scholarly journals Modeling the processes of friction and wear under dynamic influences on the tribosystem

2020 ◽  
Vol 97 (3) ◽  
pp. 45-49
Author(s):  
A. Voitov ◽  
Keyword(s):  
Wear Rate ◽  
Coefficient Of Variation ◽  
Friction And Wear ◽  
Operating Time ◽  
Dynamic Effect ◽  
External Action ◽  
Volumetric Wear ◽  
Distribution Law ◽  
Sliding Speed ◽  
The Impact

On the basis of the performed analysis of works devoted to the increase in the wear rate due to the dynamic effect on the tribosystem, expressions were obtained for modeling the processes of friction and wear when changing the external influence. Based on the assumption that the dynamic impact obeys the normal distribution law, the coefficient of variation of the volumetric wear rate. The simulation of the change in the coefficient of variation when changing the load and sliding speed on the tribosystem, as well as the number of steps of changing the load and operating time at each stage. It was found that in the absence of fluctuations in the load and sliding speed, the coefficient of variation of the volumetric wear rate is 1. With an increase in the value of the standard deviation of the external action and the number of steps of change in the action, the coefficient of variation of the volumetric wear rate increases to values 2,59, those volumetric wear rate increases by 1,125 … 2,59 times. This is confirmed by experimental dependencies. The simulation results are adequate to the experimental results with a confidence level 0,9. Calculated modeling error for each series of experiments, which does not exceed 11,03 %. It was found that when changing the power of the bully tribosystem Wb, which is defined as the product of the load and the sliding speed, the coefficient of variation of the volumetric wear rate increases by 1,25 … 4,68 times. Taking into account the range of changes in the external impact and the operating time at each stage of change in the impact will provide information in the form of a coefficient of increasing the wear rate.

Resource calculation of weared equipment for electric trains of the ES2G series

2020 ◽  
pp. 43-50
Author(s):  
A. A. Vorob’ev ◽  
◽  
S.O. Zyazev ◽  
Keyword(s):  
Comparative Analysis ◽  
Wear Rate ◽  
Wear Surface ◽  
Mathematical Expectation ◽  
Operating Time ◽  
Operating Conditions ◽  
Wheel Pair ◽  
Rolling Surface ◽  
Flange Thickness ◽  
The Impact

The article discusses the impact of operating conditions on the wear of the wheels for ES2G electric trains. Thanks to the information on the controlled parameters of the wheel pairs (rolling, flange thickness and rim diameter) of ES2G electric trains operated by the MCC (Moscow Central Circle ) and the Oktyabrskaya Railway, a comparative analysis of the wear surface intensities of the rolling surfaces for seamless-rolled wheelsets has been performed. The analysis of the dependences of the mathematical expectation for the controlled parameter on the operating time showed that the wear rate of the rim for the electric trains operated by the MCC is 2,9 % higher than by the Oktyabrskaya Railway. Similar results were obtained for milling bar (2,33 % ) and the ridge thickness (24,3). Based on the results , it was concluded that the wheelsets wear of the ES2G series electric trains differs significantly in the two compared sections of circulation. Electric trains serving the Oktyabrsky direction has the intensity wheel pair wear lower than the trains serving the MCC. This will allow more time before turning to restore the profile of the rolling surface. The estimated value for the durability indicator of 90 % of the resource before changing the wheel pairs for the maximum wear of the rim is 2 million km at the MCC and 4.4 million km at the Oktyabrskaya Railway.

Friction and Wear Performance of Double Fraction Palm Olein Lubricant Using Pin-on-Disk Tribometer

2014 ◽  
Vol 554 ◽  
pp. 396-400 ◽  
Author(s):  
Samion Syahrullail ◽  
Noorawzi Nuraliza
Keyword(s):  
Aluminum Alloy ◽  
Wear Rate ◽  
Friction And Wear ◽  
Palm Olein ◽  
Normal Load ◽  
Pure Aluminum ◽  
Wear Performance ◽  
Sliding Speed ◽  
Pin On Disk ◽  
Worn Surface

In the present of analysis, the wear rate and friction coefficient of various material is investigated and it were compared below the result of sliding speed wherever the equipment pin on disk machine has been used. Experiments were carried out with 2 totally different pins fabricated from aluminum alloy (AA5083) and pure aluminum (A1100). Experiments were conducted at normal load in step with according to testing, 10 N with totally different sliding speed 1, 3, 5 m/s ,continuous flow lubricating substance, double fraction palm olein (DFPO). The result shows that the material from pure aluminum higher material compared to the aluminum alloy in sliding condition. The morphology of the worn surface was ascertained using high optical research. The magnitude of the friction constant and wear rate are totally different in material depending on the speeds and additionally material.

The Mechanical Properties and Friction and Wear Behavior of C/C-SIC

2010 ◽  
Author(s):  
Gao Wen ◽  
Chongsheng Long ◽  
Tang Rui ◽  
Jiping Wang
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Normal Load ◽  
Carbon Matrix ◽  
Specific Wear Rate ◽  
Sliding Speed ◽  
Wear Rates ◽  
Sic Composites

Carbon fiber reinforced carbon-silicon carbide composites (C/C-SiC) were prepared by chemical volume infiltration (CVI) method and reaction melt infiltration (RMI) technique of silicon liquid to carbon reinforce carbon matrix composites. The friction and wear behaviors of C/C-SiC composites at various loads and sliding speeds were investigated by MRH-3 block-on-ring tribometer at room temperature under water lubricating conditions. Furthermore, the morphologies, phase of the worn surface and the debris were observed, examined and analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis (EDAX) respectively. Experimental results showed that the C/C-SiC composites had a better wear resistence, and the friction coefficient under water lubricated conditions is about 0.02–0.06. The influence of sliding speed on the friction coefficients and the specific wear rate of C/C-SiC is more obvious than that of normal load when the load is less than 200N (inclueded200N). The friction coefficient and the specific wear rate of C/C-SiC decreased as the sliding velocity increased. At the sliding speed higher than 2m/s, the friction coefficient is less than 0.02. The specific wear rates is at a low level about (2×10−7mm3/Nm–5×10−8mm3/Nm).

Polyamide 6/Polyurethane/Graphite Composites Prepared by Anionic Polymerization Process. II. Friction and Wear

2012 ◽  
Vol 532-533 ◽  
pp. 30-34
Author(s):  
Xin Deng ◽  
Du Xin Li ◽  
Jin Wang ◽  
Jun Yang
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Anionic Polymerization ◽  
Friction And Wear ◽  
Polyamide 6 ◽  
Chromium Steel ◽  
Polymerization Process ◽  
Sliding Speed ◽  
Graphite Composites ◽  
Electronic Microscope

Polyamide 6-polyurethane (PA6-PU) block copolymers filled with graphite particles were prepared by anionic polymerization process. The friction and wear experiments were conducted using a UMT-3 machine with the chromium steel ball sliding on surface of the composites at high sliding speeds of 500rpm, 1000rpm and 1500rpm and loads of 78.5N and 157N. With adding of graphite, coefficient of friction and wear rate values of the composites decreased firstly, and then increased. And the influence of the applied load and sliding speed on tribological properties of the composites was explored in this study. The results showed coefficient of friction and wear rate values increased with the increasing of load. Coefficient of friction decreased and wear rate values increased with increasing of sliding speed. Microstructure of wear surface of the tested composites was inspected by scanning electronic microscope(SEM) and wear mechanism of the composites was studied.

scholarly journals On ways to increase protection of special structures from impact action

2021 ◽  
pp. 52-57
Author(s):  
Andriy Andrukhiv ◽  
Andriy Baranov ◽  
Nadiia Huzyk ◽  
Bohdan Sokil ◽  
Mariia Sokil
Keyword(s):  
Mechanical Characteristics ◽  
Dynamic Effect ◽  
External Action ◽  
Engineering Structures ◽  
Discrete Function ◽  
Impact Action ◽  
Protective Element ◽  
Protective Structures ◽  
The Impact ◽  
Physical And Mechanical Characteristics

The technique of research of dynamic processes of elements of engineering constructions of special purpose from explosive action of projectiles is developed. Elastically reinforced beams with hinged ends were chosen for the physical model of elements of engineering structures. It is assumed that the elastic properties of the latter satisfy the nonlinear technical law of elasticity. A mathematical model of the process of a series of impact actions of projectiles at different points of the element of the protective structure is constructed. The latter is a boundary value problem for a partial differential equation. Its peculiarity is that the external dynamic action is a discrete function of linear and time variables. To determine the dynamic effect of a series of impacts on the object under study, and thus the level of protection of the structure, the basic ideas of perturbation theory methods are extended to new classes of systems. This allowed to obtain an analytical dependence of the deformation of the elastically reinforced element on the basic physical and mechanical characteristics of the material of the protective element, its reinforcement and the characteristics of the external action of the projectiles. It is shown that the most dangerous cases, given the security of the structure, are those when the impact is repeated at equal intervals, in addition, the point of impact is closer to the middle of the protective element. The obtained theoretical results can be the basis for selection at the stage of designing the main physical and mechanical characteristics of the elements of engineering structures and their reinforcement in order to reliably protect personnel and equipment from the maximum possible impact on it of the shock series of projectiles. The reliability of the obtained results is confirmed by: a) generalization of widely tested methods to new classes of dynamical systems; b) obtaining in the limit case the consequences known in scientific sources concerning the linearly elastic characteristics of the elements of protective structures; c) their consistency with the essence of the physical process itself, which is considered in the work.

Effect of Loads on the Wear Properties of La2O3-MoSi2 Composite against SiC at Elevated Temperature

2011 ◽  
Vol 415-417 ◽  
pp. 2138-2141
Author(s):  
Si Yong Gu ◽  
Hou An Zhang ◽  
Chun Shi
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Wear Mechanisms ◽  
Friction And Wear ◽  
X Ray Diffraction ◽  
Wear Properties ◽  
Sliding Speed ◽  
X Ray

Wear behaviours of La2O3-MoSi2composite against SiC under different loads at 1000°C and 0.126m/s sliding speed in air were investigated by using an XP-5 type high temperature friction and wear tester. The worn surfaces and phase of the sample were observed by scanning election microscopy (SEM) and X-ray diffraction (XRD), respectively. Results showed that friction coefficient and wear rate of La2O3-MoSi2composite and SiC decreased with the increase of loads. The wear mechanisms of La2O3-MoSi2composite are oxidation, adhesion abrasion and fatigue pitting.

Coefficient of friction and wear rate of paper-based composite friction material against 65Mn steel

2020 ◽  
pp. 135065012097229
Author(s):  
Kingsford Koranteng ◽  
Heyan Li ◽  
Biao Ma ◽  
Chengnan Ma
Keyword(s):  
Wear Rate ◽  
Friction And Wear ◽  
Tribological Behavior ◽  
Friction Material ◽  
Operating Conditions ◽  
Sliding Speed ◽  
Operating Variables ◽  
Dynamic Friction Coefficient ◽  
Pin On Disc ◽  
High Dynamic

Studies have shown that reinforced paper-based friction material with 600 µm carbon fiber length possesses a high dynamic friction coefficient but is subjected to abrasive wear during sliding contact. This work is devoted to further investigate the effect of operating variables on this friction material subjected to high operating conditions. A pin-on-disc test was carried out to determine the tribological behavior of this friction material sliding against 65Mn steel. The friction and wear rate results from measurements were discussed. The highest friction value of about 0.3 was obtained by varying the applied load at 120 N while the lowest friction value close to 0.02 was obtained when the sliding speed was 0.026 m/s. Increasing the sliding speed above 0.30 m/s caused constant temperature (175 °C) to fluctuate due to high friction heat generation on the sliding surface. The highest wear rate was 1.42 × 10−15m3/Nm by varying the sliding speed at 1.31 m/s. In contrast, the lowest wear rate was 2.1 × 10−16m3/Nm when the temperature was at 400 °C.

scholarly journals Friction and Wear Performance of Staple Carbon Fabric-Reinforced Composites: Effects of Surface Topography

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 141 ◽  
Author(s):  
Chang-Mou Wu ◽  
Yi-Ching Cheng ◽  
Wen-You Lai ◽  
Po-Hsun Chen ◽  
Tzong-Der Way
Keyword(s):  
Wear Rate ◽  
Surface Topography ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Applied Pressure ◽  
Specific Wear Rate ◽  
Test Machine ◽  
Carbon Fabric ◽  
Sliding Speed ◽  
Resin Impregnation

Here, staple carbon fiber fabric-reinforced polycarbonate (PC)- and epoxy (EP)-based composites with different impregnating resin levels were fabricated using a modified film stacking process. The effects of surface topographies and resin types on the tribological properties of stable carbon fabric composites (sCFC) were investigated. Friction and wear tests on the carbon composites were conducted under unlubricated sliding using a disk-on-disk wear test machine. Experimental results showed that the coefficient of friction (COF) of the sCFC was dominated by matrix type, followed by peak material portion (Smr1) values, and finalized with core height (Sk) values. The COF of composites decreased by increasing the sliding speed and applied pressure. This also relied on surface topography and temperature generated at the worn surface. However, the specific wear rate was strongly affected by resin impregnation. Partially-impregnated composites showed lower specific wear rate, whereas fully-impregnated composites showed a higher wear rate. This substantially increased by increasing the sliding speed and applied pressure. Scanning electron microscopy observations of the worn surfaces revealed that the primary wear mechanisms were abrasion, adhesion, and fatigue for PC-based composites. For EP-based composites, this was primarily abrasion and fatigue. Results proved that partially-impregnated composites exhibited better tribological properties under severe conditions.

Effect of Sliding Speed on Wear Property of MoSi2 at High Temperature

2011 ◽  
Vol 66-68 ◽  
pp. 150-154
Author(s):  
Hou An Zhang ◽  
Si Yong Gu
Keyword(s):  
Electron Microscope ◽  
High Temperature ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Friction And Wear ◽  
Wear Property ◽  
Sliding Speed ◽  
X Ray ◽  
Very High ◽  
Scanning Electron

Wear behaviors of MoSi2against Al2O3or SiC under 30N at 1000°C in air have been investigated by using an XP-5 type High Temperature Friction and Wear Tester. The worn surfaces and phases of samples were characterized by scanning electron microscope (SEM) and X-ray diffractometer, respectively. Result shows the wear rate and friction coefficient of MoSi2decreases with the increase of sliding speed. SiC is superior to Al2O3as the counter-face materials of MoSi2. Serious adhesion leads to very high wear rate of Al2O3in this experiment. SiC shows a surprising mass weighing phenomenon, which is caused by oxidation. The main wear mechanism of MoSi2against Al2O3is oxidation and adhesion. However when against SiC, it is chiefly controlled by grinding.

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