Olegas Prentkovskis

Use of steel slags in automobile road construction

Abstract Building and, especially, reconstruction and repairs of highways, call for the development of stone materials manufacturing industry. Increasing need for stone materials may be satisfied by a wide use of industrial waste and secondary resources. In road building, slag of ferrous and nonferrous metallurgy is one of the most popular wastes which are increasingly widespread with every year. Such slag is a valuable raw material for preparation of macadam materials and mineral binders serving as a base for asphalt concrete mixtures and manufacturing of cement emulsions, which are widely used in road paving. The research focused on the use of different types of slag in road construction in Ukraine. Possibilities of using crushed rock and sand as recrement slag of different production for preparation of asphalt concrete and cement mixtures to be used for road-base was studied, as well as the use of slag materials for construction of lower category roads. In the given work, the opportunity to recycle ele...

The criteria describing the need for highway reconstruction based on the theory of traffic flows and repay time

Abstract General data on the network of Ukrainian highways are presented. The analysis of design methods of highway reconstruction based on the theory of traffic flows and economic calculations of its repay time is made. The relationship between traffic intensity and speed is shown by considering the theory of traffic flows. The methods, taking into account the principle of effectiveness of highway reconstruction based on its repay time, are discussed.

The Selection of Wagons for the Internal Transport of a Logistics Company: A Novel Approach Based on Rough BWM and Rough SAW Methods

The rationalization of logistics activities and processes is very important in the business and efficiency of every company. In this respect, transportation as a subsystem of logistics, whether internal or external, is potentially a huge area for achieving significant savings. In this paper, the emphasis is placed upon the internal transport logistics of a paper manufacturing company. It is necessary to rationalize the movement of vehicles in the company’s internal transport, that is, for the majority of the transport to be transferred to rail transport, because the company already has an industrial track installed in its premises. To do this, it is necessary to purchase at least two used wagons. The problem is formulated as a multi-criteria decision model with eight criteria and eight alternatives. The paper presents a new approach based on a combination of the Simple Additive Weighting (SAW) method and rough numbers, which is used for ranking the potential solutions and selecting the most suitable one. The rough Best–Worst Method (BWM) was used to determine the weight values of the criteria. The results obtained using a combination of these two methods in their rough form were verified by means of a sensitivity analysis consisting of a change in the weight criteria and comparison with the following methods in their conventional and rough forms: the Analytic Hierarchy Process (AHP), Technique for Ordering Preference by Similarity to Ideal Solution (TOPSIS) and MultiAttributive Border Approximation area Comparison (MABAC). The results show very high stability of the model and ranks that are the same or similar in different scenarios.

Influence of Shock-Absorber Parameters on Vehicle Vibrations during Braking

The main goals of the work are to define consistent patterns of impacts exercised by vibration of the vehicle in emergency braking on the vehicle’s movement mode and on the braking distance and to analyze the formation of oscillation. Besides, it is aimed to extend expert’s opportunities for modeling vehicle movement for investigation of accidents’ circumstances related to vehicle braking with the aid of the developed models. A mathematical model of impact exercised by bumper’s characteristics on the vehicle’s braking process has been designed, enabling the determination of coefficients of longitudinal relative forces of the vehicle’s front and rear axles, which depend on the road’s pavement and its condition. The obtained research results extend the vehicle vibration theory in transitional movement modes, which are used in the design and improvement of vehicle suspensions, as well as in traffic accident’s investigation and improvement of methodology of their expertise calculations.

A study of the deflections of metal road guardrail elements

Abstract Statistical data on traffic accidents in 2008 in Lithuania is presented. Referring to statistical data, grounding on an obstacle’ makes one‐tenth of all registered traffic accidents ‐ 9.4% (an obstacle may be a road guardrail, a lamp post, a tree, a bar, a gate, etc.). Road guardrails of various types are installed on the shoulders and dividing strips of urban and suburban roads. They are as follows: reinforced concrete guardrails, cable guardrails and metal guardrails. Metal guardrails, consisting of S‐shape metal posts and a protective W‐shape horizontal beam, are most popular. The authors of the present paper examine the deformation processes of the elements of the above mentioned guardrail. A mathematical model of metal road guardrail was developed. Metal road guardrail was modelled using one‐dimensional first‐order finite elements, taking into account only elastic deformations, as well as the effect of soil on the buried post section of the guardrail. Based on the developed mathematical mode...

Investigation of Potential Deformations Developed by Elements of Transport and Pedestrian Traffic Restricting Gates During Motor Vehicle-Gate Interaction

Abstract The mathematical model of transport and pedestrian traffic restricting gate is designed. One section of the gate restricted the traffic of motor vehicles while the other limited the traffic of pedestrians. The gate was modelled based on the first‐order one‐dimensional finite elements taking into account only the resilience of the gate elements and the impact of soil on the ground‐embedded parts of the gate support and auxiliary posts. The potential deformations of gate elements were determined based on the mathematical model designed. The specific traffic event was investigated using the mathematical model of gate designed – four situations of motor vehicle–gate interaction were simulated and investigated.

Optimization problems in designing automobiles

A mathematical model of optimization problems in designing automobiles is suggested and requirements raised are defined taking into account the main technical and economic characteristics of the automobile. The optimality criterion of the integral parts of the automobile is presented. The system approach to the theory of parametric optimization based on generalized models is used and the algorithm for solving the considered problem is offered.

Degradation of the main gas pipeline material and mechanisms of its fracture

AbstractThe effect of the in-service scattered damage in the pipe wall metal is evaluated, and the effect of hydrogen absorbed by metal on the variation of the structure and mechanical properties of the main gas pipeline after a long-term operation is found. The main regularities in the graded nature of the static deformation process and the effect of hydrogenation on the scattered damage and fracture accumulation are found.

Investigating traffic accidents: The interaction between a motor vehicle and a pedestrian

The paper presents the methodology for expert investigation of traffic accidents involving running over pedestrians. This methodology is aimed at determining the availability of any technical possibility for a motor vehicle driver, driving at a particular speed, to avoid hitting the pedestrian in a particular situation. Furthermore, the paper presents the analysis of different investigation methods and the description of investigation procedures. Various patterns of the path of the motor vehicle and the pedestrian travel before the accident are described, providing a deeper insight into the peculiarities of investigation of each particular pattern. The description is supported by the case study, illustrating the investigation of a specific traffic accident, involving actual hitting of a pedestrian. The methodology presented may be successfully used for investigating traffic accidents by experts.

A mathematical model of the vibrating system equivalent to the vehicle in the mode of emergency braking

Abstract A mathematical model of the vibrating system equivalent to the vehicle in the mode of emergency braking is developed and the solution is offered. The problem associated with the comparison of the vibrations of the braking vehicle with the oscillations of a uniformly translating vehicle is considered. On the basis of the analysis of the available research data some assumptions and constraints are introduced, allowing the vibrating system equivalent to the condition of the vehicle in the mode of emergency braking to be developed. The system obtained differs from the data found in the theory of the vehicle in the description of the applied tangential forces caused by the force of inertia applied to the center of gravity. Based on the equivalent system developed, the differential equations describing the displacements of masses of the above system are derived and solved.