Validation of EHL contact predictions under time varying load

Abstract: In this paper, it is investigated how accurately current models predict the response of an elasto-hydrodynamically lubricated contact to time varying load conditions. For two patterns of time varying load, under conditions of pure rolling, the results obtained experimentally on a ball on disk interferometry apparatus by Sakamoto et al. (Behaviour of point contact EHL films under pulsating loads. Proceedings of the 30th Leeds–Lyon Symposium on Tribology, Elseviers Tribology Series, Vol. 43, pp. 391–399) are compared with the results of numerical simulations using the dynamic contact model of Wijnant (Contact dynamics in the field of elastohydro

The influence of the horn effect in tyre/road noise

The horn effect is known as an important amplification mechanism in tyre/road noise. The name is referring to the geometry between tyre and road surface which resembles an exponential horn. The horn effect is a common subject for both experimental and numerical research. Contrary to previous studies which considered point sources, this paper focusses on the horn effect by simulated tyre vibrations. The amplification of acoustic pressure, however, depends largely on the location of the observer. The sound power can be used as a measure for the horn effect which is independent on the point of observation. In this paper, the sound radiation problem is solved using the boundary element method (BEM). First, a case study considering equivalent point sources is used to validate the accuracy of the boundary element model and solver using experimental results. Next, the vibrations of tyres rolling on textured road surfaces are investigated numerically. The computed tyre vibrations are used to study the horn effect using different tyre designs. The amplification by horn effect is determined by the combined tyre/road geometry and the distribution of the noise. The current method may be used to systematically study the influence of the horn effect, for example, during tyre development

A numerical study of a method for measuring the effective in situ sound absorption coefficient

The accuracy of a method [Wijnant et al., “Development and applica- tion of a new method for the in-situ measurement of sound absorption”, ISMA 31, Leuven, Belgium (2010).], for measurement of the effective area-averaged in situ sound absorption coefficient is investigated. Based on a local plane wave assump- tion, this method can be applied to sound fields for which a model is not available. Investigations were carried out by means of finite element simulations for a typical case. The results show that the method is a promising method for determining the effective area-averaged in situ sound absorption coefficient in complex sound fields