brake Disc ◽  
Friction Behavior ◽  
Braking Performance ◽  
Spray Process ◽  
The Coefficient Of Friction ◽  
Nicrbsi Coating

Abstract This paper presents the findings of comparative research conducted to find out the braking performance of a Mo/NiCrBSi coated automobile brake disc. The friction and wear behavior of the Mo/NiCrBSi coating (CD) used for the disc material was evaluated using a laboratory scale disc-pad dynamometer and compared with a reference disc (RD). The coating was deposited by means of the atmospheric plasma spray process on a grey cast iron substrate. Braking tests were performed according to the SAE-J2430 test standard. Disc microstructures were characterized by SEM and XRD. It was found that the bonding strength was good with an infinite rating between the accumulated coating layer and the substrate. The results show that the coated brake disc has a comparable coefficient of friction and that the amount of wear is lower than that of the reference disc. The addition of ductile phases to the disc coating was beneficial in reducing the coefficient of friction to an acceptable degree and also effectively improving wear resistance.

Experimental Investigations on the Effect of Long Term Biodiesel Usage on Thermal Decomposition of CI Engine Crankcase Oil

2009 ◽  
Author(s):  
Purnanand V. Bhale ◽  
Nishikant V. Deshpande ◽  
Piyush N. Deshpande
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Alternative Fuels ◽  
Lubricating Oil ◽  
Experimental Investigations ◽  
Biodiesel Fuel ◽  
Endurance Tests ◽  
Ci Engines ◽  
Thermal Stability Of

The gradual depletion of world petroleum reserves, increases in prices of petroleum based fuels and environmental pollution due to exhaust emissions have encouraged studies to search for alternative fuels. Biodiesel is an alternative diesel fuel consisting of alkyl monoesters of fatty acids derived from vegetable oils. It has been the focus of considerable amount of recent research because it is renewable and reduces the emission of some pollutants. The desirability of developing biodiesel from different tree borne oil seeds and decreasing the dependency on petroleum based fuels has been discussed by many over the last few decades. However some of the important issues like compatibility of biodiesel with the crankcase lubricating oil, thermal stability of lubricating oil with biodiesel usage, changes in physical and chemical properties of lubricating oil with biodiesel etc. have not been sufficiently investigated. This needs to be addressed in order to ensure the long term acceptability of biodiesel in an existing family of diesel engines. In the present work these issues have been addressed. For this purpose engine endurance tests were conducted on CI engines. Two new single cylinder four stroke CI engines were operated for 512 hours each for diesel and 100% biodiesel fuel. The endurance tests were conducted as per BIS 10000 part IX norms. Biodiesel from Jatropha oil was prepared in-house using transesterification process. The sample of lubricating oil was collected through a one way valve connected to the crankcase sump after every 128 hours intervals. Thermograviometric analysis (TGA) was used to evaluate the thermal stability of lubricating oil samples obtained from both the engines. The thermal decomposition of lubricating oil samples were measured as a function of various reaction parameters such as temperature, time and heating rates. This TGA test involves a weight change as the oil was heated. The weight loss data of the sample was logged using the in situ computer. Early decomposition of biodiesel fueled engine lubricating oil was observed as compared to diesel fueled engine lubricating oil. The changes in viscosity of lubricating oil were also monitored during the endurance test and discussed in detail. A higher level of crank case dilution was observed in case of biodiesel as compared to diesel.

The Design of a Linear “Out of Phase” Vibratory Conveyor

1973 ◽  
Vol 95 (1) ◽  
pp. 42-47 ◽  
Author(s):  
R. E. Schofield ◽  
M. Yousuf
Keyword(s):  
Phase Angle ◽  
Coefficient Of Friction ◽  
Experimental Investigations ◽  
Phase Effect ◽  
Theoretical Predictions ◽  
The Coefficient Of Friction ◽  
Drive Belt ◽  
The Mean ◽  
Vibratory Conveyor ◽  
Normal Track

This paper describes the development of a linear “out-of-phase” vibratory conveyor. The “out-of-phase” effect is achieved by controlling the components of motion normal to and parallel to the track independently. This is done by mounting the trough on sets of double “U” shear rubber mountings. From Fig. 1(a) it can be seen that these mountings allow motion in any direction in the plane of the rubber while substantially constraining motion perpendicular to that plane. Excitation of the trough is by two hydraulic pumps the phase angle between which is controlled by a positive drive belt. Experimental investigations into the behavior of single parts were carried out and results comparable to the theoretical predictions for “out-of-phase” were obtained. Substantial increases in the mean conveying velocity of single parts can be achieved without erratic part movement because it is possible with this system to use high values of normal track acceleration An/g combined with low vibration angles. Increases in mean conveying velocity of as much as 270 percent are obtained, depending on the coefficient of friction and vibration angles.

Development of Portable Tester for Measuring Skid Resistance and Its Speed Dependency on Pavement Surfaces

1996 ◽  
Vol 1536 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Kazuo Saito ◽  
Takashi Horiguchi ◽  
Atsushi Kasahara ◽  
Hironari Abe ◽  
John Jewett Henry
Keyword(s):  
Coefficient Of Friction ◽  
International Association ◽  
Constant Load ◽  
Skid Resistance ◽  
Test Results ◽  
Maintenance Program ◽  
Service Period ◽  
Friction Component ◽  
The Coefficient Of Friction

Skid resistance is an important factor in a rational maintenance program for pavement surfaces. Therefore, the skid resistance of a road surface is monitored by maintaining skid resistance inventories; in addition, spot checks are made at high accident sites. The equipment, called the dynamic friction tester (DF tester), is a disc-rotating-type tester that measures the friction force between the surface and three rubber pads attached to the disc. The disc rotates horizontally at a linear speed of about 80 to 20 km/hr under a constant load, so the DF tester can measure the skid resistance at any speed in this range with a single measurement. At the same time, the results provide speed dependency of skid resistance that will be as close as possible to the results obtained by other testing modes. The DF tester can measure on flat as well as rutted surfaces, the depths of which are less than 6 mm. In that case, the coefficient of variation is found to be less than 10 percent. The long-term characteristics of the coefficient of friction were measured by the DF tester, the British pendulum tester and the mini-texture meter. The coefficient of friction increases moderately with the traffic service period (up to 35 weeks) and decreases with increasing speed. The test results showed a significant speed dependency on the coefficient of friction measured by the DF tester although there was a high relationship between the coefficient of friction of the DF tester and the British pendulum number at each point and at each measuring speed. A weak relationship was found between the coefficient of friction and the sensor-measured texture depth values produced by the texture meter. Results of the Permanent International Association of Road Congresses experiment to compare and harmonize texture and skid resistance measurements indicate that the DF tester is capable of reporting the friction component (F60) of the international friction index using the friction coefficient at 60 km/hr.

scholarly journals An Experimental Study of the Frictional Properties of Steel Sheets Using the Drawbead Simulator Test

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4037 ◽  
Author(s):  
Trzepiecinski ◽  
Kubit ◽  
Slota ◽  
Fejkiel
Keyword(s):  
Coefficient Of Friction ◽  
Extreme Values ◽  
Rolling Direction ◽  
Frictional Resistance ◽  
Friction Reduction ◽  
Experimental Investigations ◽  
Sheet Rolling ◽  
The Coefficient Of Friction ◽  
The Difference ◽  
Lubrication Conditions

This article presents the results of an experimental investigation of the frictional resistance arising in a drawbead during sheet metal forming. The frictional characterization of DC04 deep drawing quality steels commonly used in the automotive industry is carried out using a friction simulator. The effects of some parameters of the friction process on the value of the coefficient of friction have been considered in the experimental investigations. The friction tests have been conducted on different strip specimens, lubrication conditions, heights of drawbead and specimen orientations in relation to the sheet rolling direction. The results of drawbead simulator tests demonstrate the relationship that the value of the coefficient of friction of the test sheets without lubrication is higher than in the case of lubricated sheets. The lubricant reduces the coefficient of friction, but the effectiveness of its reduction depends on the drawbead height and lubrication conditions. Moreover, the effectiveness of the reduction of the coefficient of friction by the lubricant depends on the specimen orientation according to the sheet rolling direction. In the drawbead test, the specimens oriented along the rolling direction demonstrate a higher value of coefficient of friction when compared to the samples cut transverse to the rolling direction. The smaller the width of the specimen, the lower the coefficient of friction observed. The difference in the coefficient of friction for the extreme values of the widths of the specimens was about 0.03–0.05. The use of machine oil reduced the coefficient of friction by 0.02–0.03 over the whole range of drawbead heights. Heavy duty lubricant even reduced the frictional resistances by over 50% compared to dry friction conditions. The effectiveness of friction reduction by machine oil does not exceed 30%.

Wear Resistance of Organic Nanocomposites

2007 ◽  
Vol 334-335 ◽  
pp. 605-608 ◽  
Author(s):  
Hong Gang Zhu ◽  
Ricky S.C. Woo ◽  
Christopher K.Y. Leung ◽  
Jang Kyo Kim
Keyword(s):  
Wear Resistance ◽  
Coefficient Of Friction ◽  
Neat Epoxy ◽  
Testing Methods ◽  
Abrasion Test ◽  
Modified Clay ◽  
The Coefficient Of Friction ◽  
Short And Long Term ◽  
Ball On Disc

The wear resistance of epoxy-based nanocomposites reinforced with octadecylamine-modified clay was studied. Two testing methods, including the ball-on-disc abrasion test and the nanoscratch test, were used to measure the macro- and micro-wear behaviors. The ball-on-disc abrasion test suggests that the short- and long-term wear behaviors of neat epoxy and 5wt% nanoclay composites were similar, although the wear resistance as measured by the volume of material removed was greater for the clay nanocomposite than for the neat epoxy. The incorporation of nanoclay into the epoxy showed little effect on the coefficient of friction.

Static and Clinging Friction of Pivot Bearings

1944 ◽  
Vol 151 (1) ◽  
pp. 274-284
Author(s):  
M. C. Hunter
Keyword(s):  
Stainless Steel ◽  
Coefficient Of Friction ◽  
Rapid Growth ◽  
Static Friction ◽  
Clear Distinction ◽  
Special Apparatus ◽  
The Coefficient Of Friction

The author points out the clear distinction which has to be drawn between kinetic and static friction, and describes the special apparatus used in the investigation carried out to determine the static friction of various combinations of metals, including stainless steel and duralumin, under several conditions of dry and viscous lubrication. The paper stresses the effect of time, and gives data showing the rapid growth of the coefficient of friction during the first twenty-four hours at rest, and the subsequent increases over a period of five days. A series of long-term tests of thirty, sixty, and ninety days, on a selected number of specimens, provides a direct comparison from which the relative merits of the various combinations of materials is drawn. Evidence is provided suggesting advantages to be derived from the use of graphite as a preventative of clinging friction. In conclusion, an explanation is put forward as to the possible causes responsible for the building up of friction with the passage of time.

scholarly journals Wax-oil lubricants to reduce the shear between skin and PPE

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kian Kun Yap ◽  
Manoj Murali ◽  
Zhengchu Tan ◽  
Xue Zhou ◽  
Luli Li ◽  
...  
Keyword(s):  
Olive Oil ◽  
Coefficient Of Friction ◽  
Static Friction ◽  
Mineral Oil ◽  
The Coefficient Of Friction ◽  
Friction Measurements ◽  
Lubricant Application ◽  
Static Coefficient Of Friction

AbstractProlonged use of tight-fitting PPE, e.g., by COVID-19 healthcare workers leads to skin injuries. An important contributor is the shear exerted on the skin due to static friction at the skin-PPE interface. This study aims to develop an optimised wax-oil lubricant that reduces the friction, or shear, in the skin-PPE contact for up to four hours. Lubricants with different wax-oil combinations were prepared using beeswax, paraffin wax, olive oil, and mineral oil. In-vivo friction measurements involving seven participants were conducted by sliding a polydimethylsiloxane ball against the volar forearms to simulate the skin-PPE interface. The maximum static coefficient of friction was measured immediately and four hours after lubricant application. It was found that the coefficient of friction of wax-oil lubricants is mainly governed by the ratio of wax to oil and the thermal stability and morphology of the wax. To maintain long-term lubricity, it is crucial to consider the absorption of oil into the PPE material. The best performing lubricant is a mixture of 20 wt% beeswax, 40 wt% olive oil, and 40 wt% mineral oil, which compared to unlubricated skin, provides 87% (P = 0.0006) and 59% (P = 0.0015) reduction in instantaneous and 4-h coefficient of friction, respectively.

scholarly journals Study on friction behavior at the interface between prosthetic socket and liner

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Jingyang Xie ◽  
Xidong Liu ◽  
Jianhua Tang ◽  
Xi Li ◽  
Wei Li
Keyword(s):  
Energy Dissipation ◽  
Coefficient Of Friction ◽  
Temperature Increase ◽  
Friction Behavior ◽  
Friction Characteristics ◽  
Frictional Behavior ◽  
Prosthetic Socket ◽  
The Coefficient Of Friction ◽  
3D Printed ◽  
Frictional Energy Dissipation

Purpose: The friction characteristics at the interface between prosthetic socket and liner have an important influence on the walking function and wearing comfort of amputees. The frictional behavior at the prosthetic socket/liner interface can provide theoretical guidance for the design and selection of prosthetic materials. So it is of great significance to study the friction behavior at prosthetic socket/liner interface. Methods: The surface roughnesses of the prosthetic socket and liner materials were measured by a laser confocal microscope. The frictional behavior at the prosthetic socket/liner interface was studied on a UMT TriboLab Tribometer by simulating the reciprocating sliding contact mode. An infrared camera was used to take thermal images and then calculated the temperature increase at the socket/liner interface. Results: The coefficient of friction of the silicon rubber fabric are significantly smaller than that of the foam liner materials. The frictional energy dissipation at the liner/acrylic socket interface is the smallest, while it is greater for 3D-printed socket materials. Meanwhile, the temperature increase has a positive correlation to the coefficient of friction and frictional energy dissipation. Conclusions: The three kinds of 3D-printed materials with high surface roughness have higher interface coefficient of friction and energy dissipation than acrylic material. The stiffness and energy consumption play an important role in the interface friction characteristics of the prosthetic liner materials. The appropriate coefficient of friction at the surface between prosthetic socket and liner is essential. A type of the reinforcement fiber has influence on the friction behavior of the 3D-printed reinforced nylon.

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