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1
Content available Impact of friction coefficient variation on temperature field in rotary friction welding of metals – FEM study
Łukaszewicz Andrzej, Józwik Jerzy, Cybul Kamil
Applied Computer Science
|
2023
|
Vol. 19, no 3
17--27
EN
A mathematical model is presented for investigating the temperature field caused by the rotary friction welding of dissimilar metals. For this purpose, an axisymmetric, nonlinear, boundary value problem of heat conduction is formulated with allowance for the frictional heating of two cylindrical specimens of finite length made of Al 6061 aluminium alloy and 304 stainless steel. The thermo-physical properties of materials change with increasing temperature. It was assumed that the coefficient of friction does not depend on the temperature. The mechanism of heat generation due to friction on the contact surface with the temperature field of samples is considered. The boundary problem of heat conduction was reduced to the set of nonlinear ordinary differential equations at time t relative to the values of temperature T at the finite elements nodes. The numerical solution of the problem was obtained with the inverse 2nd order differentiation method implemented in COMSOL FEM system (finite element method), with time step ∆t=0.1 (s). The influence of various values of friction coefficient is presented.
2
Content available Effect of the temporal profile of the friction power on temperature of a pad-disc brake system
Yevtushenko Aleksander, Kuciej Michał, Topczewska Katarzyna
Journal of Theoretical and Applied Mechanics
|
2019
|
Vol. 57 nr 2
461--473
EN
A mathematical model to analyse the influence of change of the friction power over time on temperature of a pad-disc tribosystem has been proposed. For this purpose, a boundary- -value problem of heat conduction for two semi-infinite bodies with taking into account heat generation due to friction on the contact surface has been formulated. Exact solutions of this problem were obtained for seven temporal profiles of the specific heat generation power, which were established experimentally. For selected friction materials, numerical analysis of the spatiotemporal temperature distributions and heat fluxes intensities were executed. The obtained results were compared with a corresponding data which were found by means of the known approximate solution.
3
Content available Analytical model for investigation of the effect of friction power on thermal stresses in friction elements of brakes
Topczewska K.
Journal of Theoretical and Applied Mechanics
|
2018
|
Vol. 56 nr 4
1017--1027
EN
The influence of the change with time of friction power on thermal stresses in a friction element of a brake system is investigated. For this purpose, a list of ten different temporal profiles of specific friction power is used, which has been experimentally established for a single braking process. The corresponding profiles of transient temperature fields in the considered element are applied as input parameters to find quasi-static thermal stresses. Numerical analysis concerned with spatio-temporal distributions of the stresses and their evolutions on the heated surface is presented.
4
Content available Thermal stresses due to frictional heating with time-dependent specific power of friction
Topczewska K.
Acta Mechanica et Automatica
|
2017
|
Vol. 11, no. 4
280--284
EN
In this paper influence of temporal profile of the specific friction power (i.e. the product of the coefficient of friction, sliding velocity and contact pressure) on thermal stresses in a friction element during braking was investigated. Spatio-temporal distributions of thermal stresses were analytically determined for a subsurface layer of the friction element, based on the model of thermal bending of a thick plate with unfixed edges (Timoshenko and Goodier, 1970). To conduct calculations, the fields of dimensionless temperature were used. These fields were received in the article (Topczewska, 2017) as solutions to a one-dimensional boundary-value problem of heat conduction for a semi-space heated on its outer surface by fictional heat flux with three, different time profiles of the friction power.
5
Content available Frictional heating with time-dependent specific power of friction
Topczewska K.
Acta Mechanica et Automatica
|
2017
|
Vol. 11, no. 2
111--115
EN
In this paper analytical solutions of the thermal problems of friction were received. The appropriate boundary-value problems of heat conduction were formulated and solved for a homogeneous semi–space (a brake disc) heated on its free surface by frictional heat fluxes with different and time-dependent intensities. Solutions were obtained in dimensionless form using Duhamel's theorem. Based on received solutions, evolution and spatial distribution of the dimensionless temperature were analyzed using numerical methods. The numerical results allowed to determine influence of the time distribution of friction power on the spatio-temporal temperature distribution in brake disc.
6
Content available The temperature of a brake disc during frictional heating with linear distribution of the contact pressure
Topczewska K.
Technical Issues
|
2016
|
nr 3
113--119
EN
In this paper the analytical solution of the boundary–value heat conduction problem for a brake rotor was developed. A solid brake disc is heated by frictional heat flux during braking with constant deceleration. Intensity of the heat flux affecting friction surface of the disc is proportional to the specific power of friction. It was assumed that contact pressure between the pad and the disc increases linearly, from zero in the initial moment of the braking process to the maximum value in standstill. Calculations were carried out on variables and parameters in the dimensionless form. The obtained results were compared with adequate resultsduring braking with constant deceleration, with an assumption of pressure constant in time.
7
Content available Temperature distribution in a brake disc with variable contact pressure
Topczewska K.
Technical Issues
|
2016
|
nr 1
90--95
EN
The aim of this study was to investigate the influence of the time of pressure increase during single braking on the temperature in a brake disc. The case of linear pressure increase from zero to nominal value in the initial stage of braking and maintaining this value to standstill was considered. The time distribution of the sliding velocity of frictional elements was determined from the differential equation of motion with the initial condition. Based on the time distributions of pressure and sliding velocity, the intensity of the frictional heat flux, which affects on the disc surface, was determined. Spatio-temporal distribution of the temperature in a brake disc was found from analytical solution of the heat conduction boundary–value problem for semi–space heated on the outer surface heat flux with known a priori intensity. The numerical analysis conducted allowed to determine engineering equation, which describes relation between maximum temperature and the time of pressure increase.
8
Content available Finite element analysis of the 3D thermal stress state in a brake disk
Adamowicz A.
Journal of Theoretical and Applied Mechanics
|
2016
|
Vol. 54 nr 1
205--218
EN
The quasi-static thermal stress state within the linear uncoupled elasticity is studied. The calculations were performed using the finite element method (MSC.Patran/MSC.Nastran). In order to examine smooth stress changes in a brake disk during braking, based on the temperature fields at particular time steps, additionally the script using Python programming language was developed. The numerical three-dimensional FE model of the brake disk for calculation of the transient temperature field was adopted from the previous author’s study. A single braking process at linear deceleration and constant contact pressure was simulated. The evolutions and the contours of the components of the stress tensor as well as the equivalent Huber-Mises stress were examined. The most important aspects of the stress state during braking were discussed.
9
Content available Axisymmetric fe model to analysis of thermal stresses in a brake disk
Adamowicz A.
Journal of Theoretical and Applied Mechanics
|
2015
|
Vol. 53 nr 2
357--370
EN
The preceding to this study was a finite element analysis (FEA) of transient temperature fields in a disk brake. In this paper, a FE model to determine corresponding quasi-static stresses in a such tribosystem is proposed. Numerical simulation of a single braking process for the 2D axisymmetric model of the brake disk is carried out. It is assumed that the contact pressure on the friction surfaces is constant, and the angular speed decreases linearly. Evolutions and spatial distributions of the components of the stress tensor and the equivalent Huber-Mises stress in the disk are analyzed.
10
Content available Frictional heating during sliding of two semi-spaces with arbitrary thermal nonlinearity
Och E.
Acta Mechanica et Automatica
|
2014
|
Vol. 8, no. 4
204--208
EN
Analytical and numerical solution for transient thermal problems of friction were presented for semi limited bodies made from thermosensitive materials in which coefficient of thermal conductivity and specific heat arbitrarily depend on the temperature (materials with arbitrary non-linearity). With the constant power of friction assumption and imperfect thermal contact linearization of nonlinear problems formulated initial-boundary thermal conductivity, using Kirchhoff transformation is partial. In order to complete linearization, method of successive approximations was used. On the basis of obtained solutions a numerical analysis of two friction systems in which one element is constant (cermet FMC-845) and another is variable (grey iron ChNMKh or aluminum-based composite alloy AL MMC) was conducted.
11
Content available Frictional heating of sliding semi-spaces with simple thermal nonlinearities
Och E.
Acta Mechanica et Automatica
|
2013
|
Vol. 7, no. 4
236--240
EN
In the article the nonstationary thermal problem of friction for two semi-spaces with taking into account their imperfect thermal contact and thermosensitivity of materials (simple nonlinearity), has been considered. The linearization of this problem has been carried out using Kirchhoff transformation, and next using the Laplace integral transform. The analytical solution to the problem in the case of con-stant speed sliding, has been obtained. On the basis of the obtained solutions and using Duhamel's formula, the analytical solution to the problem for sliding with constant deceleration, has been obtained, too. The results of numerical analysis are presented for two friction pairs.
12
Content available remote Wear characterization of polymeric roller bearings during normal operation conditions and overloading
Katunin A., Szrejber Z.
Scientific Problems of Machines Operation and Maintenance
|
2012
|
Vol. 47, nr 1
39--49
EN
The paper presents the results of experimental studies of the thermomechanical behaviour of the polymer roller bearings under the different operation conditions. The analysis of various combinations of materials usually used in commercial solutions was performed in order to evaluate specific states characteristic for these tribological pairs. The influence of a temperature growth during workloads was investigated, including the nature of the heating sources. The surfaces subjected to the rolling friction of elements of polymeric bearings were examined using a microscope, and typical damages resulting from the frictional heating were evaluated and discussed.
PL
Artykuł przedstawia wyniki badań eksperymentalnych dotyczących termomechanicznego zachowania polimerowych łożysk tocznych w różnych warunkach eksploatacji. Przeprowadzono analizę różnych kombinacji materiałów stosowanych zazwyczaj w rozwiązaniach komercyjnych w celu określenia charakterystycznych stanów tych par tribologicznych. Zbadano wpływ obciążeń na przyrost temperatury, uwzględniając naturę źródeł ciepła. Powierzchnie elementów łożysk polimerowych narażone na tarcie toczne zostały zbadane przy użyciu mikroskopu. Ocenie i dyskusji poddano typowe uszkodzenia wynikające z tarciowego rozgrzania.
13
Content available The comparable analysis of temperature distributions assessment in disc brake obtained using analytical method and FE model
Kuciej M.
Journal of KONES
|
2011
|
Vol. 18, No. 2
235-259
EN
In this paper the one-dimensional analytical formulation as well as the two-dimensional FE model to study the temperature distributions in the pad/disc brake system during an emergency braking process was proposed. Both the time-dependent pressure variation and the convective cooling conditions on the free surfaces of a pad have been incorporated in the contact analytical model. The one-dimensional thermal problem of friction of the strip-foundation system during braking was formulated. An exact solution of the problem using the mathematical device of the integral Laplace transform related to Duhamel theorem was obtained. In the FE formulation to discretize the heat conduction equation for the two-dimensional problem, the Galerkin method was employed. The temperature distributions were calculated exclusively for the disc employing the heat partition ratio. Furthermore, due to the symmetry of the problem the computations were restricted to the half of the entire disc. The finite element analysis of the transient heat transfer problem for the pad/disc system was carried out using the MSC Patran/Nastran program package. On order to confront and compare the resulting temperatures distributions, equal operation parameters, the thermophysical properties of materials as well as the dimensions of the brake components were used within the numerical and analytical calculation. The obtained results from the finite element analysis reveal that both the contact temperature evolution and its values in depth of the brake rotor agree well with the analytical solution and experimental data.
14
Content available remote Effects of thermal radiation and non-uniform heat source on MHD flow of viscoelastic fluid and heat transfer over a stretching sheet
Subhas Abel M., Nandeppanavar M. M.
International Journal of Applied Mechanics and Engineering
|
2007
|
Vol. 12, no 4
903-918
EN
The present paper deals with the study of momentum and heat transfer characteristics in a visco-elastic fluid flow over an impermeable stretching sheet. Where the flow is generated due to linear stretching of the sheet and influenced by a uniform magnetic field applied vertically in the flow region. Heat balance is maintained with a non-uniform heat source/sink, viscous dissipation and thermal radiation. The partial differential equations governing the flow and heat transfer are converted into ordinary differential equations by suitable similarity transformations. The proposed problem has be en solvcd by the fourth order Runge-Kutta method with shooting technique. The effects of viscous dissipation, a non-uniform heat source/sink and thermal radiation on heat transfer characteristics in two different general cases, namely (1) the prescribed surface temperature (PST) and (2) the prescribed wall heat flux (PHF) are presented graphically and discussed. The calculated values of the wall temperature gradient in the PST case and the wall temperature PHF case are tabulated and discussed.
15
Content available remote Dimensions and kinetics of local heat sources in rubbing solid contact
Bogdanovich P. N., Belov V. M., Tkachuk D. V.
International Journal of Applied Mechanics and Engineering
|
2006
|
Vol. 11, no 1
5-13
EN
The paper describes the technique for studying the kinetics of thermal processes on real contact spots. Experimental results are presented. The effect of the load on the size distribution of hot spots (sources of heat radiation) is shown. The sliding velocity, surface topography and materials used are shown to influence the number, size, and life of the spots. The ratios of mean dimensions and total area of hot spots to those of the spots making up the real contact area are analyzed.
16
Content available remote Temperature fields in a high-speed friction contact
Tkachuk D. V., Bogdanovich P. N.
Tribologia
|
2004
|
nr 1
75-89
EN
Experiments intended to understand heat phenomena in sliding contacts were performed, their results are presented below. Asperities in contact were found to undergo pulse effect of the temperature approaching the melting point of one of the friction members. It was detected that temperatures higher than the melting point can be generated in the sapphire-aluminum and sapphire-polyethylene pairs. Temperature distribution over the local heat source area as well as in depth of the parts in contact is determined.
PL
Przedstawiono wyniki badań eksperymentalnych procesów cieplnych w styku ślizgowym. Wykazano, że w obszarze styku nierówności, pulsacyjnie narastająca temperatura może osiągać wartości zbliżone do temperatury topnienia jednego z elementów pary tarciowej. Dla skojarzeń szafir-aluminium oraz szafir-polietylen, temperatura tarcia może przekroczyć punkt topnienia. Określono rozkłady temperatury na powierzchni tarcia oraz w głębi elementu stykowego.
17
Frictional heating effects in the plane contact of layer and rigid flat punch
Pauk V., Woźniak M.
Journal of Technical Physics
|
2003
|
Vol. 44, no 3
237-244
EN
Thermal effects due to the frictional heating in sliding contact of a thermoelastic layer and a rigid insulated flat punch are investigated. The contact problem is treated by the Fourier integral transform method and is reduced to the system of singular integral equations which is solved numerically. Influence of the frictional heating on distributions of the contact pressure and generated temperature is presented for different values of thickness of the layer. Comparison with the corresponding results for a half-space is done.
18
Content available Thermoelastic contact problem with frictional heating for the punch of functionally geraded materials
Kulchytsky-Zhyhailo R.
Journal of Theoretical and Applied Mechanics
|
1998
|
nr 2
279-289
EN
A contact problem with frictionalheating for a body with thefunctioally graded materials (FGMs) is considered. The FGM body slides on the surface of rigid half-space. The problem is reduced to one integral equation in pressure. The approximate solution was derived basing on the representation of deformed solid surface by a polinormal sutface. The influence of the parameters which characterise nonhomogeneity of a medium on contact region size is investigated.
PL
Rozpatrzono kontaktowe zagadnienie z uwzględnienie generacji ciepła dla stempla z materiału o ciągłej niejednorodności. Ten stempel ślizga się po powierzchni sztywnej półprzestrzeni. Zagadnienie zostało zredukowane do jednego równania całkowego na nieznane ciśnienie. Przybliżone rozwiązanie zostało znalezione stosując reprezentację odkształconej powierzchni ciała przez wielomianową powierzchnię. Zbadano wpływ parametrów charakteryzujących niejednorodność stempla na rozmiar obszaru kontaktu.
19
Content available Axi-symmetrical contact problem during breaking with frictional heating and wear
Yevtushenko A., Chapovska R.
Journal of Theoretical and Applied Mechanics
|
1998
|
nr 2
331-346
EN
The problem of transient contact with frictional heating and wear for two non-uniform sliding half-spaces is considered. One of the two halfspaces is assumed to be slightly curved to give a Hertzian initial pressure distribution; the other is a rigid non-conductor. On the assumption that the contact pressure distribution could be described by the Hertz formulas during whole the process of interaction, the problem is formulated in terms of one integral equation of the Volterra type an unknown radius of the contact area. A numerical solution of this equation is obtained using a piecewise-constant representation of unknown function. The influence of operating parameters on the contact temperature and the radius of the contact area is studied.
PL
W pracy rozpatrzono zagadnienie kontaktowe z uwzględnieniem generacji ciepła dla dwóch ślizgających się półprzestrzeni. O jednej z półprzestrzeni założono, że jest gładko zakrzywiona co powoduje Hertzowski początkowy rozkład ciśnienia. Druga z półprzestrzeni jest izolatoerm. Wykorzystując założenie, że ciśnienie kontaktowe może być założone w postaci rozkładu otrzymanego przez Hertza podczas trwania oddziaływania, zagadnienie zostało zredukowane do równania całkowego typu Voltera na nieznany promień obszaru kontaktu. Rozwiązanie numeryczne zostało przedstawione wykorzystując kawałkami stałą reprezentację nieznanej funkcji. Zbadano wpływ parametrów charakteryzujących ciała na temperaturę w obszarze kontaktu oraz promień obszaru kontaktu.
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