Effect of the temporal profile of the friction power on temperature of a pad-disc brake system

Abstract

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.

Temperature and thermal stresses distributions in a dry friction clutch

“…When increasing the thickness d, the maximum temperature drops and then stabilizes in the range of a d 3, where a = 1.29 mm, 1.17 mm, 1.11 mm for α = 0, 0.5 and 1, respectively. This parameter is a theoretical distance from the heated surface in which the temperature achieves 5% of the maximum value, and it is called the effective depth of heat penetration (Yevtushenko et al, 2019). It should be noted that increasing of the frictional facing thickness d causes more intensive convective heat exchange due to enlargement of the lateral surfaces area.…”

Effect of Pressure Fluctuations on the Temperature During Braking

“…where is the initial temperature. Solution to the problem (13)- (19) was found based on the following Duhamel's theorem (Ozisik,1993). * ( , ) = ∫ * ( )…”

“…In the case of braking, when the time of pressure increase is close to zero, → 0 (11), the solution to the thermal friction problem (13)- (19) has the following form:…”

“…assuming that pressure is invariable in time (Fazekas, 1953; Belhocine and Bouchetara, 2012; Talati and Jalalifar, 2009;Nosko et al, 2012). More precise models use an exponential function to describe the increase of contact pressure at the beginning of braking to nominal value (Topczewska, 2018;Yevtushenko et al, 1999;Matysiak et al, 2002) or its simplified form -linear growth of pressure -and maintain the achieved nominal value to the end of braking (Topczewska, 2018;Yevtushenko and Grześ, 2015;Yevtushenko et al, 2019). In the article Topczewska (2018), the evolution of temperature on friction surface was found in a closed analytical form for a classic semi-space/semi-space system with regard to the time profiles of specific friction power corresponding to the exponential and linear increase of pressure.…”

“…In the article Topczewska (2018), the evolution of temperature on friction surface was found in a closed analytical form for a classic semi-space/semi-space system with regard to the time profiles of specific friction power corresponding to the exponential and linear increase of pressure. Another possible pressure variation during braking was taken into account indirectly by applying different profiles of specific friction power during single braking (Yevtushenko et al, 2019). In the abovementioned article, the analytical solutions of one-dimensional heat conduction problem formulated for semi-space/semi-space system were found.…”