Dynamics of a motor vehicle taking into consideration the interaction of wheels and road pavement surface

The authors of this article focus on the simulation of the motor vehicle on a certain road and propose their specific solution of this problem. A mathematical model of the system “motor vehicle – road” is presented. The motor vehicle is simulated by concentrated masses interconnected by elastic and dissipative links. The presented model of the motor vehicle evaluates the movement of the motor vehicle body in space; the movement and turning of front and rear suspensions with respect to the body; the interaction of the wheel with the road pavement surface; the blocking of the wheel; the changing cohesive forces which influence the motor vehicle. The investigated road pavement surface is simulated by triangular finite elements, the certain height of road pavement surface roughness and the cohesion coefficients of road pavement surface and the motor vehicle wheel in the longitudinal and transverse directions of the wheel are selected in each finite element nodal point. The presented results illustrate: the motor vehicle movement trajectories braking at various initial conditions and on a certain pavement surface of the road section under investigation and the motor vehicle driving on the speed reduction bump (“sleeping policeman”)

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

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

Engineering solutions of traffic safety problems of road transport

The authors of this paper focus on the simulation of the motor vehicle movement (taking into consideration motor vehicle dynamics, motor vehicle hydraulic brake system influence on motor vehicle movement, interaction between its wheels with road pavements, road guardrail characteristics, interaction between motor vehicle and road guardrail) on a certain road section and propose their specific solution of this problem. The presented results, illustrating the motor vehicle movement trajectories (motor vehicle braking and interaction between motor vehicle and road guardrail at various initial conditions and at various certain pavement surface of the road section under investigation) and work of a motor vehicle hydraulic brake system. Taking into consideration the presented general mathematical model and computer aided test results it is possible to investigate various road transport traffic situations as well as to investigate various transport traffic safety problems

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

Investigation of potential deformations developed by elements of transport and pedestrian traffic restricting gates during motor vehicle–gate interaction

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

Corrosion of pipe steels 20 and 17G1S-U in ground electrolytes with a hydrogen indicator close to neutral

Purpose: of this paper is to analyse the mechanism of near-neutral pH corrosion of main gas pipelines. The stages of main gas pipelines in model environments that meet the soil conditions of Ukraine have been studied. Design/methodology/approach: The corrosion rate of steel specimens from steels 17G1S-U and 20 and the influence of borate buffers on their protective properties were evaluated. The influence of corrosion time on changes in pH of model media is shown. Morphological features of surface damages of pipe steels are established. The defect analysis of specimens from steels 17G1S-U and 20 by electron scanning microscopy is carried out. Findings: The effect of borate buffers on the protective properties of the steel grades studied was revealed, and changes in the pH of the model media during corrosion processes were described. The main regularities in corrosion, as well as the surface morphology of damaged specimens, were studied by scanning electron microscopy. Research limitations/implications: Detailed investigation of localised corrosion phenomena induced by inclusions that are present in steels 17G1S-U and 20 is extremely critical. In particular, there is still ambiguity as to whether the localised corrosion initiation induced by non-metallic inclusions is an electrochemical process or a chemical process. Practical implications: The research findings will be used when testing specimens from pipe steels under cyclic loading in the model media studied, as well as for predicting the residual life of gas pipelines with corrosion defects. Their generalization will make it possible to develop the effective methods of ground diagnostics and prediction of SCC of main pipelines. Originality/value: It was found that the corrosion rate is determined by internal (nature and properties of the metal) and external (properties of the aggressive medium and the corrosion process conditions) factors. The protective effect for steel 17G1S in medium NS4 + borate buffer (1: 1) was 61.5%. Steel 20 had the greatest protective effect in medium NS4 + borate buffer (1: 3), which was 87.05%

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

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