Acta Mech 221, 119–132 (2011) DOI 10.1007/s00707-011-0490-2 L. V. Vanegas-Useche · M. M. Abdel-Wahab · G. A. Parker Determination of friction coefficients, brush contact arcs and brush penetrations for gutter brush–road interaction through FEM Received: 21 August 2010 / Published online: 4 May 2011 © Springer-Verlag 2011 Abstract A 3-D, dynamic, non-linear Finite Element Model (FEM) involving contact is used to determine apparent coefficients of friction, μ, for the interaction between the bristles of a flicking brush for street sweeping and concrete. Also, brush contact arcs, as well as suitable brush penetrations as functions of the debris height, are determined for cutting and F128 brushes. Available experimental results are used to determine the coeffi- cients of friction. The bristles are modelled through beam elements, which are subjected to inertia forces. The results suggest that the model is valid and that the coefficient of friction affects the brush vertical force in the flicking brush, but it does not significantly affect its counterpart in the cutting brush. The results also indicate that the coefficient of friction for the flicking brush depends on the sliding velocity, v, and these were fitted to an exponential μ - v curve. 1 Introduction Street sweeping is an important service that is commonly performed by lorry-type vehicles. Sweepers normally comprise a suction system and/or a wide broom, as well as a small brush on the side of the vehicle that sweeps the debris from the gutter towards the path of the suction nozzle or wide broom. Gutter brushes have a cup-like form and may consist of steel wire bristles of rectangular cross section, arranged into one or more rows of clusters. Two types of commercial brushes are the cutting brush, typically used for compacted debris, and the flicking brush, which might be used for light debris such as leaves. The performance of these brushes is particularly important, as about 80% of the debris is found in the gutter [1, 2]. The performance depends on a number of parameters that are classified as material properties, geometric parameters and operating variables. The geometric parameters of gutter brushes are provided in Fig. 1a and Table 1 (first column). The bristle mount angle, φ, is the angle between the bristle axis and the mounting board normal (Fig. 1a). The bristle mount orientation angle, γ , defines the action of the bristles. In a cutting brush (Fig. 2a), the rectangular cross-section of the bristle is orientated so that it deflects mainly in the radial direction of the brush. This configuration provides a stiff bristle–debris collision. In a flicking brush (Fig. 2b), the bristles deflect predominantly in the tangential direction, flicking through debris. Two types L. V. Vanegas-Useche(B ) Facultad de Ingeniería Mecánica, Universidad Tecnológica de Pereira, La Julita, Pereira, Colombia E-mail: lvanegas@utp.edu.co Tel.: +576 3137124 Fax: +576 3137362 M. M. Abdel-Wahab Department of Mechanical Construction and Production, Faculty of Engineering, Ghent University, 9000 Ghent, Belgium G. A. Parker Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK