Braking performance and influence of microstructure of advanced cast irons for heavy goods vehicle brake discs

Abstract

It is well known that truck brakes dissipate several megajoules of energy every few seconds, which leads to high thermal stresses in the rubbing parts. Therefore, premature failure by cracking of truck brake discs is a matter of major concern. Improving the design and material of brake discs may enhance braking performance. This study focuses on the latter aspect and was carried out with the aim of developing new material solutions for increasing disc lifespan. To do so, braking experiments were conducted on a specially designed braking tribometer. The brake pads that were used were made from a commercial brake lining material. Two advanced cast irons with different graphite morphology were studied in comparison with the lamellar grey cast iron commonly used for brake disc. To verify the friction and thermal behaviour of the two cast irons, braking tests were carried out as a series of stop-brakings with increasing dissipated power and energy and as a series of slowdowns to achieve heat accumulation effects. Thermal phenomena were studied through bulk temperature measurements and infrared monitoring of the disc surface. Friction behaviour, braking performance and variations in thermal loading were analysed in relation to the level of energy dissipation. The two advanced cast irons and lamellar cast iron had equivalent braking performance and stored similar amounts of heat, according to their thermophysical properties. Observations of the rubbing surfaces indicated damage mechanisms affected by the graphite morphology. Less plastic deformation on the surface was observed with an interdendritic graphite.

Disc brakes for heavy vehicles: an experimental study of temperatures and cracks

“…4–6 Such numerical finite element models allow simulations of repeated brake cycles but still need to be calibrated and validated with experimental studies on wear, friction and crack propagation. 7–10 Numerical analysis of crack growth under thermomechanical conditions has also been performed. 11…”

Application of vibroacoustic diagnostics to evaluation of wear of friction pads rail brake disc

“…The test results after applying the dependences describing measurement point (2)(3)(4)(5), and the dependence of the speed of change (6) shown in Table 1. Based on the results, it was found that the most sensitive diagnostic parameter defined the dynamics of change for assessment of wear on the friction pads, obtained for the measurement of vibration acceleration Y 2 for all measurement points.…”

“…Most of the articles raise the problems abrasive wear [4,14], but noise and vibration to disrupt the process of braking and comfort during this process [12]. There are many models that describe the vibrations generated by the braking systems which include Rudolph and Popp model [17], North [16] and Millner [21] (flutter binary model In contrast, a separate issue is the brake vibroacoustic diagnostics designed to diagnose selected brake components.…”

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.…”