A method to estimate material data for rubber compounds with the aid of finite-element models

Abstract: To have reliable experimental data when forming mathematical models has always been an important aspect within numerous fields of engineering. Specifically, working with models concerning the contact between road surface and tyre, it is vital to have knowledge of the mechanical properties of the rubber compound in the tyre. Values given in tables may not always be completely accurate. The aim of this thesis is to present and evaluate a method of investigating dynamical material properties of rubber compounds, i.e. viscoelastic materials.The fundamental principle of this method is a velocity profile comparison. The response of a sinusoidally excited, beam-like rubber sample is measured along the sample with a laser Doppler vibrometer. A velocity profile is interpolated from the solution of a finite-element model. The error that arises from the comparison is minimized using a gradient descent algorithm that continuously updates the material data the finite-element model. The method proposed successfully determines stiffness and damping over a broad frequency range. Results depict good agreement of the velocity profiles, and independent measurements indicate repeatability of the method. The limits of the methods seems to be governed by measurement accuracy.