Temperature and thermoelastic instability at tread braking using cast iron friction material

Abstract

Braking events in railway traffic often induce high frictional heating and thermoelastic instability (TEI) at the interfacing surfaces. In the present paper, two approaches are adopted to analyse the thermomechanical interaction in a pin-on-disc experimental study of railway braking materials. In a first part, the thermal problem is studied to find the heat partitioning between pin and disc motivated by the fact that wear mechanisms can be explained with a better understanding of the prevailing thermal conditions. The numerical model is calibrated using the experimental results. In a second part, the frictionally induced thermoelastic instabilities at the pin-disc contact are studied using a numerical method and comparing them with the phenomena observed in the experiments. The effects of temperature on material properties and on material wear are considered. It is found from the thermal analysis that the pin temperature and the heat flux to the pin increase with increasing disc temperatures up to a transition stage. This agrees with the behaviour found in the experiments. Furthermore, the thermoelastic analysis displays calculated pressure and the temperature distributions at the contact interface that are in agreement with the hot spot behaviour observed in the experiments. KEYWORDSRailway tread braking, frictional heating, heat partitioning, thermoelastic instability (TEI), hot spots, pin-on-disc test, numerical analysis.

Indication of Thermoelastic Instability of Sliding Contact Using Embedded Piezoceramic Interlayer

“…личных технических системах со скользящим фрикционным контактом, в том числе в дисковых тормозных системах [1][2][3][4], в уплотнениях валов [5] и др.…”

Identification of the hot spots phenomenon in brakes by using a thermal imaging camera

“…The rest of the article shows the increases in temperature (hot spots) on the brake disc during braking with organic pads. It should be pointed out that the phenomenon of hot spots is widely considered by many researchers who deal with the both brake systems and the friction clutches of the means of transport [1,2,5,8,16]. Number of papers presents the results of studies that allow to identify the phenomenon in respect of the location and number of hot spots on the brake disc [5,6].…”

“…10.21611/qirt.2016.115 Figure 7 and 8 shows the value of the average maximum and a minimum temperature defined form linear segments between the inner and outer radius of the brake disc, passing through the hot spots. Then, by using the equations (1). The values of temperature rise in the hot area was calculated.…”

Analytical model coefficient of friction (COF ) of rail disc brake on the basis of multi-phase stationary tests

“…The work presents examples of uneven wear of friction linings such as higher wear on the outer radius of the disc relative to the inner radius of the disc, edge defects and cracking or tearing of the entire lining parts from the bearing plate. In this respect, works are underway on such a selection of the friction pair materials as to ensure a compromise among the costs of manufacturing (additional thermal and chemical processes when making the casts of the brake discs), the component wear and the friction mechanical properties of the friction pair, as described in [1,3,10,13,14,42]. On the other hand, [7,11,37] presents problems related to friction models and friction wear modeling of brake system components based on operational tests.…”