Three Rollers – Cone Test. New Possibilities of Wear Calculation

2006 ◽  
Vol 113 ◽  
pp. 363-366
Author(s):  
Wiesław Zwierzycki ◽  
Tomasz Rochatka
Keyword(s):  
Mathematical Model ◽  
Constant Load ◽  
Wear Intensity ◽  
Contact Stresses ◽  
Model Systems ◽  
Linear Wear ◽  
Special Experiment ◽  
Good Convergence ◽  
Wear Calculation ◽  
The Mathematical Model

In tests presented in the paper the authors made use of M.M. Chruščov’s concept of determining linear wear intensity Ih in model systems operating under constant load in which the contact stresses decrease in the effect of wear. They elaborated the mathematical model binding vertical approach of samples in four ball apparatus equipped with the three rollers – cone couple with rollers wear trace dimension. The model was verified in the special experiment obtaining a very good convergence of results of calculations and the experiment.

scholarly journals Numeric modeling and estimating the performance characteristics of a pneumatic driven high pressure pump

2018 ◽  
Vol 245 ◽  
pp. 09014 ◽  
Author(s):  
Nikita Zhurkin ◽  
Anatolij Donskoj ◽  
Aleksandr Zharkovskij
Keyword(s):  
Mathematical Model ◽  
High Pressure ◽  
Constant Load ◽  
Constant Volume ◽  
Performance Characteristics ◽  
High Pressure Pump ◽  
Operating Modes ◽  
Computational Data ◽  
The Mathematical Model ◽  
Main Operating

Pneumatic driven high pressure pumps (PDHPPs), having a number of considerable advantages in comparison to other types of high pressure pumps, are widely used in different sectors of modern industry. However, estimating the performance characteristics of a PDHPP is complicated due to the specifics of physical processes taking place during its operation. A mathematical model was developed to solve this problem. Two main operating modes are considered: for constant load and for constant volume, which cover the most common uses of the PDHPPs. The solution of the model made it possible to estimate how various parameters affect the operation of the pump. Thus, with an increasing pressure of compressed air, the volume flow grows at the pump outlet; with a higher pressure of the pumped liquid due to compressibility and a higher load on the drive cylinder, the flow, on the contrary, reduces. In case the PDHPP operates for the constant volume, the time of pressure increase grows with an increase of the required pressure and the value of this volume. The mathematical model and computational data can be used in the development of new and modification of the existing pumps.

The centrally cracked Brazilian disc: implications and solutions in case of closing cracks

2014 ◽  
Vol 23 (3-4) ◽  
pp. 59-77 ◽  
Author(s):  
Christos F. Markides ◽  
Dimitrios N. Pazis ◽  
Stavros K. Kourkoulis
Keyword(s):  
Mathematical Model ◽  
Boundary Conditions ◽  
Fundamental Problem ◽  
Mathematical Problem ◽  
Radial Pressure ◽  
Contact Stresses ◽  
Displacement Fields ◽  
Brazilian Disc ◽  
Wide Range ◽  
The Mathematical Model

AbstractA recently presented closed-form analytic solution for the displacement field and stress field in a cracked Brazilian disc, under uniform radial pressure along two symmetric arcs of its periphery, revealed that for a wide range of crack-axis inclinations, the lips of the crack tend to overlap each other, leading to a kind of an “unnatural” geometrical configuration. It is here proven that this behavior is a consequence of the inability of the mathematical model to simulate the change of the boundary conditions that appears (for some special configurations) in the physical problem and render the mathematical problem an “ill-posed” one. Indeed, what happens in praxis is that for a given interval of crack inclination angles, the initially stress-free lips are coming in contact and contact stresses appear violating the boundary conditions initially adopted in the mathematical model. This problem is here solved by superposing to the above-mentioned solution the respective one of an auxiliary mixed fundamental problem solved according to Muskhelishvili’s complex potentials method. In this way, physically acceptable displacement fields and stress fields are obtained all over the cracked disc independently from the crack inclination angle. In addition, the contact stresses developed along the crack lips are determined. Moreover, naturally sound formulae for the corresponding stress intensity factors (in case of cracks with lips in contact to each other) are obtained, which are of crucial engineering importance. The solution obtained enlightens some critical aspects related to the practical application of the cracked Brazilian disc as a tool for the standardized determination of the fracture toughness of brittle rock-like materials and concrete.

DETERMINATION OF PERFORMANCE INDICATORS OF THE TRUCK KrAZ-6510TE

2020 ◽  
pp. 19-26
Author(s):  
Olexandr Pavlenko ◽  
Serhii Dun ◽  
Maksym Skliar
Keyword(s):  
Mathematical Model ◽  
Surface Friction ◽  
Building Structures ◽  
Maximum Torque ◽  
Military Equipment ◽  
Military Vehicles ◽  
Force Magnitude ◽  
Vehicle Mobility ◽  
The Mathematical Model

In any economy there is a need for the bulky goods transportation which cannot be divided into smaller parts. Such cargoes include building structures, elements of industrial equipment, tracked or wheeled construction and agricultural machinery, heavy armored military vehicles. In any case, tractor-semitrailer should provide fast delivery of goods with minimal fuel consumption. In order to guarantee the goods delivery, tractor-semitrailers must be able to overcome the existing roads broken grade and be capable to tow a semi-trailer in off-road conditions. These properties are especially important for military equipment transportation. The important factor that determines a tractor-semitrailer mobility is its gradeability. The purpose of this work is to improve a tractor-semitrailer mobility with tractor units manufactured at PJSC “AutoKrAZ” by increasing the tractor-semitrailer gradeability. The customer requirements for a new tractor are determined by the maximizing the grade to 18°. The analysis of the characteristics of modern tractor-semitrailers for heavy haulage has shown that the highest rate of this grade is 16.7°. The factors determining the limiting gradeability value were analyzed, based on the tractor-semitrailer with a KrAZ-6510TE tractor and a semi-trailer with a full weight of 80 t. It has been developed a mathematical model to investigate the tractor and semi-trailer axles vertical reactions distribution on the tractor-semitrailer friction performances. The mathematical model has allowed to calculate the gradeability value that the tractor-semitrailer can overcome in case of wheels and road surface friction value and the tractive force magnitude from the engine. The mathematical model adequacy was confirmed by comparing the calculations results with the data of factory tests. The analysis showed that on a dry road the KrAZ-6510TE tractor with a 80 t gross weight semitrailer is capable to climb a gradient of 14,35 ° with its coupling mass full use condition. The engine's maximum torque allows the tractor-semitrailer to overcome a gradient of 10.45° It has been determined the ways to improve the design of the KrAZ-6510TE tractor to increase its gradeability. Keywords: tractor, tractor-semitrailer vehicle mobility, tractor-semitrailer vehicle gradeability.

EXPERIMENTAL STUDIES OF CAR PROPERTIES ON A PHYSICAL MODEL

2019 ◽  
pp. 10-16
Author(s):  
Oleksii Timkov ◽  
Dmytro Yashchenko ◽  
Volodymyr Bosenko
Keyword(s):  
Mathematical Model ◽  
Remote Control ◽  
Physical Model ◽  
Model Experiment ◽  
Experimental Studies ◽  
Electrical Energy ◽  
Short Term ◽  
Motor Current ◽  
Memory Card ◽  
The Mathematical Model

The article deals with the development of a physical model of a car equipped with measuring, recording and remote control equipment for experimental study of car properties. A detailed description of the design of the physical model and of the electronic modules used is given, links to application libraries and the code of the first part of the program for remote control of the model are given. Atmega microcontroller on the Arduino Uno platform was used to manage the model and register the parameters. When moving the car on the memory card saved such parameters as speed, voltage on the motor, current on the motor, the angle of the steered wheel, acceleration along three coordinate axes are recorded. Use of more powerful microcontrollers will allow to expand the list of the registered parameters of movement of the car. It is possible to measure the forces acting on the elements of the car and other parameters. In the future, it is planned to develop a mathematical model of motion of the car and check its adequacy in conducting experimental studies on maneuverability on the physical model. In addition, it is possible to conduct studies of stability and consumption of electrical energy. The physical model allows to quickly change geometric dimensions and mass parameters. In the study of highway trains, this approach will allow to investigate the various layout schemes of highway trains in the short term. It is possible to make two-axle road trains and saddle towed trains, three-way hitched trains of different layout. The results obtained will allow us to improve not only the mathematical model, but also the experimental physical model, and move on to further study the properties of hybrid road trains with an active trailer link. This approach allows to reduce material and time costs when researching the properties of cars and road trains. Keywords: car, physical model, experiment, road trains, sensor, remote control, maneuverability, stability.

RESEARCH OF INDICATORS OF A VEHICLE WITH A DIESEL WORKING ON DIESEL AND DIESEL GAS CYCLES USING THE MATHEMATICAL MODEL

2020 ◽  
pp. 14-19
Author(s):  
Serhii Kovbasenko ◽  
Andriy Holyk ◽  
Serhii Hutarevych
Keyword(s):  
Mathematical Model ◽  
Diesel Engine ◽  
Environmental Performance ◽  
Energy Performance ◽  
Dual Fuel ◽  
Fuel System ◽  
Compressed Natural Gas ◽  
Diesel Vehicles ◽  
Diesel Cycle ◽  
The Mathematical Model

The features of an advanced mathematical model of motion of a truck with a diesel engine operating on the diesel and diesel gas cycles are presented in the article. As a result of calculations using the mathematical model, a decrease in total mass emissions as a result of carbon monoxide emissions is observed due to a decrease in emissions of nitrogen oxides and emissions of soot in the diesel gas cycle compared to the diesel cycle. The mathematical model of a motion of a truck on a city driving cycle according to GOST 20306-90 allows to study the fuel-economic, environmental and energy indicators of a diesel and diesel gas vehicle. The results of the calculations on the mathematical model will make it possible to conclude on the feasibility of converting diesel vehicles to using compressed natural gas. Object of the study – the fuel-economic, environmental and energy performance diesel engine that runs on dual fuel system using CNG. Purpose of the study – study of changes in fuel, economic, environmental and energy performance of vehicles with diesel engines operating on diesel and diesel gas cycles, according to urban driving cycle modes. Method of the study – calculations on a mathematical model and comparison of results with road tests. Bench and road tests, results of calculations on the mathematical model of motion of a truck with diesel, working on diesel and diesel gas cycles, show the improvement of environmental performance of diesel vehicles during the converting to compressed natural gas in operation. Improvement of environmental performance is obtained mainly through the reduction of soot emissions and nitrogen oxides emissions from diesel gas cycle operations compared to diesel cycle operations. The results of the article can be used to further develop dual fuel system using CNG. Keywords: diesel engine, diesel gas engine, CNG

Glycemia monitoring

1998 ◽  
Vol 2 ◽  
pp. 23-30
Author(s):  
Igor Basov ◽  
Donatas Švitra
Keyword(s):  
Diabetes Mellitus ◽  
Mathematical Model ◽  
Numerical Methods ◽  
Differential Equations ◽  
Blood Sugar ◽  
Self Regulation ◽  
Physiological System ◽  
Non Linear ◽  
The Mathematical Model

Here a system of two non-linear difference-differential equations, which is mathematical model of self-regulation of the sugar level in blood, is investigated. The analysis carried out by qualitative and numerical methods allows us to conclude that the mathematical model explains the functioning of the physiological system "insulin-blood sugar" in both normal and pathological cases, i.e. diabetes mellitus and hyperinsulinism.

Mathematical Models of Papermaking

2001 ◽  
Vol 6 (1) ◽  
pp. 9-19 ◽  
Author(s):  
A. Buikis ◽  
J. Cepitis ◽  
H. Kalis ◽  
A. Reinfelds ◽  
A. Ancitis ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Initial Value Problems ◽  
Moisture Transfer ◽  
Bound Water ◽  
Drying Process ◽  
Initial Value ◽  
First Order ◽  
Heat And Moisture ◽  
The Mathematical Model ◽  
The Web

The mathematical model of wood drying based on detailed transport phenomena considering both heat and moisture transfer have been offered in article. The adjustment of this model to the drying process of papermaking is carried out for the range of moisture content corresponding to the period of drying in which vapour movement and bound water diffusion in the web are possible. By averaging as the desired models are obtained sequence of the initial value problems for systems of two nonlinear first order ordinary differential equations. 

The mathematical modelling of corrosion in hot dip galvanized steel reinforced concrete

2011 ◽  
Vol 2 (1) ◽  
pp. 1-12
Author(s):  
A. Hegyi ◽  
H. Vermeşan ◽  
V. Rus
Keyword(s):  
Mathematical Model ◽  
Reinforced Concrete ◽  
Numerical Model ◽  
Equation System ◽  
Galvanized Steel ◽  
Steel Reinforced Concrete ◽  
Numeric Model ◽  
Physical And Mathematical Models ◽  
Physical Phenomena ◽  
The Mathematical Model

Abstract In this paper we wish to present the numerical model elaborated in order to simulate some physical phenomena that influence the general deterioration of steel, whether hot dip galvanized or not, in reinforced concrete. We describe the physical and mathematical models, establishing the corresponding equation system, the initial and boundary conditions. We have also presented the numeric model associated to the mathematical model and the numeric methods of discretization and solution of the differential equations system that describes the mathematical model.

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