Modeling and Experimental Tests on Motion Resistance of Double-Flanged Rollers of Rubber Track Systems Due to Sliding Friction Between the Rollers and Guide Lugs of Rubber Tracks

2019 ◽

Vol 233 (11) ◽

pp. 1773-1781 ◽

Cited By ~ 1

Author(s):

Wojciech Litwin

Keyword(s):

Load Capacity ◽

Environmentally Friendly ◽

Experimental Tests ◽

Mineral Oil ◽

Hydrodynamic Load ◽

Significant Excess ◽

The Past ◽

Motion Resistance ◽

Promising Solution ◽

Legal Restrictions

Bearings of propeller shafts are very crucial elements of the propulsion system of each of the ships. The safety of shipping depends on their durability and reliability. The new legal restrictions mean that today we are looking for environmentally friendly solutions. That is why water-lubricated bearings are becoming more and more popular. So, will oil-lubricated shaft bearings belong to the past? The bearing with a white metal bushing lubricated with mineral oil, which was subjected to experimental tests, has a number of advantages. First of all, it works in the area of full fluid friction, and in typical shipbuilding conditions it has a significant excess of hydrodynamic load capacity. Therefore, replacing mineral oil with an environmentally friendly lubricant with a similar viscosity seems to be a promising solution. Motion resistance larger than that in water-lubricated bearings compensates for the reliability and durability of this solution.

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The Investigation into the Tribological Impact of Alternative Fuels on Engines Based on Acoustic Emission

Energies ◽

10.3390/en14082315 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2315

Author(s):

Nasha Wei ◽

Zhi Chen ◽

Yuandong Xu ◽

Fengshou Gu ◽

Andrew Ball

Keyword(s):

Acoustic Emission ◽

High Performance ◽

Alternative Fuels ◽

Sliding Friction ◽

Cylinder Liner ◽

Experimental Tests ◽

Ic Engine ◽

System A ◽

High Speeds ◽

Liner System

The wide use of different alternative fuels (AL) has led to challenges to the internal combustion (IC) engine tribology. To avoid any unpredicted damages to lubrication joints by using AL fuels, this study aims to accurately evaluate the influences of alternative fuels on the tribological behavior of IC engines. Recent achievements of the acoustic emission (AE) mechanism in sliding friction provide an opportunity to explain the tribological AE responses on engines. The asperity–asperity–collision (AAC) and fluid–asperity–shearing (FAS) mechanisms were applied to explain the AE responses from the piston ring and cylinder liner system. A new adaptive threshold–wavelet packets transform (WPT) method was developed to extract tribological AE features. Experimental tests were conducted by fueling three fuels: pure diesel (PD), biodiesel (BD), and Fischer–Tropsch (F–T) diesel. The FAS–AE indicators of biodiesel and F–T diesel show a tiny difference compared to the baseline diesel using two types of lubricants. Biodiesel produces more AAC impacts with higher AAC–AE responses than F–T diesel, which occurs at high speeds due to high temperatures and more particles after combustion than diesel. This new algorithm demonstrated the high performance of using AE signals in monitoring the tribological impacts of alternative fuels on engines.

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Performance Evaluation of bi-directional Roller Bearings for Seismic Isolation of Buildings Under Near-fault Earthquakes

10.21203/rs.3.rs-834301/v1 ◽

2021 ◽

Author(s):

Nelson Ortiz-Cano ◽

Ricardo González-Olaya ◽

Carlos Gaviria-Mendoza ◽

Carlos Magluta ◽

Ney Roitman

Keyword(s):

Friction Force ◽

Seismic Isolation ◽

Sliding Friction ◽

Roller Bearing ◽

Experimental Tests ◽

Element Model ◽

Building Model ◽

Near Fault ◽

Frame Element ◽

Near Fault Earthquakes

Abstract An advantage bidirectional sloped rolling type isolation device composed of multiple rollers in both orthogonal-in-plane directions is studied in this research. The analytical model of a single direction of roller bearing (RB) system is extended to a two-direction RB system. Also, a 3D linear-elastic frame element to build the finite element model is used to incorporate the response of the building model. Several experimental tests of a physical building model with and without an RB system are used to validate the numerical model. The model is used to assess the nonlinear response history analysis of a four-story multi-column building system with two different physical properties that represent buildings with low and high lateral stiffness when subjected to pairs of scaled near-fault earthquake records. The effect of the angle of inclination of bearing plates in the range of 1.0o to 4.0o and sliding friction force is also investigated in a parametric analysis to evaluate the performance of RB with supplementary damping mechanisms ranging from 0.0 to 0.5N/kg, i.e., friction force normalized with the structure mass. Results show that the proposed bi-directional RB system is suitable for reducing the seismic response of rigid and flexible multi-column structures. In particular, the RB system reduces structure acceleration responses by 5–85% in the flexible structure and 86–96% in the rigid structure. Furthermore, an angle of inclination of bearing plates greater than or equal to 3.0o is an advantage to ensure the self-centering capacity.

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Determination of mining equipment motion resistance

MATEC Web of Conferences ◽

10.1051/matecconf/201926301003 ◽

2019 ◽

Vol 263 ◽

pp. 01003

Author(s):

Leopold Hrabovský ◽

Václav Janek

Keyword(s):

Indirect Method ◽

Rotation Speed ◽

Experimental Tests ◽

Mining Equipment ◽

Speed Sensor ◽

Motion Resistance ◽

Recorded Data ◽

Instantaneous Speed ◽

Mining Plant

The article presents the experimental measurement of the mining equipment motion resistance in the Mining Plant 1, the Lazy mine location district. The procedure of the experimental tests was as follows, one of the transport vessels was fitted with a weight of a known weight. The mining cage was loaded with the weight and pulled up in the traffic pit to the required depth, then the mining equipment was released and, using the IRC rotation speed sensor attached to the rope drum shaft, the travelled trajectory and the instantaneous mining cage speed were recorded with an indirect method. Upon reaching the speed of the transport vessels, a maximum of 3.15 m/s, the vessels were equipped with the mining equipment brakes and the transport vessels were slowed down to zero speed. From the recorded data in the PC memory, ie initial positions of both transport vessels, travelled trajectory and instantaneous speed values, the values were consequently calculated and added to the stated tables.

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The Efficiency of Involute Spur Gears

Journal of Mechanical Design ◽

10.1115/1.3254855 ◽

1981 ◽

Vol 103 (1) ◽

pp. 160-169 ◽

Cited By ~ 23

Author(s):

K. F. Martin

Keyword(s):

Coefficient Of Friction ◽

Sliding Friction ◽

Experimental Tests ◽

Rolling Friction ◽

Gear Train ◽

Small Range ◽

Load Effect ◽

Coefficient Of Sliding Friction ◽

The Coefficient Of Friction ◽

Basic Characteristics

Approximate equations produced by Trachman |15| are used to predict the coefficient of sliding friction between the gear teeth. These equations apply when the lubrication regime is elastohydrodynamic; this is true during many gear contacts. The equations, which require only certain basic characteristics of the lubricant and the gears, are relatively simple and produce values for the coefficient of friction which are acceptable. The use of this coefficient of friction, together with a calculation for the rolling friction force allows the calculation of instantaneous and overall efficiency of the gear train. Contact ratios greater than one are accounted for and the load is assumed to be shared equally between the pairs of teeth. The computed values show that the load torque has a significant effect on both coefficient of friction and efficiency; as the load increases the coefficient of friction increases and the efficiency decreases. The effect of speed does not, over the small range of computations made, have as much significance as load, although it appears that efficiency will probably increase as the speed increases. Comparison of these predicted results with the few experimental tests which are relevant indicates some support, especially for the load effect.

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INFLUENCE OF PAD GEOMETRY MODIFICATION ON THE PERFORMANCE OF THRUST BEARINGS LUBRICATED WITH MAGNETORHEOLOGICAL FLUID

Tribologia ◽

10.5604/01.3001.0012.6965 ◽

2018 ◽

Vol 278 (2) ◽

pp. 29-35 ◽

Cited By ~ 2

Author(s):

Wojciech HORAK ◽

Marcin SZCZĘCH ◽

Józef SALWIŃSKI

Keyword(s):

Sliding Friction ◽

Experimental Tests ◽

Magnetic Fluids ◽

Performance Parameters ◽

System Operation ◽

Precise Control ◽

Thrust Bearings ◽

Wide Range ◽

The Magnetic Field

Magnetic fluids belong to the class of controllable materials. The influence of magnetic fields on this type of substance results in a change in its internal structure and an almost immediate change in its rheological properties. The ability to control the rheological characteristics in a very wide range, in combination with the ease of generating and controlling the magnetic field, creates the possibility of using this type of substance in systems with controlled operating parameters. The use of magnetic fluids in bearings may allow the design of some types of bearings to be simplified and enable efficient, fast, and precise control of the system operation, with a much shorter response time and higher stiffness than is the case with conventional sliding friction bearings. The paper presents the results of experimental tests carried out on a laboratory stand designed for thrust bearings lubricated with magnetic fluids. The analyses carried out concerned the determination of how the pad surface modification of the slide bearing, lubricated with magnetorheological fluids, influences the system performance parameters.

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The Influence of Geometrical Parameters on the Friction Process in the Needle Bearing

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.490.288 ◽

2011 ◽

Vol 490 ◽

pp. 288-295

Author(s):

Jerzy Nachimowicz ◽

Robert Korbut

Keyword(s):

Contact Area ◽

Ball Bearing ◽

Sliding Friction ◽

Friction Pair ◽

Rolling Friction ◽

Geometrical Parameters ◽

Friction Process ◽

Motion Resistance ◽

Initial Clearance ◽

Analogical Process

The article analyses the process of friction in the needle bearing as the function of the alterations of geometrical parameters, namely the diameter of the shaft – D, the needle – d and the bearing clearance. The change in the relation between the diameters D and d results in the change of the contact area of the friction pair; in the case of two shafts with parallel axes (the needle of the bearing and the shaft pin) the contact area, if compared with the analogical process in the ball bearing, alters significantly and leads to resistance in motion. There are two types of friction in the needle bearing: the rolling friction and the sliding friction; the analysis of the movement of the bearing elements enabled the estimation of the extent to which the sliding friction matters in the overall balance of motion resistance. The article also defines the type of wear as the function of initial clearance.

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