scholarly journals Wear Calculation for Sliding Friction Pairs

2014 ◽  
Vol 51 (2) ◽  
pp. 41-54 ◽  
Author(s):  
G. Springis ◽  
J. Rudzitis ◽  
A. Avisane ◽  
A. Leitans

Abstract One of the principal objectives of modern production process is the improvement of quality level; this means also guaranteeing the required service life of different products and increase in their wear resistance. To perform this task, prediction of service life of fitted components is of crucial value, since with the development of production technologies and measuring devices it is possible to determine with ever increasing precision the data to be used also in analytical calculations. Having studied the prediction theories of wear process that have been developed in the course of time and can be classified into definite groups one can state that each of them has shortcomings that might strongly impair the results thus making unnecessary theoretical calculations. The proposed model for wear calculation is based on the application of theories from several branches of science to the description of 3D surface micro-topography, assessing the material’s physical and mechanical characteristics, substantiating the regularities in creation of the material particles separated during the wear process and taking into consideration definite service conditions of fittings.

2015 ◽  
Vol 220-221 ◽  
pp. 361-366
Author(s):  
Guntis Springis ◽  
Janis Rudzitis ◽  
Anita Avišāne ◽  
Maris Kumermanis ◽  
Jevgenijs Semjonovs ◽  
...  

A number of different mechanisms and devices may involve sliding-friction surfaces. The issues of service life and its prediction for the details of such surfaces have always been of particular importance. The article determines the most suitable wear calculation model that allows considering the set of parameters necessary for calculating slide-friction pair. The offered model is based on the application of the theories of several branches of sciences. Since the wear process is variable and many-sided, it is influenced by numerous different parameters, for example, surface geometry (roughness, waviness, form deviation, etc.), physical and mechanical conditions of the upper layer, material components, wear regime, wear temperature, etc.


2017 ◽  
Vol 260 ◽  
pp. 202-211
Author(s):  
Guntis Springis ◽  
Janis Rudzitis ◽  
Eriks Gerins ◽  
Natalija Bulaha

A number of different mechanisms and devices in mechatronic systems may involve sliding-friction surfaces. The issues of service life and its prediction for the details of such surfaces have always been of particular importance. Having studied the wear process prediction theories that have been developed in the course of time, which can be classified by dividing them in definite groups based on similar theoretical approach one can state that each of them has different shortcomings, which might affect the result precision, when essential basic parameters have been disregarded, as well as create a need for useless additional practical experiments, as a result of which theoretical calculation becomes unnecessary. [4] The article determines the most suitable wear calculation model that allows considering the set of parameters necessary for calculating slide-friction pair. Wearing usually proceeds in three stages: the running-in stage, the normal wear stage, and the intensive wear stage. The proposed model is provided for normal wear stage calculations. The proposed model for wear calculation is based on the application of theories from several branches of science to the description of 3D surface micro-topography in accordance with random field theory, assessing the material’s physical and mechanical characteristic quantities, substantiating the regularities in creation of material particles separated during the wear process and taking into consideration definite service conditions of fittings. Since the wear process is variable and many-sided, it is influenced by numerous different parameters, for example, surface geometry (roughness, waviness, form deviation, etc.), physical and mechanical conditions of the upper layer, material components, wear regime, wear temperature, etc. Based on the regularities stated in the article one can propose the following wear calculation sequence [4]:1) Initial data should be stated which will be further necessary in calculations: constructive-kinematic characteristic quantities (rated area Aa of wearing component, load P, gliding movement speed v, movement time t), fatigue characteristic of friction component material (friction coefficient f (f≤0,1) and material fatigue destruction parameters (m, σ-1, N0), mechanical characteristic quantities of material (E, μ);2) Parameters should be stated after attachment: surface roughness parameters (Sa, Sm1, Sm2, Sm2a), initial wear Up and corresponding time Tp, tolerated wear Umax.


2014 ◽  
Vol 604 ◽  
pp. 59-62 ◽  
Author(s):  
Oskars Linins ◽  
Armands Leitans ◽  
Guntis Springis ◽  
Janis Rudzitis

The problem of evaluating the life period of different mechanisms is of great importance nowadays. This could be explained by the fact that the wear process is very complex and very many factors take place simultaneously. During the history a variety of theories that offered different methods of wear calculation models were developed. However still there is no exact wear calculation model that could be applied to all cases of wear processes. The offered method is dealing with the calculation of rough surface peaks that make the contact between two surfaces. Taking into account the number of these peaks and applying fatigue wear model based on 3D surface micro-topography, assessing the materials physical and mechanical characteristic quantities and considering definite service conditions of sliding friction pair it is possible to make the wear calculation of friction pair under definite working conditions.


2020 ◽  
Vol 157 ◽  
pp. 01022
Author(s):  
Victor Philippov ◽  
Alexandr Smerdin

The use of contact elements with an extended service life is one of the most economical and least costly ways to ensure reliable, economical and environmentally friendly transmission of electricity to rolling stock. To evaluate the service life in OSTU, a methodology for conducting experimental studies of contact pairs of pantograph has been developed and successfully tested, involving bench tests for each pair of contact materials “contact insert - contact wire” in order to determine their optimal combination to reduce wear and increase service life. Assessment of the amount of wear and prediction of the life of the contact elements are made, including using mathematical modeling. The purpose of this article is to improve the mechanical component of the wear model of the contact elements of pantograph in high-speed conditions. The results of experimental studies and theoretical calculations of the mechanical wear of contact elements are presented. The analysis of the graphs allows us to conclude that it is possible to use an improved mathematical model for modeling the mechanical component of the wear process of the elements of contact pairs with a maximum error value of not more than 5%.


2013 ◽  
Vol 278-280 ◽  
pp. 414-417 ◽  
Author(s):  
Geng Pei Zhang ◽  
Xiao Jun Liu ◽  
Wen Long Lu

Running-in is an important and inevitable wear process for machine system, and it plays an indispensable role in extending service life and improving operating performance. Surface topography appears as a significant feature of friction pairs. Therefore, study on modification of surface topography in running-in is crucial to control surface quality and then achieve improvement of machine system. In this paper, to understand the evolution of surface topography in running-in process, steel dry sliding running-in experiments were conducted, and surface topographies in running-in were evaluated with the areal surface evaluation parameters. The results reveal that surface topography evaluation could provide valuable information about wear status of steel running-in process of dry sliding friction, amplitude parameters, area and volume parameters, and hybrid parameters play different and important roles in characterization of surface topography modification in running-in.


2021 ◽  
pp. 1-49
Author(s):  
Li Xiao ◽  
Yingqiang Xu ◽  
Zhiyong Chen

Abstract In this paper, a multi-layer body model in which material properties and wear coefficient change with node coordinates is proposed, so that the wear profile is not restricted by the singularity of the interface of the coated contact pairs. The conversion rate of the adhered particles was obtained to describe the growth and expansion of the debris at the fretting interface based on experiments, and the wear model of coated contact pair considering the dynamic evolution of the debris layer was established. By comparing the previous experimental and computational results, the wear calculation method proposed in this paper is more reasonable to predict the wear profile of the coated contact pair. In addition, the influence of the debris layer on the wear depth, friction width, and contact pressure in the fretting process is analyzed, indicating that the existence of the debris layer can delay the wear process. Finally, the fretting wear life of the SCMV steel contact pair deposited with the W-DLC coating is estimated.


Author(s):  
Sergey Smolyak

We propose a model describing the decrease in the market value of machines (depreciation) with age. Usually it is characterized by the percent good factor, i.e. the ratio of machine’s value to the value of similar new machinery item. Often, appraisers know about a used machinery item only by its age, but not its performance. Therefore, for the valuation of the machinery item of a known age, they have to use the mean (for machines of this age) of percent good factor. In the proposed model, the state of the machine is characterized by the intensity of the benefits it brings. In this case, the benefits from using the machine in a certain period are defined as the market value of the work performed by it minus operating costs. We describe the change in the intensity of benefits over time by the Wiener process with negative drift. This allows us to take into account the tendency for the performance of machine to deteriorate during operation. The market value of a machine is defined as the maximum mathematical expectation of the sum of discounted benefits from its use. It is shown that it corresponds to the moment the machine reaches a certain boundary state. The parameters of the Wiener process (drift and volatility) are expressed through the known characteristics of the machine's durability, namely the average value and the coefficient of variation of the service life. The dependences of the mean percent good factor of machines on the relative age (the ratio of age to the average service life) are found. It turned out that these dependencies are almost independent of the discount rate and average service life.


2018 ◽  
Vol 940 ◽  
pp. 72-76
Author(s):  
Fang Quan ◽  
Zhi Tong Chen ◽  
Qian Tong Li ◽  
Huan Ye

The wear process of electroplated CBN grinding wheel is difficult to predict and control because of the lack of unified evaluation index of wear degree. This paper investigates the service life cycle of electroplated CBN grinding wheel in grinding of nickel-based superalloy GH4169. The evolution of topography of grinding wheel, diameter of grinding wheel, grinding force and surface roughness are tracked in the wear process. Using the analytic hierarchy process (AHP), the optimal evaluation index of service life of electroplated CBN grinding wheel is proposed.


Author(s):  
Y Cao ◽  
J Mao ◽  
H Ching ◽  
J Yang

Using the quality loss function developed by Taguchi, the manufacturing time and cost of a product can be reduced to improve the factory's competitiveness. However, the fuzziness in quality loss has not been considered in the Taguchi method. This article presents a fuzzy quality loss function model. First, fuzzy logic is used to describe the semantic of the quality, and the quality level is divided into several grades. Then the fuzzy quality loss function is developed utilizing the loss in monetary terms, which indicates the quality loss of each quality level and the normalized expected probability to each quality grade. Moreover, a new optimization model for tolerance design under fuzzy quality loss function is established. An example is used to illustrate the validity of the proposed model. The result shows that the proposed method is more flexible and can achieve the balance of quality and cost in tolerance design. It can be easily used in accordance with practical engineering applications.


Sign in / Sign up

Export Citation Format

Share Document