Modeling, Experimental Analysis and Stability of Systems with Anisotropic Dry Friction

Anisotropic friction occurs in a variety of technical applications. It is characterized by a dependence of the magnitude as well as the direction of the friction force on the sliding direction. To date, no generally accepted anisotropic friction law exists and the influence of anisotropic friction on the dynamics of mechanical systems is largely unknown. This work is concerned with the formulation of friction laws, the stability of mechanical systems with friction and the experimental investigation of anisotropic frictional behavior.
Due to the different behavior of stick and slip, the constitutive description of friction leads to set-valued force laws, which can often be expressed as normal cone inclusions. This formulation allows for the direct implementation in numerical time-stepping schemes. Various mechanisms of isotropic friction induced instability are known. Here, the influence of anisotropic friction on the stability of equilibria is examined. In previous experimental investigations of anisotropic friction, the fact that the friction force is not always acting parallel to the sliding direction is often neglected. In this thesis, experimental setups are developed that enable a detailed analysis of the frictional behavior. The gained knowledge contributes to an increase in the accuracy of numerical simulations of nonsmooth mechanical systems.