On higher complexity for interface/contact laws with arbitrary anisotropy - development of numerical models and their experimental validations.

• Applicant: Professor Dr.-Ing. Karl Schweizerhof
• Subject Area: Mechanics
• Term: from 2009 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 133672527

Forces of various nature, e.g. elastic, viscoelastic, plastic forces, are observed during the contact interaction of bodies in the most general case. These forces are reflecting the real structure and the properties of a rough surface. Sliding friction forces and so-called adhesion forces are the main me-chanical characteristics to describe contact interaction. They are representing 2D surface constitutive laws in analogy to elasto-plasticity for 3D continuum. A key to the generalization of the construction of various interface contact laws (besides e.g. the well known Coulomb friction law) is based on proper combinations of known constitutev relations for elasticity, plasticity, viscosity etc. in completely nonlinear form. These combinations can be obtained with regards to main thermodynamical principles leading to the principle of maximum dissipation expressed in the arbitrary surface metrics in covariant form. This leads to a set of a-priory stable numerical algorithms including various combinations of the decoupled interaction in both normal and tangential directions. The focus in the project will be on constitutive relations in the tangential direction, where equations for the elastic region – in nonlinear form – represent the tangential adhesion – reflecting the surface structure – and plastic laws, also in nonlinear form, represent frictional interaction. An important issue of the project is the verification based on homogenization and multi-scale tchniques. For the micro-level a model with exact asperities possessing a certain global geometrical structure is taken while the derived surface interface model is taken as an average model for the macro-level to achieve a model usable in large scale computations. A set of experiments will be provided to define global macro-characteristics of the developed averaged model such as the structures of the adhesion tensor as well as of the friction tensor.

• DFG Programme: Research Grants
• Participating Person: Professor Dr. Alexander Konyukhov