Adjustment of Friction Models in Elastomers Using the Finite Element Method and Model Updating Techniques

Abstract

AbstractDefining the best friction model in elastomers for studies with the Finite Element Method (FEM) is a complex task. Hyper-elastic materials have a non-linear mechanical behavior that favors the storage and transfer of deformation energy in an unpredictable way when they are subjected to an external action. This abrupt change determines unpredictable friction coefficients and even with negative values. Furthermore, the coefficient of friction depends on the surface and the contact pressure. This article shows the process of adjusting a friction model based on the MEF according to the standardized test UNE-EN ISO 13287 for the characterization of friction in shoe soles. Using “model updating” techniques, a search was made for the most appropriate friction model for a specimen made of nitrile butadiene rubber (NBR). Five friction models based on Coulomb and Shear together with hexahedral and tetrahedral elements with different mesh sizes, contact pressure and sliding speed were studied according to a Design of Experiments (DoE) and validated experimentally. The best friction model obtained in this case was the Coulomb model with a hexahedral element size of 0.5 mm.KeywordsFriction modelsElastomersHyper-elasticFEMFootwear