Introduction. The age composition of the main pipelines of Russia significantly exceeds the period of their standard operation, which necessitates the provision of their reliable, trouble-free operation sometimes in difficult environmental conditions. Timely delivery of the required amount of hydrocarbon raw materials to various regions of our country and abroad depends on the quality and speed of the repair work. The speed of the pipeline overhaul, which consists in replacing old pipes with new ones, depends on the effectiveness of the entire repair string as a whole. The main excavation machine is a hydraulic excavator. Soil is removed on both sides of the pipeline, but there is a problem of excavation under the pipeline. Existing solutions to the problem are highly complex, which only complicates the repair process. Therefore, the authors develop the working equipment of the excavator, which is installed after digging the pits of the trench.

Materials and methods. The authors performed a review and analysis of existing equipment designs for the soil development under the pipeline. Moreover, the authors developed a new design of interchangeable working equipment for a single-bucket excavator.

Results. As a result, the authors presented a detailed description of the working equipment of a single-bucket excavator and the principle of its operation.

Discussion and conclusions. The proposed technical solution allows excluding excavation under the main pipeline, which is carried out using a trench tool. This method significantly increases the efficiency of excavation and the pace of repair work as a whole.

The authors have read and approved the final manuscript. Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Introduction. The problem of increasing the efficiency of power machines is important to develop a new design of the main elements or drive with the possibility of widespread use of hybrid drives. To preserve the power characteristics of the drive and its technical and operational indicators, the authors consider a hybrid with the available electric and hydraulic drive parts that form a complex synergistic mechanism as an alternative. The proposed combined tracking system with the specified parameters allows for the efficient operation of the drive of many machines.

Materials and methods. The paper presented the results of an analytical study, the prospects for the development of mechatronic systems in engineering and technological complexes. The research also identified the industry area with a high development potential for mechatronic and hybrid drives. The authors formulated the problem of designing and developing hybrid drives due to the fact that there was no single method for substantiating the energy efficiency indicators of a power hybrid drive that ensured the interaction of two dissimilar systems (electric drive and hydraulic drive with fundamentally different parameters).

Results. Therefore, the authors conducted the analysis of the structural, technological and operational parameters of the hybrid drive systems and proposed a combined servo drive system.

Discussion and conclusions. The authors prove and justify the extensive possibilities of using hybrid drives as an alternative to pneumatic and hydraulic drives The results of the research allow specifying the directions and prospects of using hybrid synergetic drives and systems for the functioning of working equipment, machines and complexes.

Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Introduction. For the durable road at the minimum necessary cost of its construction the topsoil should be removed without affecting the ground. The problem of cheaper road construction without reducing the quality can be solved by creating an aggregate for the sublayer’s formation. The aggregate removes the topsoil from half of the road sublayer and one of the ditch. The buckets of the moving aggregate cut off the soil layer from below and from one side. Therefore, each bucket is mounted by the bottom blade, the right blade and the console blade, partially cutting the topsoil from below for the passage of the next bucket. The blade of the lower knife with the 10 degrees’ angle to the plank of the bucket; the blade of the right knife and the blade of the console knife – with the 45 degrees’ angle towards the direction of the bucket moving.

Materials and methods. To determine the speed of chains and the size of the soil layer the author carried out the bucket kinematics’ analysis and considered mathematical transformations. For checking the received parameters, the paper demonstrated the turn of the bucket on the leading 90 degrees’ lower drive. The author revealed the scheme of forces acting on the ground, located in the bucket, when it turned on the leading lower drive. Based on the system’s transformations of two equations and the inequality, the research established the inadmissibility of the bucket’s phasing out when it turned on the leading lower drive.

Results. As a result, by using the developed method of determining parameters, based on the accepted raw data, the author calculated the speed of the chains, to which the buckets were attached, and the width of the soil, cut off by the bucket. After substitution of the received parameters in the inequality the author established that the ground would not fall out of the bucket by turning under such parameters of the bucket and of the leading lower drive.

Discussion and conclusions. As a result, the author obtains the geometric parameters from the structural layout of the aggregate for removing the topsoil from the road sublayer. Based on the analysis of the kinematics of the interaction of the bucket with the ground, the paper reveals the speed of the chains, to which the buckets are attached and the width of the soil layer cut off by the bucket. Analysis of the forces acting on the ground and locating in the bucket at the moment of the bucket turn on the leading lower drive shows the rationality of the accepted and calculated parameters. The author determines the energy costs of cutting the ground with the buckets of the aggregate for removing the topsoil from the road sublayer.

Financial transparency: the author has no financial interest in the presented materials or methods. There is no conflict of interest.

Introduction. The contact interaction of the associated elements of the hydraulic cylinder (piston with sleeve, guide sleeve with cylinder and rod) determines the reliability of the reciprocating hydraulic motor. Assessing the effect of gaps of articulated hydraulic cylinder elements is an urgent task in view of the fact that the formation of gaps is inevitable, since friction is always accompanied by tribological wear processes. The paper investigates the determination and assessment of the influence of the gaps of the hydraulic cylinders’ mating elements on the stress-strain state of the contacting bodies on the example of the hydraulic cylinder for the Sokol 80.01 railway crane.

Materials and methods. The author used the finite element method implemented in the Simulation SolidWorks module. Moreover, the author applied the Huber–Mises criterion as a criterion for the material plasticity. The paper also considered theoretically possible spatial design schemes of loading and depending on the type of the mating elements’ contacting of the hydraulic cylinder.

Results. As a result, the author presented plots and graphical dependences, which were three-dimensional surfaces constructed according to the results of numerical experiments. The calculations took into account the joint deformation of the piston, sleeve, rod, guide sleeve and supporting guide rings of the hydraulic cylinder. The author carried out the analysis of the obtained diagrams and dependences of the contact interaction of the hydraulic cylinder for various options of the elements contacting. The paper presented the results that were useful for studying all types of hydraulic cylinders and working equipment of the road, construction and hoisting-andtransport machines.

Financial transparency: the author has no financial interest in the presented materials or methods. There is no conflict of interest.

Introduction. The process of shifting gears under load is one of the most complex types of dynamic process in the transmissions of transport, road and construction vehicles. Currently, the existing calculation methods do not fully reflect the features of the engine and automated gearbox interaction by switching stages under load using more than two friction clutches at the same time. The paper discusses the method of calculating the dynamic characteristics of the gearbox with the simultaneous use of both two and four friction clutches by shifting gears under load with forward and reverse switching. The authors present the results of the dynamic characteristics of the theoretical study of the automated gearbox with frictional stages’ switching under load and without breaking the power flow.

Materials and methods. The main method was based on a system approach to the dynamic processes study and on the modeling of the gearbox operation together with the internal combustion engine. The authors took into account the regulatory, speed and load engine characteristics, resistive torque variation, rate of pressure rise in clutches by shifting to higher and lower gears. The paper performed theoretical modeling of processes using the MATLab package and the Simulink application. Using the main blocks of this application, the authors created models of physical components: an internal combustion engine, friction clutches, gear reducers, elastic shafts, damping devices and tractor power transmission control systems.

Results. As a result, the authors obtained calculated data of the dynamic processes, variations in speed and rotational torque on the gearbox shafts; the load on the engine by shifting gears at different values of the start and finish time in switching on and off the gearbox friction controls. The paper presented the relevant graphs of the processes.

Discussion and conclusions. The developed method of calculating the dynamic characteristics of the gearbox allows simulating workflows by shifting to higher and lower gears. This method takes into account both the parameters of the gearbox design and of the control actions: the rate of switching on the friction clutches; the time intervals of overlapping the “on and off” clutches. Therefore, in relation to the considered gearbox, the authors determine the values of the optimal time control commands of the friction by shifting.

Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Introduction. The paper discusses the problems of organizing the vehicles’ parking near large shopping centers and also describes their relevance, taking into account the transport services of retail outlets and residence places. The authors present the research of the problem by leading scientists, which is reflected in the regulatory documentation.

Materials and methods. The authors used a mathematical description of the average parking duration and identified the main affecting factors, taking into account the proportion of workers in the mass gravity center. The authors proposed a mathematical dependence based on the average parking duration, taking into account reservation of parking places for workers and the required number of parking spaces for other categories. The paper considered the possibility of the intra-hour deficit of parking places based on the PHF-factor.

Results. As a result, the authors made the comparison of the obtained values of the required parking spaces with the standard ones. The paper provided more than 30 types of mass gravity centers and urban areas. In addition, the authors considered the examples of assessing the required number of parking spaces near a large housing estate at the 8 km distance from the city center. Therefore, the authors proposed the technique for assessing the required number of parking spaces based on normative values per 100 m2 of the area of the mass gravity centers.

Discussion and conclusions. The authors present recommendations are made for the practical application of the required number of parking spaces by the normative values.

Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Introduction. In the process of operation of cars there is a need for quality repairs with minimal time and resources. There is a constant search for ways to reduce the cost of operating cars by reducing the cost of buying original spare parts. One way to reduce the cost of spare parts is the restoration of resource-defining expensive car parts. In this regard, there is a search for the selection of optimal ways to restore machine parts that meet the economic and technical requirements and which have a resource of a new spare part. The purpose of the research is to substantiate the feasibility of using galvanic coatings in particular chrome plating in the restoration of machine parts.

Materials and methods. The authors proved a rationale recovery of parts of machines galvanized coating and the method of choice of the rational restoration of car details. Moreover, the authors established that a large number of parts are in the range of 0.1...0.5 mm, as a result, the authors used wear-resistant coatings of electrolytic chrome plating.

Results. As a result of optimizing the composition of the existing cold self-regulating electrolyte, the authors expanded the operating temperature range (up to 35 o C), at which it was possible to obtain high-quality coatings with high performance.

Discussion and conclusions. The authors conclude that in modern conditions of the car production and repair and for certain nomenclature of resource-defining details, it is possible to use one of the restoration ways, namely, chrome plating. In order to reduce costs and increase the performance of chrome plating, it is necessary to improve it by optimizing the electrolyte composition and electrolysis modes.

Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Introduction. The paper substantiates the relevance of reducing costs for regular passenger traffic and increasing their reliability in relation to cities with city-forming enterprises. The organizational and technological specificity of the regular route network of urban transport in such cities is disclosed. The authors propose a method for organizing regular transportation routes based on a rational combination of basic routes that require boarding and disembarking passengers only at stopping points and backup routes with boarding and disembarking passengers in any place not prohibited by the rules of road traffic. The authors demonstrate route network optimization of the regular passenger transportation using the proposed economic and mathematical model and taking into account the costs of forming the infrastructure for organizing traffic on backup routes, operating costs of transportation, as well as the cost of eliminating failures in urban transport. The developed mathematical model for assessing the reliability of regular passenger transportation differs from the well-known models, which take into account the availability of backup routes in the regular route network. The research proves the practical implementation of the proposed recommendations by the example of public transport routes in Magnitogorsk.

Materials and methods. The authors used the analysis of scientific and regulatory literature; economic and mathematical modeling of transport processes; methods for calculating the reliability of technical and transport systems; the statistical, technical and economic system analysis.

Results. As a result, the authors revealed the optimization of the economic and mathematical model of the regular passenger transportation in cities with city-forming enterprises and a mathematical model for assessing the reliability of regular passenger transportation. Moreover, the paper presented practical recommendations on the organization of reserve routes for regular passenger transport on the example of Magnitogorsk.

Discussion and conclusions. By the implementation of theoretical principles, mathematical models and recommendations developed in the course of the research, the authors show the effect of implementation and the possibility to obtain new scientific results. Moreover, the authors demonstrate the formation of an additional volume of traffic by 178 thousand passengers a year, an increase in the speed of communication by 7 km per hour, a decrease in the cost of transporting one passenger by 7% and an increase in reliability by 1.14.

Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Introduction. The calculation of effective indicators of the vortex ejector used in the diesel air supply system is a pressing task as it allows significantly reducing time for determination of rational design parameters at the design stage. One of the modifications of the particle dynamics method is a promising direction, allowing with high physical adequacy, “from the first principles,” to model aerodynamic processes in vortex devices. Therefore, the purpose of the paper is to develop a mathematical model of a vortex ejector.

Materials and methods. The paper discussed a method of the mathematical simulation of ejection and ejection flows in a vortex ejector. The proposed modification of the particle dynamics method allowed describing aerodynamic processes with the help of simple laws of classical dynamics, and modeling them with the help of software of the Delphi 7 System. The author presented differential equations, which were solved by the Runge-Kutt method of the second order. As a result of the solution, the authors determined paths of air elements movement in the vortex ejector, which allowed estimating effective parameters of vortex devices.

Results. To study the model, the author developed a program with the possibility to set geometric parameters of the vortex ejector in the interface window and to display the current values of the process parameters.

Discussion and conclusions. Proposed mathematical model and computer program make it possible to quantify efficiency of vortex devices at their design stage. The advantage of the proposed mathematical model lies in more accurate calculation of vortex flow parameters from the vortex ejector design and physical properties of ejecting and ejecting flows.

Financial transparency: the author has no financial interest in the presented materials or methods. There is no conflict of interest.

Introduction. The paper devotes to the features of hydration and hardening of polymineral composite binders. The authors carry out the complex research of the phase composition, hydration and structure formation processes of hardened composite binders with active mineral additives by X-ray phase analysis, differential scanning calorimetry and electron microscopy. The study using a Tescan MIRA 3 scanning electron microscope reveals differences in the microstructure of hardened binders and the authors confirm the results by microprobe studies. The authors study the hydration of the composite binder prepared on the basis of Portland cement and mineral components. Moreover, the paper demonstrates the dynamics of the system’s heat dissipation from the moment of mixing with water and hardening up to 24 hours and up to 72 hours by the expressed bond of dQ / dt = f (t) using a differential calorimeter.

Methods and materials. The authors carried out experimental studies at Belgorod State Technological University named after V.G. Shukhov, at the Department of Building Materials, Products and Structures, at the High Technology Center and “BelGTASM-Certificate” Test Center. Therefore, the authors used the existing basic research methods, including modern physicochemical methods of analysis: X-ray phase, scanning electron microscopy, etc. The paper determined the main characteristics of raw materials, composite binders and foam concrete using standard methods and regulatory requirements.

Results. The authors obtained the results that testified the peculiarities of hydration and hardening processes of polymineral composite binders on the basis of Portland cement and mineral additives: opoka marl and fly ash.

Conclusion. The research establishes the hydration and hardening processes of polymineral composite binders. As a result, the authors demonstrate that the opoka marl introduced into the cement leads to the increased hydration in the induction and accelerated periods and also increases the hydration completeness of the main clinker minerals due to the manifestation of the pozzolanic reaction and the active binding of blocking Portlandite, as well as to the higher concentration of accumulated neoplasms, second generation calcium hydrosilicates.

Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Introduction. Studying the designing and constructing experience of beam bridges with composite log girders indicates the possibility of the load bearing capacity rising of the structures and their further usage in the IV and V categories bridges’ construction under A-11 and H-11 loads. The purpose of the research is to evaluate the effect on the magnitude and distribution of shear forces in shear bonds, considering the permissible pliability of fixation in wood and on the nature of the stress state change in the rods of the composite girders.

Materials and methods. The authors presented the construction of the composite girder in the form of three rows united by means of tie bolts and gaskets of four-tier single-row composite girders and made of edged logs. The proposed studying method of a composite girder stress-strain state with discrete placement of concentrated shear bonds in the joints based on the classical method of forces for rod systems, taking into account the interaction of longitudinal forces and bending moments arising in the rods composing the girder of unknown forces in the shear bonds.

Results. The determination of single displacements with joint account of bending and stretching-compression deformations haв a significant impact on the redistribution of shear forces in the direction of increasing them in the support zones and reducing them in the middle of the span, and, consequently, on the design of the connecting elements. The character of distribution of normal stresses on the stretching-compression indicated the rods’ girders between relationships under the eccentric compression (stretching).

Discussion and conclusions. The proposed solutions demonstrate the most accurate assessment of the composite girders in the structures of spans wooden bridges and present the application possibility in modern conditions.

Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.