scholarly journals Pressure profile definition over the metal orthotropic deck surface of the decking superstructure ballast pocket from the local load action

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
Ilya Zasukhin
Keyword(s):  
Theoretical Study ◽  
Pressure Profile ◽  
Rolling Stock ◽  
Infinite Length ◽  
Problem Solution ◽  
Short Beam ◽  
Load Action ◽  
The Cross ◽  
Rolling Load ◽  
Different Thickness

The article discusses the interaction issue between the track and the rolling stock to determine the forces working on the track during the passage of a rolling load, and their further distribution through the ballast bed. The study aims to determine the vertical pressure profile working on the orthotropic metal ballast bed slab of the railway superstructure. To determine the load share from the rolling stock transferred from the rails to the cross-sleepers, the rail is represented as a beam of infinite length with one or several concentrated forces. To determine the cross-sleeper stress-strain state, it is considered as a short beam on a cushion course. The article presents the substantiation of the flow mechanics formulas application possibility to the ballast bed. Based on the Boussinesq problem solution, calculation formulas are obtained for determining the pressure along with the ballast bed plate. The results obtained by the proposed method were compared with other authors’ experimental data and the finite element modeling results in the Midas FEA software package. The analysis took into account the design features of the ballast bed plates and the track superstructure on the existing superstructures. A theoretical study of the influence of the sheet of the covering bending stiffness on the pressure profile northing is carried out. The proposed method is applicable for various superstructure and the ballast bed slab, and also takes into account the uneven pressure distribution on the inner and outer rails from the trainload, changes in eccentricity along the length of the structure, different thickness of the ballast bed under the cross-sleepers ends, as well as the effect of centrifugal force.

Cross Wind Protection Systems for High Speed Railway Lines

2010 ◽  
Author(s):  
Paula Alvarez-Legazpi ◽  
Marta Vargas-Mun˜oz ◽  
Jose´ Conrado Marti´nez-Acevedo ◽  
Joaqui´n Botella-Malago´n ◽  
Manuel Rodri´guez-Ferna´ndez
Keyword(s):  
High Speed ◽  
Rolling Stock ◽  
Railway Traffic ◽  
Protection Systems ◽  
Active Protection ◽  
Rail Line ◽  
Forecast Models ◽  
Key Issues ◽  
Wind Detection ◽  
The Cross

Higher operating rail speeds and lighter rolling stock means that cross wind, a factor that had not been considered for railway operations until recent times, has acquired vital importance in keeping adequate safety levels for railway transport of passengers. The overturn risk for a train circulating on a high speed line is determined by three key issues: • TRAIN: its aerodynamic and dynamic characteristics. • LINE: radius, azimuth, type of infrastructure, etc. • WIND: speed and angle with the train: – Wind statistics at the cross wind detection stations. – Wind models with spatial extrapolation for estimating average and actual wind on each section of the line. – Temporal forecast models at the cross wind detection stations. The combination of a certain rail line and a specific vehicle allows the determination of the criticality of each site. Once the authoritative safety target has been defined, according to this overturn risk, the adequate operating procedures must be defined. There are three possible types of protection systems: • Passive protection: protection walls or wind screens. • Active protection: short term (minutes) wind alert systems that impose restrictions to train speed when strong cross wind conditions are predicted. • Special procedures to regulate railway traffic under critical wind conditions. This paper presented hereby describes the studies to determine the susceptible sections to be protected, focus afterwards, specifically on active protection systems themselves, and main actions for its implementation.

Dynamic response of a thick functionally graded material tube under a moving load

2007 ◽  
Vol 221 (12) ◽  
pp. 1545-1554 ◽  
Author(s):  
S M Hasheminejad ◽  
M Komeili
Keyword(s):  
Functionally Graded Material ◽  
Shell Thickness ◽  
Moving Load ◽  
Functionally Graded ◽  
Solution Technique ◽  
Infinite Length ◽  
Problem Solution ◽  
Outer Interface ◽  
Normal Ring ◽  
Graded Material

An analysis for axisymmetric steady-state response of an arbitrarily thick, isotropic, and functionally graded circular cylindrical shell of infinite length subjected to an axially moving normal ring load is presented. The mechanical properties of the graded shell are assumed to vary smoothly and continuously with the change of volume concentrations of the constituting materials across the thickness of the shell according to a power law distribution. The problem solution is derived by using Fourier transformation with respect to a moving reference frame in conjunction with the T-matrix solution technique that involves a system global transfer matrix, formed by applying continuity of the displacement and stress components at the interfaces of neighbouring layers. The analytical results are illustrated with numerical examples in which a metal-ceramic functionally graded material (FGM) pipe, composed of aluminium and zirconia, is subjected to a normal ring load travelling along the tube at constant speed. Four types of pipes are configured, i.e. a ceramic-rich composition with the ceramic at the inner (or outer) interface, and also a metal-rich composition with the metal at the inner (or outer) interface of the pipe. The presented model is used to determine the critical velocity of the moving load as a function of shell thickness for the selected material compositional gradient profiles. The effects of load velocity and shell thickness on the basic dynamic field quantities such as the mid-plane radial displacement and hoop stress amplitude along the pipe axis are also evaluated and discussed. Moreover, the response curves for the FGM shells are compared with those of equivalent bi-laminate shells containing comparable total volume fractions of constituent materials. Limiting cases are considered and good agreements with the solutions available in the literature are obtained.

scholarly journals The cross-disciplinary approach to analysis and forecast of operational damage tolerance of the oil pipeline system – part 2

2020 ◽  
Vol 4 (1) ◽  
pp. 62-73
Author(s):  
Sergei S. Sherbakov ◽  
◽  
Keyword(s):  
Damage Tolerance ◽  
Weld Zone ◽  
Fatigue Tests ◽  
Pipeline System ◽  
Transverse Strain ◽  
Problem Solution ◽  
Line Pipe ◽  
Internal Corrosion ◽  
Oil Pipeline ◽  
The Cross

The paper presents the cross-disciplinary approach to the analysis of the oil pipeline system based on the methodologies of tribo-fatigue and mechano-thermodynamics. The pipeline section is analyzed as a complex system pipe-soil- flow of liquid subject to the set of mechanical, thermal and friction loads. It is shown that theses loads are mainly repeatedlyalternated, and the pipe metal works in the multi-cycle fatigue conditions. The procedure of resonance accelerated fatigue tests is proposed, and their results are presented. Also, the unorthodox method of integrated wear-fatigue tests of the pipeline steel was proposed with the model of simultaneous pressure and wall friction actions. The presented field test results of pipes subject to the long-term operation showed that their fracture may occur not only in the near-weld zone, but also in the vicinity of internal corrosion damages. New models of three-dimensional stress-strain state and volumetric damage tolerance for the system pipe-soil-liquid flow were developed. These models were applied with regard to the pipe internal corrosion damages, defined using the inline inspection technique. A new efficient method to describe static and cyclic elastic-plastic fracture of the pipe steel with crack using the transverse strain is proposed and tested. Results of the computer-simulated propagation of the crack-like damage are based upon the model of deformed solid with dangerous volume. The new model is proposed for risk and safety assessment with regard to the ultrasonic inspection data. The algorithm of the ‘oil line pipe’ problem solution is presented for drafting a short-term plan of particular R&D actions.

Application of a multipole potential in a theoretical investigation of collision cross-sections for ions with linear molecules

1970 ◽  
Vol 318 (1532) ◽  
pp. 107-118 ◽  
Keyword(s):  
Large Deviations ◽  
Angular Dependence ◽  
Theoretical Investigation ◽  
Cross Sections ◽  
Theoretical Study ◽  
Multipole Expansion ◽  
Rotational State ◽  
Experimental Results ◽  
Linear Molecules ◽  
The Cross

A theoretical study has been made of the effects of permanent dipoles and quadrupoles on the cross-sections of ion-neutral collisions. The angular dependence of the multipole potential is investigated and its implications regarding experimental results are described. Anisotropy in the polarizability as it influences cross-sections has also been studied. For linear molecules the theory indicates that large deviations from the cross-sections predicted by a simple Langevin treatment will be visible if the neutral is selected according to its rotational state, but that 'bulk' experiments will only be weakly affected by the presence of angle dependent terms in the multipole expansion.

scholarly journals Study on the Cross Plane Thermal Transport of Polycrystalline Molybdenum Nanofilms by Applying Picosecond Laser Transient Thermoreflectance Method

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Tingting Miao ◽  
Weigang Ma ◽  
Xing Zhang ◽  
Keisuke Kubo ◽  
Masamichi Kohno ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Thermal Transport ◽  
Picosecond Laser ◽  
Free Electrons ◽  
Optical Components ◽  
Glass Substrates ◽  
The Cross ◽  
Significant Size ◽  
Different Thickness ◽  
Polycrystalline Molybdenum

Thin metal films are widely used as interconnecting wires and coatings in electronic devices and optical components. Reliable thermophysical properties of the films are required from the viewpoint of thermal management. The cross plane thermal transport of four polycrystalline molybdenum nanofilms with different thickness deposited on glass substrates has been studied by applying the picosecond laser transient thermoreflectance technique. The measurement is performed by applying both front pump-front probe and rear pump-front probe configurations with high quality signal. The determined cross plane thermal diffusivity of the Mo films greatly decreases compared to the corresponding bulk value and tends to increase as films become thicker, exhibiting significant size effect. The main mechanism responsible for the thermal diffusivity decrease of the present polycrystalline Mo nanofilms is the grain boundary scattering on the free electrons. Comparing the cross plane thermal diffusivity and inplane electrical conductivity indicates the anisotropy of the transport properties of the Mo films.

scholarly journals Effects of Proximity Potentials on the Cross-Sections of 6,8He + 65Cu Halo Fusion Reactions

2019 ◽  
Vol 64 (5) ◽  
pp. 363
Author(s):  
M. Aygun
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Theoretical Study ◽  
Fusion Reactions ◽  
The Cross ◽  
Theoretical Results

The comprehensive theoretical study is performed to determine the best proximity potentials in reproducing 6,8He + 65Cu fusion reactions. Twenty three different versions of proximity potentials that consist of Prox 66, Prox 76, Prox 77, Prox 79, Prox 81-I, Prox 81-II, Prox 81-III, Prox 84, Prox 88, Mod-Prox-88, Prox 95, Prox 2003-I, Prox 2003-II, Prox 2003-III, Prox 2010, BW 91, AW 95, Bass 73, Bass 77, Bass 80, CW 76, Ngo 80, and D are used. The theoretical results are compared with experimental data on 6,8He + 65Cu fusion reactions. The appropriate proximity potentials are determined.

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