scholarly journals IMPROVING THE STABILITY TWO-LEVEL CAR HAULER

2017 ◽  
Vol 1 (48) ◽  
pp. 8-18
Author(s):  
N. N. Shpilka
Keyword(s):  
Mathematical Model ◽  
Elastic Properties ◽  
Correct Choice ◽  
Center Of Gravity ◽  
Dynamic Processes ◽  
Lateral Stability ◽  
Location Parameters ◽  
Simulation Results ◽  
The Stability

To improve the lateral stability of car hauler way you value optimal cargo location parameters, elastically mounted on a platform, developed a mathematical model of its motion. At the same time take into account fluctuations in cargo and car hauler. According to the simulation results revealed that the system for car «hauler – cargo» accounting for elastic properties leads to a significant decrease in the frequency and amplitude of the system vertical oscillations. Therefore, the presence of the cargo can be regarded as a dynamic passive damping (in the case of a correct choice and design of layout parameters). There is proposed to reduce the distance between the cargo and the upper platform by determination of maximum values of the cargo oscillations amplitudes. In turn, the reduction of the height of the platform reduces the height of the center of gravity of the system, improves the stability of car hauler. Keywords: car hauler, dynamic processes, fluctuations, platform, stability.  

TO THE STABILITY OF TANK VEHICLES IN THE BRAKE MODE

2019 ◽  
pp. 27-32
Author(s):  
Denys Popelysh ◽  
Yurii Seluk ◽  
Sergyi Tomchuk
Keyword(s):  
Mathematical Model ◽  
Control Systems ◽  
Distribution Systems ◽  
Traffic Accidents ◽  
Road Traffic ◽  
Center Of Mass ◽  
Dynamic Processes ◽  
Course Stability ◽  
The Stability ◽  
Tank Vehicles

This article discusses the question of the possibility of improving the roll stability of partially filled tank vehicles while braking. We consider the dangers associated with partially filled tank vehicles. We give examples of the severe consequences of road traffic accidents that have occurred with tank vehicles carrying dangerous goods. We conducted an analysis of the dynamic processes of fluid flow in the tank and their influence on the basic parameters of the stability of vehicle. When transporting a partially filled tank due to the comparability of the mass of the empty tank with the mass of the fluid being transported, the dynamic qualities of the vehicle change so that they differ significantly from the dynamic characteristics of other vehicles. Due to large displacements of the center of mass of cargo in the tank there are additional loads that act vehicle and significantly reduce the course stability and the drivability. We consider the dynamics of liquid sloshing in moving containers, and give examples of building a mechanical model of an oscillating fluid in a tank and a mathematical model of a vehicle with a tank. We also considered the method of improving the vehicle’s stability, which is based on the prediction of the moment of action and the nature of the dynamic processes of liquid cargo and the implementation of preventive actions by executive mechanisms. Modern automated control systems (anti-lock brake system, anti-slip control systems, stabilization systems, braking forces distribution systems, floor level systems, etc.) use a certain list of elements for collecting necessary parameters and actuators for their work. This gives the ability to influence the course stability properties without interfering with the design of the vehicle only by making changes to the software of these systems. Keywords: tank vehicle, roll stability, mathematical model, vehicle control systems.

New Methodology for the Determination of the Vertical Center of Gravity of In-Service Semisubmersibles: Proposal and Numerical Assessment

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Ivan N. Porciuncula ◽  
Claudio A. Rodríguez ◽  
Paulo T. T. Esperança
Keyword(s):  
Accurate Determination ◽  
Center Of Gravity ◽  
Practical Implementation ◽  
Numerical Assessment ◽  
Neutral Equilibrium ◽  
Inclination Angles ◽  
Numerical Tools ◽  
The Stability ◽  
Metacentric Height

Along its lifetime, an offshore unit is subjected to several equipment interventions. These modifications may include large conversions in loco that usually are not adequately documented. Hence, the accurate determination of the platform's center of gravity (KG) is not possible. For vessels with low metacentric height (GM), such as semisubmersibles, Classification Societies penalize the platform's KG, inhibiting the installation of new equipment until an accurate measurement of KG is provided, i.e., until an updated inclining test is performed. For an operating semisubmersible, the execution of this type of test is not an alternative because it implies in removing the vessel from its in-service location to sheltered waters. Relatively recently, some methods have been proposed for the estimation of KG for in-service vessels. However, as all of the methods depend on accurate measurements of inclination angles and, eventually, on numerical tools for the simulation of vessel dynamics onboard, they are not straightforward for practical implementation. The objective of the paper is to present a practical methodology for the experimental determination of KG, without the need of accurate measurements of inclinations and/or complex numerical simulations, but based on actual operations that can be performed onboard. Indeed, the proposed methodology relies on the search, identification, and execution of a neutral equilibrium condition where, for instance, KG = KM. The method is exemplified using actual data of a typical semisubmersible. The paper also numerically explores and discusses the stability of the platform under various conditions with unstable initial GM, as well as the effect of mooring and risers.

scholarly journals Introducing a particular mathematical model for predicting the resistance and performance of prismatic planing hulls in calm water by means of total pressure distribution

2015 ◽  
Vol 12 (2) ◽  
pp. 73-94 ◽  
Author(s):  
P. Ghadimi ◽  
S. Tavakoli ◽  
M. A. Feizi Chekab ◽  
A. Dashtimanesh
Keyword(s):  
Mathematical Model ◽  
Pressure Distribution ◽  
Total Pressure ◽  
Center Of Gravity ◽  
Governing Equations ◽  
Calm Water ◽  
Hydrodynamic Study ◽  
Pass Through ◽  
And Performance

Mathematical modeling of planing hulls and determination of their characteristics are the most important subjects in hydrodynamic study of planing vessels. In this paper, a new mathematical model has been developed based on pressure distribution. This model has been provided for two different situations: (1) for a situation in which all forces pass through the center of gravity and (2) for a situation in which forces don not necessarily pass through the center of gravity. Two algorithms have been designed for the governing equations. Computational results have been presented in the form of trim angle, total pressure, hydrodynamic and hydrostatic lift coefficients, spray apex and total resistance which includes frictional, spray and induced resistances. Accuracy of the model has been verified by comparing the numerical findings against the results of Savitsky's method and available experimental data. Good accuracy is displayed. Furthermore, effects of deadrise angle on trim angle of the craft, position of spray apex and resistance have been investigated.

Fuzzy Parameter Based Mathematical Model on Forest Biomass

2018 ◽  
Vol 13 (04) ◽  
pp. 179-193 ◽  
Author(s):  
Prabir Panja
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Time Delay ◽  
Human Population ◽  
Equilibrium Points ◽  
Forest Biomass ◽  
Simulation Results ◽  
The Stability ◽  
Fuzzy Parameter

In this paper, a fuzzy mathematical model has been developed by considering forest biomass, human population and technological effort for the conservation of forest biomass as separate compartments. We have assumed that the forest biomass and human population grows logistically. We have considered that forest biomass decreases due to industrialization, food, shelter, etc., for humans. For the conservation of forest biomass, some modern technological efforts have been used in this model. Also, time delay of use of modern technological effort for the conservation of forest biomass has been considered on forest biomass. According to the assumptions, a fuzzy mathematical model on forest biomass is formulated. Next we have determined different possible equilibrium points. Also, the stability of our proposed system around these equilibrium points has been discussed. Finally, some numerical simulation results have been presented for better understanding of our proposed mathematical model.

scholarly journals Alternative Models for Calculation of Static Overturning Angle and Lateral Stability Analysis of Subcompact and Universal Tractors

Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 861
Author(s):  
Radoslav Majdan ◽  
Rudolf Abrahám ◽  
Katarína Kollárová ◽  
Zdenko Tkáč ◽  
Eva Matejková ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Calculation Method ◽  
Rear Axle ◽  
Rear Wheel ◽  
Center Of Gravity ◽  
Lateral Stability ◽  
Regression Effect ◽  
Minimal Difference ◽  
Significant Regression ◽  
The Stability

Vehicle lateral stability is evaluated using the static overturning angle. The correct value of this parameter depends on the calculation method. The aim of this study was to compare the latest standard with previously published methodology, to propose two alternative methodologies (Models 1 and 2) and to analyze the influence of various levels of rear wheel ballast weights and overall tire widths on the stability of universal and subcompact tractors. The results showed a significant regression effect of the rear wheel ballast weight on static overturning angle. The influence of the rear wheel ballast weight was higher in the subcompact tractor than in the universal tractor due to a larger distance between the height of the center of gravity and the center of the rear axle. Comparing the latest standard with the previously published methodology, the highest difference values were 13.82% and 7.30%. Both models are based on the previously published methodology and differ from each other in rolling and slope lines. The methodology proposed in Model 2 differed from the standard similarly to the previously published methodology; therefore, it is irrelevant. Model 1 reached differences of only −1.81% and −1.63%, representing a minimal difference from the standard.

scholarly journals Determination of critical flow velocity for tube-bundle with application of numerical investigation method

Energetika ◽  
2016 ◽  
Vol 61 (3-4) ◽  
Author(s):  
Alexey Samolysov ◽  
Saveliy Kaplunov ◽  
Natalia Vales ◽  
Olga Marchevskaya ◽  
Elena Dronova
Keyword(s):  
Mathematical Model ◽  
Numerical Investigation ◽  
Tube Bundle ◽  
Connection Matrix ◽  
Investigation Method ◽  
Elastic Tubes ◽  
Tube Bundles ◽  
The Creation ◽  
The Stability

The work is devoted to the creation and application of mathematical models for the most dangerous oscillation excitation mechanisms of tubes and cylindrical form bluff structures in liquid or gas flow, as well as to the creation of efficient computational methods for description of these models. A numerical investigation method of hydrodynamic forces arising from a  separated flow and tube-bundle oscillations excited by these forces was developed by the authors. The method is based on the  application of created original tube-bundle hydroelastic oscillation excitation in a cross-flow mathematical model. Hydroelastic excitation problem is reduced to the stability analysis of undisturbed state of elastic tubes. Analysis is conducted with the assumption of linearity of the destabilizing forces. On the basis of the mathematical model, the necessary and sufficient condition for the  stability, expressed through the  dimensionless system parameters (mass, damping, velocity), was obtained. Numerical identification of the  linear hydrodynamic connection matrix algorithm for particular tube-bundles was elaborated. Verification of algorithm and programs based on it was performed by results of simulations and available experimental data correlation. A method for determination of a linear hydrodynamic connection matrix for tube-bundles with a regular arrangement of the cross-section was offered. It is based on computation of a relatively small, but sufficient for reliable results, part of the tube-bundle.

Simulation Technologies for Tamper System of Asphalt-Paver Based on AMESim

2010 ◽  
Vol 129-131 ◽  
pp. 1098-1103 ◽  
Author(s):  
Tian Hong Luo ◽  
Xin Fu Gan ◽  
Wen Jun Luo
Keyword(s):  
Mathematical Model ◽  
Simulation Model ◽  
Pid Controller ◽  
Dynamic Performance ◽  
Operating Principle ◽  
Simulation Results ◽  
The Stability ◽  
The Mathematical Model

Tamper mechanism is one of the most important parts in all of Asphalt-pavers. In this article, the mathematical model of the tamper system has been established and the stability of the system has been analyzed by using Matlab. According to the operating principle of tamper system of Asphalt-paver, the simulation model of tamper system of Asphalt-paver has been established by using AMESim. The main parameters of the model were set, and then, the simulation results were analyzed, which show that the system is stable and the dynamic performance of system will be improved, when accumulator and PID controller were equipped. Besides, the tamping frequency of hammer is very important to the performance of system. When tamping frequency of hammer over 20HZ, the performance of system will go bad.

scholarly journals OPTIMIZATION PARAMETERS OF IRRIGATION PROCESS ACCORDING TO THE UNIFORMITY

2012 ◽  
Vol 15 (1) ◽  
pp. 80-89
Author(s):  
Tuyen Vo ◽  
Nam Thanh Nguyen ◽  
Lien Duc Hoang
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Experimental Determination ◽  
Optimal Parameters ◽  
Optimization Parameters ◽  
Simulation Results

In order to determine the optimal parameters of irrigation process in order to verify the accuracy of the numerical simulation results of experimental determination of the effective spray during irrigation [2], [6]. This paper will conduct empirical planning, establishing empirical mathematical model to determine the diameter of the nozzle, swirl coefficient and irrigation output according to the uniformity.

scholarly journals Mathematical Model for Errors Estimation of Object’s Location Parameters Determination Using Flying Platform

2019 ◽  
Vol 10 ◽  
pp. 26-30
Author(s):  
Volodimir Korolov ◽  
Stepan Savchuk ◽  
Olha Korolova ◽  
Ihor Milkovich ◽  
Yaroslav Zaec
Keyword(s):  
Mathematical Model ◽  
Estimation Error ◽  
Observation Point ◽  
Location Parameters ◽  
Range Determination ◽  
Aerial Observation ◽  
Object Parameters ◽  
Errors Estimation ◽  
The Mathematical Model

Some tasks require identification of landmarks in districts beyond the reach of existing optical observation facilities. The accuracy of their determination significantly affects the effectiveness of the use necessary equipment during the task. In the paper an algorithm to determine the object parameters using a flying platform is offered. An observation point is installed which is equipped with a navigation system to solve this task. This ensures its orientation and positioning. From the observation point an aerial observation point is displayed. It is suggested to use a flying platform. The coordinates of the flying platform are determined relative to the observation point, the coordinates of the landmarks are determined relative to the flying platform. The mathematical model of the estimation error determination of object coordinates with the help of a flying platform is proposed. The analysis of errors in determining the parameters of the object using a flying platform is conducted. Analysis of the results of mathematical modeling is conducted using the package of applications Mathcad. The dependence of these parameters on the relative position of the observation point, platforms and object is examined. It is shown that the main contribution to the error of determining the coordinates of the landmark is given by the errors of determining the observation point location and measuring the range. An analytical correlation is obtained, which allows to estimate the errors of determining the coordinates of the landmark using the flying platform with known errors in determining the observation point coordinates and the range determination of the range finder.

scholarly journals ANALISIS DINAMIK MODEL PENDANGKALAN DANAU LIMBOTO DENGAN PEMBERSIHAN ECENG GONDOK DAN PENGERUKAN ENDAPAN

2020 ◽  
Vol 14 (4) ◽  
pp. 597-608
Author(s):  
Sri Lestari Mahmud ◽  
Novianita Achmad
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Stability Condition ◽  
Water Hyacinth ◽  
First Order ◽  
Lake Volume ◽  
Cleaning Solution ◽  
Simulation Results ◽  
The Stability ◽  
First Order Differential Equations

This article discusses about mathematical model of Limboto lake silting with water hyacinth cleaning solution. Modelling begins with constructing a model based on the factors that affect silting which is then formed into a system of first order differential equations. Furthermore, the model is analyzed by looking for equilibrium and stability. To see the condition of lake silting based on the stability condition, a numerical simulation was performed. The simulation results show that with water hyacinth cleaning, the lake will maintain its existence, which is indicated by an increase the Limboto lake volume, although there is still a decrease in volume due to the presence of sediment and nutrients from the river.

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