Vol 38, No 3 (2017)

The parameter of the wear law of bronze coupled with steel under dry friction is identified by comparing the results of mathematical modeling with experimental data. The wear tests were carried out according to the steel-ball–flat-bronze sample scheme under relative reciprocal sliding of the tested samples. The modeling of the wear of the sample was based on asymptotic behavior of the solution of the corresponding wear-contact problem. The effectiveness of using this asymptotic behavior to identify the wear law based on the tribological test results has been demonstrated.

A vibroplatform model has been presented, which is used in industry for the separation and transportation of granular materials. An analysis of the results of theoretical and experimental studies of the coefficient of friction between the screen and sand granules has been carried out in real operating conditions of the vibroplatform.

As the most common example of multiple-support shafts, the crankshaft of a multicylinder internal combustion engine (ICE) resting on the supports with journal bearings operating in steady-state regimes under the conditions of hydrodynamic lubrication has been considered. It has been taken into account that the supports can be deformed elastically causing a bending of the shaft, the deviation of shaft journals, and the change in the working conditions of the bearings up to the occurrence of the regime of mixed lubrication. Methods of estimating the performance of the tribosystem have been described.

A hydroabrasive wear analyzing apparatus has been developed which makes it possible to study wear resistance of various materials and coatings in hydroabrasive flow simulation. The paper shows efficiency of the developed apparatus for testing various materials and coatings being subject to hydroabrasive effect. After a 96-h test, the developed apparatus obtained comparative characteristics of the resistance to hydroabrasive wear of fiberglass pipes with and without polyurethane coating.

The paper presents the study of the operation of the prototype of the dual leaf spring that consists of a four-leaf main spring and a two-leaf auxiliary spring under the action of a cyclic load close to the actual operating conditions of a car suspension. The importance of friction in an operation of this type of structure has been mentioned; numerical methods and an experimental facility for studying the effect of friction on the spring operation have been considered. The investigation results have been presented in the form of summary tables, color-coded images, and diagrams of the temperature distribution for measuring points located on single leaves of the double spring. The methodology of experimental studies and the used equipment made it possible to evaluate the effect of friction and accompanying thermal stresses during the operation of the dual leaf spring.

This article discusses the development of procedure and assembly for testing metals and alloys for abrasive wear at ambient and higher temperatures of up to 600°C. The procedure can be applied both to evaluate the operating properties of alloys used to clad of machine parts and tools of metallurgical and refractory purposes, and to test various metal and composite materials. The wear of alloys as a function of temperature, the pressure on specimen, and its shape, as well as of the composition and dispersity of abrasive mass have been determined. Hardness and wear resistance of some experimental and commercial alloys have been presented, and the influence of alloy doping and modifying on their wear resistance at higher temperatures has been established.

The results of research focused on the specifics of frictional interaction between contacting surfaces of radial seal working in the environment with high abrasive content have been presented. The effect of the abrasive penetration through sealing during its axial play on the shaft, called the pumping effect, which results in the wear of the sealed friction joint parts and leads to the premature failure, has been found.

Micro- and nanocrystalline uniform diamond coatings with barrier tungsten layers for improved adhesion were deposited in a microwave plasma from methane-hydrogen mixtures on cemented carbide WC–6% Co substrates with high aspect ratios. Dynamic study of cutting forces and sliding friction has shown a significant improvement in the tribological properties of diamond-coated tools in cutting highly abrasive materials, such as A390 silumin and carbon-carbon composites. Confocal Raman spectrometry has been used to examine the features of wear mechanism in nano- and microcrystalline diamond coatings deposited in a microwave plasma.