Influence of Thermal Sensitivity of Functionally Graded Materials on Temperature during Braking

Abstract

The model of the frictional heating process during single braking to determine the temperature of the functionally graded friction elements with an account of the thermal sensitivity of materials was proposed. The basis of this model is the exact solution of the one-dimensional thermal problem of friction during braking with constant deceleration. The formulas approximating the experimental data of the temperature dependencies of properties of the functionally graded materials (FGMs) were involved in the model to improve the accuracy of the achieved results. A comparative analysis was performed for data obtained for temperature-dependent FGMs and the corresponding data, calculated without consideration of thermal sensitivity. The results revealed that the assumption of thermal stability of FGMs during braking may cause a significant overestimation of temperature of the friction pair elements.

Temperature during Repetitive Short-Term Operation of a Brake with Functionally Graded Friction Element

“…An analytical scheme was proposed to determine the temperature during the repeated short-term (RST) operation mode of the braking system, in which one of the friction elements is made of a functionally gradient material (FGM). The proposed approach is a generalization of the authors’ results concerning a single braking process [ 10 , 11 , 12 ]. Calculations were carried out for a friction pair made of a two-component FGM (base ZrO 2 , core Ti–6Al–4V) and ChNMKh gray cast iron, for five braking actions.…”

The Heat Partition Ratio during Braking in a Functionally Graded Friction Couple

“…The thermo-physical properties of these materials are demonstrated in Table 1. The other operating parameters are the nominal heat flux intensity of q 0 = 3.78 MW m −2 , the braking time of t s = 121 s, and the temperature at the initial time moment of T 0 = 20 • C [32]. The dimensionless material gradient parameters of each element were calculated from the relation [47] as follows:…”

“…The aim of this study is to obtain the theoretical formulas for estimating the HPR during the braking of friction pair elements that are made of functionally graded materials (FGMs). One of the proposed applications of the results could be the determination of the bulk temperature of friction elements that are made of thermally sensitive FGM, during a single braking process [32] or a repetitive short-term braking mode [33].…”

Temperature in the Friction Couple Consisting of Functionally Graded and Homogeneous Materials

“…Reviews of investigations on methods for establishing the temperature of systems containing friction elements made of functionally gradient materials (FGMs) can be found in previous articles [ 1 , 2 , 3 ]. In these studies, the methodology of determining the temperature in such friction couples under uniform sliding [ 1 ], during braking with time-dependent contact pressure [ 2 ], and considering the thermal sensitivity of component materials of FGMs was investigated [ 3 ]. The main factor in this methodology is an exact solution to the boundary–value heat conduction problem, taking into account the frictional heating of two semi-infinite bodies made of FGMs.…”