The purpose of the presented paper is to optimize technological parameters of hardening high-energy processing used for sprayed coatings made of materials based on oxide ceramics with inclusions of solid lubricant. The paper presents results of the investigations on influence of power density and total number of laser irradiation impulses in a spot treatment on thickness of treated coating layers made of materials based on oxide ceramics. The considered wear-resistant coatings require increased cohesive and adhesive strength. Therefore, the total number of impulses should ensure melting and sealing of the coatings along the whole thickness that will fully contribute to obtain hardened nano-crystalline and amorphous structures.

The work is based on complex metallography, X-ray diffraction and electron-microscopic investigations on modified structural elements of composite coatings being treated with highly concentrated energy sources. The following main processes of hardened plasma coating formations have been revealed in the paper: com paction of sprayed materials due to thermal and shock-wave impacts of laser irradiation impulses. In this case material porosity is decreasing, cohesive and adhesive strength of coatings is increasing, grain structure is crushed, amorphous and nano-crystalline phases of higher strength are formed all these facts are evidenced by an increase in average micro-hardness of deposited compositions. Duration of thermal laser irradiation impulse impact on the material is sufficient to activate chemical processes in the boundaries of main phases of the composite coating. This leads to formation of finely dispersed (including nanoparticle size) compounds that strengthen boundaries of the main phases and the coating as a whole. This is confirmed by the results of an X-ray diffraction analysis.

An engine oil is capable reliably and longtime to perform specified functions only in the case when its properties correspond to those thermal, mechanical and chemical impacts to which the oil is subjected in the engine. Compatibility of the engine design, its uprate and oil properties is one of the main conditions for provision of high operational reliability. Type and properties of fuel, quality of an engine oil, engine type, its design, its health, its operational regime and conditions and a number of other factors influence on intensity of oil contamination in the operated engine. Oil quality is deteriorated due to accumulation of incomplete combustion products in it and this process is associated with the engine's health. This leads to reduction of viscosity, deterioration of lubrication ability, troubles in fluid friction mode. Combustion products have rather high amount of aggressive corrosive oxides.

Service-life of engine oil prior to its change is determined not only by automobile mileage or tractor operating time but also by the period of time within which this work has been carried out. Corrosion processes are speeding up, protective processes are worsening, oil ageing is accelerating when vehicles have short daily and small mileages. So it is necessary to change oil at least annually.

A new method for onboard monitoring of engine oil resource working-out rate in wheeled and caterpillar machines has been developed in the paper. Usage of fuel expended volume by engine while determining engine oil resource working-out rate makes it possible timely to assess a residual resource of the engine oil and also predict the date of its change at any operational period of wheeled and caterpillar machines.

The aim of the paper is to reveal and analyze resonance modes of a large-scale milling-drilling-boring machine. The machine has a movable column with vertical slot occupied by a symmetrical carriage with horizontal ram. Static rigidity of the machine is relatively low due to its large dimensions. So it is necessary to assess possible vibration activity. Virtual and operational trials of the machine have been carried out simultaneously. Modeling has been executed with the help of a finite element method (FEM). The FEM-model takes into account not only rigidity of machine structures but also flexibility of bearings, feed drive systems and guides. Modal FEM-analysis has revealed eight resonance modes that embrace the whole machine tool. They form a frequency interval from 12 to 75 Hz which is undesirable for machining. Three closely located resonances (31-37 Hz) are considered as the most dangerous ones. They represent various combinations of three simple motions: vertical oscillations of a carriage, horizontal vibrations of a ram and column torsion. Reliability of FEM- estimations has been proved by in-situ vibration measurements.

An effect for stabilization of resonance modes has been detected while making variations in design parameters of the machine tool. For example, a virtual replacement of cast iron for steel in machine structures practically does not have any effect on resonance frequencies. Rigidity increase in some parts (e.g. a ram) has also a small effect on a resonance pattern. On the other hand, resonance stability makes it possible to avoid them while selecting a spindle rotation frequency.

It is recommended to set double feed drives for all axes. A pair of vertical screws prevents a “pecking” resonance of the carriage at frequency of 54 Hz. It is necessary to foresee an operation of a main drive of such heavy machine tool in the above resonance interval with the spindle frequency of more than 75 Hz. For this purpose it is necessary to proceed to high-speed machining (HSM).

The objective of the paper is to develop a program, a methodology and execute vibration load tests of Common Rail fuel system components for a diesel engine. The paper contains an analysis of parameters that characterize vibration activity of research object and determine its applicability as a part of the specific mechanical system. A tests program has been developed that includes measurements of general peak values of vibration acceleration in the fuel system components, transformation of the obtained data while taking into account the fact that peak vibration acceleration values depend on crank-shaft rotation frequency and spectrum of vibration frequency, comparison of these dependences with the threshold limit values obtained in the process of component tests with the help of vibration shaker. The investigations have been carried out in one of the most stressed elements of the Common Rail fuel system that is a RDS 4.2-pressure sensor in a fuel accumulator manufactured by Robert Bosch GmbH and mounted on the MMZ D245.7E4-engines.

According to the test methodology measurements have been performed on an engine test bench at all fullload engine curves. Vibration measurements have resulted in time history of the peak vibration acceleration values in three directions from every accelerometer and crank-shaft rotation frequency.

It has been proposed to increase a diameter of mounting spacers of the fuel accumulator and install a damping clamp on high pressure tubes from a high pressure fuel pump to the fuel accumulator that permits to reduce a maximum peak vibration acceleration value on the pressure sensor in the fuel accumulator by 400 m/s² and ensure its application in the given engine.

Nowadays heavy vehicles constitute a considerable volume in the transportation flow on the territory of the Republic of Belarus and bridge inequalities significantly increase a load on their bearing elements and cause a vibration in bridge superstructures. This leads to rapid wear and reduction in time between bridge repairs. The given problem has been insufficiently studied and it is considered as an actual one. Revision of analytical models is required in order to make prediction and evaluation of bridge structure wear. These models must take into account a dynamic impact of heavy vehicles caused by their movement on bridge rough riding surface.

The purpose of scientific investigations is to develop a dynamic interactional model of a vehicle and a bridge plate. The paper proposes such dynamic model that permits to investigate impact forces of a heavy vehicle on bridge superstructures which have been initiated by bridge traffic-way inequalities. Weight of an vehicle and plate, rigidity and viscous damping of vehicle suspensions, a plate and piers have been taken into account while making the required calculations.

An analysis of free oscillatory motions of the plate and vehicle have been carried out with due account of viscous damping. A dynamic interactional calculation for a vehicle and a plate has been made in the paper. Character of plate oscillatory motions has been determined at various parameters of the dynamic model. In this case non-linearity of reinforced concrete plate deformation has been taken into account and its calculation has been executed in accordance with the norms of the Republic of Belarus. The calculations have made it possible to obtain dynamic interaction coefficients of front axle wheels and bridge plate at various bench heights and also investigate its influence on maximum bending moments in plate sections.

The purpose of the paper is to estimate an application of pulse-periodical mode for improvement of laser treatment efficiency. Laser technologies have been widely used in the processes of material treatment with the purpose to provide them the required surface properties and also for high accuracy cutting of sheet materials. Application of complex treatment is of great interest and especially when it is used for worn-out surfaces with formation of a coating by gas-flame laying of powder mixture of specific composition and subsequent laser fusion.

Increase of laser unit capacity is very important task for higher efficiency of laser technology application in mechanical engineering. Nowadays technological processes using lasers with high average power (more than 100 W) have been applying only sources that are working in two modes, namely: continuous and pulse- periodical (P-P) with pulse repetition rate from some units to several hundred hertz and pulse duration within dozens to hundreds of microseconds and even within milliseconds. On the other hand, in some cases shielding effect of plasma cloud formed during laser alloying, cladding or welding reduces the efficiency of laser treatment up to 50 % depending on plasma composition and laser beam length. High frequency P-P laser systems with high average power working in mode of Q-factor modulation allow to realize principally other mechanism of irradiation interaction with materials that is an ablation. In this case it is possible to provide local energy release both in space and time.

The performed analysis has revealed that P-P mode of laser operation for a majority of treatment processes is much better and more efficient from energetic point of view in comparison with the continuous mode. On the basis of the developments it is possible to make a conclusion that there is a possibility to create laser systems working in high frequency P-P mode with high average power above hundreds watt.

The paper describes development of the methodology for optimization of parameters for an additional operating force mechanism in a device for pneumo-centrifugal machining of glass balls. Specific feature in manufacturing glass balls for micro-optics in accordance with technological process for obtaining ball-shaped workpieces is grinding and polishing of spherical surface in a free state. In this case component billets of future balls are made in the form of cubes and the billets are given preliminary a form of ball with the help of rough grinding. An advanced method for obtaining ball-shaped work-pieces from brittle materials is a pneumocentrifugal machining. This method presupposes an application of two conic rings with abrasive working surfaces which are set coaxially with large diameters to each other and the billets are rolled along these rings. Rotation of the billets is conveyed by means of pressure medium.

The present devices for pneumo-centrifugal machining are suitable for obtaining balls up to 6 mm. Machining of the work-pieces with full spherical surfaces and large diameter is non-productive due to impossibility to ensure a sufficient force on the billet in the working zone. For this reason the paper proposes a modified device where an additional force on the machined billet is created by upper working disc that is making a reciprocating motion along an axis of abrasive conic rings. The motion is realized with the help of a cylindrical camshaft mechanism in the form of a ring with a profile working end face and the purpose of present paper is to optimize parameters of the proposed device.

The paper presents expressions for calculation of constitutive parameters of the additional operating force mechanism including parameters of loading element motion, main dimensions of the additional operating force mechanism and parameters of a profile element in the additional operating force mechanism.

Investigation method is a mathematical simulation of the operating zone of the device for pneumocentrifugal machining.

The paper considers an influence of a cutting zone cooling method on the chip shape and thickening ratio while turning R35 steel with the hardness of НВ 1250 МРа. Cutting with various types of cooling - dry, compressed air and emulsion fog has been investigated in the paper. OPORTET RG-2 emulsol with emulsion concentration of 4% has been used as an active substation. Cutting tool is a turning cutter with a changeable square plate SNUN120408 made of Р25 hard alloy with multilayer wear-resistant coating, upper titanium nitride layer. Front plate surface is flat. Range of cutting speeds - 80-450 m/min, motions - 0,1-0,5 mm/rev, emulsion flow - 1,5-3,5 g/min and compressed air - 4,5-7,0 m³/h, cutting depth - 1,0 mm. In order to reduce a number of single investigations it is possible to use plans based on ЛПх-sequences.

It has been shown that the method for cutting zone cooling exerts significant influence on conditions for chip formation. Regression equation describing influence of machining conditions on Ка-chip thickening ratio has been obtained in the paper. The range of cutting modes is extended while using emulsion fog for cooling. In the process of these modes chip is formed in the shape of short spiral fragments or elements. Favourable form of chips is ensured while using the following rate of emulsion - not more than 2 g/min. The investigations have made it possible to determine conditions required for cooling emulsion fog. In this case it has been observed minimum values in chip thickening ratio and chip shape that ensures its easy removal from cutting zone. While making dry turning values of Ка is higher not less than 15 % in comparison with other methods for cutting zone cooling.

The paper has investigated influence of various technologies on recycling of vegetal raw material with the purpose to obtain the desired product used for package printing. Influence of various technological regimes and introduction of fresh polyethylene additives for recycled raw material on qualitative indices of the desired product has been studied in the paper. Investigations of preliminary aquatic hydrolysis of vegetal raw material have shown that in order to obtain high quality cellulose from vegetal raw material it is necessary that this cellulose has not less than 2-3 % of hemicellulose otherwise its qualitative indices are significantly deteriorated that is important for packaging printing. Usage of carbon dioxide aqueous solution for preliminary vegetal raw material hydrolysis contributes to reduction in destruction of cellulose carbo-hydrate. This improves qualitative indices of the obtained desired product that is cellulose which is used for package printing.

Recommendations for sulphate pulping of vegetal raw material with preliminary hydrolysis have been prepared with the purpose to improve physical and mechanical characteristics of the obtained desired product - cellulose on the basis of the obtained data on content of hemicellulose in cellulose.

While investigating recycled polymers the obtained results have demonstrated that increase of low- molecular product content in them looks rather typical. This suggests that packaging will have lower qualitative indices while using polymers being kept in waste deposits. In order to avoid this phenomena it is necessary to add 20-30 % of fresh polymers during their recycling.

The purpose of the paper is to make an experimental impact assessment of parameters pertaining to blank two-dimensional circular blank motion on intensity of its cutting and quality of the machined surfaces. Experimental data have been obtained that reveal efficiency in application of blank circular motion and improvement of its output cutting indices.

A methodology has been developed for execution of comparative experimental investigations on cutting glass, nephrite and jasper specimens as under conventional conditions required for the operation so while transferring induced oscillations to boom suspension assembly that ensure specimen.

The proposed methodology makes it possible to assess quantitatively intensity of specimen cutting and quality of its machined surface. The paper has shown that a positive impact of the specimen circular motion on quality improvement of its cross-cut surface is related to peculiar kinematics features pertaining to relative motion of disc side surface with cross-cut portions of the specimen surface. It has been shown that the intensifying impact of the specimen circular motion on the cutting process is primarily related to the changes in dynamic conditions of its interaction with the cutting edge of the disc. In contrast to conventional cutting when the process is going on under static pressure of contacting surfaces there is their periodical impact-frictional interaction due to transfer of circular motion to the specimen along elliptical trajectory. In this case the rate of the positive impact of the specimen circular motion on its cross-cut surface becomes higher while increasing vertical velocity component that concerns its sliding relative to disc side surface that is ensured by increasing oscillation frequency which is transferred to the boom suspension assembly. Moreover, the rate of positive impact of the specimen circulatory motion on the quality of its cross-cut surface becomes higher while increasing vertical velocity component of its sliding relative to disc surface.

Processes of high-speed shaping changes and especially high-speed hot extrusion create efficient conditions for treatment of weakly plastic and poorly deformable materials which are widely used in tool making facilities. Due to the fact that high-speed stamping provides accurate billets with increased mechanical properties, it can be used as a technological process for manufacturing shaping parts of die tooling parts operating which are subjected to increased loads and wear.

The purpose of the paper is to carry out experimental investigations on the possibility to obtain a bimetallic tool where structural steel is considered as a basis of the tool and a working cavity is made of high-alloyed tool steel with its saving up to 90 %. A scheme of loading and geometry of conjugated surfaces of the composite billet have been developed in the paper. Technology for obtaining bimetallic shaping parts of die tooling with deformation at speed of v_R = 40-50 m/s and composite billet temperature of T = 1150 °C has been experimentally tested with formation of a compound due to plastic flow of two billet parts on contact surface with removal of surface oxide films.

Microstructures of the bimetallic compounds obtained with the help of high-speed hot extrusion method for compositions of structural and high-alloy steels have been investigated and their high quality has been proved during the investigations. Dependences of micro-hardness distribution have been established outbound two- steel contact plane in the zone of connection that are characterized by a minimum micro-hardness value in the connection joint. Availability of more plastic zone in the contact plane contributes to reduction of residual stresses due to their relaxation in this zone and higher joint strength.

The paper contains requirements to parameters of an automobile being designed with axle arrangement 6x4 and technically permissible mass of 25 tons with its all year round operation in agricultural industry with the purpose to ensure in-time load transportation and technological cycle in crop production of the agricultural complex in accordance with time schedule of the executed mechanized works. The future automobile should also have a power takeoff device.

The paper presents operation chart flowsheets for cultivation of main crops on mineral and peat soils with indication of automobile motion modes and type of transported loads. Specific properties of peat-bog soils are given in the paper. The paper considers off-road capability of mobile machines when they are moving on soils with low bearing capacity. The paper indicates field applications of automobiles with limited and high off-road capability. Description of wheel interaction with bearing surface area, values of soil resistivity after multiple automobile passages have been given in the paper.

The paper specifies values of rolling resistance coefficient and adhesion coefficient of the automobile undercarriage systems in spring and autumn for wheeled and crawler units. Schemes of the automobile front axle drives (electric, hydraulic, mechanical) and their characteristics have been analyzed in the paper. An elastic flexible drive with separation of flow power has been proposed for reduction of dynamic loads in a power transmission drive. The paper describes a drive system of auto-analogue steering wheels with hydraulic hydrostatic drive which is located within a front wheel hub that ensure additional thrust. Recommendations for MAZ-automobile modernization with axle arrangement 6x4 have been given with the purpose to improve its off- road capability.

Metallic anti-skid chain, segment and small link, track and crawler chains, wideners have obtained a wide application for improvement of automobile off-road capacity in various soil preparations. The paper notes the conditions required for provision of the automobile off-road capacity.

The paper presents a schematic diagram of the powertrain automated control system based on dry friction clutch and manual gearbox. Mechatronic system has a modular configuration and allows to make the vehicle starting-up, low speed maneuvering and command or automatic gearshifting. Diesel engine, clutch and 10-step gearbox control is carried out at all movement modes by electronic modules when affected on mode selector, accelerator pedal and, if necessary, on brake pedal. Data exchange between electronic units is carried by SAE-J1939 protocol with a transmission rate of 250 kbit/s. Change in diesel fuel supply, clutch engagement and gearshifting take place automatically as a result of pneumatic power actuator operation by a signal from the controller to the corresponding solenoid valve or a combination thereof.

Presents the results of semi-natural experiment on research of gear shifting process in the command mode of powertrain control. Transient gearshift oscillograms with various control algorithm structure have been given in the paper. The paper contains a ^iT^rative analysis of the oscillograma and a conclusion on expediency of gear shifting automation. A graphic representation of the semi-natural experiment results has been performed with the help of CoDeSys V2.3-visualization facilities.

The paper is devoted to the topical subject which is related to development of a new technology on interaction of a man and exercise machines while cultivating force characteristics which are important for sports and everyday life as well. The research objective is to determine kinematic and dynamic specific features of articular joint performance when a trainee is interacting with stationary exercise machines while performing power exercises. An original approach for determination and numerical representation of man position based on ascertainment of regularities on changes in joint angles taking into account anatomically possible degree of freedom of locomotor system joints has been used a main method for investigations. Training exercises using typical modern press machines with gravitational, elastic and dissipative forces for loading have been analyzed in the process of investigations. The investigations have revealed that the main problem of stationary exercise systems is an absence of the possibility to create loading simultaneously for several degrees of freedom for joint motions which are characteristic for natural spatial motions of a man. Other problems are connected with strict predeterminacy of human body link trajectories that reduce requirements to coordination of muscle forces, presence of uncontrollable inertial power additives arising at accelerated motion of weights used for loading and necessity to disperse mechanical energy while making exercises.

On the basis of the research we have formulated the promising direction for further development of training technologies connected with weight and health-improving training that implies creation of exercise machines providing simultaneous loading with several degrees of freedom for a human locomotor system with minimum inertance and possibility of effective energy dispersion.