Initial Penetration of an Elastic Axially Symmetric Indenter into a Rigid-Perfectly-Plastic Half-Space

This paper is concerned with the axially symmetric plastic flow of a rigid perfectly-plastic nonhardening halfspace. The initial penetration of the elastic indenter is studied based on Haar and von Karman hypothesis. The analytical distribution of contact stress and the approximate penetration depth of the indenter are obtained

Contact Displacements of Spatial Contact of a Rough Body and a Body with Coating

This paper is an example of the application of a structural nonlocal theory to the solution of the contact problem of a rough curvilinear body with plastic coating on another body. The main goal of these investigations is the creation of extrapolation methods of results of theoretical investigations from flat surfaces to any tribological system with curvilinear macro surfaces. This paper deals with the application of a phenomenological approach which is based on using the middle layer. It allows to represent a contact problem for real bodies as a superposition of two problems. The first one is the problem of penetration of rigid roughness in a plastic coating taking into account statistical characteristics of the surface. The second problem is the elastic deformation of smooth bodies with a circular area of interaction. The external load is supposed to be constant. The solution is obtained with the help of the contracting mapping principle and a simple iteration method. It is established that the first analytical approximation of solutions of the corresponding equations is useful for practical applications with sufficient accuracy. The paper deals with the case of plastic penetration of a surface asperity only when the macro contact stress is less than the yield stress of the coating, i.e. without macro plastic penetration of curvilinear bodies into this coating

Arbitrary Penetration of a Rigid Axially Symmetric Indenter into an Axially Heterogeneous Rigid-Perfectly-Plastic Half-Space

This paper is concerned with the axially symmetric plastic flow of an axially heterogeneous rigid-perfectly-plastic nonhardening half-space. The directions of heterogeneity coincide with the axis of symmetry of indenter and the radial direction in cylindrical frame of references. The arbitrary depth of penetration of the rigid indenter is studied on the basis of the Haar and v. Karman hypothesis. The analytical distribution of contact stress is obtained. It allows for taking into account the local adhesion of an indenter surface and the surface of the half-space. The conical indenter is investigated as a particular case. The dependence between the applied force and the penetration depth of the conical indenter for several cases of heterogeneity is determined

Investigation of micro/nanomechanical and micro/nanotribological behaviour of materials, in particular ultrathin films

Przedstawiono metody i niektóre wyniki badań materiałów, w szczególności ultracienkich warstw, umożliwiając ocenę ich własności mechanicznych i zachowania się trybologicznego w skali mikro/nano. Wyniki tych badań są w szczególności przydatne przy budowie mikrosystemów elektromechanicznych (MEMS - Micro Electro Mechanical Systems) i urządzeń do magnetycznego zapisu informacji (twarde dyski).The methods of investigation and some results relating to the micro/nanomechanical and micro/nanotribological behaviour of materials, in particular ultrathin films, are discussed. The results of such studies are applicable in particular in the construction of Micro Elecro Mechanical Systems (MEMS) and devices for magnetic recording (hard disks)