ViVaCE „Virtual Materials and their Validation: German-French School of Computational Engineering” – IRTG 1627 Results Multiscale FEM for Rubber Friction on Rough Surfaces Motivation Prof. Dr.-Ing. habil. Dr. h.c. mult. P. Wriggers Goals Methods • Hysteresis: Internal energy dissipation due to cyclic loading and unloading, induced by the asperities of the rough surface • High contribution of small road track length scales (λ < 0.1 mm), see Persson.2010 Dipl.-Ing. P. Wagner 0% 20% 40% 60% 80% 100% Dry Wet Percentage μ(t) t ε σ Homogenization μ(p, v) p v Some aspects available in Wriggers/Reinelt.2009 μ(t) t [s] Finite Linear Viscoelastic Model A power spectrum of a surface is calculated Real surface approximated with a sum of sinusoidal waves Decomposition of reconstructed surface Real surf. Surface fit Macro Micro Simulation μ(v) vs. experiment, Grosch.1953 Finer and rougher models increase μ 2 1 0 μ log v Multiscale calc. Comparison Full calc. Coefficient of friction 0% 20% 40% 60% 80% 100% 120% t calc. μ Model represents qualitative behavior Prediction of frictional response Frictional response: Sum of physical influences Rough surface decomposition The Multiscale FEM concept Microscale results Numerical validation of the method Macroscale Hysteresis Adhesion Lubrication, Cohesion (not considered) Microscale Experimental Setup Coefficient of friction Frictional Force, guess Hysteresis friction is modeled → Significant influence of small length scales → Therefore Multiscale FEM Split in macro- and micro-part → Micro friction law → Include friction law in macro calculation Macroscale Microscale Reasonable results on microscale – Good agreement of multiscale and full simulation – 90% less calculation time • Multiphysics Homogenization Schemes for Microstructured Interfaces (N. Noii) • Development of Non-Convex Shaped Particles for the Discrete Element Method (DEM) (M. Hothan) • Application of Plasticity Models at the Contact Layer (C. Weißenfels) • Multi-Scale Constitutive Modeling of Carbon Black Reinforced Rubber in a Finite Strain Framework for FE Analysis (O. Stegen) • Development of a Friction Approach for the FE Method of Sheet Metal Forming Based on Multi- Scale Modeling (B. Homann) • hp-BEM for Contact Problems and Extended Ms- FEM in Linear Elasticity (A. Issaoui) ViVaCE-Projects with strong Interaction