This application-oriented book introduces the associations between contact mechanics and friction and with it offers a deeper understanding of tribology. It deals with the associated phenomena of contact, adhesion, capillary forces, friction, lubrication, and wear from one consistent viewpoint. The author goes into (1) methods of rough estimation of tribological quantities, (2) methods for analytical calculations which attempt to minimize the necessary complexity, (3) the crossover into numerical simulation methods. With these methods the author conveys a consistent view of tribological processes in various scales of magnitude (from nanotribology to earthquake research). Also, system dynamic aspects of tribological systems, such as squeal and its suppression as well as other types of instabilities and spatial patterns are investigated. This book contains problems and worked solutions for individual chapters in which the reader can apply the theory to practical situations and deepen the understanding of the material.

The paper is devoted to the contributions of Coulomb and Amontons to the physics of friction from the viewpoint of current discussions and attempts to formulate generalized laws of friction.

This open access book contains a structured collection of complete solutions of all significant axially symmetric contact problems. It provides solutions for classical profiles such as the sphere, cone or flat cylindrical punch as well as a multitude of other technically relevant shapes, e.g. the truncated cone, the worn sphere, rough profiles, hollow cylinders, etc. Normal, tangential and torsional contacts with and without adhesion are examined. Elastically isotropic, transversally isotropic, viscoelastic and functionally graded media are addressed. The solutions of the contact problems cover the relationships between the macroscopic quantities of force and displacement, the contact configuration as well as the stress and displacement fields at the surface and in some cases within the half-space medium. The solutions are obtained by the simplest available method – usually involving the method of dimensionality reduction or approaches of reduction to the non-adhesive normal contact problem. The target audiences This book is geared towards engineers working in e.g. mechanical engineering, the tire industry, the automotive industry, polymer- and elastomer manufacturing. Additionally, it functions as a reference work for research and teaching. Prof. Dr. rer. nat. Valentin L. Popov studied physics and obtained his doctorate in 1985 from the Lomonosov Moscow State University. He habilitated 1994 at the Institute of Strength Physics and Materials Science of the Russian Academy of Sciences. Since 2002 he has headed the Chair of System Dynamics and Friction Physics in the Institute of Mechanics at TU Berlin. Dr. Markus Heß studied Engineering Science at TU Berlin. He obtained his doctorate in 2011 and in the same year received the research award of the German Tribology Society for his dissertation. From 2011 to 2015 he headed the physics department of the preparatory college of TU Berlin and since 2015 has been working as an assistant professor at the Chair of System Dynamics and Friction Physics. M.Sc. Emanuel Willert studied Engineering Science at TU Berlin and the Tomsk Polytech-nic University. Since 2015 he has been working as a research assistant at the Chair of System Dynamics and Friction Physics.

Design of attachment devices in insects varies enormously in relation to different functional loads. Many systems, located on different parts of the body, involve surfaces with particular frictional properties. Such systems evolved to attach parts of the body to each other, or to attach an insect to the substratum by providing fast and reversible attachment/detachment. Among these systems, there are some that deal with predefined surfaces, and others, in which one surface remains unpredictable. The first type of system occurs, for example, in wing-locking devices and head-arresting systems and is called probabilistic fasteners. The second type is mainly represented by insect attachment pads of two alternative designs: hairy and smooth. The relationship between surface patterns and/or mechanical properties of materials of contact pairs results in two main working principles of the frictional devices: mechanical interlocking, or maximization of the contact area. We give an overview of the functional design of two main groups of friction-based attachment devices in insects: probabilistic fasteners and attachment pads.

Using the boundary element method, we calculate the normal interfacial stiffness and constriction resistance of two elastic bodies with randomly rough surfaces and varying fractal dimensions. The contact stiffness as a function of the applied normal force can be approximated by a power law, with an exponent varying from 0.51 to 0.77 for fractal dimensions varying from 2 to 3.