Full-Scale Dynamometer Tests of Composite Railway Brake Shoes: Effect of the Resin-Rubber Ratio on Friction Performance and Wear

Abstract

Designing a friction material for a brake system entails considering the effects of each constituent and the interactions that they may present between them. In the present work, a characterization of the influence of the resin-rubber ratio in a brake block material is carried out. Railway brake shoes were produced and tested in a full-scale railway dynamometer in demanding conditions. The brake blocks had also their physical and mechanical properties tested. The progressive addition of resin was proven to heavily affect the friction level in dry and wet conditions. Interestingly, the use of 5% of resin showed significantly higher friction in wet conditions. This composition also presented more severe metal pick-up. The nature of the binder also affected wear rates (which were lower for lower resin contents), and the wear mechanism. The sample using only rubber presented thermal cracks and heavier delamination as specific failure modes. Differences on the microstructure of the friction materials were observed depending on the binder. A 5% of resin appears as a very interesting choice to avoid friction loss in wet environments without incurring in high wear rates, as long as metal pick-up is by different means diminished. Otherwise, a 100% of rubber as a binder grants the instantaneous friction stability that is often threaten by thermal fade.

Braking distance prediction for vehicle consist in low-speed on-sight operation: a Monte Carlo approach

“…[20] for wear. Other studies focus on single ingredients of the brake block [21,22], or on the behaviour under different weather conditions [23].…”

Morphology and Composition of the Third Body on the Friction Surface of an Organic Composite Railway Brake Shoe

“…For example, although scholars such as Yin et al [20,21] and Ghosh et al [22] studied the morphology of third bodies, they did not study the composition. Monreal et al [23] studied the morphology and elemental composition of third bodies using scanning electron microscopy and energy spectroscopy; however, the structural changes of inorganic fillers were not studied.…”