Title: Study on a test rig of dynamic tyre/road contact forces at the origin of rolling noise
Abstract:The dynamic contact models for tyre/road noise are often based on a quasi-static assumption and a half-space approximation for the tyre. The aim of the thesis is to assess these assumptions by measuri...The dynamic contact models for tyre/road noise are often based on a quasi-static assumption and a half-space approximation for the tyre. The aim of the thesis is to assess these assumptions by measuring contact forces on a test rig composed of a smooth reduced-sized tyre rolling on a cylindrical basis. Beforehand, the experimental modal analysis of the tyre allows the identification of eigenmodes of classical shapes. Although a finite element model based on a homogeneous elastic tyre section yields satisfactory modes, a hyper-viscoelastic heterogeneous section provides a good compromise between vibrations and static contact. The dynamic contact force on a single spherical or conical asperity during rolling of the tyre is then measured. The relationship between the maximum force and the height of the asperity is consistent with theoretical contact laws. The contact duration on the asperity is inversely proportional to the speed. The contact calculations based on an elastic half-space assumption lead to a proper estimation of the maximum force measured on high asperity heights, but not on low asperity heights. The dissymmetry of the force time signal is well modelled by introducing the viscoelasticity in the model. The dynamic contact forces measured between the tyre and several asperities of simple shapes confirm the previous results, demonstrating the quasistatic nature of the rolling contact. However, the calculated forces are underestimated at the edges of the contact area, showing a limitation of the half-space assumption to describe the tyre structure.Read More