A Survey of the Present State of Friction Modelling in the Analytical and Numerical Investigation of Brake Noise Generation

Abstract

Noise and vibration have become key issues in the design of automotive braking systems. Efforts to improve present day braking systems must take noise and vibration behaviour into account. Good knowledge of the mechanisms involved in the generation of brake noise has thus become an important competitive factor in the design of automotive brake systems. The present paper summarizes some facts and hypotheses concerning the generation of brake noise. First the different brake noise phenomena are classified. Then several approaches, including models of various levels of detail which have been suggested to explain the root causes of brake noise generation are discussed in detail. It will be pointed out that friction and wear processes at the interface of brake pad and rotor play an important role in the understanding of brake noise generation. Unfortunately, our present day knowledge on these processes is quite limited. Further research of basic processes is still needed to improve the quality of analytical and numerical models of friction and wear processes, before reliable predictions of brake noise generation become possible. Based on a discussion of simple models frequently used in engineering practice, guidelines for further research in tribological modelling of the interface processes in pad/rotor interaction will be formulated.

A Cellular Automaton model to describe the three-dimensional friction and wear mechanism of brake systems

“…Tab. 4 shows the measured values sorted by the zones. There is no outstanding zone recognizable, so for interpretation reasons we summarize the zones into top -middle -bottom (Tab.…”

“…14). This course of action allows interpretations of possible differences in the run-in (3,6,9) and run-out side (1,4,7) of the pad as well as the influence of the minor relative velocity at the lower part of the pad (7,8,9) related to the upper part (1,2,3).…”

“…Macroscopic models of brake systems, such as FEM-models, e.g. [1], KIRCHHOFF-plate assumptions [2] and complex multibody systems [3] have been successfully introduced computing characteristic modes corresponding with several oscillation-phenomena, for example the squealing (also see [4], [5], [6]), the judder (also see [7] [8]) and the hot spots (also see [9] [10]). All these phenomena are primarily caused by lateral mechanisms.…”

Friction-induced noise in drum brakes: finite-element modeling and experiments with special focus on damping

“…The lining consisting of several components [54] shows a nonlinear and transversal isotropic material behavior [63,68]. There is an anisotropy, meaning that characteristics in out of plane direction are different than in in-plane direction [55].…”

New insights into the tribology of brake systems

“…In the past decade, many scientists from universities and industry were researching the origin of brake noises [1], especially squealing. Measurements of the natural modes of running brake systems [2] as well as eigenvalue analysis approaches based on finite element method (FEM) models [3][4][5] together with mode-coupling investigations [6], multibody systems [7], and Kirchhoff plates [8] have been allowed to detect the squealing-relevant oscillations and to implement constructive changes to reduce it.…”