Analytical approach to determination of surface strengthening of chevron gears

The construction of an information model of the processes of gear processing of hardened large-modular chevron gears is one of the stages of control of the technological structure and parameters of the automation of the design of the technological process. Taking into account the principles of information classification, the automated gear processing process is considered as a control object, consisting of a number of technological objects: initial material (input of the control object); environment (process conditions); gear wheel (output of the control object, quantitative and qualitative characteristics of the surface layer) The construction of an information model of the processes of gear processing of hardened large-modular chevron gears is one of the stages of control of the technological structure and parameters of the automation of the design of the technological process.

Efficiency evaluation of using lubricants with fullerene compositions during operation of trucks in the urban driving cycle

The assessment of a car fuel efficiency during operation using lubricants (motor and transmission oils) with fullerene compositions in a urban driving cycle is executed. Fullerene compositions were added to the engine and transmission oil at a mass concentration 10%. The guiding document that defines the procedure for testing vehicles for fuel efficiency is GOST 20306-90. Urban driving cycle tests were carried out on a truck ZIL-5301 "Bull" at an outside air temperature of +20°С (summer operation period) and at an outside air temperature of -5°С (winter operation period). It is established that operating a car in the urban driving cycle using of fullerene composition in both engine and transmission oils reduces the fuel consumption of the car by 14.54 ... 17.45% in the summer period. The value of 17.45% corresponds to the mileage of the car without cargo (m = 0), and the value of 14.54% – to the mileage with a cargo (m = 3000 kg). The coefficient of variation of the measured value of fuel consumption was 0.039 ... 0.042. This allows us to conclude that the measurement error is in the range of 3.9 ... 4.2%. When operating the car in the urban driving cycle in the winter operation period, the use of fullerene composition (mass concentration 10%) Simultaneously in the engine oil and transmission oil reduces fuel consumption by 13.24 ... 15.15%. The value of 15.15% corresponds to the mileage of the car without cargo (m = 0), and the value of 13.24% – mileage with cargo (m = 3000 kg). The coefficient of variation of the measured value of fuel consumption was 0.039 ... 0.044. This allows us to conclude that the measurement error is in the range of 3.9 ... 4.4%.

Modeling of crack opening mode sif for a crack in a thin-walled structural channel beam

The analysis of engineering methods for determining stress intensity factors (SIF) for defective elements of open profile (channels) under bending is carried out. Mathematical models are created and dependences for calculation of SIF are deduced using two methods: using nominal stresses in net-section and using change of the inertia-moment of the profile cross-section. The obtained results are compared with the data of SIF for the crack in the channel obtained during simulation modeling using finite element method.

Modified VIKOR method as a component of decision support of information technology of the dual form of education

The model for supporting the student decision in choosing the subjects of specialty educational program based on VIKOR multi-criteria optimization method is developed in this paper. The developed model is the component of the dual education information system (when the student is trained in the company and educational institution at the same time on the basis of the contract). This component is a decision support tool for a student training by a dual education, taking into account the expert opinion of stakeholders in the learning process. The criteria of dual education stakeholders for ranking alternatives (subjects of the specialty program): student, educational institution, company are outlined. VIKOR method is modified by the selection of subsystems criteria in order to derive an integrated assessment of experts from different subsystems. The algorithm for integrating ratings of ranking subsystems is developed, taking into account the strategy of maximum group usefulness of VIKOR method. The weighting coefficients of subsystems and their criteria are determined by T. Saati method of hierarchies analysis. In order to take into account the uncertainty associated with the lack of information, intuitionistic fuzzy sets are used to assign assessments of the alternatives ranking by subsystem experts. The proposed modification of VIKOR method makes it possible to rank the alternatives with the involvement of different specialists with their own criteria system. This approach increases the accuracy of the obtained results, as the criteria are further divided into holders subsystems of the ranking problem. This approach enables to carry out deeper and broader analysis of ranking problem aspects. Numerical example of the developed model which confirms the acceptability of its application in practice in the dual educational process application is illustrated in this paper.

The molecular mobility of the epoxy binder in a modified composites by electric-hammer

In this work, the study of molecular mobility in the surface layers by the method of determining the dielectric characteristics of materials modified by electrospark hydraulic shock, determined the optimal content of the dispersed filler. Comparative data of the tangent of the dielectric loss angle of treated and untreated composite materials are presented.

Separation of the 3D stress state of a loaded plate into two-dimensional tasks: bending and symmetric compression of the plate

The three-dimensional stress-strain state of an isotropic plate loaded on all its surfaces is considered in the article. The initial problem is divided into two ones: symmetrical bending of the plate and a symmetrical compression of the plate, by specified loads. It is shown that the plane problem of the theory of elasticity is a special case of the second task. To solve the second task, the symmetry of normal stresses is used. Boundary conditions on plane surfaces are satisfied and harmonic conditions are obtained for some functions. Expressions of effort were found after integrating three-dimensional stresses that satisfy three equilibrium equations. For a thin plate, a closed system of equations was obtained to determine the harmonic functions. Displacements and stresses in the plate were expressed in two two-dimensional harmonic functions and a partial solution of the Laplace equation with the right-hand side, which is determined by the end loads. Three-dimensional boundary conditions were reduced to two-dimensional ones. The formula was found for experimental determination of the sum of normal stresses via the displacements of the surface of the plate.

Innovative technologies in corrosion-resistant coatings development aimed at ship navigation equipment protection

The efficient use of some innovative technologies in adhesives with advanced operational characteristics development aimed at anti-corrosion properties increase of transport means has been substantiated in the paper under discussion. The above-mentioned technologies involving the use of some interaction-active ingredients forming the cross-linkable coatings composition, including some polymers, have provided their cohesion properties essential improvement. Epoxy diane oligomer ED-16 has been chosen as the main component for the matrix in the composite formation. The aliphatic resin DЕG-1 (GOST 10136-77) as a plasticizer has been added to the epoxy oligomer. The compound has been formed of the following concentration: epoxy resin ED-16: plasticizer DЕG -1 – 100: 40. The hardener of cold hardening polyethelenepolyamine PEPA (ТУ 6-05-241-202-78) has been used at the epoxy resin-based developed materials polymerization. Phthalic acid anhydride has been used as a modifier to improve the properties of epoxy composite materials. The modifier was added to the matrix in the following ratio: from 0,10 to 2,00 pts.wt. per 100 pts.wt. of epoxy oligomer ЕD-20. The molecular formula of the modifier is as follows: C8H4O3. Molar mass is 148,1 g/mol. Density is ρ = 1,52 г/см³. To form a composite material or a protective coating with some improved adhesive properties and inconsiderable residual stresses the phthalic acid anhydride as a modifier was found to be added to the epoxy matrix with the content q = 1,25 pts.wt. per 100 pts.wt. of the epoxy matrix (oligomer ЕD-20 + plasticizer DЕG -1). In this case, the adhesive strength of the coating is being increased from sа = 28,3 MPа to sа = 46,4 MPа, and residual stresses – from sз = 1,9 MPа to sз = 2,1 MPа. First of all, the improved properties of the modified materials were caused by the interaction of active carbonyl (С=О) groups of the modifier with nitrogen-containing (NH-) groups of the hardener. It has provided the increase of the composite cross-linking degree resulted in their both adhesive and cohesion properties improvement. Moreover, it was found that the modifier use in the compound with the content q = 1,0…1,5 00 pts.wt. per 100 00 pts.wt. of the matrix has provided the increase of the river water influenced coatings resistance from ρ = 12,1 Оm·cm2 до ρ = 21,2…22,4 Оm·cm2. Though, some further increase of the additive content in the coating has caused the deterioration of anti-corrosion characteristics of the materials. Thus, the conducted study has contributed to the determination of the most efficient content ratio of phthalic acid anhydride as a modifier to for the coatings of functional use.

Calculation of the stress – strain state of blades made of polymer composite materials of starting turboexpanders in resonance zones

An overview of the successful application of modern composite materials for the manufacturing of turbine blades of aircraft gas turbine engines, axial mine and blast furnace compressors. Their main advantages of these materials in comparison with metal are analyzed. Analytical calculations of stresses arising in the material of plastic blades of starting turboexpanders are carried out. The possibility of successful application of glass-filled polyamide for the manufacturing of moving and guide blades of starting turboexpanders and their successful operation at compressor stations of main gas pipelines is substantiated.

Automated planning of the optimal movement trajectories of mobile mechatronic devices

The compatible work is considered and the obtained results of the known algorithms generating unobstructed trajectories of different length and smoothness are investigated. Their operation is performed within the framework of the developed software product LSTr. The use of the analyzed set of these algorithms on the set of considered sections of the generated trajectories according to the obtained results allows a differentiated approach to the use of different algorithms on different sections of trajectories, determined by the accepted criteria of length and / or smoothness. The scientific novelty of the work and its practical significance in this area of research are determined.

Investigation of the operation of vibration-centrrifugal installation for automobile parts machining

The scheme of vibration-centrifugal installation, providing the increase of productivity and efficiency of machine parts vibration treatment is presented in this paper. The influence of the treated environment on the technological vibration treatment process and determination of its optimal parameters is investigated on the basis of mathematical modeling. Graphical dependences of specific kinetic energy on the crank rotational velocity at different values of the fork rotational velocity are presented. Effective ways of technological process parameters optimization and new ways of its development are identified.