International Journal of Applied Mechanics and Engineering
Technological problems related to the application of laser cutting machines are in insufficient knowledge of the laser technique application as well as due to absence of sufficiently reliable practical data and knowledge about the parameters influencing the work process itself. This paper gives results of the experimental research referring to the determination of cutting quality functions.
In the paper will be discussed problems, which have to be taken into consideration when tribological pairs are analysed in such machines and mechanisms like IC engines, toothed gears, gas turbines, presses and others. There will be also discussed tribological problems in micromechanisms. In such mechanisms could appear entirely different problems. They will occur in mechanisms of computers or players...
Machine parts failure during service life might be due to fatigue as well as due to wear of the surface layers of the parts in contact. Those two factors acting simultaneously can lead to intensification of failure process. In the paper the analytical estimation of that process based on the accumulation of the damages is presented. The hypothesis for estimation of the ultimate strength of machine...
In general, Magnetic Chip Detectors (MCD) are used to collect ("catch") ferrous debris for further analysis. The analysts should use microscopic examination of debris morphology characteristics such as shape, size, color, surface texture, thickness ratio, and edge detail as their principal analysis technique. Wear debris is also quantified and trends are plotted to support the visual examination...
The effect of MoDTC with and without ZnDTP on reduction in friction and wear was determined under partial EHL conditions with a two roller machine, where the experiments were conducted using polyalphaolefin (PAO), polyol ester (POE), and their blended oils as the base fluids. When using PAO as a base fluid, a significant friction and wear reducing effect appeared at a low Mo concentration. On the...
Sn matrix soft overlays for the three-layer plain bearings were prepared by ECR-DC hybrid sputtering. Overlays with Vickers hardness between 5-20Hv, measured at loads of 49mN, were obtained by using pure Sn and Ag-Sn composite targets with Ag/Sn target area ratios of 0.5/44.5 - 6/39. The hardness of the overlays across the wear scar exhibited progressive increase due to densification of coatings and...
The influence of organometallic complexes on friction was investigated. 8-hydroxyquinoline and cadmium, cobalt and lead complexes were applied as additives to lithium grease. The influence of these additives on antiseizure properties of lithium grease was compared. Dependence of friction torque on time for linearly increasing load was tested on a four-ball machine. The results show that the highest...
The behavior of hydrodynamic Newtonian lubricant film at the die-workpiece interface in plane strain forging, when the conduction and convection mode of heat transfer is taking place has been theoretically investigated. A complete analysis of plane strain forging process for the case when die extends beyond the workpiece is developed. Viscous shear in the film, friction between the tool and the workpiece...
Bionic coatings have wonderful mechanical properties, and are used in micro-electronic mechanical systems (MEMS) as a method to prolong their service lives. The authors studied the design process and performances of a kind of bionic coatings. The mechanical properties of different integrated coatings were analyzed with a finite element method. Two kinds of systems, i) with gradient coatings and ii)...
The experience in application of electro sensitive fluids in rubbing interfaces is discussed. The electric field is used for managing the thickness of the lubricant layer.
In presented in this paper method of determination of resistances coefficient, theoretical distribution of load inside the bearings was assumed as input base into consideration. Results of experimental researches were used too. Functions of influence of some constructional features of bearing's elements on torque of resistance to motion were determined on their base. The mathematical model which approximates...
This paper describes the model of the FEM based calculation of leakage through the movable surfaces in the plunged pair. Taking into account that the average gap is far smaller than the diameter of plunger, the investigation was limited by the flat model of the operating media flow.
Application of alternate fuel in I. C. engine is a result of petroleum energy limited resources. CNG, LPG, Methanol, Alcohol etc. gaseous fuels are found feasible either in gasoline or diesel engines. All gaseous fuels are resulted better with respect to emission pollutants. 17-18% frictional losses are found in any I.C. engine. 40-45% of total frictional loss is due to PRA. Scope of research work...
The special features of electrorheological control over effective viscosity of dilute suspension with axisymmetric rigid suspended particles in a simple shear flow using a cross electric field are investigated. It is demonstrated that if the suspension carrier fluid is anisotropic then the orientation of suspended particles under the action of hydrodynamic forces and forces of electric field can lead...
Analytical calculations of pressure and velocity components in human hip joint for synovial unsymmetrical fluid flow are presented in this paper. Following assumptions are taking into account: unsteady, isothermal and incompressible synovial unsymmetrical non Newtonian synovial fluid flow, rotational motion of bone head, variable magnetic field and constant synovial fluid density. The method of solutions...
Hydrophilic properties upon electrophysical treatment of UHMWPE have been estimated and optimum regimes of such treatment have been determined. Variation kinetics of water receptive capacity on the sample surface has been defined and dynamics of spontaneous extraction of introduced into the microporous matrix drugs has been studied.
In this study, fluid flow behavior in microchannel is examined because of its relevance to the design and development of micro-devices. Previous research has indicated that micropolar fluid theory may provide a better model of fluid flow in microfluidic devices than classical Navier-Stokes theory. An analysis of the plane Couette flow between two parallel plates of a viscous, incompressible, micropolar...
Concepts of approximating endoprostheses to natural joints are stated, namely application of polymer units similar to natural cartilage, generation of electret charge on the polymer members and transformation of the metal unit into a source of magnetic field.
In the paper characteristics of mechanical and tribological properties of materials applied in biomedical engineering have been given. It has been taken note of a high difference in modulus of elasticity of metal materials applied in endoprostheses and modulus of elasticity of bone. Test results of friction coefficient and wear of materials applied in endoprostheses have been given.
The main purpose of presented work was to describe basic tribological properties of Fe-Al intermetalics depending on their structure and selected mechanical properties. Two different kind of intermetallic alloys with predominant contents of Fe3Al or FeAl intermetallic phases, in as-cast, homogenized or softened conditions were investigated by microstructure and chemical analysis, microhardness measurement,...