scholarly journals A STUDY OF THE DEFLECTIONS OF METAL ROAD GUARDRAIL ELEMENTS

Transport ◽  
2009 ◽  
Vol 24 (3) ◽  
pp. 225-233 ◽  
Author(s):  
Olegas Prentkovskis ◽  
Andrey Beljatynskij ◽  
Rasa Prentkovskienė ◽  
Ivan Dyakov ◽  
Laima Dabulevičienė
Keyword(s):  
Mathematical Model ◽  
Finite Elements ◽  
Traffic Accidents ◽  
Statistical Data ◽  
Elastic Deformations ◽  
One Dimensional ◽  
First Order ◽  
Horizontal Beam ◽  
Deformation Processes ◽  
The Impact

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 model of metal road guardrail, the deflections of its elements caused by the impact of a vehicle moving at varying speed were determined. The obtained values of deflections of guardrail elements (a protective W‐shape horizontal beam and a S‐shape post) presented in paper do not exceed the admissible values (of beam deflections).

scholarly journals INVESTIGATION OF POTENTIAL DEFORMATIONS DEVELOPED BY ELEMENTS OF TRANSPORT AND PEDESTRIAN TRAFFIC RESTRICTING GATES DURING MOTOR VEHICLE–GATE INTERACTION

Transport ◽  
2007 ◽  
Vol 22 (3) ◽  
pp. 229-235 ◽  
Author(s):  
Olegas Prentkovskis ◽  
Rasa Prentkovskienė ◽  
Ona Lukoševičienė
Keyword(s):  
Mathematical Model ◽  
Finite Elements ◽  
Motor Vehicle ◽  
The Other ◽  
Motor Vehicles ◽  
One Dimensional ◽  
First Order ◽  
Pedestrian Traffic ◽  
The Impact ◽  
The Mathematical Model

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.

THE IMPACT OF THE DIMENSION OF A MATHEMATICAL MODEL OF INTERNAL BALLISTICS ON DESIGN PARAMETERS OF A SHOT FOR GRAIN GUNPOWDER CHARGES

2021 ◽  
pp. 95-110
Author(s):  
I.G. Rusyak ◽  
◽  
V.A. Tenenev ◽  
Keyword(s):  
Mathematical Model ◽  
Powder Mixture ◽  
Thermodynamic Model ◽  
Dynamic Models ◽  
Design Parameters ◽  
Variable Cross ◽  
One Dimensional ◽  
Gas Dynamic ◽  
Wide Range ◽  
The Impact

The problem of the impact of the mathematical model dimension on the calculated intraballistic characteristics of a shot for the charges made of granulated powder is considered. Mathematical models of the shot are studied using the spatial (axisymmetric), one-dimensional, and zero-dimensional (thermodynamic) formulations. The thermodynamic model takes into account the distribution of the pressure and velocity of a gas-powder mixture behind the shot for a channel of variable cross-section. Comparison of simulation results is carried out in a wide range of loading parameters. It is shown that there is a range of the loading parameters for a thermodynamic approach to give satisfactory approximation to the parameters obtained using the gas-dynamic approach, which describes the flow of a heterogeneous reacting mixture with a separate consideration of phases and intergranular interactions between them. Notably that in the entire range of the charging parameters studied in this work, the one-dimensional and twodimensional gas-dynamic models only slightly differ from each other. Therefore, in the main pyrodynamic period, the actuation of the charge, made of granulated powder, can be simulated using a one-dimensional gas-dynamic model or a zero-dimensional thermodynamic model with allowance for spatial distribution of the pressure and velocity of the gas-powder mixture.

One-Dimensional Model and Numerical Simulation of Two-Stage Light-Gas Launching Facility

2011 ◽  
Vol 66-68 ◽  
pp. 477-482
Author(s):  
Xin Lu ◽  
Yong Gang Yu ◽  
Yan Huang Zhou
Keyword(s):  
Mathematical Model ◽  
Structural Design ◽  
Piston Compressor ◽  
Two Stage ◽  
Numerical Accuracy ◽  
Piston Velocity ◽  
One Dimensional ◽  
First Order ◽  
Computing Model ◽  
Gas Chamber

In this paper, a one-dimensional mathematical model is established and simulated numerically for the interior ballistic cycle of two-stage light-gas launching facility with a piston-compressor type. A 35mm/130mm light-gas launcher is taken for the primary computing model, and lots of data, such as the pressure on light-gas chamber, the piston velocity, the diaphragm failure pressure, etc. are obtained by computing the model using the numerical difference scheme with the second order of numerical accuracy in space and the first order in time. On the basis of the results of analyzing these data systematically, some advices on enhancing the launching performance of light-gas launcher are put forward. The numerical results show that the developed mathematical model gives the correct trend and can provide useful calculated parameters for the structural design of the components of two-stage light-gas launcher.

Computational Algorithms For Modeling of One-Dimensional Contours Through k In Advance Given Points

2018 ◽  
Vol 6 (3) ◽  
pp. 20-32 ◽  
Author(s):  
Евгений Конопацкий ◽  
Evgeniy Konopatskiy ◽  
А. Крысько ◽  
A. Krys'ko ◽  
А. Бумага ◽  
...  
Keyword(s):  
Numerical Study ◽  
Analytical Description ◽  
Computational Algorithms ◽  
Engineering Structures ◽  
Symbolic Form ◽  
One Dimensional ◽  
First Order ◽  
Arc Shape ◽  
The Impact ◽  
Order Smoothness

In this paper have been proposed theoretical bases for formation one-dimensional contours of the first order smoothness, passing through k in advance given points, including requirements to the contour in general, and the contour’s arcs in particular, as well as representations for tangents in extreme and intermediate contour sections, which determine the contour arc shape. Based on this theoretical material have been developed computational algorithms for simulation of closed (A5, A6) and open (A1-A4) contours according to postulated conditions, which allow form irregular composite curves and surfaces with different degree of complexity, docked together on the first order smoothness. The proposed computational algorithms can also be used to construct contours of higher orders smoothness using arcs of the same ratio curves. For analytical description of computational algorithms for one-dimensional contours simulation is used the mathematical apparatus of BN-calculation (Balyuba – Naidysh point calculation). The obtained algorithms have been presented in a point form, which is a symbolic form. For transition from point equations to a system of parametric equations, it is necessary to perform a coordinate-by-coordinate calculation, which can be presented geometrically as population of projections on the global coordinate system’s axes. As an example has been presented a computational algorithm that provides the use a system of parametric equations instead of symbolic point recording. The proposed algorithms have been successfully used for computer modeling and prediction for the impact of geometric shape imperfections on the strength and stability of engineering structures’ thin-walled shells. In particular, a numerical study method for a stress-strain state of steel vertical cylindrical reservoirs with regard to imperfections of theirs geometric shapes has been proposed.

Assessing the Impact of Inverter Current-Ripple on SOFC Performance

2003 ◽  
Author(s):  
Randall S. Gemmen ◽  
Parviz Famouri ◽  
Christopher Johnson
Keyword(s):  
Fuel Cell ◽  
Transient Model ◽  
One Dimensional ◽  
Fuel Cell Stack ◽  
First Order ◽  
A Cell ◽  
Current Loading ◽  
Dc Current ◽  
The Impact ◽  
Current Ripple

The effect of inverter ripple current on fuel cell stack performance is not well understood. This paper provides a first-order examination of the impact of inverter load dynamics on SOFC fuel cell operation. Previous work using steady-state fuel cell loading has shown that DC-current loading itself results in degradation of the fuel cell, albeit in ways yet to be fully understood. This result suggests that the varying reactant conditions that result from ripple may modify degradation processes, and, therefore, the lifetime of the cells. This paper investigates these conditions through the use of a dynamic one-dimensional model for the detailed mass transport occurring within the electrode of a cell. In this work, the inverter load is imposed as a boundary condition to the transient model. Results show the behavior of the reactant concentrations within the stack electrodes under inverter loads with frequencies between 60 Hz and 1250 Hz. It is concluded that a ripple factor of less than 6% be used to ensure minor impact to the conditions at the electrode-electrolyte interface.

scholarly journals The Impact of the Efficiency of the System for Vibrations Damping on the Efficiency of Vehicle Braking

2018 ◽  
Vol 3 (1-2) ◽  
Author(s):  
N Manojlović ◽  
Drago Talijan ◽  
B Bajić
Keyword(s):  
Mathematical Model ◽  
Traffic Accidents ◽  
Braking System ◽  
Shock Absorbers ◽  
Two Systems ◽  
The Moment ◽  
The Impact ◽  
Vehicle Movement

This paper presents the plan and results of the research of the efficiency of the braking system depending on the condition of the shock absorbers and the velocity of the vehicle movement at the moment of braking. As expected, it has been proven that the braking efficiency decreases with decreasing efficiency of the system for damping vibrations. The interdependence of these two systems is also represented by a mathematical model that can serve for practical purposes in the analysis of traffic accidents.

Impact Forces of Vanes on Rotor Slots in a Rotary Compressor

2008 ◽  
Author(s):  
Yuan Mao Huang ◽  
Z. C. Yu
Keyword(s):  
Mathematical Model ◽  
Shear Deformation ◽  
Plate Theory ◽  
Hertzian Contact ◽  
Rotary Compressor ◽  
First Order ◽  
Impact Forces ◽  
The Impact ◽  
Abaqus Software ◽  
Good Agreement

This study analyzes the impact of vanes on rotor slots in a sliding vane rotary compressor that is simulated by impact of two plates. The Hertzian contact rule and the first order shear deformation plate theory with consideration of the shear deformation and the rotary inertia are utilized to generate a mathematical model. Impact forces when a vane locates at various locations and time are calculated. The calculated results are compared and show good agreement with those obtained by using ABAQUS software.

The Impact of Light Polarisation on Light Field of Scenes with Multiple Reflections

2020 ◽  
pp. 108-115 ◽  
Author(s):  
Vladimir P. Budak ◽  
Anton V. Grimaylo
Keyword(s):  
Mathematical Model ◽  
Light Field ◽  
Global Illumination ◽  
Multiple Reflections ◽  
Software Environment ◽  
The Monte Carlo Method ◽  
Mueller Matrices ◽  
Volume Integration ◽  
The Impact

The article describes the role of polarisation in calculation of multiple reflections. A mathematical model of multiple reflections based on the Stokes vector for beam description and Mueller matrices for description of surface properties is presented. On the basis of this model, the global illumination equation is generalised for the polarisation case and is resolved into volume integration. This allows us to obtain an expression for the Monte Carlo method local estimates and to use them for evaluation of light distribution in the scene with consideration of polarisation. The obtained mathematical model was implemented in the software environment using the example of a scene with its surfaces having both diffuse and regular components of reflection. The results presented in the article show that the calculation difference may reach 30 % when polarisation is taken into consideration as compared to standard modelling.

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.

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. 

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