Study on the influence of radial stiffness on the nonlinear vibration of brake system

Abstract

Purpose A dynamic model of the brake system considering the tangential and radial motion of the pad, and the torsion and wobbling motion of the disk is established in this paper. The influence of radial stiffness on the brake system is investigated under different tribological conditions. This paper aims to prove that sufficient radial stiffness is indispensable in the design of the brake system with good tribological performance. Design/methodology/approach By using the lumped mass method, a dynamic model of the brake system is established. A Stribeck-type friction model is applied to this model to correlate the frictional velocity, pressure and friction force. The stability of pad vibration is analysed by analysis methods. A new stability evaluation parameter is proposed to study the influence of radial stiffness on stability of pad vibration in a certain friction coefficient brake pressure range. Findings The findings show that the tangential vibration of the pad transits from periodic motion to quasi-periodic motion under a low tangential stiffness. The influence of radial stiffness on motion stability is stronger under a low nominal brake radius. The stability of the brake system can be ensured when the brake radius and radial stiffness are sufficient. Originality/value The influence of tangential stiffness of pad on stability of the brake system has been researched for decades. The insufficiency of stiffness in radial direction may also generate certain levels of instabilities but has not been fully investigated by modelling approach. This paper reveals that this parameter is also strongly correlated to nonlinear vibration of the brake pad.

Analysis of key brake pad parameters on brake system stability

“…The friction model is required to simulate a continuous friction coefficient curve. Hereby, this paper adopts the Stribeck-type friction model (Yan et al , 2021) to predict frictional force at different friction velocities. Notably, this model avoids divergence when v r approaches 0, thus enhancing the computational efficiency: …”

“…As speed increases, the motion of the brake pad transitions from a single-period vibration to period-doubling bifurcation, entering a chaotic state and eventually devolving back into a single-period vibration (Wei et al , 2019). Yan et al (2021) established a brake system dynamics model that considered the tangential and radial movement of the brake pads and the torsional and swaying motion of the disc. They explored the impact of radial stiffness on the brake system under different friction parameters.…”

Study on Service Vibration Characteristics of High-Speed Train Disc Brake under Thermo-Solid Coupling

“…The results showed that the brake vibration was aggravated by the increase in the braking load and speed. Yan et al [19] studied the effect of radial stiffness on the vibration stability of a disc brake system under different friction conditions. Wang et al [20] established a rigid-flexible vehicle dynamics model and a finite element model of the braking system.…”