scholarly journals Determination of railway track longitudinal profile using measured inertial response of an in-service railway vehicle

2017 ◽  
Vol 17 (6) ◽  
pp. 1425-1440 ◽  
Author(s):  
Eugene J OBrien ◽  
Paraic Quirke ◽  
Cathal Bowe ◽  
Daniel Cantero
Keyword(s):  
Longitudinal Profile ◽  
Railway Track ◽  
Railway Vehicle ◽  
Vertical Acceleration ◽  
Track Condition ◽  
Inertial Response ◽  
Measured Response ◽  
Good Agreement

The use of sensors fixed to in-service trains has the potential to provide real-time track condition monitoring to inform maintenance planning. An Irish Rail intercity train was instrumented for a period of 1 month so that a numerical method developed to find track longitudinal profile from measured vehicle inertial responses could be experimentally tested. A bogie-mounted accelerometer and gyrometer measured vertical acceleration and angular velocity as the train made regular service operations between Dublin and Belfast on the island of Ireland. Cross entropy optimisation is used to find a track longitudinal profile that generates a numerical inertial response that best fits the measured response. Tolerance limits are used to inject variance where required to ensure a good match between measured and modelled signals. A section of track with known track settlement history is selected as a case study. A level survey was undertaken during the measurement campaign to characterise the longitudinal profile through the test section. Bandpass filters are used to compare inferred profiles and the surveyed profile. Good agreement is found between the two profiles although improvements in accuracy and reproducibility are required before conformance with current standards is achieved.

scholarly journals Methodology for studying impulse disturbance from rail joints to the railway vehicle and assessment of the efficiency of the new spring suspension

2018 ◽  
Vol 239 ◽  
pp. 01032
Author(s):  
Viktor Nekhaev ◽  
Viktor Nikolaev ◽  
Evgenii Cheltygmashev
Keyword(s):  
Energy Dissipation ◽  
Comparative Assessment ◽  
Railway Track ◽  
Railway Vehicle ◽  
Vertical Acceleration ◽  
External Disturbances ◽  
Spring Suspension ◽  
Dynamic Forces ◽  
Typical Scheme ◽  
Freight Car

The methodology for studying the impulse disturbance of the railway track joints on the indicators of the dynamic qualities of the railway vehicle has been developed. The dependence of the impulse repetition factor on the energy dissipation level in the system and the speed of the vehicle is obtained. A comparative assessment of the dynamic qualities of a freight car with a typical scheme of spring suspension and a car with suspension based on the principle of compensation of external disturbances is performed. It has been established that the spring suspension of a freight car based on the principle of compensation of external disturbances delivers to it significantly better indicators of dynamic qualities in comparison with car equipped with a new three-piece truck with a typical scheme of springs. Vertical acceleration of the car’s body with a new scheme of vibration protection and dynamic forces in spring suspension is several times less than for a car with a typical three-piece truck structure.

Determination of wheel loading reduction in railway track with unsupported sleepers and rail irregularities

2020 ◽  
pp. 095440972095093
Author(s):  
Mojtaba Azizi ◽  
Majid Shahravi ◽  
Jabbar Ali Zakeri
Keyword(s):  
Railway Track ◽  
Vehicle Speed ◽  
Wheel Load ◽  
Suspension Systems ◽  
Flexible Track ◽  
Rail Irregularities ◽  
Wheel Loading ◽  
Stiffness And Damping ◽  
Good Agreement

This study investigates the simultaneous effects of unsupported sleepers and rail random irregularities on track displacement and wheel load reduction, by means of numerical simulations with vehicle-track coupling. Vehicles are simulated as multibody systems comprising the major vehicle masses and suspension systems with nonlinear stiffness and damping. Flexible track with rail, sleeper and ballast components is considered using finite element and multibody programs. Numerical results of the simulations are in good agreement with field test measurements. Findings show that in tracks with less than four unsupported sleepers the vehicle is able to move at a speed of 110 km/h; with a higher number of unsupported sleepers the vehicle is vulnerable to derailment. The vehicle speed has no effect on the maximum rail displacement in tracks with less than four unsupported sleepers.

scholarly journals Determination of longitudinal profile of railway track using vehicle-based inertial readings

2016 ◽  
Vol 231 (5) ◽  
pp. 518-534 ◽  
Author(s):  
Eugene J OBrien ◽  
Cathal Bowe ◽  
Paraic Quirke ◽  
Daniel Cantero
Keyword(s):  
Dynamic Response ◽  
Longitudinal Direction ◽  
Longitudinal Profile ◽  
Railway Track ◽  
Two Dimensional ◽  
Time Step ◽  
Least Squares Fit ◽  
Angular Velocities ◽  
Vertical Accelerations

The longitudinal profile of a railway track excites a dynamic response in a train which can potentially be used to determine that profile. A method is proposed in this paper for the determination of the longitudinal profile through an analysis of bogie vertical accelerations and angular velocities resulting from the train/track dynamic interaction. The cross-entropy optimisation technique is applied to determine the railway track profile elevations that generate a vehicle response which best fits the measured dynamic response of a railway carriage bogie. Numerical validation of the concept is achieved by using a two-dimensional quarter-car dynamic model, representing a railway carriage and bogie, traversing an infinitely stiff profile. The concept is further tested by the introduction of a two-dimensional car dynamic vehicle model and a three-layer track model to infer the track profile in the longitudinal direction. Both interaction models are implemented in Matlab. Various grades of track irregularity are generated which excite the vehicle inducing a dynamic response. Ten vertical elevations are found at a time which give a least squares fit of theoretical to measured accelerations and angular velocity. In each time step, half of these elevations are retained and a new optimisation is used to determine the next 10 elevations along the length of the track. The optimised elevations are collated to determine the overall longitudinal profile over a finite length of railway track.

A novel method for the determination of linting propensity of paper

TAPPI Journal ◽  
2012 ◽  
Vol 11 (10) ◽  
pp. 9-17
Author(s):  
ALESSANDRA GERLI ◽  
LEENDERT C. EIGENBROOD
Keyword(s):  
Ash Content ◽  
The Novel ◽  
Offset Printing ◽  
Excellent Correlation ◽  
End Conditions ◽  
Bottom Side ◽  
Novel Method ◽  
Total Fraction

A novel method was developed for the determination of linting propensity of paper based on printing with an IGT printability tester and image analysis of the printed strips. On average, the total fraction of the surface removed as lint during printing is 0.01%-0.1%. This value is lower than those reported in most laboratory printing tests, and more representative of commercial offset printing applications. Newsprint paper produced on a roll/blade former machine was evaluated for linting propensity using the novel method and also printed on a commercial coldset offset press. Laboratory and commercial printing results matched well, showing that linting was higher for the bottom side of paper than for the top side, and that linting could be reduced on both sides by application of a dry-strength additive. In a second case study, varying wet-end conditions were used on a hybrid former machine to produce four paper reels, with the goal of matching the low linting propensity of the paper produced on a machine with gap former configuration. We found that the retention program, by improving fiber fines retention, substantially reduced the linting propensity of the paper produced on the hybrid former machine. The papers were also printed on a commercial coldset offset press. An excellent correlation was found between the total lint area removed from the bottom side of the paper samples during laboratory printing and lint collected on halftone areas of the first upper printing unit after 45000 copies. Finally, the method was applied to determine the linting propensity of highly filled supercalendered paper produced on a hybrid former machine. In this case, the linting propensity of the bottom side of paper correlated with its ash content.

COMPARATIVE ACTION OF VARIOUS OESTROGENIC COMPOUNDS ON MOUSE VAGINAL SIALIC ACIDS (II)

1969 ◽  
Vol 62 (4) ◽  
pp. 663-670 ◽  
Author(s):  
Lars Carlborg
Keyword(s):  
Sialic Acid ◽  
Response Curve ◽  
Sialic Acids ◽  
Clear Cut ◽  
Suitable Parameter ◽  
Sufficient Degree ◽  
Comparative Action ◽  
Relative Potencies ◽  
Good Agreement

ABSTRACT Oestrogens administered in lower doses than necessary to induce full cornification of the mouse vagina induce mucification. It was shown previously that the degree of mucification could be estimated by quantitative determination of sialic acids. A suitable parameter for oestrogen assay was the measurement of vaginal sialic acid concentration which exhibited a clear cut dose response curve. Eleven assays of various oestrogens were performed with this method. Their estimated relative potencies were in good agreement with other routine oestrogen assays. A statistically sufficient degree of precision was found. The sensitivity was of the same order, or slightly higher, than the Allen-Doisy test.

The Calculation of Turbulent Diffusion Coefficients in Aquatic Ecosystems

2019 ◽  
Vol 70 (11) ◽  
pp. 3903-3907
Author(s):  
Galina Marusic ◽  
Valeriu Panaitescu
Keyword(s):  
Transport Equation ◽  
Turbulent Diffusion ◽  
Diffusion Coefficients ◽  
Aquatic Ecosystems ◽  
Specific Area ◽  
Left Bank ◽  
The Right ◽  
Prut River

The paper deals with the issues related to the pollution of aquatic ecosystems. The influence of turbulence on the transport and dispersion of pollutants in the mentioned systems, as well as the calculation of the turbulent diffusion coefficients are studied. A case study on the determination of turbulent diffusion coefficients for some sectors of the Prut River is presented. A new method is proposed for the determination of the turbulent diffusion coefficients in the pollutant transport equation for specific sectors of a river, according to the associated number of P�clet, calculated for each specific area: the left bank, the right bank and the middle of the river.

Tribology of rail bogie

2018 ◽  
Vol 77 (4) ◽  
pp. 230-240
Author(s):  
D. P. Markov
Keyword(s):  
Contact Fatigue ◽  
Basic Element ◽  
Difficult Problem ◽  
Railway Track ◽  
Rolling Stock ◽  
Kinematic Parameters ◽  
Approximate Estimation ◽  
Railway Bogie ◽  
Classical Calculation

Railway bogie is the basic element that determines the force, kinematic, power and other parameters of the rolling stock, and its movement in the railway track has not been studied enough. Classical calculation of the kinematic and dynamic parameters of the bogie's motion with the determination of the position of its center of rotation, the instantaneous axes of rotation of wheelsets, the magnitudes and directions of all forces present a difficult problem even in quasi-static theory. The paper shows a simplified method that allows one to explain, within the limits of one article, the main kinematic and force parameters of the bogie movement (installation angles, clearance between the wheel flanges and side surfaces of the rails), wear and contact damage to the wheels and rails. Tribology of the railway bogie is an important part of transport tribology, the foundation of the theory of wheel-rail tribosystem, without which it is impossible to understand the mechanisms of catastrophic wear, derailments, contact fatigue, cohesion of wheels and rails. In the article basic questions are considered, without which it is impossible to analyze the movement of the bogie: physical foundations of wheel movement along the rail, types of relative motion of contacting bodies, tribological characteristics linking the force and kinematic parameters of the bogie. Kinematics and dynamics of a two-wheeled bogie-rail bicycle are analyzed instead of a single wheel and a wheelset, which makes it clearer and easier to explain how and what forces act on the bogie and how they affect on its position in the rail track. To calculate the motion parameters of a four-wheeled bogie, it is represented as two two-wheeled, moving each on its own rail. Connections between them are replaced by moments with respect to the point of contact between the flange of the guide wheel and the rail. This approach made it possible to give an approximate estimation of the main kinematic and force parameters of the motion of an ideal bogie (without axes skewing) in curves, to understand how the corners of the bogie installation and the gaps between the flanges of the wheels and rails vary when moving with different speeds, how wear and contact injuries arise and to give recommendations for their assessment and elimination.

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