Mathematical models with a random frequency for the imitation of disturbances at the input of nonlinear systems are proposed. The effectiveness of different models is evaluated with a test problem of determining the standard deviation of angular velocity of motor shaft at random influences.
Results of double-strand opener testing in the soil channel in realistic conditions are brought. Mathematical models of uniformity of grain seed distribution on the length and width of sowed strand are received.
Experimental data on the visualization of transportation process of loose material are considered using Lagrange approach and radiography. On the basis of experimental data and a model of coaxial cylinders, a class of exact decisions for the speed field of loose material in spiral-screw device is received for the first time. The good consensus of trajectories of a liquid particle and a marker confirms the adequacy of developed physical and mathematical model.
Some theoretical operating conditions and parameters describing the movement and controllability of machine-tractor units, as well as their practical significance and the implementation of results of research and development activities in view of certification maintenance are considered.
Schemes of the annual cycles of transfer of value and resource recovery of tractor fleet are analyzed, depending on the economic state of production.
Performance indicators of tractor diesel engines in conditions of regulation of operating modes by the omissions of fuel supply were analyzed. Authors propose a dependence allowing to determine the coefficient of efficiency during the tractor diesel work by means of fuel supply omissions.
Vertical oscillations of front and rear axles of a wheel tractor having a semi-rigid spring suspension and unitized with one-axle trailer are considered. Mathematical model and calculation method for this unit oscillations are proposed. The influence of vertical oscillations of tractor-trailer's axels on the soil compaction was investigated. By means of computer modeling the influence of tractor-trailer speed on the axels oscillations' amplitude and frequency, and the compaction action of tractor-trailer on the soil during the field operations are revealed.
The results of research of tribological properties of polymeric materials for the seals of movable connections are brought in conditions of volume compression using the method of complete multifactorial experiment. Regressive equations adequately describing the dependence of wear intensity and friction coefficient of materials at their co-operating with a counter-body (steel of 40Х), from hydrostatical pressure, speed of skidding and temperature of working liquid are given. It is determined that the preferable complex of tribological descriptions is possessed by the rubber under the code number 7-ИРП-1269″ and the fluorine plastic Ф4К20″.
An approach to the estimation of defects after the reconstruction by thermal processing of steel and cast iron details for tractors and cars is declared. A method based on the application of optical-electronic means and computer technologies is offered. Estimation results and size of defects on the surface of details after restoration are brought. Features of construction and work of the optical device on the basis of advanced double MIS-11 microscope are considered.
The need for a new regulatory and technical document Regulations on Safety in the repair and maintenance service of agricultural machinery is grounded. The results of monitoring of repair and service enterprises, production sites, working places, technological equipment as well as the sources of occupational risks are shown.
Test results of wear resistance of some abrasive grains made of different abrasive materials during the microcutting of plasma coating and hardened steel 45 are published. As a result of given research the most wear resistant abrasives during the microcutting of specified materials have been found out. Electronic-microscopic and micro-X-ray spectral research of working surfaces of isolated grains allowed to reveal the physical and chemical processes in contact between abrasive and metal, and also to establish the adhesion activity of abrasive materials related to the plasma coating.
On the basis of the classic formula of ball volume a practical system of measurement units for dispersion index was developed instead of optional dispersion so-called «average diameter». It is proposed to include it in the SI «International System of Units».
A diesel-engine generator for the hybrid power plant of bulldozer is developed. Hybrid transmission applicability in a vehicle of given class is shown. Some optional versions of realization of the main load-bearing element of electric power plant of hybrid bulldozer-generator are analyzed. Requirements for a hybrid vehicle generator are formulated. A multi-polar generator with combined excitation combination is suggested allowing to realize the propulsion system as an integrated module. An example of practical realization of the developed generator is shown.
Specific kinematic features of milling rotor working with the forward and the row-spacing inclination of rotation axis are examined. Recommendations for the rational implementation of attachment point of L-shaped bent out cutter, in particular for the optimum setting angle of cutter pole in the plane of rotation, are given.
The problem of automotive engines' diagnosis according to the parameters of flow and pressure of crankcase gases is considered. The influence of engine speeds on the change of diagnostic parameters is described.
The state of computational and experimental studies of supporting systems of vehicles, including frames, in conditions of market relations, reducing development time and production organization was analyzed. Ways of improving the design of bearing systems, namely application of new materials and multi-objective optimization of the carriage and its components design are proposed. Authors propose a spatial mathematical model describing the complex vibrations, in which fluctuations of the motor-transmission installation and suspension are taken into account at the same time. Problems of the further development of computational and experimental methods of bearing systems in mechanical engineering are stated.
Results of bench test of the Cummins QSM11-C330 engine are analysed. A new method of construction of multiparameter fuel characteristic of diesel engine is proposed. The accuracy of obtained results relative to experimental data is estimated.