The article deals with the issues of modeling the stress-strain state of a traction device designed for towing a heavy semi-trailer, on which the equipment of the base station of a mobile transport and reloading rope complex is placed. The main design loads are defined. Geometric and computational finite element models are constructed, taking into account the features of the metal structure. The method of gluing elements of the grid model is applied. On the basis of the performed calculations, conclusions are drawn about the compliance of the developed structure with the requirements of strength.

Thick-walled high-pressure vessels are a fairly common type of technical device as part of technological equipment operated at various hazardous production facilities. Reliability indicators of pressure vessels and their change during operation largely determine the indicators of failure-free operation of technological equipment as a whole, and potential failures of pressure vessels are subject to consideration when conducting a risk analysis of the operating equipment. The article discusses probabilistic and statistical approaches to solving the problem of predicting the resource of pressure vessels with fatigue failure of the neck at the design and operation stages. For the design stage, a technique is presented for modeling the processes of nucleation and development of a high-cycle fatigue crack, as well as a technique for determining the type of law and quantitative indicators of the distribution of the resource of a pressure vessel by the condition of loss tightness. For the operation stage, a method is presented for predicting the further growth of a diagnosed fatigue crack, as well as a method for determining the type of law and quantitative indicators of the distribution of the residual life of a pressure vessel by the condition of loss tightness.

The correct choice of elements of the elevator lifting mechanism and their parameters ensures its reliability, durability, energy and economic efficiency. The paper contains recommendations for the selection of the traction elements of the elevator lifting mechanism and the sequence of determining their parameters based on a multivariate calculation. The purpose of the proposed sequence is to obtain the most rational parameters of the traction elements of the elevator lifting mechanism. The initial data for the calculation are the lifting capacity of the elevator, the nominal speed of movement, the height of the lift of the car. It is also necessary to consider the purpose of the elevator. At the first stage of the calculation, the masses of the cab and the counterweight are determined. In this case, the existing data on analogue lifts should be used. In the absence of such data, the approximate dependences proposed by the authors of the article can be used. At the second stage, the kinematic scheme of the elevator is selected. At the third stage, the type of traction element is selected. On the basis of domestic and foreign experience in elevator engineering and well-known literature, recommendations are formulated for choosing the type of traction element. The final stage is a multivariate calculation of traction elements. It is proposed to evaluate the calculation results taking into account the minimum value of the safety factor in accordance with the EN 81-1: 1998 standard. The calculation of the traction elements considered in the work is only a small part of the process of determining the optimal parameters of the elements of the elevator lifting mechanism. At the same time, already at this stage, variability is introduced, which makes the calculation quite laborious to perform it manually. Obviously, a multivariate calculation method that allows you to analyze many different combinations of parameters of the elements of the elevator lifting mechanism and choose the optimal ones is impossible without the use of a computer.

Measurement of the parameters of vibrations of the load moved by a self-propelled crane with a flexible rope suspension when the crane moves along an unprepared construction site with irregularities is an urgent task, since it will allow using the obtained numerical values of the vibration parameters to improve the accuracy of the crane’s operation in terms of moving loads. Based on the solution of this problem, it is possible to create systems for automatic damping of cargo vibrations. This will reduce the time spent on performing a work step when moving a load. This also solves the problem of reducing the dynamic loads on the elements of the crane. The article discusses one of the methods for determining the angles of deviations of the point of the load and the point of suspension of the load on the boom when moving the DEK-251 mobile crane along the unevenness of the construction site using the projection-polynomial mathematical model of the optoelectronic system. As an example, the article presents a number of graphs of time dependences of changes in the values of the angles of deviations of the load and the point of suspension of the load when moving over the unevenness of the site of a crane with a boom length of 22 meters and an angle of inclination of the boom of 48 degrees. The cargo was at a height of 4.8 meters, the weight of the cargo was 200 kilograms. The graphical time dependences of the load fluctuations and the load suspension point in the longitudinal plane are given in the form of angles of deviations from the lens center, taking into account the microrelief. The data allows you to calculate the linear coordinates of objects in space. Moreover, the results were obtained taking into account the camera errors.

Mobile ropeways formed by mobile transport and reloading rope complexes (terminal stations) on the basis of self-propelled wheeled chassis of high load capacity and cross-country ability are a promising type of transporting equipment for use in many branches of industrial production and maintenance – construction and mining industry, forestry and agriculture, elimination of the consequences of natural and man-made disasters, etc. The article develops a classification of self-propelled terminal stations based on such features as the location of the key element of the main technological equipment — the end tower of the rope system — on a wheeled chassis and the type of its fixation in the working position during the operation of the mobile ropeway. As promising variants of the structural design of mobile transport and technological rope complexes, options with an end, central and remote arrangement of the end tower; with hydraulic, rope, rope-hydraulic and rod types of fixing the end tower in the working position; with the installation of the end tower in the working position directly by a lifting hydraulic cylinder, using a folding rod and two-stage lifting are proposed. A brief description of the designs and the principle of operation of a large number of modifications of self-propelled terminal stations of various listed variants of the structural design of mobile rope complexes is given when preparing them for operation and during operation itself. A comparative analysis of the considered variants of mobile rope complexes is carried out on the basis of taking into account their main design and technical and economic characteristics, which made it possible to formulate both advantages and disadvantages of different design options.

A method for calculating the frame of a gravity roller rack for boxes based on the disclosure of the static indeterminacy of the system using the equations of three moments is proposed. Unknown reactions from the intermediate supports that provide the overall rigidity of the structure are determined. The maximum bending moments along the length of the entire roller bar are found, and statically definable systems of intermediate supports, front and rear crossbars, and side profiles are calculated. A method for selecting cross-sections of profiles is proposed and their maximum normal bending stresses are calculated, which are compared with the permissible ones.

The construction of highways is a complex, multi-stage process. Most of the construction works are carried out according to the projects of structures and quite high requirements are imposed on the quality of execution. The fulfillment of these requirements is associated with great difficulties in view of the limited accuracy of the road construction machine itself, the lack of on-board control systems and the limited capabilities of the human operator, who is unable to determine the required exact parameters of the structure being built «by eye». To meet the requirements, three-dimensional control systems are used, which allow determining 3 coordinates of the working order of the machine – the vertical coordinate and the location of the machine on the construction site. At the same time, the digital project of the constructed structure should be the setter in such a system. The system determines the current position and compares it with the project. On the basis of this information, a control effect on the operating organ of the machine is formed. The course of movement and the speed of the machine when using such systems are determined by the machine operator. Further development of these systems should be four-dimensional systems – in which all control actions are assigned to the control system, starting from calculating the trajectory of the machine, choosing the speed, determining the required number of passes and ending with controlling the position of the working body of the machine at each moment of time. For the functioning of these systems, adequate mathematical models of the turning processes of road construction machines with different steering options are necessary.

An accurate assessment of the characteristics of the aerodynamic resistance to movement is important for the preliminary selection of the parameters of the engine, transmission and chassis of a special wheeled chassis or tractor. The strength of the movement resistance affects the dynamic characteristics of the car. The existing calculation methods allow for a wide variation of the aerodynamic drag coefficient, which complicates the task of preliminary selection of car parameters. The purpose of this article is to clarify and develop the engineering methodology for carrying out traction-dynamic calculations of special wheeled vehicles and tractors based on the results of computer modeling performed using computational fluid and gas dynamics (CFD modeling) methods. The modeling methodology and calculation results of a special wheeled chassis manufactured by JSC «BAZ» are considered.

The results of the research presented in the article relate to a fundamentally new type of continuous transport machines-conveyors with a suspended load-carrying belt and a distributed drive. The main advantages of which are due to the features of the kinematic scheme, in which the load-bearing conveyor belt is held by the sides by means of roller suspensions on rolling guides closed along the route and does not interact with its base with supporting supports, and the drive is implemented according to the distributed scheme by the equipment of individual suspensions with individual motor-gear drives. A feature of such a kinematic scheme is the nature of the failures associated with the operation of highly loaded drive suspensions, the influence of which affects the main technical characteristics of the conveyor with a sufficiently increased number. The paper presents a mathematical model designed to calculate the dynamic characteristics of a conveyor with a suspended belt and a distributed drive when the types of failures characteristic of this conveyor design occur, associated with a break in the supply electrical circuit of the motor-gear drive of the suspensions. Based on the developed mathematical model for the reference design of a conveyor with a suspended belt and a distributed drive, a series of numerical calculations of dynamic characteristics in the event of failures of drive suspensions is performed. The obtained results allowed us to establish that with a reduction in the number of groups of consistently failed drive suspensions located with an equal step along the route, the technical characteristics of the conveyor deteriorate: the speed of movement of the load-bearing belt and the total power of the drives are reduced, and the longitudinal tensile stresses in the belt are increased. With an increase in the number of consistently failed drive suspensions within one group, the power and speed of the conveyor decrease non-linearly, and the longitudinal stresses in the conveyor belt increase linearly. In general, the results of calculations of the technical characteristics of the reference idealized design demonstrated the possibility of the conveyor operation in case of failure of 90% of the drive suspensions. The actual performance indicators are determined by the technical characteristics of the used gear motor drives.

The article provides general information about double-support mobile bridges designed for contactless movement of heavily loaded specialized multi-axle wheeled vehicles on top of man–made structures. Also, recommendations are given on substantiating the possibility of their use for solving specific problems. These recommendations contain expressions obtained by the methods of structural mechanics, on the basis of which it is possible to determine not only the required (minimum) camber of the mobile bridge, which is necessary to ensure the normal passage of the vehicle, but also to assess the stress state of the mobile bridge, as well as to determine the nature of the deformation of the mobile bridge when vehicle moves along it. The presented recommendations allow, at a first approximation, to assess the suitability of the available solutions of a mobile bridge for the passage of specialized multi-axle vehicles over mane–made structures, depending on the required span of the mobile bridge and the load from the vehicle on the mobile bridge. The article also provides an example of solving a specific problem on the basis of these recommendations, in accordance with which, when a mobile bridge is spanned 23.4 m and a working load from one axis of the vehicle is equal to 33.5 tons, the required camber is 400 mm, and the highest equivalent stresses will be about 380 MPa.