Analysis of tribological properties of precise contact pairs

The aim of the presented research work is to investigate the possibilities of improving the tribological efficiency of different friction pairs by surface processing to obtain different roughness values and by modifying the friction surface with fluoroligomeric materials. Wear resistance and friction reduction abilities of precise friction pairs could be improved by the modification of their friction surfaces by surface processing to obtain a particular roughness level and by means of surface modification with fluoroligomeric materials. Tribological experiments of sealing friction pairs demonstrate that there is an optimal friction roughness magnitudes which results in the lowest friction coefficient and wear. The use of fluoroligomeric materials in such friction pairs could reduce the friction and wear of the shaft (up to 1,5 times). Fluoroligomeric materials can increase the serviceability of precise plunger pairs and the service life of the dies used for wire tensioning up to 4 - 6 times. These research results are the background to start the investigations aimed at improvement of the tribological properties of different high-precision friction pairs

Tribological evaluation of nano-composite coatings in piezoelectric contact

Piezoelectric micro-engines (PEA) are used in precise positioning equipment in medical, measurement applications, space engineering etc. Tribological processes in the friction contacts of such actuators are very important because efficiency of PEA friction pairs is influenced by roughness and hardness of the surfaces. Studies indicate that friction pairs for the reliable constant operation of PEA could be developed when using surface materials of different roughness and hardness. These parameters could be controlled by application of metallic carbides and oxides as plasma coatings. The use of tribo-active materials can decrease volumetric wear of friction surfaces and increase the reliability of PEA

A new method of non-abrasive anti-friction finishing treatment (NAFP)

Vytauto Didžiojo universitetasŽemės ūkio akademij

Rheological Properties of the Contact of the Tribosurface

Bibliogr.: p. 153 (11 pavad.)Vytauto Didžiojo universitetasŽemės ūkio akademij

Techninių paslaugų žemės ūkyje plėtra : rekomendacijos

Vytauto Didžiojo universitetasŽemės ūkio akademij

Thermal and stress-strain state of friction pairs in ventilated disc brakes of lightweight vehicles

The work is dedicated to the thermal behavior and stress-strain state of ventilated disc brakes installed in the lightweight vehicles (scooters, electric bikes, ATVs, etc.) using ANSYS environment in various experiment modes. Modeling of the temperature distribution in the rotor (disc) and the corresponding brake pads is determined taking into account a number of factors and input parameters during the braking operation: the amount of rotation speed, the gap between the pads and the disc, the speed of load application, thermal expansion, etc. Numerical modeling of the transient thermal and the stress fields in the area of contact between the pads and the rotor is carried out by the method of sequential thermostructural connection of the intermediate calculation states of the brake model in the ANSYS Coupled Field Transient environment. For a comprehensive assessment of brake behavior, our research considers two load approaches: constant long-term (20 s) with an influence factor in the form of thermal expansion as a result of contact pair friction; linear load from the pads on the disс with a corresponding increase in pressure up to the moment when the rotation of the system is blocked. Our research presents an assessment of the rotor ventilation channels influence on the nature of the contact spot with the brake pads (open far-field contact, sliding contact, sticking contact, etc.). In addition, it is demonstrated that despite the linear increase in pads pressure on the rotor, the graphs of temperatures, volume (thermal expansion) and stresses are of parabolic character with a disproportionate increase in indicators. Such a result forces us to come to the conclusion that it is not possible to predict the behavior of the brakes based on the analysis during a short period of time of the experiment - conducting long-term analytical studies is extremely important in the case of brake

Participation of suspended nanoparticles in tribofilm formalion

Vytauto Didžiojo universitetasŽemės ūkio akademij

Naujo neabrazyvinio antifrikcinio išbaigiamojo apdirbimo kūrimas ir tyrimas

Santr. anglVytauto Didžiojo universitetasŽemės ūkio akademij