Enhancing the tribological behavior of high-speed train braking interfaces and suppressing stick-slip vibration via the stacking of disc springs

Abstract

During low-speed braking of high-speed trains, the frictional interaction at the braking interface often triggers severe stick-slip instability, manifesting as friction-induced stick-slip vibration (FISSV). This generates sharp frictional noise and accelerates wear, causes block detachment, and compromises system stability, posing risks to operational safety. Thus, effective strategies are urgently needed to improve tribological behavior and suppress FISSV. Floating brake blocks based on disc spring structures have shown promise; however, the theoretical basis for optimizing spring number and stiffness remains insufficient. In this work, a floating friction block design with stacked disc springs is proposed to enhance tribological performance and vibration suppression. Comparative experiments were performed on a multifunctional friction test rig, evaluating a fixed connection and three disc spring configurations (2, 4, and 6 springs). Surface morphology characterization and finite element simulations were conducted to further reveal suppression mechanisms. Results show that floating structures consistently outperform fixed ones, yet suppression exhibits a nonlinear dependence on spring number. Among the tested configurations, the four-spring (SPR4) design delivered the most favorable performance: displacement, acceleration, and noise RMS values decreased by 35.68 %, 54.37 %, and 49.14 %, respectively, while friction force RMS increased by 41.5 %. SPR2 generated unstable adhesion-slip cycles, whereas SPR6 showed noise amplification at later stages. Mechanistic analysis demonstrated that suppression is achieved through a cooperative “moderate - compliance - hysteresis - uniform - redistribution” effect, with SPR4 forming stable contact plateaus and uniform stress distribution. These findings identify medium-stiffness floating structures as the optimal solution, offering theoretical and engineering guidance for the design of high-speed train brake pads.