Том 45, № 4 (2016)

The kinematic screws that determine the topology of singular zones of parallel-structure robots are studied. It has been established that the kinematic screws depend on the actuator mount points.

A detailed survey of the operating process and formation of nitrogen oxides in the combustion chamber of a hydrogenous diesel has been carried out in three-dimensional space using a mathematical model verified by experimental data. The specific features of the thermophysical processes in the combustion chamber of the hydrogen diesel engine have been specified, providing the applicable ecological and efficient indices of a stationary hydrogen diesel engine.

The article presents the results of experiments to study the creep of an intermetallic monocrystalline alloy used to manufacture nozzle blades. The results serve as a basis for calculating the creep-rupture strength and thermal fatigue of gas-turbine engine blades.

In the curvilinear coordinate system, we describe an algorithm for generating the stiffness matrix of the quadrilateral element of the middle surface of a thin shell based on Kirchhoff’s hypothesis with nodal unknowns in the form of displacements and their derivatives using a vector approximation of the displacement fields. The developed finite element is verified by calculating the shell with the middle surface in the form of a triaxial ellipsoid in the two-dimensional formulation. The results are compared with the calculation results obtained using ANSYS software. The efficiency of the vector approximation of the displacement fields for the calculation of arbitrary thin shells in the moment stress state is shown.

The problem of numerical simulation is solved for operators (tensors) of the stress and strain concentrations, which are related material-average stresses and strains with their local values in epoxyphenolic composites reinforced randomly by short polyimide fibers with antifrictional dispersed additives of polytetrafluoroethylene. Simulation is based on the generalized singular approximation of random field theory. The dependences of mentioned operators on the percentage of isotropic components are investigated. It is shown that an increase in the antifrictional additive concentration with a fixed fiber concentration does not result in a substantial decrease in the local elastic characteristics of the composite.

The results of studying wave impact on a productive bed for extraction of capillary hydrocarbons are presented. The studies were conducted on experimental equipment that which simulates filtration processes in a system of hydrodynamically related wells. Impact waves are considered that propagated from a processed well inside a bed via a system of fractures and faults with higher permeability. It is shown that impact pressure pulses intensify filtration due to the involvement of capillary hydrocarbons and to the increase in permeability of the porous medium.

We describe a new study and research mechatronic complex, which consists of a vibration stand with electric drives of unbalanced rotors, a personal computer for controlling the stand and processing the experiment results, a system of sensors, coupling devices, and an amplifying and transforming unit. We give the results of stand experiments displaying the Sommerfeld effect and suggest ways of applying the complex to create new technologies in the processing industry and in the study process.

For a beam sector of an oil and gas pipeline with initial axial bending, a mathematical model is developed that simulates the probability of nondestruction when the pressure, diameter, wall thickness, load, span length, maximum deflection, elastic modulus, and Poisson ratio are normally distributed. The parameters that decrease the number of emergency failures are established.