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Sample records for rail rolling contact

  1. A new solution method for wheel/rail rolling contact.

    PubMed

    Yang, Jian; Song, Hua; Fu, Lihua; Wang, Meng; Li, Wei

    2016-01-01

    To solve the problem of wheel/rail rolling contact of nonlinear steady-state curving, a three-dimensional transient finite element (FE) model is developed by the explicit software ANSYS/LS-DYNA. To improve the solving speed and efficiency, an explicit-explicit order solution method is put forward based on analysis of the features of implicit and explicit algorithm. The solution method was first applied to calculate the pre-loading of wheel/rail rolling contact with explicit algorithm, and then the results became the initial conditions in solving the dynamic process of wheel/rail rolling contact with explicit algorithm as well. Simultaneously, the common implicit-explicit order solution method is used to solve the FE model. Results show that the explicit-explicit order solution method has faster operation speed and higher efficiency than the implicit-explicit order solution method while the solution accuracy is almost the same. Hence, the explicit-explicit order solution method is more suitable for the wheel/rail rolling contact model with large scale and high nonlinearity.

  2. Wheel/rail contact geometry assessment to limit rolling contact fatigue initiation at high axle loads

    NASA Astrophysics Data System (ADS)

    Fröhling, Robert; Spangenberg, Ulrich; Hettasch, Georg

    2012-01-01

    Rolling contact fatigue on any railway system has a significant impact on the safety and efficiency of the operation. This is especially true for heavy haul railways where higher axle loads and demands for higher throughput have, over the years, challenged the limits within the wheel/rail interface. The objective of this paper is to present a methodology to manage this stress state using a detailed wheel/rail contact stress analysis. Based on the results of recent wheel profile and rail profile surveys, a kinematic wheel/rail contact analysis is performed to identify and eliminate profiles that cause high stresses. The results show that the current hollow wear criterion is effective, but that an alternative or additional criterion based on the gauge side false flange gradient or the calculated peak contact stress values can further reduce the stress state. Within the wheel and rail profile combinations investigated, the contact stresses were largely independent of the transverse profile of the high rail.

  3. A study on high-speed rolling contact between a wheel and a contaminated rail

    NASA Astrophysics Data System (ADS)

    Zhao, Xin; Wen, Zefeng; Zhu, Minhao; Jin, Xuesong

    2014-10-01

    A 3-D explicit finite element model is developed to investigate the transient wheel-rail rolling contact in the presence of rail contamination or short low adhesion zones (LAZs). A transient analysis is required because the wheel passes by a short LAZ very quickly, especially at high speeds. A surface-to-surface contact algorithm (by the penalty method) is employed to solve the frictional rolling contact between the wheel and the rail meshed by solid elements. The LAZ is simulated by a varying coefficient of friction along the rail. Different traction efforts and action of the traction control system triggered by the LAZ are simulated by applying a time-dependent driving torque to the wheel axle. Structural flexibilities of the vehicle-track system are considered properly. Analysis focuses on the contact forces, creepage, contact stresses and the derived frictional work and plastic deformation. It is found that the longitudinal contact force and the maximum surface shear stress in the contact patch become obviously lower in the LAZ and much higher as the wheel re-enters the dry rail section. Consequently, a higher wear rate and larger plastic flow are expected at the location where the dry contact starts to be rebuilt. In other words, contact surface damages such as wheel flats and rail burns may come into being because of the LAZ. Length of the LAZ, the traction level, etc. are varied. The results also show that local contact surface damages may still occur as the traction control system acts.

  4. Influence of wheel and rail profile shape on the initiation of rolling contact fatigue cracks at high axle loads

    NASA Astrophysics Data System (ADS)

    Spangenberg, Ulrich; Desmond Fröhling, Robert; Schalk Els, Pieter

    2016-05-01

    The influence of wheel and rail profile shape features on the initiation of rolling contact fatigue (RCF) cracks is evaluated based on the results of multi-body vehicle dynamics simulations. The damage index and surface fatigue index are used as two damage parameters to assess the influence of the different features. The damage parameters showed good agreement to one another and to in-field observations. The wheel and rail profile shape features showed a correlation to the predicted RCF damage. The RCF damage proved to be most sensitive to the position of hollow wear and thus bogie tracking. RCF initiation and crack growth can be reduced by eliminating unwanted shape features through maintenance and design and by improving bogie tracking.

  5. A substitute model of two-dimensional dry friction exposed to dither generated by rolling contact of wheel and rail

    NASA Astrophysics Data System (ADS)

    Piotrowski, Jerzy

    2012-10-01

    Dither generated by rolling contact of wheel and rail smoothes dry friction damping provided by the primary suspension dampers of freight wagons and it should be taken into account in numerical simulations. But numerically the problem is non-smooth and this leads to long execution time during simulation, especially when the vehicle with friction dampers is modelled in the environment of an multi-body system simulation program, whose solver has to cope with many strong non-linearities. The other difficulty is the necessity of handling within the code a number of big volume files of recorded dither sampled with high frequency. To avoid these difficulties, a substitute model of two-dimensional dry friction exposed to dither is proposed that does not need application of dither during simulation, but it behaves as if dither were applied. Due to this property of the model, the excitation of the vehicle model by track irregularities may be supplied as low-frequency input, which allows fast execution and, the necessity of handling high-volume files of recorded dither is avoided. The substitute model is numerically effective. To identify parameters of the substitute model, a pre-processing employing a sample of the realistic dither is carried-out on a simple two-degrees-of-freedom system. The substitute model is anisotropic, describing anisotropic properties of the two-dimensional friction arising in the presence of one-dimensional dither. The model may be applied in other branches of engineering, for example, in mechatronics and robotics, where application of dither may improve the accuracy of positioning devices.

  6. Rail roughness and rolling noise in tramways

    NASA Astrophysics Data System (ADS)

    Chiacchiari, L.; Thompson, DJ; Squicciarini, G.; Ntotsios, E.; Loprencipe, G.

    2016-09-01

    Companies which manage railway networks have to cope continually with the problem of operating safety and maintenance intervention issues related to rail surface irregularities. A lot of experience has been gained in recent years in railway applications but the case of tramways is quite different; in this field there are no specific criteria to define any intervention on rail surface restoration. This paper shows measurements carried out on some stretches of a tram network with the CAT equipment (Corrugation Analysis Trolley) for the principal purpose of detecting different states of degradation of the rails and identifying a level of deterioration to be associated with the need for maintenance through rail grinding. The measured roughness is used as an input parameter into prediction models for both rolling noise and ground vibration to show the potential effect that high levels of roughness can have in urban environment. Rolling noise predictions are also compared with noise measurements to illustrate the applicability of the modelling approach. Particular attention is given to the way the contact filter needs to be modelled in the specific case of trams that generally operate at low speed. Finally an empirical approach to assess vibration levels in buildings is presented.

  7. Rolling-Contact Rheostat

    NASA Technical Reports Server (NTRS)

    Ruoff, C. F.

    1985-01-01

    Contact noise in rheostats and potentiometers reduced by rolling contact design. Smooth rolling action eliminates sporadic variations in resistance caused by bouncing and stick/slip motion of conventional sliding contacts.

  8. A survey of wheel-rail contact models for rail vehicles

    NASA Astrophysics Data System (ADS)

    Meymand, Sajjad Z.; Keylin, Alexander; Ahmadian, Mehdi

    2016-03-01

    Accurate and efficient contact models for wheel-rail interaction are essential for the study of the dynamic behaviour of a railway vehicle. Assessment of the contact forces and moments, as well as contact geometry provide a fundamental foundation for such tasks as design of braking and traction control systems, prediction of wheel and rail wear, and evaluation of ride safety and comfort. This paper discusses the evolution and the current state of the theories for solving the wheel-rail contact problem for rolling stock. The well-known theories for modelling both normal contact (Hertzian and non-Hertzian) and tangential contact (Kalker's linear theory, FASTSIM, CONTACT, Polach's theory, etc.) are reviewed. The paper discusses the simplifying assumptions for developing these models and compares their functionality. The experimental studies for evaluation of contact models are also reviewed. This paper concludes with discussing open areas in contact mechanics that require further research for developing better models to represent the wheel-rail interaction.

  9. A method for improved accuracy in three dimensions for determining wheel/rail contact points

    NASA Astrophysics Data System (ADS)

    Yang, Xinwen; Gu, Shaojie; Zhou, Shunhua; Zhou, Yu; Lian, Songliang

    2015-11-01

    Searching for the contact points between wheels and rails is important because these points represent the points of exerted contact forces. In order to obtain an accurate contact point and an in-depth description of the wheel/rail contact behaviours on a curved track or in a turnout, a method with improved accuracy in three dimensions is proposed to determine the contact points and the contact patches between the wheel and the rail when considering the effect of the yaw angle and the roll angle on the motion of the wheel set. The proposed method, with no need of the curve fitting of the wheel and rail profiles, can accurately, directly, and comprehensively determine the contact interface distances between the wheel and the rail. The range iteration algorithm is used to improve the computation efficiency and reduce the calculation required. The present computation method is applied for the analysis of the contact of rails of CHINA (CHN) 75 kg/m and wheel sets of wearing type tread of China's freight cars. In addition, it can be proved that the results of the proposed method are consistent with that of Kalker's program CONTACT, and the maximum deviation from the wheel/rail contact patch area of this two methods is approximately 5%. The proposed method, can also be used to investigate static wheel/rail contact. Some wheel/rail contact points and contact patch distributions are discussed and assessed, wheel and rail non-worn and worn profiles included.

  10. Simplified contact filters in wheel/rail noise prediction

    NASA Astrophysics Data System (ADS)

    Ford, R. A. J.; Thompson, D. J.

    2006-06-01

    When predicting rolling noise due to wheel and rail roughness a "contact filter" is generally applied to account for the effect of the finite size of the wheel/rail contact. For time-domain analysis these calculations must be fast enough to get results in a reasonable time. Remington and Webb have devised a versatile three-dimensional 'distributed point reacting spring' (DPRS) contact model that is relatively quick, but if only one line of data is available along the contact it is unnecessarily complex, so a simpler two-dimensional version has been developed here. When this new model was checked against a Boussinesq analysis of the contact, the results in one-third octave bands were found to agree to within 3 dB. These results further suggest that the two-dimensional DPRS model might have an unexpectedly wide range of applicability, including large amplitude sinusoidal roughness and discrete features such as a rail joint. When implemented at each step in a time-domain wheel/rail interaction analysis, this model gave similar results to quasi-static roughness filtering with a constant load for moderate roughness, but dynamic effects became significant when the roughness amplitudes were large, particularly with dipped rail joints.

  11. Rail-wheel interaction monitoring using Acoustic Emission: A laboratory study of normal rolling signals with natural rail defects

    NASA Astrophysics Data System (ADS)

    Thakkar, N. A.; Steel, J. A.; Reuben, R. L.

    2010-01-01

    This paper presents a laboratory study on the Acoustic Emission (AE) generated during railway wheel-rail track interaction, with a view to developing methods of in situ rail-wheel interaction monitoring using rail-mounted sensors. It is known that the physical processes of impact and wear generate AE and it was therefore expected that axle loads, speed and traction would influence the AE generated by an interaction and that the characteristics of "normal" interaction would be affected by wheel and/or track defects and/or any misalignment between rail and track. A set of laboratory experiments were carried out on a scaled test rig to characterise the continuous AE generated by a wheel rolling on a rail and, secondarily, to assess the effect on the AE characteristic of the natural defects present on the contact profile of the rail. The natural defects were of a relatively minor nature and their assessment serves as part of the calibration of background AE for experiments with more significant simulated defects. A simplified analytical model, devised for AE waves propagating from a moving source, based on "vehicle" speed and wave damping coefficients, has been developed for the test track and fitted to the measured results. As a wheel rolls towards a sensor and then away from the sensor the measured AE generally rises and falls in a predictable way. The effects of wheel and rail surface features were found to introduce deviations from this "background", and a method to identify the location of surface defects, based on identifying peaks above the background is also demonstrated.

  12. Effect of wheelset flexibility on wheel-rail contact behavior and a specific coupling of wheel-rail contact to flexible wheelset

    NASA Astrophysics Data System (ADS)

    Zhong, Shuoqiao; Xiao, Xinbiao; Wen, Zefeng; Jin, Xuesong

    2016-04-01

    The flexibility of a train's wheelset can have a large effect on vehicle-track dynamic responses in the medium to high frequency range. To investigate the effects of wheelset bending and axial deformation of the wheel web, a specific coupling of wheel-rail contact with a flexible wheelset is presented and integrated into a conventional vehicle-track dynamic system model. Both conventional and the proposed dynamic system models are used to carry out numerical analyses on the effects of wheelset bending and axial deformation of the wheel web on wheel-rail rolling contact behaviors. Excitations with various irregularities and speeds were considered. The irregularities included measured track irregularity and harmonic irregularities with two different wavelengths. The speeds ranged from 200 to 400 km/h. The results show that the proposed model can characterize the effects of flexible wheelset deformation on the wheel-rail rolling contact behavior very well.

  13. Mechanisms of rolling contact spalling

    NASA Technical Reports Server (NTRS)

    Kumar, A. M.; Kulkarni, S. M.; Bhargava, V.; Hahn, G. T.; Rubin, C. A.

    1987-01-01

    The results of a study aimed at analyzing the mechanical material interactions responsible for rolling contact spalling of the 440 C steel, high pressure oxygen turbopump bearings are presented. A coupled temperature displacement finite element analysis of the effects of friction heating under the contact is presented. The contact is modelled as a stationary, heat generating, 2 dimensional indent in an elastic perfectly plastic half-space with heat fluxes up to 8.6 x 10000 KW/m sq comparable to those generated in the bearing. Local temperatures in excess of 1000 C are treated. The calculations reveal high levels of residual tension after the contact is unloaded and cools. Efforts to promote Mode 2/Mode 3 fatigue crack growth under cyclic torsion in hardened 440 C steel are described. Spalls produced on 440 C steel by a 3 ball/rod rolling contact testing machine were studied with scanning microscopy. The shapes of the cyclic, stress strain hysteresis loops displayed by hardened 440 C steel in cyclic torsion at room temperature are defined for the plastic strain amplitudes encountered in rolling/sliding contact. Results of these analyses are discussed in detail.

  14. Rolling Contact Fatigue of Ceramics

    SciTech Connect

    Wereszczak, Andrew A; Wang, W.; Wang, Y.; Hadfield, M.; Kanematsu, W.; Kirkland, Timothy Philip; Jadaan, Osama M.

    2006-09-01

    High hardness, low coefficient of thermal expansion and high temperature capability are properties also suited to rolling element materials. Silicon nitride (Si{sub 3}N{sub 4}) has been found to have a good combination of properties suitable for these applications. However, much is still not known about rolling contact fatigue (RCF) behavior, which is fundamental information to assess the lifetime of the material. Additionally, there are several test techniques that are employed internationally whose measured RCF performances are often irreconcilable. Due to the lack of such information, some concern for the reliability of ceramic bearings still remains. This report surveys a variety of topics pertaining to RCF. Surface defects (cracks) in Si{sub 3}N{sub 4} and their propagation during RCF are discussed. Five methods to measure RCF are then briefly overviewed. Spalling, delamination, and rolling contact wear are discussed. Lastly, methods to destructively (e.g., C-sphere flexure strength testing) and non-destructively identify potential RCF-limiting flaws in Si{sub 3}N{sub 4} balls are described.

  15. Non-contact ultrasonic guided wave inspections of rails

    NASA Astrophysics Data System (ADS)

    Nguyen, Thompson V.; Mariani, Stefano; Lanza di Scalea, Francesco

    2014-03-01

    The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail integrity evaluation. A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection, in pair with a real-time statistical analysis algorithm, is under development. Experimental tests results, carried out at the UCSD Rail Defect Farm, indicate that the prototype is able to detect internal rail defects with high reliability. Extensions of the system are planned to add rail surface characterization to the internal rail defect detection.

  16. Modelling of dynamic contact length in rail grinding process

    NASA Astrophysics Data System (ADS)

    Zhi, Shaodan; Li, Jianyong; Zarembski, A. M.

    2014-09-01

    Rails endure frequent dynamic loads from the passing trains for supporting trains and guiding wheels. The accumulated stress concentrations will cause the plastic deformation of rail towards generating corrugations, contact fatigue cracks and also other defects, resulting in more dangerous status even the derailment risks. So the rail grinding technology has been invented with rotating grinding stones pressed on the rail with defects removal. Such rail grinding works are directed by experiences rather than scientifically guidance, lacking of flexible and scientific operating methods. With grinding control unit holding the grinding stones, the rail grinding process has the characteristics not only the surface grinding but also the running railway vehicles. First of all, it's important to analyze the contact length between the grinding stone and the rail, because the contact length is a critical parameter to measure the grinding capabilities of stones. Moreover, it's needed to build up models of railway vehicle unit bonded with the grinding stone to represent the rail grinding car. Therefore the theoretical model for contact length is developed based on the geometrical analysis. And the calculating models are improved considering the grinding car's dynamic behaviors during the grinding process. Eventually, results are obtained based on the models by taking both the operation parameters and the structure parameters into the calculation, which are suitable for revealing the process of rail grinding by combining the grinding mechanism and the railway vehicle systems.

  17. Influence of wheel-rail contact modelling on vehicle dynamic simulation

    NASA Astrophysics Data System (ADS)

    Burgelman, Nico; Sichani, Matin Sh.; Enblom, Roger; Berg, Mats; Li, Zili; Dollevoet, Rolf

    2015-08-01

    This paper presents a comparison of four models of rolling contact used for online contact force evaluation in rail vehicle dynamics. Until now only a few wheel-rail contact models have been used for online simulation in multibody software (MBS). Many more models exist and their behaviour has been studied offline, but a comparative study of the mutual influence between the calculation of the creep forces and the simulated vehicle dynamics seems to be missing. Such a comparison would help researchers with the assessment of accuracy and calculation time. The contact methods investigated in this paper are FASTSIM, Linder, Kik-Piotrowski and Stripes. They are compared through a coupling between an MBS for the vehicle simulation and Matlab for the contact models. This way the influence of the creep force calculation on the vehicle simulation is investigated. More specifically this study focuses on the influence of the contact model on the simulation of the hunting motion and on the curving behaviour.

  18. Rolling Contact Fatigue and Wear Behavior of High-Performance Railway Wheel Steels Under Various Rolling-Sliding Contact Conditions

    NASA Astrophysics Data System (ADS)

    Faccoli, Michela; Petrogalli, Candida; Lancini, Matteo; Ghidini, Andrea; Mazzù, Angelo

    2017-07-01

    An experimental investigation was carried out to study and compare the response to cyclic loading of the high-performance railway wheel steels ER8 EN13262 and SUPERLOS®. Rolling contact tests were performed with the same contact pressure, rolling speed and sliding/rolling ratio, varying the lubrication regime to simulate different climatic conditions. The samples, machined out of wheel rims at two depths within the reprofiling layer, were coupled with UIC 900A rail steel samples. The wear rates, friction coefficients and hardness were correlated with the deformation beneath the contact surface. The crack morphology was studied, and the damage mechanisms were identified. The distribution of crack length and depth at the end of the dry tests was analyzed to quantify the damage. The main difference between the steels lies in the response of the external samples to dry contact: SUPERLOS® is subjected to a higher wear and lower friction coefficient than ER8, and this reduces the density of surface cracks that can propagate under wet contact conditions. The analysis of feedback data from in-service wheels confirmed the experimental results.

  19. Stress evaluations under rolling/sliding contacts

    NASA Technical Reports Server (NTRS)

    Kannel, J. W.; Tevaarwerk, J. L.

    1981-01-01

    The state of stress beneath traction drive type of contacts were analyzed. Computing stresses and stress reversals on various planes for points beneath the surface were examined. The effect of tangential and axial friction under gross slip conditions is evaluated with the models. Evaluations were performed on an RC (rolling contact) tester configuration and it is indicated that the classical fatigue stresses are not altered by friction forces typical of lubricated contact. Higher values of friction can result in surface shear reversal that exceeds the stresses at the depth of maximum shear reversal under rolling contact.

  20. Improvement of rolling modes of long length rails on the universal rail and structural steel mill “EVRAZ ZSMK”

    NASA Astrophysics Data System (ADS)

    Golovatenko, A. V.; Umansky, A. A.; Kadykov, V. N.

    2016-09-01

    Using the results of theoretical and experimental research a new rolling mode of long-length rails on the universal rail-and-structural steel mill JSC “EVRAZ Consolidated West Siberian Metallurgical Plant” (“EVRAZ ZSMK”) was developed with a reduced number of passes in the breakdown stands. Experimental and industrial testing and implementation of the new rolling mode showed a high technical and economic efficiency of its use - reduction in the specific energy consumption was registered, as well as decrease in rejection of rails due to their surface defects, consumption of mill rolls and increase in mill productivity. The cost- effectiveness after implementation was more than 98 million RUB per year.

  1. Non-contact rail flaw detection system: first field test

    NASA Astrophysics Data System (ADS)

    Rizzo, Piervincenzo; Coccia, Stefano; Lanza di Scalea, Francesco; Bartoli, Ivan; Fateh, Mahmood

    2007-04-01

    Researchers at UCSD, with the initial support of NSF and the current support of the Federal Railroad Administration (FRA), have been working on a flaw detection prototype for rails that uses non-contact ultrasonic probing and robust data processing algorithms to provide high speed and high reliability defect detection in these structures. Besides the obvious advantages of non-contact probing, the prototype uses ultrasonic guided waves able to detect and quantify transverse cracks in the rail head, notoriously the most dangerous of all rail track defects. This paper will report on the first field test which was conducted in Gettysburg, PA in March 2006 with the technical support of ENSCO, Inc. Good results were obtained for the detection of both surface-breaking and internal cracks ranging in size from 2% cross-sectional head area (H.A.) reduction to 80% H.A. reduction.

  2. The influence of the contact zone on the excitation of wheel/rail noise

    NASA Astrophysics Data System (ADS)

    Thompson, D. J.

    2003-10-01

    Rolling noise is excited by surface roughness at the wheel/rail contact. The contact patch is known to attenuate the excitation at wavelengths that are short in comparison with its length. A distributed point-reacting spring (DPRS) model is used with measured roughness data to determine the contact filter effect, and this result is compared with analytical predictions. It is found that the analytical model gives an attenuation that is too large at short wavelengths but is usable for wavelengths down to somewhat smaller than the length of the contact patch. Additionally, variations in the detailed geometry of the profile can cause the contact point on the wheel and rail to oscillate laterally. This introduces an oscillating moment that can induce additional vibration and noise. The DPRS model and rolling noise prediction model are both extended and used together to allow an estimate of the contribution to the radiated noise. It is found that, while the direct roughness excitation is still more important, the moment excitation can be significant, particularly for conforming profiles.

  3. The influence of strain hardening on cumulative plastic deformation in rolling and sliding line contact

    NASA Astrophysics Data System (ADS)

    Bower, A. F.; Johnson, K. L.

    THE INFLUENCE of strain hardening on the cumulative plastic deformation (ratchetting) which takes place in repeated rolling and sliding contacts has been assessed by the use of a non-linear kinematic hardening law proposed and tested by B OWER ( J. Mech. Phys. Solids37,455, 1989). Both the sub-surface flow, which occurs at low traction coefficients ( <0.25), and the surface flow which occurs at high traction ( >0.25), have been investigated. Two materials have been studied: hard-drawn copper and rail steel. Good correlation was found for copper between the theory and rolling contact experiments.

  4. Non-contact ultrasonic guided wave inspection of rails

    NASA Astrophysics Data System (ADS)

    Mariani, Stefano; Nguyen, Thompson V.; Phillips, Robert Ronald; Kijanka, Piotr; Lanza di Scalea, Francesco; Staszewski, Wieslaw Jerzy

    2013-04-01

    The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail integrity evaluation. A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection in pair with a real-time statistical analysis algorithm has been realized. This solution presents an improvement over the previously considered laser/air-coupled hybrid system because it replaces the costly and hard-to-maintain laser with a much cheaper, faster, and easier-to-maintain air-coupled transmitter. This system requires a specialized filtering approach due to the inherently poor signal-to-noise ratio of the air-coupled ultrasonic measurements in rail steel. Various aspects of the prototype have been designed with the aid of numerical analyses. In particular, simulations of ultrasonic guided wave propagation in rails have been performed using a LISA algorithm. Many of the system operating parameters were selected based on Receiver Operating Characteristic (ROC) curves, which provide a quantitative manner to evaluate different detection performances based on the trade-off between detection rate and false positive rate. Experimental tests have been carried out at the UCSD Rail Defect Farm. The laboratory results indicate that the prototype is able to detect internal rail defects with a high reliability. A field test will be planned later in the year to further validate these results. Extensions of the system are planned to add rail surface characterization to the internal rail defect detection.

  5. Rolling contact deformation of 1100 aluminum disks

    NASA Astrophysics Data System (ADS)

    Hahn, G. T.; Huang, Q.

    1986-09-01

    The plastic deformation produced by pure, two dimensional, rolling contacts has been studied by subjecting 1100 aluminum disks to repeated contacts with well-defined relative peak contact pressures in the range 2 ≤ P 0/ k c ≤ 6.8. Two microstructural conditions are examined: as-received (warm worked) and annealed, displaying cyclic softening and cyclic hardening, respectively. Measurements of the distortion of wire markers imbedded in the rims, microhardness values of the plastically deformed layer, and changes in disk radius and width are reported. These are used to evaluate the plastic circumferential, radial, and axial displacements of the rim surface and the depth of the plastically deformed layer. These features are compared with the classical, elastic-quasi plastic analysis of rolling, and with recent elastic-plastic finite element calculations. The results show that the rim deformation state approaches plane strain when the disk width-to-Hertzian half contact width-ratio B/w ≥ 200. The presence of a solid lubricant has no detectable influence on the character of the plane strain deformation. The measurements of the per cycle forward (circumferential) displacements for the two conditions are self-consistent and agree with the finite element calculations when the resistance to plastic deformation is attributed to the instantaneous cyclic yield stress, but not when the resistance is identified with the initial monotonie yield stress. At the same time, the extent of the plastic zone is 5× greater than predicted by the analyses. These and other results can be rationalized by drawing on the special features of the resistance to cyclic deformation. They support the view that the deformation produced by the N th rolling contact is governed by the shape of the stress-strain hysteresis loop after the corresponding number of stress-strain cycles which depends on the cycle strain amplitude, degree of reversibility, and the strain path imposed by the contact

  6. A fast-simplified wheel-rail contact model consistent with perfect plastic materials

    NASA Astrophysics Data System (ADS)

    Sebès, Michel; Chevalier, Luc; Ayasse, Jean-Bernard; Chollet, Hugues

    2012-09-01

    A method is described which is an extension of rolling contact models with respect to plasticity. This new method, which is an extension of the STRIPES semi-Hertzian (SH) model, has been implemented in a multi-body-system (MBS) package and does not result in a longer execution time than the STRIPES SH model [J.B. Ayasse and H. Chollet, Determination of the wheel-rail contact patch in semi-Hertzian conditions, Veh. Syst. Dyn. 43(3) (2005), pp. 161-172]. High speed of computation is obtained by some hypotheses about the plastic law, the shape of stresses, the locus of the maximum stress and the slip. Plasticity does not change the vehicle behaviour but there is a need for an extension of rolling contact models with respect to plasticity as far as fatigue analysis of rail is concerned: rolling contact fatigue may be addressed via the finite element method (FEM) including material non-linearities, where loads are the contact stresses provided by the post-processing of MBS results [K. Dang Van, M.H. Maitournam, Z. Moumni, and F. Roger, A comprehensive approach for modeling fatigue and fracture of rails, Eng. Fract. Mech. 76 (2009), pp. 2626-2636]. In STRIPES, like in other MBS models, contact stresses may exceed the plastic yield criterion, leading to wrong results in the subsequent FEM analysis. With the proposed method, contact stresses are kept consistent with a perfect plastic law, avoiding these problems. The method is benchmarked versus non-linear FEM in Hertzian geometries. As a consequence of taking plasticity into account, contact patch area is bigger than the elastic one. In accordance with FEM results, a different ellipse aspect ratio than the one predicted by Hertz theory was also found and finally pressure does not exceed the threshold prescribed by the plastic law. The method also provides more exact results with non-Hertzian geometries. The new approach is finally compared with non-linear FEM in a tangent case with a unidirectional load and a complete

  7. Railgun rail gouging by hypervelocity sliding contact

    SciTech Connect

    Barker, L.M.; Trucano, T.G. ); Susoeff, A.R. )

    1989-01-01

    A description is given of a recently resolved mechanisms of gouging which occurs during hypervelocity sliding contact between two materials. A parameter study based on computer modeling of the gouging mechanism is presented in which gouging velocity thresholds are determined for several combinations of sliding materials. Materials which can gouge each other are found to do so only within a certain range of velocities. Related calculations of gaseous material ahead of railgun projectiles are also presented. Gun bore gouging experience with the Lawrence Livermore National Laboratory railgun project is reviewed.

  8. Railgun rail gouging by hypervelocity sliding contact

    SciTech Connect

    Barker, L.M.; Trucano, T.G.; Susoeff, A.R.

    1988-01-01

    A description is given of a recently resolved mechanism of gouging which occurs during hypervelocity sliding contact between two materials. A parameter study based on computer modelling of the gouging mechanism is presented in which gouging velocity thresholds are determined for several combinations of sliding materials. Materials which can gouge each other are found to do so only within a certain range of velocities. Related calculations of gaseous material ahead of railgun projectiles are also presented. Gun bore gouging experience with the Lawrence Livermore National Laboratory railgun project is reviewed.

  9. Split-Rail, Rolling-Friction Robotic Gripper With Tool Drive

    NASA Technical Reports Server (NTRS)

    Voellmer, George M.

    1992-01-01

    Robotic gripper includes split-rail drive assembly that moves two gripping fingers toward or away from each other. Gripping fingers equipped with rollers mating with recesses and seating ramps on specially designed object. Similar in design and operation, to those described in "Rolling-Friction Robotic Gripper" (GSC-13261). Present gripper includes rotary tool operating on mechanism in gripped object.

  10. Development of a self-lubricating plasma sprayed coating for rolling/sliding contact wear

    NASA Astrophysics Data System (ADS)

    Niebuhr, David Vernon

    The friction and wear that occurs between wheel and rail exacts millions of dollars out of maintenance budgets each year. Standard lubrication practices have been found to be unreliable in effectively lubricating curved track sections. Consequently, a method of reducing cost and increasing rail life is of significance to the railroad industry. Through the use of self-lubricating materials and thermal spray technology a composite surface coating was developed. A 1080 steel coating provided a wear-resistant matrix, in which to incorporate solid lubricants. The 1080 steel coating was found to provide increased wear resistance and some friction reduction (mu = 0.46 vs. mu = 0.5-0.7 for uncoated rail). The reduced wear stems from the coatings resistance to degenerate into severe wear modes. The wear rate of uncoated rail steel can be an order of magnitude greater than that of a 1080 steel coating. Three solid lubricant/steel coating systems were investigated; graphite incorporated into 1080 steel, copper incorporated into 1080 steel, and various polymers deposited over a 1080 steel coating. The structure of the coatings were evaluated by metallography and wear performance. Metallographic analysis included optical, SEM, and FIB. Polymer film analysis was performed with FTIR. Wear testing and friction measurement were accomplished with the Amsler twin disk wear testing machine. Coatings were tested against class C wheel steel at 5% and 35% slide/roll ratios, with contact pressures ranging from 700 to 1315 N/mmsp2. The work identified unique wear mechanisms for each coating system. The friction reduction and durability of the graphite/steel coatings was good at low slide/roll ratios. The copper/steel coatings were unable to control friction and had limited life. The polymer/steel coatings, particularly nylon/steel, had excellent performance at a wide range of slide/roll ratios and contact pressures. The nylon/1080 steel coatings were applied to rail sections for large

  11. The influence of wheel/rail contact conditions on the microstructure and hardness of railway wheels.

    PubMed

    Molyneux-Berry, Paul; Davis, Claire; Bevan, Adam

    2014-01-01

    The susceptibility of railway wheels to wear and rolling contact fatigue damage is influenced by the properties of the wheel material. These are influenced by the steel composition, wheel manufacturing process, and thermal and mechanical loading during operation. The in-service properties therefore vary with depth below the surface and with position across the wheel tread. This paper discusses the stress history at the wheel/rail contact (derived from dynamic simulations) and observed variations in hardness and microstructure. It is shown that the hardness of an "in-service" wheel rim varies significantly, with three distinct effects. The underlying hardness trend with depth can be related to microstructural changes during manufacturing (proeutectoid ferrite fraction and pearlite lamellae spacing). The near-surface layer exhibits plastic flow and microstructural shear, especially in regions which experience high tangential forces when curving, with consequentially higher hardness values. Between 1 mm and 7 mm depth, the wheel/rail contacts cause stresses exceeding the material yield stress, leading to work hardening, without a macroscopic change in microstructure. These changes in material properties through the depth of the wheel rim would tend to increase the likelihood of crack initiation on wheels toward the end of their life. This correlates with observations from several train fleets.

  12. The Influence of Wheel/Rail Contact Conditions on the Microstructure and Hardness of Railway Wheels

    PubMed Central

    Davis, Claire

    2014-01-01

    The susceptibility of railway wheels to wear and rolling contact fatigue damage is influenced by the properties of the wheel material. These are influenced by the steel composition, wheel manufacturing process, and thermal and mechanical loading during operation. The in-service properties therefore vary with depth below the surface and with position across the wheel tread. This paper discusses the stress history at the wheel/rail contact (derived from dynamic simulations) and observed variations in hardness and microstructure. It is shown that the hardness of an “in-service” wheel rim varies significantly, with three distinct effects. The underlying hardness trend with depth can be related to microstructural changes during manufacturing (proeutectoid ferrite fraction and pearlite lamellae spacing). The near-surface layer exhibits plastic flow and microstructural shear, especially in regions which experience high tangential forces when curving, with consequentially higher hardness values. Between 1 mm and 7 mm depth, the wheel/rail contacts cause stresses exceeding the material yield stress, leading to work hardening, without a macroscopic change in microstructure. These changes in material properties through the depth of the wheel rim would tend to increase the likelihood of crack initiation on wheels toward the end of their life. This correlates with observations from several train fleets. PMID:24526883

  13. Fatigue and material response in rolling contact

    SciTech Connect

    Voskamp, A.P.

    1998-12-31

    Metal softening, induced during the so-called third stage of material response to rolling contact loading, increases the probability of spalling fatigue failure. Metal softening in the most heavily loaded subsurface region leads to micro-plastic deformation noticeable from the occurrence of microstructural change. The probability of crack initiation increases with the growth of the plastically deformed subsurface region. Subsequent crack growth in that region is stimulated by the induced residual stress and texture. Fatigue failure in modern clean bearing steel develops only when the material has reached the third stage. The threshold to the third stage can be determined, and thus fatigue life can be assessed from observations of microstructural change. Examples are discussed of observed reduction of the ferrite (211) diffraction-line width in relation to observed endurance.

  14. Rolling-contact deformation of MgO single crystals

    NASA Technical Reports Server (NTRS)

    Dufrane, K. F.; Glaeser, W. A.

    1976-01-01

    Magnesium oxide single crystals were used as a model bearing material and deformed by rolling contact with a steel ball 0.64 cm in diameter. A dependence of depth of slip on rolling velocity which persisted with increasing numbers of rolling-contact cycles was discovered. The track width, track hardness and dislocation interactions as observed by transmission electron microscopy all increased in a consistent manner with increasing cycles. The rolling-contact state of stress produces a high density of dislocations in a localized zone. Dislocation interaction in this zone produces cleavage-type cracks after a large number of rolling-contact cycles. The orientation of the crystal influences the character of dislocation accumulation.

  15. On-line 2D monitoring of rolling contact fatigue/wear phenomena in dry tests

    NASA Astrophysics Data System (ADS)

    Bodini, I.; Petrogalli, C.; Mazzù, A.; Faccoli, M.; Lancini, M.; Pasinetti, S.; Sansoni, G.; Docchio, F.

    2017-08-01

    We present the in-field use of a recently developed on-line, real time, optical monitoring system for bi-disk rolling contact tests on railway-wheel- and rail- steel disks, based on laser illumination and a high-speed camera. Qualitative, as well as quantitative information can be obtained by the use of specific indexes derived from the images using blob analysis. Monitoring the tests provides information about the initial transients of turning-crest removal, on the steady state reached, and on the dynamics of the surface in between. Blob anisotropy is a key element to draw information of the mechanisms governing this intermediate state.

  16. Kinematic stability of roller pairs in free rolling contact

    NASA Technical Reports Server (NTRS)

    Savage, M.; Loewenthal, S. H.

    1976-01-01

    A set of generalized stability equations was developed for roller pairs in free rolling contact. A symmetric, dual contact model was used. Four possible external contact profiles that possess continuous contacting surfaces were studied. It was found that kinematic stability would be insured if the larger radius of transverse curvature, in absolute value, and the smaller rolling radius both exist on the roller that has the apex of its conical surface outboard of its main body. The stability criteria developed are considered to be useful for assessing axial restraint requirements for a variety of roller mechanisms and in the selection of roller contact geometry for traction drive devices.

  17. Mechanical analysis and measurement of wheel-rail contact system in large aperture radio telescope

    NASA Astrophysics Data System (ADS)

    Chen, Z. P.; Kong, D. Q.; Li, C. G.; Zhu, N. J.; Shi, H. L.

    2016-07-01

    The azimuth rotation part of a large aperture radio telescope usually takes one wheel-rail system; therefore, wheel-rail pointing errors and wheel-rail wear are very important to antenna point accuracy. First, this paper discusses the wheelrail contact theory and some specific characteristics of wheel-rail system in large aperture radio telescope. Second, one 3D model of wheel-rail contact system is built according to the parameters of 50m antenna in China, and the model is analyzed by one whole body in MSC.Patran/Nastran. Third, we use the multi-body dynamic method to build the model of wheel-rail and simulate it in RecurDyn software. Comparing the simulation results, we find that the coupling of rigidbody and soft-body is much more precise than one whole body in describing the contact deformation. And the results also explain the crevice's influence on the mechanical properties of wheel-rail contact system. Finally, some experiments and measurements of 50m antenna are made, by which we get some useful tips for large aperture radio telescope. The test results show that the multi-body dynamic method is much more suitable to the mechanical analysis in wheel-rail contact system.

  18. Adaptive methods, rolling contact, and nonclassical friction laws

    NASA Technical Reports Server (NTRS)

    Oden, J. T.

    1989-01-01

    Results and methods on three different areas of contemporary research are outlined. These include adaptive methods, the rolling contact problem for finite deformation of a hyperelastic or viscoelastic cylinder, and non-classical friction laws for modeling dynamic friction phenomena.

  19. Rolling behavior of a micro-cylinder in adhesional contact

    PubMed Central

    Saito, Shigeki; Ochiai, Toshihiro; Yoshizawa, Fumikazu; Dao, Ming

    2016-01-01

    Understanding the rolling behavior of a micro-object is essential to establish the techniques of micro-manipulation and micro-assembly by mechanical means. Using a combined theoretical/computational approach, we studied the critical conditions of rolling resistance of an elastic cylindrical micro-object in adhesional contact with a rigid surface. Closed-form dimensionless expressions for the critical rolling moment, the initial rolling contact area, and the initial rolling angle were extracted after a systematic parametric study using finite element method (FEM) simulations. The total energy of this system is defined as the sum of three terms: the elastic energy stored in the deformed micro-cylinder, the interfacial energy within the contact area, and the mechanical potential energy that depends on the external moment applied to the cylindrical micro-object. A careful examination of the energy balance of the system surprisingly revealed that the rolling resistance per unit cylindrical length can be simply expressed by “work of adhesion times cylindrical radius” independent of the Young’s modulus. In addition, extending a linear elastic fracture mechanics based approach in the literature, we obtained the exact closed-form asymptotic solutions for the critical conditions for initial rolling; these asymptotic solutions were found in excellent agreement with the full-field FEM results. PMID:27677706

  20. Rolling behavior of a micro-cylinder in adhesional contact

    NASA Astrophysics Data System (ADS)

    Saito, Shigeki; Ochiai, Toshihiro; Yoshizawa, Fumikazu; Dao, Ming

    2016-09-01

    Understanding the rolling behavior of a micro-object is essential to establish the techniques of micro-manipulation and micro-assembly by mechanical means. Using a combined theoretical/computational approach, we studied the critical conditions of rolling resistance of an elastic cylindrical micro-object in adhesional contact with a rigid surface. Closed-form dimensionless expressions for the critical rolling moment, the initial rolling contact area, and the initial rolling angle were extracted after a systematic parametric study using finite element method (FEM) simulations. The total energy of this system is defined as the sum of three terms: the elastic energy stored in the deformed micro-cylinder, the interfacial energy within the contact area, and the mechanical potential energy that depends on the external moment applied to the cylindrical micro-object. A careful examination of the energy balance of the system surprisingly revealed that the rolling resistance per unit cylindrical length can be simply expressed by “work of adhesion times cylindrical radius” independent of the Young’s modulus. In addition, extending a linear elastic fracture mechanics based approach in the literature, we obtained the exact closed-form asymptotic solutions for the critical conditions for initial rolling; these asymptotic solutions were found in excellent agreement with the full-field FEM results.

  1. Rolling behavior of a micro-cylinder in adhesional contact.

    PubMed

    Saito, Shigeki; Ochiai, Toshihiro; Yoshizawa, Fumikazu; Dao, Ming

    2016-09-28

    Understanding the rolling behavior of a micro-object is essential to establish the techniques of micro-manipulation and micro-assembly by mechanical means. Using a combined theoretical/computational approach, we studied the critical conditions of rolling resistance of an elastic cylindrical micro-object in adhesional contact with a rigid surface. Closed-form dimensionless expressions for the critical rolling moment, the initial rolling contact area, and the initial rolling angle were extracted after a systematic parametric study using finite element method (FEM) simulations. The total energy of this system is defined as the sum of three terms: the elastic energy stored in the deformed micro-cylinder, the interfacial energy within the contact area, and the mechanical potential energy that depends on the external moment applied to the cylindrical micro-object. A careful examination of the energy balance of the system surprisingly revealed that the rolling resistance per unit cylindrical length can be simply expressed by "work of adhesion times cylindrical radius" independent of the Young's modulus. In addition, extending a linear elastic fracture mechanics based approach in the literature, we obtained the exact closed-form asymptotic solutions for the critical conditions for initial rolling; these asymptotic solutions were found in excellent agreement with the full-field FEM results.

  2. Analysis of bearing steel exposed to rolling contact fatigue

    NASA Astrophysics Data System (ADS)

    Hansen, K. T.; Fæster, S.; Natarajan, A.; Mishin, O. V.; Danielsen, H. K.; Jensen, D. Juul; Klit, P.

    2017-07-01

    The objective of this work is to characterize fatigue damage in roller bearings under conditions of high load and slippage. A test rig constructed for rolling contact fatigue tests of rings is described, and test results are presented for rings taken from two spherical roller bearings. The preparation of the rings and the loading situation are explained. Test conditions are chosen with the aim of achieving pitting formation at the contacting surfaces. During testing the contact pressure, torque and the rotational speed are monitored and recorded. After testing the tested rings have been characterized using X-ray tomography and scanning electron microscopy. The observations confirm that rolling contact fatigue testing at high loads leads to pitting failure at the contacting surfaces. The pitting mostly appears on one side of the contact, attributed to a non-uniform contact pressure in the axial direction.

  3. 49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Contact element, mechanical trip type; location... Instructions; Locomotives § 236.560 Contact element, mechanical trip type; location with respect to rail. Contact element of automatic train stop device of the mechanical trip type shall be maintained at a height...

  4. 49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Contact element, mechanical trip type; location... Instructions; Locomotives § 236.560 Contact element, mechanical trip type; location with respect to rail. Contact element of automatic train stop device of the mechanical trip type shall be maintained at a height...

  5. 49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Contact element, mechanical trip type; location... Instructions; Locomotives § 236.560 Contact element, mechanical trip type; location with respect to rail. Contact element of automatic train stop device of the mechanical trip type shall be maintained at a height...

  6. 49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Contact element, mechanical trip type; location... Instructions; Locomotives § 236.560 Contact element, mechanical trip type; location with respect to rail. Contact element of automatic train stop device of the mechanical trip type shall be maintained at a height...

  7. 49 CFR 236.560 - Contact element, mechanical trip type; location with respect to rail.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Contact element, mechanical trip type; location... Instructions; Locomotives § 236.560 Contact element, mechanical trip type; location with respect to rail. Contact element of automatic train stop device of the mechanical trip type shall be maintained at a height...

  8. Contact Stress Analysis in Wheel-Rail by Hertzian Method and Finite Element Method

    NASA Astrophysics Data System (ADS)

    Srivastava, J. P.; Sarkar, P. K.; Ranjan, V.

    2014-10-01

    Safety and economy of railway traffic is enormously influenced by the contact stress variation caused by wheel rail contact profile changes. A change in designed surface topology may result from wear that brings in a wide change in contact geometry and stresses. To study the influence of interacting wheel and rail profile topology of standard rail UIC60, the standard wheel profile as per Indian Railway standards are considered in this paper. Rail profile radii, wheel profile radii and wheel profile taper are chosen for six different values. The analytical formulation is based on Timoshenko's approach and Finite Element Method (FEM) based simulation of the problems is undertaken. With these tools, distribution of contact zones, contact stress and contact pressure for different configuration of the wheel and rail profiles are obtained. The mesh density in contact region is found to have a direct influence on the accuracy of the solution [1]. To standardize the analysis of the contact region, mesh with an element size of 1 mm for all the configurations are chosen. Using stress response obtained through FEM analysis and multiaxial fatigue crack initiation model, the effects of vertical loading on fatigue crack initiation life are investigated. This may allow a direct design application for railways in particular.

  9. Investigation of transient temperature's influence on damage of high-speed sliding electrical contact rail surface

    NASA Astrophysics Data System (ADS)

    Zhang, Yuyan; Sun, Shasha; Guo, Quanli; Yang, Degong; Sun, Dongtao

    2016-11-01

    In the high speed sliding electrical contact with large current, the temperature of contact area rises quickly under the coupling action of the friction heating, the Joule heating and electric arc heating. The rising temperature seriously affects the conductivity of the components and the yield strength of materials, as well affects the contact state and lead to damage, so as to shorten the service life of the contact elements. Therefore, there is vital significance to measure the temperature accurately and investigate the temperature effect on damage of rail surface. Aiming at the problem of components damage in high speed sliding electrical contact, the transient heat effect on the contact surface was explored and its influence and regularity on the sliding components damage was obtained. A kind of real-time temperature measurement method on rail surface of high speed sliding electrical contact is proposed. Under the condition of 2.5 kA current load, based on the principle of infrared radiation non-contact temperature sensor was used to measure the rail temperature. The dynamic distribution of temperature field was obtained through the simulation analysis, further, the connection between temperature changes and the rail surface damage morphology, the damage volume was analyzed and established. Finally, the method to reduce rail damage and improve the life of components by changing the temperature field was discussed.

  10. Traction forces at solid-lubricated rolling/sliding contacts

    NASA Technical Reports Server (NTRS)

    Aggarwal, B. B.; Bovenkerk, R. L.

    1985-01-01

    A single-element traction rig was used to measure the traction forces at a solid-lubricated contact of a ball against a flat disk at room temperature under combine rolling and sliding. The load and speed conditions were selected to match those anticipated for bearing applications in adiabatic diesel engines. Traction vs slide/roll ratio curves were similar to those for liquid lubricants but the traction forces were an order of magnitude higher. The test data were used to derive equations to predict traction force as a function of contact stress and rolling speed. The data showed that the magnitude of traction forces were almost the same for all the lubricants tested. The lubricants, should, therefore, be selected on the basis of their ability to limit the wear of contact surfaces.

  11. Control of mechanical systems with rolling contacts: Applications to robotics

    NASA Astrophysics Data System (ADS)

    Sarkar, Nilanjan

    1993-01-01

    The problems of modeling and control of mechanical dynamic systems subject to rolling contacts are investigated. There are two important theoretical contributions in this dissertation. First, contact kinematic relationships up to second order are developed for two rigid bodies in point contact. These equations relate gross rigid body motion to the changes in the positions of the points of contact. Second, a unified approach to the control of mechanical systems subject to both holonomic and nonholonomic constraints is proposed. The basic approach is to extend the state-space to include, in the addition to the generalized coordinates and velocities, contact coordinates which describe the displacements of the contact points and their derivatives. This redundant state-space formulation provides a convenient way to specify output equations to control contact motion. The control problem is formulated as an affine nonlinear problem and a differential-geometric, control-theoretic approach is used to decouple and linearize such systems. It is shown that such a system, even though not input-state linearizable, is input-output linearizable. Further, the zero dynamics of such a system is shown to be Lagrange stable. The proposed methodology is applied to three different robotic systems: (1) wheeled mobile robots; (2) two arms manipulating an object with rolling contact between each arm and the object; and (3) a single robot arm maintaining controlled contact against a moving environment. In each case, a nonlinear controller is designed to achieve the desired performances. For mobile robots, a new control algorithm called dynamic path following is proposed and shown to be quite effective and robust. In the context of two arm manipulation, grasp adaptation through the control of contact motion is demonstrated. Maintaining rolling contact with a moving surface is formulated as an acatastatic system. The proposed scheme involves simultaneously controlling interaction forces as

  12. Hybrid bearing technology for advanced turbomachinery: Rolling contact fatigue testing

    SciTech Connect

    Dill, J.F.

    1996-01-01

    The purpose of this paper is to describe the basic structure and results to date of a major ARPA funded effort to provide a tribological performance database on ceramic bearing materials and their interaction with standard bearing steels. Program efforts include studies of material physical properties, machining characteristics, and tribological performance. The majority of the testing completed to date focuses on rolling contact fatigue testing of the ceramic materials, including efforts to arrive at optimum approaches to evaluating ceramic/steel hybrid combinations in rolling contact fatigue.

  13. Dynamic model for the wheel-rail contact friction

    NASA Astrophysics Data System (ADS)

    Lee, HyunWook; Sandu, Corina; Holton, Carvel

    2012-02-01

    Accurately estimating the coefficient of friction (CoF) is essential in modelling railroad dynamics, reducing maintenance costs, and increasing safety in rail operations. The typical assumption of a constant CoF is widely used in theoretical studies; however, it has been noticed that the CoF is not constant, but rather depends on various dynamic parameters and instantaneous conditions. In this paper, we present a newly developed three-dimensional nonlinear CoF model for the dry rail condition and test the CoF variation using this model with estimated dynamic parameters. The wheel-rail is modelled as a mass-spring-damper system to simulate the basic wheel-rail dynamics. Although relatively simple, this model is considered sufficient for the purpose of this study. Simulations are performed at a train speed of 20 m/s using rail roughness as an excitation source. The model captures the CoF extremes and illustrates its nonlinear behaviour and instantaneous dependence on several structural and dynamic parameters.

  14. A contact-type tensionmeter for hot rolling mills

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaoyan; Zhang, Zhaohui; Sun, Yikang; Wang, Jun; Que, Cheng

    2008-12-01

    To improve the hot rolled strip quality and operational stability, a novel tensionmeter based on lever principle is developed which inspects latent waves and provides real references for flatness control in hot rolling process. The contact-type tensionmeter including two segmented rolls can get the transverse tension distribution along the strip width. Tension profile is deduced by different ratio of four force values from the embedded force sensors in tensionmeter system. The compact mechanical structure ensures the tensionmeter's robust stability in hot rolling process, standard hardware and software for data acquisition make the system easy to operate and maintain. The trails have proven tensionmeter successful in improving both strip flatness and mill performance.

  15. Rolling contact fatigue testing of peek based composites

    NASA Astrophysics Data System (ADS)

    Avanzini, A.; Donzella, G.; Gallina, D.; Pandini, S.; Petrogalli, C.

    2010-06-01

    Rolling contact fatigue phenomenon was investigated on unfilled PEEK and on three different PEEK composites: 10% carbon micro-fiber, graphite and PTFE filled matrix, 30% carbon micro-fiber filled matrix, 30% glass micro-fiber filled matrix. For this aim, roller-shaped specimens were machined from extruded bars of these materials and subjected to rolling contact tests at different contact pressure levels by means of a four roller machine. Contact pressure-life diagrams and wear rates were so obtained and compared, highlighting a relationship with monotonic and hardness materials properties. Microscopic observations of contact surfaces and transversal section of the specimens also allowed observing the damage mechanisms occurred in the materials tested and the effects of the filler. In particular way, deep radial cracks appeared on unfilled PEEK, while spalling and delamination phenomena where found on composites. Diffuse microcracks were found at the filler-matrix interface of the composites specimens, confirming that the fatigue life of these materials is essentially determined by the crack propagation phase, also under rolling contact loading.

  16. Experimental investigation on the electrical contact behavior of rolling contact connector

    SciTech Connect

    Chen, Junxing; Yang, Fei Luo, Kaiyu; Zhu, Mingliang; Wu, Yi; Rong, Mingzhe

    2015-12-15

    Rolling contact connector (RCC) is a new technology utilized in high performance electric power transfer systems with one or more rotating interfaces, such as radars, satellites, wind generators, and medical computed tomography machines. Rolling contact components are used in the RCC instead of traditional sliding contacts to transfer electrical power and/or signal. Since the requirement of the power transmission is increasing in these years, the rolling electrical contact characteristics become more and more important for the long-life design of RCC. In this paper, a typical form of RCC is presented. A series of experimental work are carried out to investigate the rolling electrical contact characteristics during its lifetime. The influence of a variety of factors on the electrical contact degradation behavior of RCC is analyzed under both vacuum and air environment. Based on the surface morphology and elemental composition changes in the contact zone, which are assessed by field emission scanning electron microscope and confocal laser scanning microscope, the mechanism of rolling electrical contact degradation is discussed.

  17. Experimental investigation on the electrical contact behavior of rolling contact connector

    NASA Astrophysics Data System (ADS)

    Chen, Junxing; Yang, Fei; Luo, Kaiyu; Zhu, Mingliang; Wu, Yi; Rong, Mingzhe

    2015-12-01

    Rolling contact connector (RCC) is a new technology utilized in high performance electric power transfer systems with one or more rotating interfaces, such as radars, satellites, wind generators, and medical computed tomography machines. Rolling contact components are used in the RCC instead of traditional sliding contacts to transfer electrical power and/or signal. Since the requirement of the power transmission is increasing in these years, the rolling electrical contact characteristics become more and more important for the long-life design of RCC. In this paper, a typical form of RCC is presented. A series of experimental work are carried out to investigate the rolling electrical contact characteristics during its lifetime. The influence of a variety of factors on the electrical contact degradation behavior of RCC is analyzed under both vacuum and air environment. Based on the surface morphology and elemental composition changes in the contact zone, which are assessed by field emission scanning electron microscope and confocal laser scanning microscope, the mechanism of rolling electrical contact degradation is discussed.

  18. Experimental investigation on the electrical contact behavior of rolling contact connector.

    PubMed

    Chen, Junxing; Yang, Fei; Luo, Kaiyu; Zhu, Mingliang; Wu, Yi; Rong, Mingzhe

    2015-12-01

    Rolling contact connector (RCC) is a new technology utilized in high performance electric power transfer systems with one or more rotating interfaces, such as radars, satellites, wind generators, and medical computed tomography machines. Rolling contact components are used in the RCC instead of traditional sliding contacts to transfer electrical power and/or signal. Since the requirement of the power transmission is increasing in these years, the rolling electrical contact characteristics become more and more important for the long-life design of RCC. In this paper, a typical form of RCC is presented. A series of experimental work are carried out to investigate the rolling electrical contact characteristics during its lifetime. The influence of a variety of factors on the electrical contact degradation behavior of RCC is analyzed under both vacuum and air environment. Based on the surface morphology and elemental composition changes in the contact zone, which are assessed by field emission scanning electron microscope and confocal laser scanning microscope, the mechanism of rolling electrical contact degradation is discussed.

  19. Rolling contact fatigue of various unfilled and fiber reinforced polymers

    NASA Astrophysics Data System (ADS)

    Almajid, Abdulhakim; Friedrich, Klaus

    2012-07-01

    The wear behavior of Polyamide 6 (PA6), Polyoxymethylene (POM), Polyetheretherketone (PEEK), and Polyparaphenylene (PPP) materials under rolling contact was investigated. The ball on plate principle, i.e. a steel ball (as counterpart) rolls on a polymer plate specimen in rotational or linear motion, was used. The results are shown for different stress parameters which vary by load (50 N up to 300 N) and testing time (up to 50 hours). Differences in surface fatigue mechanisms were illustrated by microscopic methods. The best performance was found for PEEK. All the neat polymers were superior to any reinforced versions of them.

  20. Fatigue resistant carbon coatings for rolling/sliding contacts

    SciTech Connect

    Singh, Harpal; Ramirez, Giovanni; Eryilmaz, Osman; Greco, Aaron; Doll, Gary; Erdemir, Ali

    2016-06-01

    The growing demands for renewable energy production have recently resulted in a significant increase in wind plant installation. Field data from these plants show that wind turbines suffer from costly repair, maintenance and high failure rates. Often times the reliability issues are linked with tribological components used in wind turbine drivetrains. The primary failure modes in bearings and gears are associated with micropitting, wear, brinelling, scuffing, smearing and macropitting all of which occur at or near the surface. Accordingly, a variety of surface engineering approaches are currently being considered to alter the near surface properties of such bearings and gears to prevent these tribological failures. In the present work, we have evaluated the tribological performance of compliant highly hydrogenated diamond like carbon coating developed at Argonne National Laboratory, under mixed rolling/sliding contact conditions for wind turbine drivetrain components. The coating was deposited on AISI 52100 steel specimens using a magnetron sputter deposition system. The experiments were performed on a PCS Micro-Pitting-Rig (MPR) with four material pairs at 1.79 GPa contact stress, 40% slide to roll ratio and in polyalphaolefin (PAO4) basestock oil (to ensure extreme boundary conditions). The post-test analysis was performed using optical microscopy, surface profilometry, and Raman spectroscopy. The results obtained show a potential for these coatings in sliding/rolling contact applications as no failures were observed with coated specimens even after 100 million cycles compared to uncoated pair in which they failed after 32 million cycles, under the given test conditions.

  1. Assessing the accuracy of different simplified frictional rolling contact algorithms

    NASA Astrophysics Data System (ADS)

    Vollebregt, E. A. H.; Iwnicki, S. D.; Xie, G.; Shackleton, P.

    2012-01-01

    This paper presents an approach for assessing the accuracy of different frictional rolling contact theories. The main characteristic of the approach is that it takes a statistically oriented view. This yields a better insight into the behaviour of the methods in diverse circumstances (varying contact patch ellipticities, mixed longitudinal, lateral and spin creepages) than is obtained when only a small number of (basic) circumstances are used in the comparison. The range of contact parameters that occur for realistic vehicles and tracks are assessed using simulations with the Vampire vehicle system dynamics (VSD) package. This shows that larger values for the spin creepage occur rather frequently. Based on this, our approach is applied to typical cases for which railway VSD packages are used. The results show that particularly the USETAB approach but also FASTSIM give considerably better results than the linear theory, Vermeulen-Johnson, Shen-Hedrick-Elkins and Polach methods, when compared with the 'complete theory' of the CONTACT program.

  2. UCSD/FRA non-contact ultrasonic guided-wave system for rail inspection: an update

    NASA Astrophysics Data System (ADS)

    Coccia, Stefano; Phillips, Robert; Nucera, Claudio; Bartoli, Ivan; Salamone, Salvatore; Lanza di Scalea, Francesco; Fateh, Mahmood; Carr, Gary

    2011-04-01

    The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail defect detection. A prototype has been designed and field tested with the support of Volpe National Transportation Systems Center and ENSCO, Inc. The goal of this project is to develop a rail defect detection system that provides (a) better defect detection reliability (including internal transverse head defects under shelling and vertical split head defects), and (b) higher inspection speed than achievable by current rail inspection systems. This effort is also in direct response to Safety Recommendations issued by the National Transportation Safety Board (NTSB) following the disastrous train derailments at Superior, WI in 1992 and Oneida, NY in 2007 among others. The UCSD prototype uses non-contact ultrasonic probing of the rail head (laser and air-coupled), ultrasonic guided waves, and a proprietary real-time statistical analysis algorithm that maximizes the sensitivity to defects while minimizing false positives. The current design allows potential inspection speeds up to 40 mph, although all field tests have been conducted up to 15 mph so far. This paper summarizes (a) the latest technology development test conducted at the rail defect farm of Herzog, Inc. in St Joseph, MO in June 2010, and (b) the completion of the new Rail Defect Farm facility at the UCSD Camp Elliott Field Station with partial in-kind donations from the Burlington Northern Santa Fe (BNSF) Railway.

  3. Development of a second generation rolling contact fatigue tester

    NASA Astrophysics Data System (ADS)

    Deshmukh, Satyam U.

    Contact fatigue failure has been in research since the early twentieth century. The need for a second generation sliding-rolling contact fatigue tester was proposed by Gregory Dvorak and Dr. Marcellin Zahui. The first generation RCF tester was used for testing super finishing processes for gear surfaces. The second generation RCF tester was funded by the Advanced Engineering Materials lab of University of North Dakota. Verification of the second generation Rolling Contact Fatigue Tester will be discussed in this thesis including the design details, assembly and testing procedure and to discuss its different parameters. The tester will have the capability of testing hollow specimens using a bobbin eddy current testing probe. This tester will allow a wide range of experiments and is not built for one specific purpose. An eddy current device is used for detecting cracks. The loading force is applied using hydraulic cylinders and a hydraulic power unit. Before testing began, the machine was run for some time at full speed. A lot of minor problems were detected and fixed. Three specimens of AISI 8620 were tested in this tester. All tests gave results matching with some of the other well-known RCF testers. These tests were performed to evaluate mechanical limits of the tester and to evaluate the software performance of the tester.

  4. Development of method for experimental determination of wheel-rail contact forces and contact point position by using instrumented wheelset

    NASA Astrophysics Data System (ADS)

    Bižić, Milan B.; Petrović, Dragan Z.; Tomić, Miloš C.; Djinović, Zoran V.

    2017-07-01

    This paper presents the development of a unique method for experimental determination of wheel-rail contact forces and contact point position by using the instrumented wheelset (IWS). Solutions of key problems in the development of IWS are proposed, such as the determination of optimal locations, layout, number and way of connecting strain gauges as well as the development of an inverse identification algorithm (IIA). The base for the solution of these problems is the wheel model and results of FEM calculations, while IIA is based on the method of blind source separation using independent component analysis. In the first phase, the developed method was tested on a wheel model and a high accuracy was obtained (deviations of parameters obtained with IIA and really applied parameters in the model are less than 2%). In the second phase, experimental tests on the real object or IWS were carried out. The signal-to-noise ratio was identified as the main influential parameter on the measurement accuracy. Тhе obtained results have shown that the developed method enables measurement of vertical and lateral wheel-rail contact forces Q and Y and their ratio Y/Q with estimated errors of less than 10%, while the estimated measurement error of contact point position is less than 15%. At flange contact and higher values of ratio Y/Q or Y force, the measurement errors are reduced, which is extremely important for the reliability and quality of experimental tests of safety against derailment of railway vehicles according to the standards UIC 518 and EN 14363. The obtained results have shown that the proposed method can be successfully applied in solving the problem of high accuracy measurement of wheel-rail contact forces and contact point position using IWS.

  5. High-speed defect detection in rails by non-contact guided ultrasonic testing

    NASA Astrophysics Data System (ADS)

    Rizzo, Piervincenzo; Bartoli, Ivan; Lanza di Scalea, Francesco; Coccia, Stefano; Fateh, Mahmood

    2005-05-01

    Recent train accidents and associated direct and indirect repair costs have reaffirmed the need for developing rail defect detection systems more effective than those used today. The group at the UCSD NDE & Structural Health Monitoring Laboratory, in collaboration with the US Federal Railroad Administration, is conducting a study that aims at developing an inspection strategy for rails based on guided ultrasonic waves. This paper illustrates a guided-wave inspection system that is targeted to the detection of transverse-type cracks in the rail head, that are among the most dangerous flaws in rails. The methodology is based on a hybrid non-contact system that uses a pulsed laser for generating waves and multiple air-coupled sensors for detecting waves. The remote sensors are positioned as far away as 76 mm (3") from the top of rail head. Signal processing based on the Continuous Wavelet Transform is used to characterize the time-frequency content of the propagating waves. Features extracted after Discrete Wavelet processing of the wave signals result in a damage index that is robust with respect to noise and is related to the crack depth; the method allows for fast inspection with the potential for quantifying the extent of the flaw. It is demonstrated that the adopted setup allows for the detection of small cracks, as shallow as 1 mm in depth. It is also shown that the ultrasonic wave features considered in this study are directly related to the reduction of the rail head cross-sectional area caused by a transverse crack.

  6. Effect of biomimetic coupling units' morphologies on rolling contact fatigue wear resistance of steel from machine tool rolling tracks

    NASA Astrophysics Data System (ADS)

    Yang, Wanshi; Zhou, Hong; Sun, Liang; Wang, Chuanwei; Chen, Zhikai

    2014-04-01

    The rolling contact fatigue wear resistance plays an important role on ensuring machining precision of machine tool using rolling tracks. Bio-inspired wearable surfaces with the alternated hardness were prepared on the specimen of steel material from machine tool rolling tracks by biomimetic coupling laser remelting method to imitate biological coupling principle. The microstructures and micromorphologies of bionic units in different sizes were characterized by optical microscope. The specimens with bionic units in different sizes and distributions were tested for rolling contact fatigue wear resistance. Combining the finite element analysis and the results of wear tests, a discussion on rolling contact fatigue wear was had. The specimens with bionic units had better rolling contact fatigue wear resistance than the untreated one, while the specimens with bionic units in the alternative depth's distributions present a better rolling contact fatigue wear resistance than the ones with bionic units in the single depth's distribution. It attributed to the alternative distribution made further improvement on the dispersion of depth of stress concentration.

  7. Rational chemical composition and heat treatment models of rails made from E76HF steel using the heat of rolling heating

    NASA Astrophysics Data System (ADS)

    Polevoy, E. V.; Temlyantsev, M. V.

    2016-09-01

    On the pilot plant the experiments in the differentiated heat treatment by air using the heat of rolling heating of rails produced from steel E76HF with three chemical compositions comprising various contents of chromium, manganese and silicon were carried out. The effect of heat treatment parameters on the structure and properties of rails was examined. According to the results of experiments the rational chemical composition was determined, as well as the heat treatment modes recommended for a mass production of differentially thermo-strengthened rails of DT350 category.

  8. Non-contact ultrasonic guided wave inspection of rails: field test results and updates

    NASA Astrophysics Data System (ADS)

    Mariani, Stefano; Nguyen, Thompson V.; Zhu, Xuan; Lanza di Scalea, Francesco; Fateh, Mahmood

    2015-04-01

    The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail defect detection. A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection, paired with a real-time statistical analysis algorithm, has been realized. This system requires a specialized filtering approach based on electrical impedance matching due to the inherently poor signal-to-noise ratio of air-coupled ultrasonic measurements in rail steel. Various aspects of the prototype have been designed with the aid of numerical analyses. In particular, simulations of ultrasonic guided wave propagation in rails have been performed using a Local Interaction Simulation Approach (LISA) algorithm. The system's operating parameters were selected based on Receiver Operating Characteristic (ROC) curves, which provide a quantitative manner to evaluate different detection performances based on the trade-off between detection rate and false positive rate. Results from the first field test of the non-contact air-coupled defect detection prototype conducted at the Transportation Technology Center (TTC) in Pueblo, Colorado, in October 2014 are presented and discussed in this paper. The results indicate that the prototype is able to detect internal cracks with high reliability.

  9. Environmental Assessment for the Transfer of 1100 AREA, Southern Rail Connection and Rolling Stock, Hanford Site, Richland, Washington

    SciTech Connect

    N /A

    1998-08-01

    This environmental assessment (EA) has been prepared to assess potential environmental impacts associated with the U.S. Department of Energy's proposed action: the transfer of the 1100 Area, southern rail connection and rolling stock to a non-federal entity. Impact information contained herein will be used by the U.S. Department of Energy, Richland Operations Office Manager, to determine if the proposed action is a major federal action significantly affecting the quality of the human environment. If the proposed action is determined to be major and significant, an environmental impact statement will be prepared. If the proposed action is determined not to be major and significant, a Finding of No Significant Impact (FONSI) will be issued and the action can proceed. Criteria used to evaluate significance can be found in Title 40, Code of Federal Regulations (CFR) 1508.27. This EA was prepared in compliance with the ''National Environmental Policy Act'' (NEPA) of 1969, as amended, the Council on Environmental Quality (CEQ) Regulations for Implementing the Procedural Provisions of NEPA (40 CFR 1500-1508), and the U.S. Department of Energy Implementing Procedures for NEPA (10 CFR 1021). The following is a description of each section of the EA. (1) Purpose and Need for Action. This provides a brief statement concerning the problem or opportunity the U.S. Department of Energy is addressing with the proposed action. As necessary, background information is provided. (2) Description of the Proposed Action. A description with sufficient detail to identify potential environmental impacts is provided. (3) Alternatives to the Proposed Action. Reasonable alternative actions, which would address the Purpose and Need, are described. A no action alternative, as required by 10 CFR 1021, also is described. (4) Affected Environment. This provides a brief description of the locale in which the proposed action takes place, and which may be environmentally impacted. (5) Environmental

  10. The role of compressional viscoelasticity in the lubrication of rolling contacts.

    NASA Technical Reports Server (NTRS)

    Harrison, G.; Trachman, E. G.

    1972-01-01

    A simple model for the time-dependent volume response of a liquid to an applied pressure step is used to calculate the variation with rolling speed of the traction coefficient in a rolling contact system. Good agreement with experimental results is obtained at rolling speeds above 50 in/sec. At lower rolling speeds a very rapid change in the effective viscosity of the lubricant is predicted. This behavior, in conjunction with shear rate effects, is shown to lead to large errors when experimental data are extrapolated to zero rolling speed.

  11. Restoration of rolling-contact-fatigued surfaces via nanoskin technology.

    PubMed

    Pyun, Young Sik; Kim, Jun Hyong; Kayumov, Ravil; He, Yinsheng; Shin, Kee Sam

    2013-09-01

    Rolling contact fatigue (RCF) is known as the dominant factor determining the service life of bearing materials. In this work, the fatigue life of the typical bearing alloy was significantly improved by introducing a nanoskin layer on the surfaces of the test specimens. The nanoskin layer structure was obtained by means of the ultrasonic nanocrystal surface modification (UNSM) technology. The microstructure of the nanoskin was analyzed via scanning electron microscope (SEM), electron back-scatter diffraction (EBSD), and transmission electron microscope (TEM). SUJ2 and SUJ3 bearings at different states of fatigue were subjected to UNSM treatment. For SUJ2 a rotary-bending fatigue (RBF) life average for three untreated specimens was chosen as 100% life, and then several untreated specimens were fatigued to 25%, 50% and 75% of life with subsequent UNSM treatment. This way used bearing conditions were simulated. The rotary-bending fatigue (RBF) tests of fatigue+UNSM SUJ2 specimens have shown 377-430% improvement of fatigue life, comparing to untreated specimens. For SUJ3 a RCF life untreated specimen was chosen as 100% life, and then several specimens were fatigued to approximately 100% of surface damage with subsequent UNSM treatment. Thus damaged surface conditions were simulated. The RCF tests of fatigue+UNSM SUJ3 specimens have shown 218% improvement of fatigue life, comparing to untreated specimens. This indicates the possibility of the restoration of the RCF life of bearing alloys by means of nanoskin treatment via UNSM technology.

  12. Effects of wheel/rail contact patterns and vehicle parameters on lateral stability

    NASA Astrophysics Data System (ADS)

    Wilson, Nicholas; Wu, Huimin; Tournay, Harry; Urban, Curtis

    2010-12-01

    In North American freight service, lateral instability (vehicle hunting) is normally associated with light vehicles and high-speed operations. However, recent research conducted by Transportation Technology Center, Inc. (TTCI), under the Association of American Railroads' Strategic Research Initiatives Program, has shown that some new designs of heavy axle load freight cars are now susceptible to hunting when fully loaded at normal freight train operating speeds. Undesirable wheel/rail (W/R) contact conditions interacting with the car body dimensions and inertial parameters, combined with the characteristics of the suspensions, contribute to hunting. A summary of the investigation is presented here, which includes results of the vehicle tests, wheel and rail profile measurements and analyses, and NUCARS®1 computer simulations. The effects of the vehicle suspension parameters and car body inertial parameters, combined with undesirable W/R contact patterns, are shown to have a significant influence on the vehicle's lateral stability performance, with potential consequences for damage to both vehicles and track, and increased potential for derailment.

  13. A novel optical apparatus for the study of rolling contact wear/fatigue based on a high-speed camera and multiple-source laser illumination.

    PubMed

    Bodini, I; Sansoni, G; Lancini, M; Pasinetti, S; Docchio, F

    2016-08-01

    Rolling contact wear/fatigue tests on wheel/rail specimens are important to produce wheels and rails of new materials for improved lifetime and performance, which are able to operate in harsh environments and at high rolling speeds. This paper presents a novel non-invasive, all-optical system, based on a high-speed video camera and multiple laser illumination sources, which is able to continuously monitor the dynamics of the specimens used to test wheel and rail materials, in a laboratory test bench. 3D macro-topography and angular position of the specimen are simultaneously performed, together with the acquisition of surface micro-topography, at speeds up to 500 rpm, making use of a fast camera and image processing algorithms. Synthetic indexes for surface micro-topography classification are defined, the 3D macro-topography is measured with a standard uncertainty down to 0.019 mm, and the angular position is measured on a purposely developed analog encoder with a standard uncertainty of 2.9°. The very small camera exposure time enables to obtain blur-free images with excellent definition. The system will be described with the aid of end-cycle specimens, as well as of in-test specimens.

  14. A novel optical apparatus for the study of rolling contact wear/fatigue based on a high-speed camera and multiple-source laser illumination

    NASA Astrophysics Data System (ADS)

    Bodini, I.; Sansoni, G.; Lancini, M.; Pasinetti, S.; Docchio, F.

    2016-08-01

    Rolling contact wear/fatigue tests on wheel/rail specimens are important to produce wheels and rails of new materials for improved lifetime and performance, which are able to operate in harsh environments and at high rolling speeds. This paper presents a novel non-invasive, all-optical system, based on a high-speed video camera and multiple laser illumination sources, which is able to continuously monitor the dynamics of the specimens used to test wheel and rail materials, in a laboratory test bench. 3D macro-topography and angular position of the specimen are simultaneously performed, together with the acquisition of surface micro-topography, at speeds up to 500 rpm, making use of a fast camera and image processing algorithms. Synthetic indexes for surface micro-topography classification are defined, the 3D macro-topography is measured with a standard uncertainty down to 0.019 mm, and the angular position is measured on a purposely developed analog encoder with a standard uncertainty of 2.9°. The very small camera exposure time enables to obtain blur-free images with excellent definition. The system will be described with the aid of end-cycle specimens, as well as of in-test specimens.

  15. Resistance to Rolling in the Adhesive Contact of Two Elastic Spheres

    NASA Technical Reports Server (NTRS)

    Dominik, C.; Tielens, A. G. G. M.

    1995-01-01

    For the stability of agglomerates of micron sized particles it is of considerable importance to study the effects of tangential forces on the contact of two particles. If the particles can slide or roll easily over each other, fractal structures of these agglomerates will not be stable. We use the description of contact forces by Johnson, Kendall and Roberts, along with arguments based on the atomic structure of the surfaces in contact, in order to calculate the resistance to rolling in such a contact. It is shown that the contact reacts elastically to torque forces up to a critical bending angle. Beyond that, irreversible rolling occurs. In the elastic regime, the moment opposing the attempt to roll is proportional to the bending angle and to the pull-off force P(sub c). Young's modulus of the involved materials has hardly any influence on the results. We show that agglomerates of sub-micron sized particles will in general be quite rigid and even long chains of particles cannot be bent easily. For very small particles, the contact will rather break than allow for rolling. We further discuss dynamic properties such as the possibility of vibrations in this degree of freedom and the typical amount of rolling during a collision of two particles.

  16. Ceramic Rail-Race Ball Bearings

    NASA Technical Reports Server (NTRS)

    Balzer, Mark A.; Mungas, Greg S.; Peters, Gregory H.

    2010-01-01

    Non-lubricated ball bearings featuring rail races have been proposed for use in mechanisms that are required to function in the presence of mineral dust particles in very low-pressure, dry environments with extended life. Like a conventional ball bearing, the proposed bearing would include an inner and an outer ring separated by balls in rolling contact with the races. However, unlike a conventional ball bearing, the balls would not roll in semi-circular or gothic arch race grooves in the rings: instead, the races would be shaped to form two or more rails (see figure). During operation, the motion of the balls would push dust particles into the spaces between the rails where the particles could not generate rolling resistance for the balls

  17. Dynamic contact stress and rolling resistance model for total knee arthroplasties.

    PubMed

    Waldman, S D; Bryant, J T

    1997-08-01

    Problems associated with premature failure of total knee replacements (TKR's) include: wear, creep, and oxidation of ultrahigh-molecular-weight polyethylene (UHMWPe) as well as adverse tissue reactions to polyethylene wear debris. These problems are associated in part with the mechanical behavior of UHMWPe. In TKR's, contact stress analyses have been performed on the UHMWPe tibial component; however, most have employed simplified material properties and not accounted for joint kinematics. A nonlinear viscoelastic rolling model was developed for TKR's to predict the contact stress and rolling friction for varying rolling speed, conformity, applied load, and tibial plateau thickness. Results indicated that the contact stress increased and rolling friction decreased with increasing rolling speed. Effects of conformity, applied load, and tibial plateau thickness were consistent with previous models. At large rolling speeds, predicted peak contact stresses were almost twice their static value, resulting in a compound fatigue problem in UHMWPe components due to normal cyclic loading, moving point of contact, and velocity-dependent stresses.

  18. Experimental study of tyre/road contact forces in rolling conditions for noise prediction

    NASA Astrophysics Data System (ADS)

    Cesbron, Julien; Anfosso-Lédée, Fabienne; Duhamel, Denis; Ping Yin, Hai; Le Houédec, Donatien

    2009-02-01

    This paper deals with the experimental study of dynamical tyre/road contact for noise prediction. In situ measurements of contact forces and close proximity noise levels were carried out for a slick tyre rolling on six different road surfaces between 30 and 50 km/h. Additional texture profiles of the tested surfaces were taken on the wheel track. Normal contact stresses were measured at a sampling frequency of 10752 Hz using a line of pressure sensitive cells placed both along and perpendicular to the rolling direction. The contact areas obtained during rolling were smaller than in static conditions. This is mainly explained by the dynamical properties of tyre compounds, like the viscoelastic behaviour of the rubber. Additionally the root-mean-square of the resultant contact forces at various speeds was in the same order for a given road surface, while their spectra were quite different. This is certainly due to a spectral influence of bending waves propagating in the tyre during rolling, especially when the wavelength is small in comparison with the size of the contact patch. Finally, the levels of contact forces and close proximity noise measured at 30 km/h were correlated. Additional correlations with texture levels were performed. The results show that the macro-texture generates contact forces linearly around 800 Hz and consequently noise levels between 500 and 1000 Hz via the vibrations transmitted to the tyre.

  19. Analysis of rolling contact spall life in 440 C steel bearing rims

    NASA Technical Reports Server (NTRS)

    Bastias, P. C.; Bhargava, V.; Bower, A. P.; Du, J.; Gupta, V.; Hahn, G. T.; Kulkarni, S. M.; Kumar, A. M.; Leng, X.; Rubin, C. A.

    1991-01-01

    The results of a two year study of the mechanisms of spall failure in the HPOTP bearings are described. The objective was to build a foundation for detailed analyses of the contact life in terms of: cyclic plasticity, contact mechanics, spall nucleation, and spall growth. Since the laboratory rolling contact testing is carried out in the 3 ball/rod contact fatigue testing machine, the analysis of the contacts and contact lives produced in this machine received attention. The results from the experimentally observed growth lives are compared with calculated predictions derived from the fracture mechanics calculations.

  20. A precise integration method for solving coupled vehicle-track dynamics with nonlinear wheel-rail contact

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Gao, Q.; Tan, S. J.; Zhong, W. X.

    2012-10-01

    A new method is proposed as a solution for the large-scale coupled vehicle-track dynamic model with nonlinear wheel-rail contact. The vehicle is simplified as a multi-rigid-body model, and the track is treated as a three-layer beam model. In the track model, the rail is assumed to be an Euler-Bernoulli beam supported by discrete sleepers. The vehicle model and the track model are coupled using Hertzian nonlinear contact theory, and the contact forces of the vehicle subsystem and the track subsystem are approximated by the Lagrange interpolation polynomial. The response of the large-scale coupled vehicle-track model is calculated using the precise integration method. A more efficient algorithm based on the periodic property of the track is applied to calculate the exponential matrix and certain matrices related to the solution of the track subsystem. Numerical examples demonstrate the computational accuracy and efficiency of the proposed method.

  1. Imaging geological contact utilizing 2D resistivity method for light rail transit (LRT) track alignment

    NASA Astrophysics Data System (ADS)

    Ali, Nisa'; Saad, Rosli; Muztaza, Nordiana M.; Ismail, Noer E. H.

    2013-05-01

    The purpose of this study was to locate the geological contact using 2D resistivity method for Light Rail Transit (LRT) track alignment. The resistivity method was conducted on eight survey lines with the length of line 1 was 600m. The length of line 2, 3, 4, 5, 6, and 7 were 200m each while line 8 is 115m. All the survey used minimum electrode spacing of 5m and using Pole-dipole array with minimum current is 2mA and maximum was 20mA. The result obtained from the pseudosection showed that the area generally divided into three main zones, fill materials/residual soil with a resistivity value of <500 Ωm, saturated zone with a resistivity value of 30-100 Ωm and bedrock with a resistivity value of >2000 Ωm. Three fractured zones were detected along line L1 and a lot of boulders were detected at L1, L3, L4, L5 and L6. The geological contact was between the residual soil and granite bedrock.

  2. Surface observations of stick-slip oscillations in tightly conformal wheel/rail contacts

    NASA Astrophysics Data System (ADS)

    Kalousek, J.

    The reasons for the growth of corrugations on rails and wheels in the Vancouver (Canada) mass transit system are described. The measures taken to eliminate them are outlined. In the Vancouver transit system, by design, the longitudinal and lateral creepages in the wheel/rail interface were absent. The fastener subassembly contains a 25 mm thick layer of natural rubber to absorb vibrations and provide the desired resiliency. The track gauge is maintained to an accuracy of +/- 1 mm. According to the corrugation theories, the lack of longitudinal and lateral creepage in the rail wheel interface was expected to keep the system free from wheel rail vibrations, excessive noise, and corrugations. Yet, six months after opening, 85% of the track was corrugated and the noise levels were rather high. The corrugations on the rails and the wheels are eliminated by means of controlling the friction characteristic and the conformity of rail wheel profiles.

  3. Measuring Tyre Rolling Noise at the Contact Patch

    NASA Astrophysics Data System (ADS)

    Kozak, P.; Matuszkova, R.; Radimsky, M.; Kudrna, J.

    2017-06-01

    This paper deals with noise generated by road traffic. A focus is concentrated solely on one of its sources related to tyre/road interaction referred as rolling noise. The paper states brief overview of various approaches and methods used to measure this particular source of road traffic noise. On the basis of literature reviews, a unique device has been designed. Development of the measuring device and possibilities of its usage are described in detail in this paper. Obtained results of noise measurements can then be used to design measures that increase safety and a lead to better comfort on the road.

  4. A study of subsurface crack initiation produced by rolling contact fatigue

    NASA Technical Reports Server (NTRS)

    Kumar, Arun M.; Hahn, George T.; Rubin, Carol A.

    1993-01-01

    Results of subsurface crack initiation studies produced by pure rolling contact fatigue in 7075-T6 aluminum alloy are presented in this article. Microstructural changes and subsequent crack initiation below the contacting surface in cylindrical test specimens subjected to repeated rolling contact are illustrated. The rolling conditions are simulated in a three-dimensional elastic-plastic finite element model in order to estimate the plastic strains and residual stresses in the test material. The numerically estimated distribution of plastic strains in the model correlate well with the extent of microstructural changes observed in the test specimen. Results also indicate that a combination of plastic strains and low values of residual stresses is conducive to subsurface crack initiation and growth.

  5. Wear Enhancement of Wheel-Rail Interaction by Ultrasonic Nanocrystalline Surface Modification Technique

    PubMed Central

    Chang, Seky; Pyun, Young-Sik; Amanov, Auezhan

    2017-01-01

    In this study, an ultrasonic nanocrystalline surface modification (UNSM) technique was applied to normal and heat-treated rails made of 60 kgK steel to enhance the wear resistance of the wheel-rail interaction. The hardness and compressive residual stress values of the untreated and UNSM-treated rails were measured by the Brinell hardness tester and X-ray diffraction technique, respectively. It was found, according to the measurement results, that the hardness was increased by about 20% and 8%, whereas the compressive residual stress was induced by about 52% and 62% for the UNSM-treated normal and heat-treated rails, respectively. The UNSM-treated normal rail showed a slightly higher hardness than the heat-treated rail. The wear resistance of rails with respect to rotating speed and rolling time was assessed using a rolling contact wear (RCW) tester under dry conditions. The RCW test results revealed that the wear of the UNSM-treated rails was enhanced in comparison with those of the untreated rails. Also, the wear amount of the rails was increased with increasing the rotation speed. The UNSM-treated normal rail exhibited the highest wear resistance with respect to the rotation speed. The wear mechanisms of the rails are also discussed based on microscopic images of the worn out surfaces. PMID:28772549

  6. Two-dimensional Gaussian processes applied to the determination of contact between lubricated rolling surfaces

    NASA Technical Reports Server (NTRS)

    Sidik, S. M.

    1974-01-01

    The effectiveness of a lubricant film preventing metallic contact between two rolling surfaces (such as in ball bearings) as a function of surface roughness parameters was investigated. The parameters considered are the spectral moments of the two-dimensional surface obtained by superposition of the two rolling surfaces. The peak height distribution, estimation of one-dimensional profile spectral moments, and the estimation of two-dimensional surface moments from several profile measurements were considered. Also given is an asymptotic relation between the mean film thickness and contact occurrences.

  7. Fabrication of a roller type PDMS stamp using SU-8 concave molds and its application for roll contact printing

    NASA Astrophysics Data System (ADS)

    Park, Jongho; Kim, Beomjoon

    2016-03-01

    Continuous fabrication of micropatterns at low-cost is attracting attention in various applications within industrial fields. To meet such demands, we have demonstrated a roll contact printing technique, using roller type polydimethylsiloxane (PDMS) stamps with roll-to-flat and roll-to-roll stages. Roller type PDMS stamps for roll contact printing were fabricated using a custom-made metal support and SU-8 microstructures fabricated on concave substrates as a mold. The molding/casting method which we developed here provided faster and easier fabrication than conventional methods for roller type stamps. Next, roll contact printing was performed using fabricated roller type PDMS stamps with roll-to-flat and roll-to-roll stages. Patterns with minimum widths of 3 μm and 2.1 μm were continuously fabricated for each stage, respectively. In addition, the relationship between applied pressures and dimensional changes of roll contact printed patterns was investigated. Finally, we confirmed that roll contact printing and the new fabrication method for roller stamps presented in this study demonstrated the feasibility for industrial applications.

  8. Influence of adsorbed fluids on the rolling contact deformation of MgO single crystals

    NASA Technical Reports Server (NTRS)

    Dufrane, K. F.

    1977-01-01

    Basic phenomena associated with rolling contact deformation were studied using MgO as a model bearing material. A hardened steel ball was rolled on MgO single crystals in slow-speed reciprocating motion and in high-speed circular motion. The resulting deformation was studied by dislocation etch-pit techniques. The presence of adsorbed fluids, such as silicone oil, white mineral oil, and toluene, with slow-speed sliding caused a dramatic change in slip mode and premature surface spalling compared with similar experiments in air or under water. In contrast, dimethyl formamide inhibited these slip processes. The results are consistent with the dependence of dislocation mobility on adsorbed species. High-speed hydrodynamic rolling with mineral oil lubrication produced a different slip phenomena entirely from the slow-speed rolling. The slip bands resembled those produced in tensile tests, and all slip apparently initiated at subsurface sites.

  9. Rolling-element bearings. [contact sliding friction study of solid bodies

    NASA Technical Reports Server (NTRS)

    Anderson, W. J.

    1980-01-01

    In contrast to hydrodynamic bearings, which depend for low-friction characteristics on a fluid film between the journal and the bearing surfaces, roller-element bearings employ a number of balls or rollers that roll in an annular space. The paper briefly outlines the advantages and disadvantages of roller-element bearings as compared to hydrodynamic bearings. The discussion covers bearing types, rolling friction, friction losses in rolling bearings, contact stresses, deformations, kinematics (normal and high speeds), bearing dynamics including elastohydrodynamics, load distribution, lubrication (grease, solid oil, oil-air mist), specific dynamic capacity and life, specific static capacity, and fatigue or wearout (elastohydrodynamics, wear). Rolling bearing wear factor as a function of operating environment is plotted and discussed.

  10. Rolling-element bearings. [contact sliding friction study of solid bodies

    NASA Technical Reports Server (NTRS)

    Anderson, W. J.

    1980-01-01

    In contrast to hydrodynamic bearings, which depend for low-friction characteristics on a fluid film between the journal and the bearing surfaces, roller-element bearings employ a number of balls or rollers that roll in an annular space. The paper briefly outlines the advantages and disadvantages of roller-element bearings as compared to hydrodynamic bearings. The discussion covers bearing types, rolling friction, friction losses in rolling bearings, contact stresses, deformations, kinematics (normal and high speeds), bearing dynamics including elastohydrodynamics, load distribution, lubrication (grease, solid oil, oil-air mist), specific dynamic capacity and life, specific static capacity, and fatigue or wearout (elastohydrodynamics, wear). Rolling bearing wear factor as a function of operating environment is plotted and discussed.

  11. Analysis of distribution rule of surface stress on cross wedge rolling contact zone by finite element method

    NASA Astrophysics Data System (ADS)

    Shu, Xuedao; Li, Lianpeng; Hu, Zhenghuan

    2005-12-01

    Contact surface of cross-wedge rolling is a complicated space surface and distribution rule of contact surface stress is very complicated. So far, its analyzed result was still based on slippery line method. Designing mould and actual production mainly depend on experiential factor. Application and development of cross-wedge rolling was baffled seriously. Based on the forming characteristics of cross-wedge rolling with flat wedge-shape, the ANSYS/DYNA software was developed secondly on the basis of itself, and the corresponding command program was compiled. Rolling process of cross-wedge rolling with flat wedge-shape was simulated successfully. Through simulation, space surface shape of contact surface was achieved, and distribution rule of contact surface stress was analyzed detailed and obtained. The results provide important theoretical foundation for avoiding appearing bug on surface of rolled part, instructing to design cross-wedge mould and confirming force and energy parameter.

  12. Constitutive modelling of lubricants in concentrated contacts at high slide to roll ratios

    NASA Technical Reports Server (NTRS)

    Tevaarwerk, J. L.

    1985-01-01

    A constitutive lubricant friction model for rolling/sliding concentrated contacts such as gears and cams was developed, based upon the Johnson and Tevaarwerk fluid rheology model developed earlier. The friction model reported herein differs from the earlier rheological models in that very large slide to roll ratios can now be accommodated by modifying the thermal response of the model. Also the elastic response of the fluid has been omitted from the model, thereby making it much simpler for use in the high slide to roll contacts. The effects of this simplification are very minimal on the outcome of the predicted friction losses (less than 1%). In essence then the lubricant friction model developed for the high slide to roll ratios treats the fluid in the concentrated contact as consisting of a nonlinear viscous element that is pressure, temperature, and strain rate dependent in its shear response. The fluid rheological constants required for the prediction of the friction losses at different contact conditions are obtained by traction measurements on several of the currently used gear lubricants. An example calculation, using this model and the fluid parameters obtained from the experiments, shows that it correctly predicts trends and magnitude of gear mesh losses measured elsewhere for the same fluids tested here.

  13. Rules for Rolling as a Rotation about the Instantaneous Point of Contact

    ERIC Educational Resources Information Center

    Jensen, Jens Hoejgaard

    2011-01-01

    It is a widespread misunderstanding in introductory physics courses that the motion of rolling bodies in general can be calculated using the point of contact as a reference point when equating the rate of change of angular momentum to the torque. In this paper I discuss in general two correct rules to be used instead, in order to derive the…

  14. An Analytical Means for Determination of Scoring Limited Load Capacity in Sliding/Rolling Contact

    DTIC Science & Technology

    1979-12-01

    Scoring limited load capacity of paired discs in sliding/rolling lubricated contact is addressed. The approach used previously acquired data in a multiple regression analysis. The resulting mathematical expression for load capacity at failure has a correlation coefficient greater than 99%.

  15. Rules for Rolling as a Rotation about the Instantaneous Point of Contact

    ERIC Educational Resources Information Center

    Jensen, Jens Hoejgaard

    2011-01-01

    It is a widespread misunderstanding in introductory physics courses that the motion of rolling bodies in general can be calculated using the point of contact as a reference point when equating the rate of change of angular momentum to the torque. In this paper I discuss in general two correct rules to be used instead, in order to derive the…

  16. Dry Lubrication of High Temperature Silicon Nitride Rolling Contacts.

    DTIC Science & Technology

    1980-11-01

    comparable to M50 bearing steel [2]. Quality control measures were implemented in the areas of raw material inspection as well as non-destructive evaluation...related defect rate of 1 defect per 2.8 in 2 (18.1 cm 2 ) of silicon nitride surface area inspected. The billet material inspected during this program had...3. Cage pockets for the silicon nitride balls were designed to permit transfer of the solid lubricant from the cage surface to the contact area

  17. Effect of the residual near-surface stresses of the working surface on the contact resistance of rolls

    NASA Astrophysics Data System (ADS)

    Rusakov, A. D.

    2010-05-01

    The results of contact resistance tests of roll steel samples with various levels of near-surface residual compressive stresses are analyzed. A relation between these stresses and the contact resistance is found. Recommendations are made for the formation of rational near-surface residual stresses in the active surfaces of rolls in order to increase their resistance.

  18. Rolling contact mounting arrangement for a ceramic combustor

    DOEpatents

    Boyd, Gary L.; Shaffer, James E.

    1995-01-01

    A combustor assembly having a preestablished rate of thermal expansion is mounted within a gas turbine engine housing having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the combustor assembly. The combustor assembly is constructed of a inlet end portion, a outlet end portion and a plurality of combustor ring segments positioned between the end portions. A mounting assembly is positioned between the combustor assembly and the gas turbine engine housing to allow for the difference in the rate of thermal expansion while maintaining axially compressive force on the combustor assembly to maintain contact between the separate components.

  19. Rolling contact mounting arrangement for a ceramic combustor

    DOEpatents

    Boyd, G.L.; Shaffer, J.E.

    1995-10-17

    A combustor assembly having a preestablished rate of thermal expansion is mounted within a gas turbine engine housing having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the combustor assembly. The combustor assembly is constructed of a inlet end portion, a outlet end portion and a plurality of combustor ring segments positioned between the end portions. A mounting assembly is positioned between the combustor assembly and the gas turbine engine housing to allow for the difference in the rate of thermal expansion while maintaining axially compressive force on the combustor assembly to maintain contact between the separate components. 3 figs.

  20. Measurement of stress distributions in truck tyre contact patch in real rolling conditions

    NASA Astrophysics Data System (ADS)

    Anghelache, Gabriel; Moisescu, Raluca

    2012-12-01

    Stress distributions on three orthogonal directions have been measured across the contact patch of truck tyres using the complex measuring system that contains a transducer assembly with 30 sensing elements placed in the road surface. The measurements have been performed in straight line, in real rolling conditions. Software applications for calibration, data acquisition, and data processing were developed. The influence of changes in inflation pressure and rolling speed on the shapes and sizes of truck tyre contact patch has been shown. The shapes and magnitudes of normal, longitudinal, and lateral stress distributions, measured at low speed, have been presented and commented. The effect of wheel toe-in and camber on the stress distribution results was observed. The paper highlights the impact of the longitudinal tread ribs on the shear stress distributions. The ratios of stress distributions in the truck tyre contact patch have been computed and discussed.

  1. An observation on subsurface defects of ultra high molecular weight polyethylene due to rolling contact.

    PubMed

    Ohashi, M; Tomita, N; Ikada, Y; Ikeuchi, K; Motoike, T

    1996-01-01

    Ultra high molecular weight polyethylene (UHMWPE) has been used in artificial joints for a few decades, and wear of UHMWPE has been one of the main problems. Though many other materials have been tested over the years, the best clinical results are still achieved with UHMWPE. This makes the study of UHMWPE, especially in relation to artificial joints, very important. Frequently, more severe wear can be observed in artificial knee joints than in artificial hip joints especially when the flaking-like wear occurs. This flaking-like wear can lead to significant destruction of the artificial knee joint. Macroscopically, artificial knee joints have combinational movements of rolling and sliding in order to simulate the motion of the normal knee joint. The components of motion are separated to make study easier. Fatigue tests of UHMWPE under the rolling contact condition were performed in this study. Three ceramic spheres were rolled over the UHMWPE specimen using 37 degrees C distilled water as a lubricant. The UHMWPE specimen was observed by the scanning acoustic tomography, microscopy, and SEM. Some subsurface defects could be observed by SAT even before experiments. Although the apparent wear is not observed on the surface, there was an increase in the number of observable subsurface cracks in the UHMWPE specimen. This shows that cracks occur under the surface after a 10(7) rolling contact loading, which is very close to the cyclic loading and unloading with very little friction compared to the sliding contact.

  2. Detection of rolling contact sub-surface fatigue cracks using acoustic emission technique

    SciTech Connect

    Yoshioka, T. )

    1993-04-01

    A method of locating the position of acoustic emission sources has been developed to analyze the mechanism of rolling contact fatigue. Using this method, sub-surface fatigue cracks were found at positions corresponding to the actual source positions of acoustic emissions. When fatigue tests were run under maximum stresses of 5.75 GPa and lubricant film parameters of 0.19, the cracks propagated parallel to the surface, had a maximum length of approximately 200 microns in the rolling direction of balls, and were distributed between 50 microns and 200 microns below the surface. Although the lubricant film parameter was small, no cracks from the surface were found. 12 refs.

  3. Effect of tangential traction and roughness on crack initiation/propagation during rolling contact

    NASA Technical Reports Server (NTRS)

    Soda, N.; Yamamoto, T.

    1980-01-01

    Rolling fatigue tests of 0.45 percent carbon steel rollers were carried out using a four roller type rolling contact fatigue tester. Tangential traction and surface roughness of the harder mating rollers were varied and their effect was studied. The results indicate that the fatigue life decreases when fraction is applied in the same direction as that of rolling. When the direction of fraction is reversed, the life increases over that obtained with zero traction. The roughness of harder mating roller also has a marked influence on life. The smoother the mating roller, the longer the life. Microscopic observation of specimens revealed that the initiation of cracks during the early stages of life is more strongly influenced by the surface roughness, while the propagation of these cracks in the latter stages is affected mainly by the tangential traction.

  4. Analysis and design of rolling-contact joints for evaluating bone plate performance.

    PubMed

    Slocum, Alexander H; Cervantes, Thomas M; Seldin, Edward B; Varanasi, Kripa K

    2012-09-01

    An apparatus for testing maxillofacial bone plates has been designed using a rolling contact joint. First, a free-body representation of the fracture fixation techniques utilizing bone plates is used to illustrate how rolling contact joints accurately simulate in vivo biomechanics. Next, a deterministic description of machine functional requirements is given, and is then used to drive the subsequent selection and design of machine elements. Hertz contact stress and fatigue analysis for two elements are used to ensure that the machine will both withstand loads required to deform different plates, and maintain a high cycle lifetime for testing large numbers of plates. Additionally, clinically relevant deformations are presented to illustrate how stiffness is affected after a deformation is applied, and to highlight improvements made by the machine over current testing standards, which do not adequately re-create in vivo loading conditions. The machine performed as expected and allowed for analysis of bone plates in both deformed and un-deformed configurations to be conducted. Data for deformation experiments is presented to show that the rolling-contact testing machine leads to improved loading configurations, and thus a more accurate description of plate performance. A machine for evaluation of maxillofacial bone plates has been designed, manufactured, and used to accurately simulate in vivo loading conditions to more effectively evaluate the performance of both new and existing bone plates. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

  5. Defect detection performance of the UCSD non-contact air-coupled ultrasonic guided wave inspection of rails prototype

    NASA Astrophysics Data System (ADS)

    Mariani, Stefano; Nguyen, Thompson V.; Sternini, Simone; Lanza di Scalea, Francesco; Fateh, Mahmood; Wilson, Robert

    2016-04-01

    The University of California at San Diego (UCSD), under a Federal Railroad Administration (FRA) Office of Research and Development (R&D) grant, is developing a system for high-speed and non-contact rail defect detection. A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection, paired with a real-time statistical analysis algorithm, has been realized. This system requires a specialized filtering approach based on electrical impedance matching due to the inherently poor signal-to-noise ratio of air-coupled ultrasonic measurements in rail steel. Various aspects of the prototype have been designed with the aid of numerical analyses. In particular, simulations of ultrasonic guided wave propagation in rails have been performed using a Local Interaction Simulation Approach (LISA) algorithm. The system's operating parameters were selected based on Receiver Operating Characteristic (ROC) curves, which provide a quantitative manner to evaluate different detection performances based on the trade-off between detection rate and false positive rate. The prototype based on this technology was tested in October 2014 at the Transportation Technology Center (TTC) in Pueblo, Colorado, and again in November 2015 after incorporating changes based on lessons learned. Results from the 2015 field test are discussed in this paper.

  6. Identification and prioritization of rail squat defects in the field using rail magnetisation technology

    NASA Astrophysics Data System (ADS)

    Kaewunruen, Sakdirat

    2015-04-01

    Inevitably, rail squats and studs are continuing to be a serious problem for railway organisations around the world in the 21st century. They are typically classified as the growth of any cracks that have grown longitudinally through the subsurface and some of the cracks propagating to the bottom of rails transversely, and have branched from initial longitudinal cracks with a depression of rail surface. The horizontal crack, which results in a depression of rail surface, induces increased maintenance level, more frequent monitoring, compromised rail testing (as the crack shields the signal echoes), and possible broken rails. This paper presents field investigations using a magnetised-rail testing device developed by MRX Technologies to identify and prioritise the rail squats. Most of the in situ squats were found on the high rail of the transition (variable-radius curved track), which is associated with rolling contact fatigue (RCF). This investigation highlights the field performance of the MRX's surface crack detection technology in comparison with the traditional ultrasonic method and detailed walking inspection. Visually, it was found in the field that the size of the RCF squats varies from very small to moderate. The predicted crack data were obtained by scanning the magnitised rails. The comparison of the actual crack depths (ultrasonic) and the predicted crack depths (MRX device) shows: • A possible correlation for small RCF/ squat cracks. • Poor interpretation of larger defects and welds. The field assessment also suggests some practical issues required for further development, including the detection of rail spalling, deep transverse crack, welding, and so on.

  7. Fractal properties of worn surface of Fe-based alloy coatings during rolling contact process

    NASA Astrophysics Data System (ADS)

    Chen, Shu-ying; Wang, Hai-dou; Ma, Guo-zheng; Kang, Jia-jie; Xu, Bin-shi

    2016-02-01

    The rolling contact fatigue (RCF) failure procedure of Fe-based alloy coating, fabricated by high efficient plasma spray (PS) technology, was investigated by a double-roller test machine with oil lubrication under pure rolling contact condition. The fractal dimension (FD) was utilized to quantitatively characterize the profile of the worn surface at different experiment stage and the failure mechanism of the coating was discussed. The results indicated that the nonlinear morphologies of the worn surface of Fe-Cr alloy coating possessed excellent fractal properties. The failure procedure could be divided into four stages according to the value and change rule of FD, i.e. (1) running-in stage, (2) stable abrade stage, (3) accelerated damage stage, (4) unstable removal stage.

  8. Residual stresses and retained austenite distribution and evolution in SAE 52100 steel under rolling contact loading

    SciTech Connect

    Dommarco, R.C.; Kozaczek, K.J.; Hahn, G.T.

    1996-07-01

    Residual stresses are introduced and modified during manufacturing and also by normal use. In this paper the changes in magnitude and distribution of residual stresses, attending the strain induced transformation of retained austenite are examined. Tests were conducted on SAE 52100 bearing steel with different amounts of retained austenite in a 5-ball-rod rolling contact fatigue machine. The tests were accelerated by applying well-controlled micro- indentations on the wear track and using rough balls. The magnitude and distribution of residual stresses and retained austenite were measured using x-ray diffraction techniques. The contribution of the residual stresses and amount of retained austenite to the rolling contact fatigue life is analyzed.

  9. Improvement of rolling contact fatigue life of ion implanted M50 steel

    NASA Astrophysics Data System (ADS)

    Torp, B.; Nielsen, B. R.; Dodd, A.; Kinder, J.; Rangel, C. M.; DaSilva, M. F.; Courage, B.

    1993-06-01

    With the overall objective to improve the service life and reliability of gas turbine engine bearings by increasing their corrosion resistance and rolling contact fatigue life a collaborative project under the EEC BRITE/EURAM program has been initiated and is now in its third year. The aim of the project is to develop an ion implantation technique to implant bearing components with metallic species and to optimise the process, particularly for applications where salt water contamination of the lubricant may occur. As part of the programme leading up to implantation of bearing components, test specimens of M50 bearing steel implanted with Cr + and Ta + at several doses have been characterised by various techniques. This article reports on the implantation work and the rolling contact fatigue measurements which have been performed in order to determine the optimum treatment.

  10. Calculation of optimal modes for electric-contact welding of rails of mine haulage tracks

    NASA Astrophysics Data System (ADS)

    Shevchenko, R. A.; Kozyrev, N. A.; Usoltsev, A. A.; Kriukov, R. E.; Shishkin, P. E.

    2017-09-01

    The choice of thermal regime is based on the exclusion of formation of quenching structures (martensite and bainite), causing additional stresses and cracks which lead to the destruction of rails. After welded joint upset and cooling at the time of reaching the required temperature it is proposed to perform quasi-isothermal exposure by passing pulses of alternating current through the welded joint. The method for calculating the quasi-isothermal exposure is described that depends on the strength of the welding current and different rails section. It is suggested that after welding the rails during quenching, a quasi-isothermal holding is carried out in the temperature range of the formation of the fine-dispersed structure by passing pulses of alternating electric current through the welded joint maintaining this temperature until the end of the transformation. It is shown that the use of quasi-isothermal exposure at a chosen temperature of 600 – 650 °C makes it possible to obtain a finely dispersed structure of the welded seam of rails of mine haulage tracks without additional heat treatment.

  11. Nucleation and growth of rolling contact failure of 440C bearing steel

    NASA Technical Reports Server (NTRS)

    Gupta, V.; Bastias, P. C.; Hahn, G. T.; Rubin, C. A.

    1992-01-01

    A 'two-body' elasto-plastic finite element model of 2-dimensional rolling and rolling-plus-sliding was developed to treat the effect of surface irregularities. The model consists of a smooth cylinder in contact with a semi-infinite half-space that is either smooth or fitted with one of 0.4 microns deep or 7 microns deep groove, or a 0.4 microns high ridge-like asperity. The model incorporates elastic-linear-kinematic hardening-plastic (ELKP) and non-linear-kinematic hardening-plastic (NLKP) material constitutive relations appropriate for hardened bearing steel and the 440C grade. The calculated contact pressure distribution is Hertzian for smooth body contact, and it displays intense, stationary, pressure spikes superposed on the Hertzian pressure for contact with the grooved and ridged surface. The results obtained for the 0.4 microns deep groove compare well with those reported by Elsharkawy and Hamrock for an EHD lubricated contact. The effect of translating the counterface on the half space as opposed to indenting the half space with the counter face with no translation is studied. The stress and strain values near the surface are found to be similar for the two cases, whereas they are significantly different in the subsurface. It is seen that when tiny shoulders are introduced at the edge of the groove in the finite element model, the incremental plasticity and residual stresses are significantly higher in the vicinity of the right shoulder (rolling direction is from left to right) than at the left shoulder. This may explain the experimental observation that the spall nucleation occurs at the exit end of the artificially planted indents. Pure rolling calculations are compared with rolling + sliding calculations. For a coefficient of friction, mu = 0.1, the effect of friction is found to be small. Efforts were made to identify the material constitutive relations which best describe the deformation characteristics of the bearing steels in the initial few cycles

  12. Bearing material. [composite material with low friction surface for rolling or sliding contact

    NASA Technical Reports Server (NTRS)

    Sliney, H. E. (Inventor)

    1976-01-01

    A composite material is described which will provide low friction surfaces for materials in rolling or sliding contact and is self-lubricating and oxidation resistant up to and in excess of about 930 C. The composite is comprised of a metal component which lends strength and elasticity to the structure, a fluoride salt component which provides lubrication and, lastly, a glass component which not only provides oxidation protection to the metal but may also enhance the lubrication qualities of the composite.

  13. Charge transport in organic nanocrystal diodes based on rolled-up robust nanomembrane contacts.

    PubMed

    Bandari, Vineeth Kumar; Varadharajan, Lakshmi; Xu, Longqian; Jalil, Abdur Rehman; Devarajulu, Mirunalini; Siles, Pablo F; Zhu, Feng; Schmidt, Oliver G

    2017-01-01

    The investigation of charge transport in organic nanocrystals is essential to understand nanoscale physical properties of organic systems and the development of novel organic nanodevices. In this work, we fabricate organic nanocrystal diodes contacted by rolled-up robust nanomembranes. The organic nanocrystals consist of vanadyl phthalocyanine and copper hexadecafluorophthalocyanine heterojunctions. The temperature dependent charge transport through organic nanocrystals was investigated to reveal the transport properties of ohmic and space-charge-limited current under different conditions, for instance, temperature and bias.

  14. Track dynamic behavior at rail welds at high speed

    NASA Astrophysics Data System (ADS)

    Xiao, Guangwen; Xiao, Xinbiao; Guo, Jun; Wen, Zefeng; Jin, Xuesong

    2010-06-01

    As a vehicle passing through a track with different weld irregularities, the dynamic performance of track components is investigated in detail by using a coupled vehicle-track model. In the model, the vehicle is modeled as a multi-body system with 35 degrees of freedom, and a Timoshenko beam is used to model the rails which are discretely supported by sleepers. In the track model, the sleepers are modeled as rigid bodies accounting for their vertical, lateral and rolling motions and assumed to move backward at a constant speed to simulate the vehicle running along the track at the same speed. In the study of the coupled vehicle and track dynamics, the Hertizian contact theory and the theory proposed by Shen-Hedrick-Elkins are, respectively, used to calculate normal and creep forces between the wheel and the rails. In the calculation of the normal forces, the coefficient of the normal contact stiffness is determined by transient contact condition of the wheel and rail surface. In the calculation of the creepages, the lateral, roll-over motions of the rail and the fact that the relative velocity between the wheel and rail in their common normal direction is equal to zero are simultaneously taken into account. The motion equations of the vehicle and track are solved by means of an explicit integration method, in which the rail weld irregularities are modeled as local track vertical deviations described by some ideal cosine functions. The effects of the train speed, the axle load, the wavelength and depth of the irregularities, and the weld center position in a sleeper span on the wheel-rail impact loading are analyzed. The numerical results obtained are greatly useful in the tolerance design of welded rail profile irregularity caused by hand-grinding after rail welding and track maintenances.

  15. Use of a genetic algorithm to improve the rail profile on Stockholm underground

    NASA Astrophysics Data System (ADS)

    Persson, Ingemar; Nilsson, Rickard; Bik, Ulf; Lundgren, Magnus; Iwnicki, Simon

    2010-12-01

    In this paper, a genetic algorithm optimisation method has been used to develop an improved rail profile for Stockholm underground. An inverted penalty index based on a number of key performance parameters was generated as a fitness function and vehicle dynamics simulations were carried out with the multibody simulation package Gensys. The effectiveness of each profile produced by the genetic algorithm was assessed using the roulette wheel method. The method has been applied to the rail profile on the Stockholm underground, where problems with rolling contact fatigue on wheels and rails are currently managed by grinding. From a starting point of the original BV50 and the UIC60 rail profiles, an optimised rail profile with some shoulder relief has been produced. The optimised profile seems similar to measured rail profiles on the Stockholm underground network and although initial grinding is required, maintenance of the profile will probably not require further grinding.

  16. Numerical techniques for rolling rubber wheels: treatment of inelastic material properties and frictional contact

    NASA Astrophysics Data System (ADS)

    Ziefle, M.; Nackenhorst, U.

    2008-08-01

    Arbitrary Lagrangian Eulerian (ALE) methods provide a well established basis for the numerical analysis of rolling contact problems. Whereas the theoretical framework is well developed for elastic constitutive behavior, special measures are necessary for the computation of dissipative effects like inelastic properties and friction because the path of material points is not traced inherently. In this presentation a fractional step approach is suggested for the integration of the evolution equations for internal variables. A Time-Discontinuous Galerkin (TDG) method is introduced for the numerical solution of the related advection equations. Furthermore, a mathematically sound approach for the treatment of frictional rolling within the ALE-description is suggested. By this novel and fully implicit algorithm the slip velocities are integrated along their path-lines. For dissipative effects due to both, inelastic behavior and friction, physical reliable results will be demonstrated as well as the computability of large scaled finite element tire-models.

  17. Rolling-element fatigue life with traction fluids and automatic transmission fluid in a high-speed rolling-contact rig

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Nahm, A. H.; Loewenthal, S. H.

    1982-01-01

    Rolling-element fatigue tests were run in standard and high-speed rolling-contact rigs at bar speeds from 5000 to 50,000 rpm to determine the effects of speed and lubricant film parameter on rolling-element fatigue life. AISI 52100 test bars were tested at a maximum Hertz stress of 4.83 GPa (700,000 psi) with three traction fluids and an automatic transmission fluid. Rolling-element fatigue life increased with speed, with the greatest increases occurring from 10,000 to 50,000 rpm. The life data tended to follow published life-versus-lubricant-film-parameter data up to a film parameter of approximately 3.

  18. Unsupervised learning algorithm for high-speed defect detection in rails by laser/air-coupled non-contact ultrasonic testing

    NASA Astrophysics Data System (ADS)

    Rizzo, Piervincenzo; Coccia, Stefano; Lanza di Scalea, Francesco; Bartoli, Ivan; Fateh, Mahmood

    2006-03-01

    Recent train accidents and associated direct and indirect costs including cost of repair of equipment and infrastructure as well as delay and death/injury costs, have reaffirmed the need for developing rail defect detection systems more effective than those used today. In fact, rail defect detection has been identified as a priority area in the U.S. Federal Railroad Administration 5-year R&D plan. This paper proposes an unsupervised learning algorithm for defect detection in rails. The algorithm is used in a non-contact inspection system that is targeted to the detection of transverse-type cracks in the rail head (including transverse fissures and detail fractures), notoriously the most dangerous flaws in rails. The system uses ultrasonic guided waves that are generated by a pulsed laser and are detected by air-coupled sensors positioned as far away as 76 mm (3") from the top of rail head. The inspection ranges is at least 500 mm (20") for surface head cracks as shallow as 1 mm. Fast data output is achieved by processing the ultrasonic defect signatures by Wavelet Transform algorithms. The features extracted after wavelet processing are analyzed by a learning algorithm based on novelty detection. This algorithm attempts to detect the presence of damage despite the normal variations in ultrasonic signal features that may be found in a field test.

  19. Preliminary metallographic studies of ball fatigue under rolling-contact conditions

    NASA Technical Reports Server (NTRS)

    Bear, H Robert; Butler, Robert H

    1957-01-01

    The metallurgical results produced on balls tested in the rolling-contact fatigue spin rig were studied by metallographic examination. Origin and progression of fatigue failures were observed. These evaluations were made on SAE 52100 and AISI M-1 balls fatigue tested at room temperature (80 F) and 200 to 250 F. Most failures originated subsurface in shear; inclusions, structure changes, and directionalism adversely affected ball fatigue life. Structures in the maximum-shear-stress region of the balls of both materials were stable at room temperature and unstable at 200 to 250 F. Failures were of the same type as those found in full-scale bearings.

  20. Effect of Fiber Orientation on Ball Failures Under Rolling-contact Conditions

    NASA Technical Reports Server (NTRS)

    Butler, Robert H; Bear, H Robert; Carter, Thomas L

    1957-01-01

    The rolling-contact fatigue spin rig was used to test bails of a bearing steel at maximum Hertz stresses of 600,000 to 750,000 psi. The effect of fiber orientation was observed with the ball track restricted to passing directly over the poles, coincident with the equator, or randomly around the ball. The polar areas were found to be weaker in fatigue than the nonpolar areas. This resulted in a much greater portion of the failures occurring in the polar areas than would be expected from a homogeneous material. The early failures are discussed.

  1. Rolling contact fatigue life of chromium ion plated 440C bearing steel

    NASA Technical Reports Server (NTRS)

    Bhat, B. N.; Davis, J. H.

    1985-01-01

    Rolling contact fatigue (RCF) test specimens of heat treated 440C bearing steel were chromium ion plated in thicknesses from 0.1 to 8.0 micron and tested in RCF tester using 700 ksi maximum Hertzian stress. Heavy coatings, greater than about 5 micron in thickness, peeled off or spalled readily, whereas thin coatings, less than 3 micron thick, were tenacious and did not come off. Furthermore, significant improvement in RCF life was obtained with thin chromium ion plated test specimens. The average increase in B10 life was 75% compared with unplated 440C. These preliminary results indicate that ion plating is a promising way to improve bearing life.

  2. Stress-life relation of the rolling-contact fatigue spin rig

    NASA Technical Reports Server (NTRS)

    Butler, Robert H; Carter, Thomas L

    1957-01-01

    The rolling-contact fatigue spin rig was used to test groups of SAE 52100 9.16-inch-diameter balls lubricated with a mineral oil at 600,000-, 675,000-, and 750,000-psi maximum Hertz stress. Cylinders of AISI M-1 vacuum and commercial melts and MV-1 (AISI M-50) were used as race specimens. Stress-life exponents produced agree closely with values accepted in industry. The type of failure obtained in the spin rig was similar to the subsurface fatigue spells found in bearings.

  3. Experimental and numerical investigation of crack initiation and propagation in silicon nitride ceramic under rolling and cyclic contact

    NASA Astrophysics Data System (ADS)

    Raga, Rahul; Khader, Iyas; Zdeněk, Chlup; Kailer, Andreas

    2017-05-01

    The focus of the work was to investigate crack initiation and propagation mechanisms in silicon nitride undergoing non-conforming hybrid contact under various tribological conditions. In order to understand the prevailing modes of damage in silicon nitride, two distinct model experiments were proposed, namely, rolling contact and cyclic contact experiments. The rolling contact experiment was designed in order to mimic the contact conditions appearing in hybrid bearings at contact pressures ranging from 3 to 6 GPa. On the other hand, cyclic contact experiments with stresses ranging from 4 to 15 GPa under different media were carried out to study damage under localised stresses. In addition, the experimentally observed cracks were implemented in a finite element model to study the stress redistribution and correlate the generated stresses with the corresponding mechanisms. Crack propagation under rolling contact was attributed to two different mechanisms, namely, fatigue induced fracture and lubricant driven crack propagation. The numerical simulations shed light on the tensile stress driven surface and subsurface crack propagation mechanisms. On the other hand, the cyclic contact experiments showed delayed crack formation for lubricated cyclic contact. Ceramographic cross-sectional analysis showed crack patterns similar to Hertzian crack propagation under cyclic contact load.

  4. Accumulated damage process of thermal sprayed coating under rolling contact by acoustic emission technique

    NASA Astrophysics Data System (ADS)

    Xu, Jia; Zhou, Zhen-yu; Piao, Zhong-yu

    2016-09-01

    The accumulated damage process of rolling contact fatigue (RCF) of plasma-sprayed coatings was investigated. The influences of surface roughness, loading condition, and stress cycle frequency on the accumulated damage status of the coatings were discussed. A ball-ondisc machine was employed to conduct RCF experiments. Acoustic emission (AE) technique was introduced to monitor the RCF process of the coatings. AE signal characteristics were investigated to reveal the accumulated damage process. Result showed that the polished coating would resist the asperity contact and remit accumulated damage. The RCF lifetime would then extend. Heavy load would aggravate the accumulated damage status and induce surface fracture. Wear became the main failure mode that reduced the RCF lifetime. Frequent stress cycle would aggravate the accumulated damage status and induce interface fracture. Fatigue then became the main failure mode that also reduced the RCF lifetime.

  5. An investigation of rolling-sliding contact fatigue damage of carburized gear steels

    NASA Astrophysics Data System (ADS)

    Kramer, Patrick C.

    The goal of this study was to evaluate the differences in RSCF performance between vacuum and gas carburized steels as well as to investigate the evolution of damage (wear and microstructure changes) leading to pitting. Vacuum and gas carburizing was performed on two gear steels (4120 and 4320) at 1010°C. The carburized specimens were tested in the as-carburized condition using a RSCF machine designed and built at the Colorado School of Mines. The tests were conducted at 3.2 GPa nominal Hertzian contact stress, based on pure rolling, 100°C, and using a negative twenty percent slide ratio. Tests were conducted to pitting failure for each condition for a comparison of the average fatigue lives. Pure rolling tests were also conducted, and were suspended at the same number of cycles as the average RSCF life for a comparison of fatigue damage developed by RCF and RSCF. Incremental tests were suspended at 1,000, 10,000, 100,000, and 200,000 cycles for the vacuum carburized steels to evaluate the wear and damage developed during the initial cycles of RSCF testing and to relate the wear and damage to pitting resistance. Incremental damage was not investigated for gas carburizing due to the limited number of available specimens. The vacuum carburized samples showed a decreased pitting fatigue resistance over the gas carburized samples, possibly due to the presence of bainite in the vacuum carburized cases. Pitting was observed to initiate from surface micropitting and microcracking. A microstructural change induced by contact fatigue, butterflies, was shown to contribute to micropitting and microcracking. Incremental testing revealed that the formation of a microcrack preceded and was necessary for the formation of the butterfly features, and that the butterfly features developed between 10,000 and 100,000 cycles. The orientation and depth of butterfly formation was shown to be dependent upon the application of traction stresses from sliding. RSCF butterflies formed

  6. Tribo-chemical behavior of eutectoid steel during rolling contact friction

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Cai, Z. B.; Peng, J. F.; Cao, B. B.; Jin, X. S.; Zhu, M. H.

    2016-12-01

    The tribo-chemical behavior of the eutectoid steel during rolling contact friction is investigated via scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and electron probe X-ray microanalysis. The worn surface is divided into three zones: matrix zone (without friction), tribo-film zone (formed during friction) and delamination zone (tribo-film spalling). The different chemical states of atoms between those three zones and the air were investigated using the XPS analysis. The results showed that the matrix zone is composed of Fe2O3, FeO and metallic Fe, while the tribo-film and delamination zones only contain Fe2O3 and FeO. Where the tribo-film is formed, the absorptive ability of O and C atoms on the top 2-3 atomic layers is probably weakened, while the exposed fresh metal in the delamination zone tends to be continuously oxidized and form tribo-film. The tribo-chemical reaction in the delamination zone is more activated than that in the other two zones. The protective nature of the tribo-film probably maintains a low friction coefficient under rolling contact friction condition.

  7. Effects of Mo ion implantation on rolling contact fatigue behavior of carbon steel

    SciTech Connect

    Yang, D.; Zhou, J.

    1996-11-01

    Rolling Contact Fatigue (RCF) is one of the most serious material surface damage problems encountered by many critical components, especially in ball-bearing applications. RCF is sensitive to the material strength, hardness, surface morphology, microstructure and stress status, which may be dramatically changed by surface modifications. In present work, the surface modification of molybdenum ion implantation into quenched carbon steel was employed, and RCF tests on the implanted specimens, as well as the unimplanted, were performed. It was found out that carbon steel specimens, with and without ion implantation, have the same fatigue damage characteristics. They both have circular and fan-like pits on the fatigue failed surfaces, with many spherical debris existing in the fan-like pits. However, molybdenum ion implantation reduced the rolling contact fatigue life of quenched carbon steel. The possible reasons are the following: the ion beam current is too large, which causes the specimen to undergo the annealing process and soften during the implantation process; the incident angles of ions are different for different spots of curve specimen surface, which causes the uneven distribution of residual stress. These will promote the crack initiation and propagation.

  8. A film thickness analysis for line contacts under pure rolling conditions with a non-Newtonian rheological model

    NASA Technical Reports Server (NTRS)

    Gecim, B.; Winer, W. O.

    1980-01-01

    The non-Newtonian constitutive equation of Winer and Bair (1979) is applied to a conventional isothermal film thickness analysis of line contact lubrication of rolling elements providing dimensionless film thickness equations for four lubrication methods. The equations can be applied to high viscosity and rolling speed and low limiting shear stress cases where Newtonian methods are not applicable. This analysis is based on a reasonable range of limiting shear stress which is smaller than the Newtonian values for low viscosity lubricants.

  9. Modifying rib rail placement for the powered roll gin stand: Results from studies conducted on a retrofitted Lummus gin stand

    USDA-ARS?s Scientific Manuscript database

    The powered roll gin stand (PRGS) is a technology that has shown evidence of improving ginning rate, turnout, and fiber quality. However, results from the numerous studies comparing the technology against the conventional gin stand has given rise to speculation that the technology is only fitting fo...

  10. Rolling contact fatigue of low hardness steel for slewing ring application

    NASA Astrophysics Data System (ADS)

    Knuth, Jason A.

    This thesis discusses the rolling contact fatigue of steel utilized in anti-friction bearings, also referred to as slewing bearings. These slewing bearings are utilized in cranes, excavators, wind turbines and other similar applications. Five materials composed of two different material types were tested. The two material types were high carbon steel and medium carbon alloy steel. The test specimens were processed from forged rolled rings. Two machines were evaluated a ZF-RCF and 3-Ball test machine. The evaluation was to determine which machine can best simulate the application in which the slewing bearing is utilized. Initially, each specimen will be pretested to determine the appropriate testing direction from within the forged rolled rings. Pretesting is needed in order to establish consistent failure modes between samples. The primary goal of the test is to understand the life differences and failure modes between high carbon steel and medium carbon alloy steel. The high carbon steel ring was cut into two sections, one of which was stress relieved and the other was quenched and tempered. The medium carbon alloy steel was cut into three sections, all of which were quenched and tempered to different hardness levels. The test program was dynamically adjusted based upon the previous sample's life and load. An S-N curve was then established from the 5 materials tested at two target loads. The samples were run until the first sign of a crack was detected by an eddy current. At the completion of the rolling contact test, select sample's microstructure was evaluated for crack initiation location. The selected samples were divided into four groups which represent different maximum shear stress levels. These samples displayed indications of material deformation in which the high carbon steel experienced an increased amount of cold work when compared to medium carbon alloy steel. The life of the high carbon steel was nearly equivalent to the expected life of the medium

  11. "Roll-bar" for protective posture splint limits potential trauma to dorsal hand grafts.

    PubMed

    Kaine, Edward C; Fidler, Phillip; Schulz, John; Kahn, Shaher; Crombie, Roselle; Dalton, Sally; Warren, Andrea; LaBonte, Eric; Palmer, John; Possenti, Paul; Laird, Jacqueline; Atweh, Nabil

    2008-01-01

    The expectation of excellent functional and cosmetic outcomes adds to the challenges of managing the burned hand. The initial fragility of the grafted surface warrants extra measures of protection. A "roll-bar " attached to a splint over a grafted area can serve as protection against mechanical trauma. Two "intrinsic plus " protective posture splints were fabricated; one had a roll-bar extending from the D2 ray to the distal forearm. Three simulated patients wearing each of the splints attempted to contact the bed rail from supine. Pictures, transferred ink, observation, and subjective comments were used to establish percentage of the surface at risk because of bed rail contact and its ease. Without the roll-bar 100% of the dorsal surface of the hand was accessible to contact with the bed rail. With the roll-bar all subjects were prevented from contact to the dorsum of the hand and contact to the dorsal fingers was less than 40% in all subjects, decrease of risk at the wrist was also significant. The roll-bar can prevent mechanical trauma to grafts on the fingers and dorsum of the hand because of contact with the bed rail. The ease of the application and the potential benefits to patient outcome make it an appropriate addition to the protective posture splint when seeking to minimize area of the surface at risk.

  12. Microstructural and Material Quality Effects on Rolling Contact Fatigue of Highly Elastic Intermetallic Ball Bearings

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Howard, S. Adam; Thomas, Fransua; Stanford, Malcolm K.

    2016-01-01

    Rolling element bearings made from highly-elastic intermetallic materials (HIM)s, such as 60NiTi, are under development for applications that require superior corrosion and shock resistance. Compared to steel, intermetallics have been shown to have much lower rolling contact fatigue (RCF) stress capability in simplified 3-ball on rod (ASTM STP 771) fatigue tests. In the 3-ball tests, poor material quality and microstructural flaws negatively affect fatigue life but such relationships have not been established for full-scale 60NiTi bearings. In this paper, 3-ball-on-rod fatigue behavior of two quality grades of 60NiTi are compared to the fatigue life of full-scale 50mm bore ball bearings made from the same materials. 60NiTi RCF rods with material or microstructural flaws suffered from infant mortality failures at all tested stress levels while high quality 60NiTi rods exhibited no failures at lower stress levels. Similarly, tests of full-scale bearings made from flawed materials exhibited early surface fatigue and through crack type failures while bearings made from high quality material did not fail even in long-term tests. Though the full-scale bearing test data is yet preliminary, the results suggest that the simplified RCF test is a good qualitative predictor of bearing performance. These results provide guidance for materials development and to establish minimum quality levels required for successful bearing operation and life.

  13. Rolling contact fatigue behavior of heat resistant bearing steels at high operational temperatures

    SciTech Connect

    Boehmer, H.J.; Hirsch, T.; Streit, E.

    1998-12-31

    An approach was made to estimate the endurance limit in rolling contact fatigue in dependence of the operational conditions for the bearing steels M50 (AMS 6491), M50 NiL (AMS 6278) and the nitrogen-alloyed Cronidur 30 (AMS 5898) by investigating the changes in the residual stress profiles after 5 million cycles of overrolling. Real main shaft bearings with a pitch diameter of 168 mm have been tested. To simulate the heat generated in the turbine engines even under boundary operational conditions oil inlet temperatures between 80 and 210 C have been applied, the rotational speed has been varied between 2,500 and 14,000 r/min and the interference fit has been changed to produce different hoop stress levels.

  14. Rolling-contact and wear resistance of hard coatings on bearing-steel substrates

    SciTech Connect

    Erdemir, A.

    1992-02-01

    Ever-increasing needs for high-performance ball- and roller-bearing components that can endure extreme applications have led to a growing interest in hard coatings for improved fatigue life and wear resistance. In particular, hard TiN and TiC coatings and, quite recently, diamond like carbon films have attracted much attention from manufacturers that produce bearing systems for both rolling- and sliding-contact applications. This paper presents an overview that highlights recent incremental progress in achieving improved fatigue and wear resistance in bearing steels through the use of hard coatings. Effects of coating adhesion, thickness, and morphology on fatigue and wear resistance of hard coatings are discussed in detail. Specific references are made to a few mechanistic models that correlate coating thickness and adhesion to improved fatigue life and wear resistance.

  15. Rolling contact fatigue behavior of Cu and TiN coatings on bearing steel substrates

    NASA Technical Reports Server (NTRS)

    Hochman, R. F.; Erdemir, A.; Dolan, F. J.; Thom, R. L.

    1985-01-01

    The resistance of copper and TiN coatings on various bearing substrates to high-load rolling contact fatigue (RCF) is investigated. Special attention is given to the lubricating characteristics of copper deposited by ion plating, and the wear resistant characteristics of TiN deposited by ion plating and magnetron sputtering techniques. RCF samples of 440C and AMS 5749 bearing steels were coated. Sputter deposited and ion plated films were on the RCF samples in a range of thickness from about 2000 A to 2 microns. Results showed a marked improvement of the RCF for pure copper tested on 440C, but a degradation for copper on AMS 5749. It is also found that the 2000 A TiN films behave favorably on the 440C and AMS 5749 bearing steels at RCF stress levels of 786 ksi. Scanning electron microscopy, X-ray diffraction, and electron spectroscopy for chemical analysis were used during the investigation.

  16. Influence of the Inclusion Shape on the Rolling Contact Fatigue Life of Carburized Steels

    NASA Astrophysics Data System (ADS)

    Neishi, Yutaka; Makino, Taizo; Matsui, Naoki; Matsumoto, Hitoshi; Higashida, Masashi; Ambai, Hidetaka

    2013-05-01

    It has been well known that the flaking failure in rolling contact fatigue (RCF) originates from nonmetallic inclusions in steels, and their apparent size is one of the important factors affecting RCF life. However, the influence of inclusion shape on the RCF life has not been fully clarified. In this study, attention was paid to the influence of the inclusion shape on the RCF life. This was evaluated by using carburized JIS-SCM420 (SAE4320) steels that contained two different shapes of MnS—stringer type and spheroidized type—as inclusions. Sectional observations were made to investigate the relation between the occurrence of shear crack in the subsurface and the shape of MnS. It was found that the RCF life was well correlated with the length of MnS projected to the load axis, and the initiation of shear crack in subsurface was accelerated as the length of MnS increased.

  17. Rolling Contact Fatigue Life of Steel Rollers Treated by Cavitation Peening and Shot Peening

    NASA Astrophysics Data System (ADS)

    Seki, Masanori; Soyama, Hitoshi; Kobayashi, Yuji; Gowa, Daisuke; Fujii, Masahiro

    The purpose of this study is to investigate the influence of peening on the rolling contact fatigue (RCF) life of steel rollers. First, steel rollers were treated by three types of peenings to ensure the same surface roughness of peened rollers. One is the cavitation peening (CP) used a cavitating jet in water with an injection pressure of 30 MPa, and the others are the fine particle peening (FPP) with a shot diameter of 0.1 mm and the normal shot peening (NSP) with a shot diameter of 0.3 mm. The surface hardness and the surface compressive residual stress of the steel rollers were increased by all the peenings. In particular, they were most increased by the FPP. On the other hand, the work-hardened depth due to the CP and the NSP was larger than that due to the FPP. As a result of the RCF tests, the RCF lives of the steel rollers were improved by all the peenings, and they were most improved by the NSP. Judging from the pmax - N curves and the [A(σy/√3 HV)]max - N curves, the improvement in RCF lives due to the FPP depended heavily on the increase in surface hardness due to that, and the effects of the CP and the NSP on the RCF were equivalent under the same surface roughness and the same surface hardness. It follows from these that the surface treatment condition should be selected according to the rolling contact conditions and the failure modes of machine elements.

  18. Quasi-Static Compression and Rolling Contact Analysis of Maxxis Victra MA-Z1 Tire on Dry Roadway

    NASA Astrophysics Data System (ADS)

    Jenq, S. T.; Ting, Yucheng; Liang, S. M.; Lin, David; Shih, Mike

    Quasi-static contact behavior of an inflated MAXXIS VICTRA MA-Z1 (235/45/R17) radial tire is reported in this work. Compressional response of the inflated tire with a prescribed weight loaded quasi-statically was examined. Both experimental and numerical results were obtained and compared. In addition, dynamic contact simulation of the tire rolling on a dry-flat roadway was also studied. A commercial finite element commercial Code (LS-DYNA) was used to construct the complex tire model and to perform both quasi-static contact and dynamic rolling simulations. The Mooney-Rivlin constitutive relationship was adopted to describe the non-linear elastic behavior of rubber material, and the classical laminated theory was used to model the stress-strain behavior of the fiber reinforced composite layers of tire. Quasi-static contact force and compression displacement of tire were measured and numerically simulated. Contact pressure distribution of the tire tread in touch with simulated rigid dry-flat road surface was also numerically and experimentally obtained. Good relationship between the test findings and simulated results were reported. In addition, the dynamic contact simulations of the inflated tire rolling on a dry-flat rigid roadway with a prescribed weight loaded are presented, and the deformation pattern and local contact stress distribution are also reported.

  19. Micro-structuring of CIGS thin-film coated on Mo back contact by ultrafast laser 'rail-roading' patterning.

    PubMed

    Jeoung, Sae Chae; Lee, Heung-Soon; Yahng, Ji Sang; Lee, Hyun Kyu; Moon, Heh Young; Kim, Kyoun Joon; Lee, Dong Geun; Park, Duck Hoon; Yu, Young Sam; Ji, Suk-Jae

    2011-08-29

    We report selective patterning process, laser 'rail-roading' scribing method, of which operating principle is based on transient force balance between the material properties including cohesion and adhesion forces subjected to underlying substrate and laser-induced shock compression and shear forces. By using dual fs-laser beam lines with an interval larger than laser spot size, we provide a proof of the concept by patterning the photovoltaic modules based on CIGS (Cu(In,Ga)Se2) coated on Mo electrode. With varying the interval between the two laser beam tracks, we can provide intact Mo back contact surface without any residues in a manner of more facile, high-speed and high scribing efficiency. We have interpreted the effect of the ambient gases and grooving width on the scribing performance in terms of the cohesion forces between the grains of CIGS thin films as well as adhesion force between underlying Mo layer and CIGS, which are mainly governed by local laser ablation and peening process followed by laser-induced shock compression, respectively.

  20. Rolling contact fatigue of surface modified 440C using a 'Ge-Polymet' type disc rod test rig

    NASA Technical Reports Server (NTRS)

    Thom, Robert L.

    1989-01-01

    Through hardened 440 C martensitic stainless steel test specimens were surface modified and tested for changes in rolling contact fatigue using a disc on rod test rig. The surface modifications consisted of nitrogen, boron, titanium, chromium, tantalum, carbon, or molybdenum ion implantation at various ion fluences and energies. Tests were also performed on specimens reactively sputtered with titanium nitride.

  1. Rolling contact fatigue of surface modified 440C using a 'Ge-Polymet' type disc rod test rig

    SciTech Connect

    Thom, R.L.

    1989-03-01

    Through hardened 440 C martensitic stainless steel test specimens were surface modified and tested for changes in rolling contact fatigue using a disc on rod test rig. The surface modifications consisted of nitrogen, boron, titanium, chromium, tantalum, carbon, or molybdenum ion implantation at various ion fluences and energies. Tests were also performed on specimens reactively sputtered with titanium nitride.

  2. Rolling contact fatigue in high vacuum using ion plated nickel-copper-silver solid lubrication

    SciTech Connect

    Danyluk, Mike; Dhingra, Anoop

    2011-01-15

    Ion plated, nickel-copper-silver coated steel ball bearings that were tested in rolling contact fatigue (RCF) experiments in high vacuum are presented in this article. ANSI T5 ball bearings were coated with approximately 10 nm of nickel-copper followed by 100 nm of silver using a dc ion plating process. The balls were then tested for RCF in vacuum in the 10{sup -7} Torr range at 130 Hz rotational speed and at 4.1 GPa Hertzian contact stress. The significance of this work is in the extension of RCF testing to an ultrahigh vacuum (UHV) application using silver as a lubricant instead of oil. The effects of pressure and voltage on the ion plating process were also investigated using scanning electron microscopy and RCF life testing in UHV. Test results with a ball size of 5/16 in. in UHV show that deposition at voltages greater than 2.5 kV shortens the RCF life and introduces a unique failure mode. Voltage and pressure fluctuations during the deposition process result in significant thickness monitor measurement errors as well. A regulator control scheme that minimizes the process pressure overshoot is also simulated.

  3. Rolling Contact Fatigue Failure Mechanisms of Plasma-Nitrided Ductile Cast Iron

    NASA Astrophysics Data System (ADS)

    Wollmann, D.; Soares, G. P. P. P.; Grabarski, M. I.; Weigert, N. B.; Escobar, J. A.; Pintaude, G.; Neves, J. C. K.

    2017-05-01

    Rolling contact fatigue (RCF) of a nitrided ductile cast iron was investigated. Flat washers machined from a pearlitic ductile cast iron bar were quenched and tempered to maximum hardness, ground, polished and divided into four groups: (1) specimens tested as quenched and tempered; (2) specimens plasma-nitrided for 8 h at 400 °C; (3) specimens plasma-nitrided and submitted to a diffusion process for 16 h at 400 °C; and (4) specimens submitted to a second tempering for 24 h at 400 °C. Hardness profiles, phase analyses and residual stress measurements by x-ray diffraction, surface roughness and scanning electron microscopy were applied to characterize the surfaces at each step of this work. Ball-on-flat washer tests were conducted with a maximum contact pressure of 3.6 GPa, under flood lubrication with a SAE 90 API GL-5 oil at 50 °C. Test ending criterion was the occurrence of a spalling. Weibull analysis was used to characterize RCF's lifetime data. Plasma-nitrided specimens exhibited a shorter RCF lifetime than those just quenched and tempered. The effects of nitriding on the mechanical properties and microstructure of the ductile cast iron are discussed in order to explain the shorter endurance of nitrided samples.

  4. Rolling Contact Fatigue Performances of Carburized and High-C Nanostructured Bainitic Steels

    PubMed Central

    Wang, Yanhui; Zhang, Fucheng; Yang, Zhinan; Lv, Bo; Zheng, Chunlei

    2016-01-01

    In the present work, the nanostructured bainitic microstructures were obtained at the surfaces of a carburized steel and a high-C steel. The rolling contact fatigue (RCF) performances of the two alloy steels with the same volume fraction of undissolved carbide were studied under lubrication. Results show that the RCF life of the carburized nanostructured bainitic steel is superior to that of the high-C nanostructured bainitic steel in spite of the chemical composition, phase constituent, plate thickness of bainitic ferrite, hardness, and residual compressive stress value of the contact surfaces of the two steels under roughly similar conditions. The excellent RCF performance of the carburized nanostructured bainitic steel is mainly attributed to the following reasons: finer carbide dispersion distribution in the top surface, the higher residual compressive stress values in the carburized layer, the deeper residual compressive stress layer, the higher work hardening ability, the larger amount of retained austenite transforming into martensite at the surface and the more stable untransformed retained austenite left in the top surface of the steel. PMID:28774081

  5. Rolling Contact Fatigue Performances of Carburized and High-C Nanostructured Bainitic Steels.

    PubMed

    Wang, Yanhui; Zhang, Fucheng; Yang, Zhinan; Lv, Bo; Zheng, Chunlei

    2016-11-25

    In the present work, the nanostructured bainitic microstructures were obtained at the surfaces of a carburized steel and a high-C steel. The rolling contact fatigue (RCF) performances of the two alloy steels with the same volume fraction of undissolved carbide were studied under lubrication. Results show that the RCF life of the carburized nanostructured bainitic steel is superior to that of the high-C nanostructured bainitic steel in spite of the chemical composition, phase constituent, plate thickness of bainitic ferrite, hardness, and residual compressive stress value of the contact surfaces of the two steels under roughly similar conditions. The excellent RCF performance of the carburized nanostructured bainitic steel is mainly attributed to the following reasons: finer carbide dispersion distribution in the top surface, the higher residual compressive stress values in the carburized layer, the deeper residual compressive stress layer, the higher work hardening ability, the larger amount of retained austenite transforming into martensite at the surface and the more stable untransformed retained austenite left in the top surface of the steel.

  6. A theoretical solution for the frictionless rolling contact of cylindrical biphasic articular cartilage layers.

    PubMed

    Ateshian, G A; Wang, H

    1995-11-01

    Previous studies have shown that interstitial fluid pressurization plays an important role in the load support mechanism of articular cartilage under normal step loading. These studies have demonstrated that interstitial fluid pressurization decreases with time if the applied load is maintained constant. In the present study, a theoretical solution is obtained for another common loading of articular cartilage, namely the contact of surfaces in rolling motion. Pure rolling of symmetrical frictionless cylindrical cartilage layers is analyzed under steady state. The linear biphasic model of Mow et al. [J. Biomech. Engng 102, 73-84 (1980)] is used to describe the mechanical response of articular cartilage. The solution of this contact problem reduces to simultaneously solving a set of four integral equations, akin to the dual integral problem of elastic contact. It is found that the solution is dependent on four non-dimensional parameters: Rh = Vb/HAk, W/2 mu b, R/b, and v, where V is the surface velocity, b the cartilage thickness, HA the aggregate modulus, mu the shear modulus, v Poisson's ratio, k the permeability, R the radius of cylindrical surfaces, and W the applied load per unit cylinder length. For Rh < 1, interstitial fluid pressurization is found to be negligible, and all the applied load is supported by the solid collagen-proteoglycan phase of the tissue, thus causing significant cartilage deformation. As Rh increases to a physiological level (Rh approximately 10(4)), interstitial fluid pressurization may support more than 90% of the total applied load, shielding the solid matrix from high effective stresses and reducing matrix strains and deformation. The protective effect of interstitial fluid pressurization is observed to increase with increasing joint congruence (R/b); similarly, as the applied load (W/2 mu b) is increased, a greater proportion of it is supported by the fluid. In degenerative cartilage, Rh may drop by one or more orders of magnitude

  7. Scuffing Characteristics of High-Load Rolling/Sliding Contacts Operating in Liquid Oxygen: Effects of Materials and Surface Roughness

    NASA Technical Reports Server (NTRS)

    Chang, L.; Hall, P. B.; Thom, R.

    1996-01-01

    This research reports on an experimental study of the effects of materials and surface roughness on the scuffing characteristics of rolling/sliding contacts cooled and lubricated with liquid oxygen. Experiments were carried out under heavy loading with a Hertzian pressure in the range of 2.0 GPa to 3.0 GPa and with a high rolling velocity of up to 48 m/s. For contacts between AISI 440 C stainless-steel elements, the results showed that the scuffing behavior of the system was fairly consistent under a wide range of rolling velocity. Scuffing commenced at a small slide-to-roll ratio of around 0.02, and the scuffing behavior of the contact was not sensitive to surface roughness for the test-sample RMS roughness ranging from 0.02 microns to 0.10 microns. For contacts between 440 C and Si3N4 elements, on the other hand, the scuffing behavior of the system was not very consistent and somewhat unpredictable. The results were sensitive to surface roughness particularly that of the Si3N4 test sample. With well polished test samples, consistent results were obtained; the level of traction was lower than that with a 440 C toroid and scuffing did not take place up to a slide-to-roll ratio of near 0.03. The results strongly suggest that significant hydrodynamic effect can be generated by liquid oxygen under heavy loading and high velocity conditions. The results also suggest that the hydrodynamic action is likely generated by the conventional viscous mechanism as it can be largely destroyed by a narrow circumferential surface scratch running through the central region of the contact.

  8. Research of the indirect friction sensor for prediction of contact stress by improved inverse method in strip rolling

    NASA Astrophysics Data System (ADS)

    Li, Si; Wang, Zhigang; Ruan, Jinhua; Liu, Changming; Xu, Zengbing

    2017-10-01

    In order to avoid strip marks or perturbation of local lubricant flow at the interface between strip and work roll in strip rolling, an indirect friction sensor has been designed. This sensor is based on the inverse method improved by envelope fitting method, which utilizes strain gage to measure strains at one point inside the work roll to evaluate the contact stress in roll gap. Then several cold rolling tests have been performed at different reductions to demonstrate the rational and the validity of this indirect friction sensor. Comparing the results evaluated by finite element method with the results reconstructed by different inverse methods, it is found that the improved inverse method leads to a better solution to evaluation of the contact stress, in particular for prediction of shear stress. In addition, reasonable prediction is obtained for large reduction but not for small reduction (only the order of magnitude is obtained). It is believed that this research has a strategic importance for practical application.

  9. Evolution of cyclic plasticity during rolling contact fatigue of a case-hardened bearing steel

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Abir

    A combined experimental and numerical methodology is developed for the investigation of progressive evolution of subsurface plasticity during prolonged rolling contact fatigue (RCF) loading of a M50 NiL case hardened steel. Three balls-on-rod RCF tests have been performed on a M50 NiL steel rod a using silicon nitride balls over several hundred million cycles at 5.5 GPa contact stress level. A systematic investigation of the evolution of surface contact area between the ball and the rod reveals that the contact pressure evolves continuously during several hundred million cycles of RCF due to substantial surface and subsurface plasticity. Various stages of plastic deformation has been identified based on the nature of the evolution of contact patch during the first phase of study. In the second phase of research, systematic investigation on the nucleation and the growth of the plastically deformed subsurface regions in a case hardened M-50 NiL steel rod has been done. The microhardness measurements within the RCF affected subsurface regions revealed existence of hardened and softened regions, which grow in size and severity with stress cycles. A mechanistic explanation behind the formation of the hardened and softened regions inside the plastic zone and its growth in size and severity has been proposed in the second phase of the work. In the final phase of the study, we propose a generalized methodology to determine the cyclic constitutive response of the various case layers of M-50 NiL steel. A 3-dimenstional finite element (FE) model of the ball-on-rod test was simulated in ABAQUS and the obtained von Mises stresses were used along with measured microhardness values and Neuber's rule to obtain the cyclic strain amplitudes at various points inside the RCF affected region. The S-N diagram of M-50 NiL steel is constructed and the fatigue limit of the material under RCF loading is determined after considering the effect of compressive mean stress. It has been shown

  10. Effect of track irregularities on initiation and evolution of rail corrugation

    NASA Astrophysics Data System (ADS)

    Jin, X. S.; Wen, Z. F.; Wang, K. Y.

    2005-07-01

    The effect of track irregularities on rail corrugation is investigated in detail with the numerical method when a wheelset is steadily curving. The irregularities considered in the analysis include initial running surface of rail with periodically varying and different wave length, stochastic roughness on the rail running surface, and vertical uneven support stiffness of the rail due to the discrete sleeper supports. The numerical method considers a combination of Kalker's rolling contact theory with non-Hertzian to be modified, a linear frictional work model and a vertical dynamics model of railway vehicle coupled with a curved track. The model is also validated by an experiment with a full scale facility. The influence of different speeds of wheelset curving on the development of the corrugation is taken into account in the calculation. The numerical results indicate that (1) for existing of the initial corrugation of new rail with any wavelength the depth from the peak to trough of it decreases gradually with an increase of wheelset passage, but the initial corrugation evolved has a tendency to move in the rolling direction, (2) the amplitude of the initial stochastic roughness of new rail is gradually leveled out and but a corrugation with very small depth and a few fixed passing frequencies is initiated, the passing frequencies are the same as the natural frequencies of the track, and (3) the discrete rail supports by sleepers have a great influence on the formation of the corrugation.

  11. Modelling the effect of rail dampers on wheel-rail interaction forces and rail roughness growth rates

    NASA Astrophysics Data System (ADS)

    Croft, B. E.; Jones, C. J. C.; Thompson, D. J.

    2009-06-01

    Trains generate rolling noise because of the roughness of the wheel and rail running surfaces. Special acoustic grinding programmes have been introduced on some railways specifically to control rolling noise. Rail dampers are also used to reduce rolling noise; this paper studies rail damping as a possible mechanism to slow the rate of development of roughness on the surface of rails. This would reduce noise further over time or reduce the required frequency of grinding. High roughness growth on the rail occurs in situations with stiff vertical structural dynamics of the track. In particular the antiresonance above a sleeper at the pinned-pinned frequency has been identified as a wavelength fixing mechanism for short pitch corrugation. Rail dampers change the dynamic response of the rail, shifting the pinned-pinned frequency and smoothing the track receptance. Here, a simple time-stepping model is applied to calculate the interaction forces between wheel and rail for a track with and without rail dampers. The calculations show that rail dampers reduce dynamic interaction forces and shift the force spectrum to longer wavelengths. The interaction forces are used as input to an abrasive wear model to predict the roughness growth rate and the change in roughness after many wheel passages. Track without rail dampers is predicted to develop corrugation at the wavelength corresponding to the pinned-pinned frequency. With rail dampers the corrugation growth is reduced and shifted to a longer wavelength where its significance is diminished.

  12. Nanometer Contact Physics of Water Ice in Protoplanetary Disks, Breakup, Twisting and Rolling

    NASA Astrophysics Data System (ADS)

    Aumatell, Guillem; Wurm, Gerhard

    2013-07-01

    The formation of planetary bodies is not yet fully understood. Beyond the snow line in protplanetary disks, volatile components like water condense to solid state. The interaction between these solid particles can cause the formation of larger objects due to aggregation at low velocities, or sometimes -depending on the conditions- their own destruction [1,2] . Water ice has been detected in protoplanetary disks [3,4] and in order to understand its role in the formation of icy bodies like icy planets, asteroids and comets, we carried out laboratory experiments. Water ice aggregates have been formed from frozen liquid water droplets at ~ 190 K. Droplets are smaller than 20 μm in radius and show a well defined size distribution. At pressure between 0.1 - 1 mbar and temperatures about 200 K, several effects like sublimation, twisting, rolling and breakup have been observed and measured. By the quantification of parameters like mass, acceleration after breakup and aggregate size and structure, the adhesion force that exist in the contact area between the aggregates' monomers, and other parameters, can be determined

  13. Effect of TiN coatings on the rolling contact fatigue behavior of M50 bearing steel. Final report

    SciTech Connect

    Middleton, R.M.; Huang, P.J.; Wells, M.G.; Kant, R.A.

    1992-12-01

    There is a continuing requirement for improved bearing performance for both commercial and military applications. Service temperatures are increasing steadily due to increased power requirements and corrosion of components remains a major concern as well, particularly for bearings in military systems. In our ongoing study, a number of different coatings were applied to VIM-VAR M50 bearing steel to improve both corrosion resistance and rolling contact fatigue behavior. This report deals specifically with coatings produced by the ion beam assisted deposition IBAD of TiN, details of the coating process, and test results obtained. The rolling contact fatigue performance of IBAD TiN coated M50 samples demonstrated increased lifetime performance and durability for a 1 micrometer thick coating. Preliminary data on corrosion properties is also presented.

  14. The effect of TiN coatings on the rolling contact fatique behavior of M50 bearing steel

    NASA Astrophysics Data System (ADS)

    Middleton, R. M.; Huang, P. J.; Wells, M. G. H.; Kant, R. A.

    1992-12-01

    There is a continuing requirement for improved bearing performance for both commercial and military applications. Service temperatures are increasing steadily due to increased power requirements and corrosion of components remains a major concern as well, particularly for bearings in military systems. A number of different coatings were applied to VIM-VAR M50 bearing steel to improve both corrosion resistance and rolling contact fatigue behavior. This report deals specifically with coatings produced by the ion beam assisted deposition (IBAD) of TiN, details of the coating process, and test results obtained. The rolling contact fatigue performance of IBAD TiN coated M50 samples demonstrated increased lifetime performance and durability for a 1 micrometer thick coating. Preliminary data on corrosion properties is also presented.

  15. GMT azimuth bogie wheel-rail interface wear study

    NASA Astrophysics Data System (ADS)

    Teran, Jose; Lindh, Cory; Morgan, Chris; Manuel, Eric; Bigelow, Bruce C.; Burgett, William S.

    2016-07-01

    Performance of the GMT azimuth drive system is vital for the operation of the telescope and, as such, all components subject to wear at the drive interface merit a high level of scrutiny for achieving a proper balance between capital costs, maintenance costs, and the risk for downtime during planned and unplanned maintenance or replacement procedures. Of particular importance is the interface between the azimuth wheels and rail, as usage frequency is high, the full weight of the enclosure must be transferred through small patches of contact, and replacement of the rail would pose a greater logistical challenge than the replacement of smaller components such as bearings and gearmotors. This study investigates tradeoffs between various wheel-rail and roller-track interfaces, including performance, complexity, and anticipated wear considerations. First, a survey of railway and overhead crane industry literature is performed and general detailing recommendations are made to minimize wear and the risk of rolling contact fatigue. Second, Adams/VI-Rail is used to simulate lifetime wear of four specific configurations under consideration for the GMT azimuth wheel-rail interface; all studied configurations are shown to be viable, and their relative merits are discussed.

  16. Nucleation of squat cracks in rail, calculation of crack initiation angles in three dimensions

    NASA Astrophysics Data System (ADS)

    Naeimi, Meysam; Li, Zili; Dollevoet, Rolf

    2015-07-01

    A numerical model of wheel-track system is developed for nucleation of squat-type fatigue cracks in rail material. The model is used for estimating the angles of squat cracks in three dimensions. Contact mechanics and multi-axial fatigue analysis are combined to study the crack initiation mechanism in rails. Nonlinear material properties, actual wheel-rail geometries and realistic loading conditions are considered in the modelling process. Using a 3D explicit finite element analysis the transient rolling contact behaviour of wheel on rail is simulated. Employing the critical plane concept, the material points with the largest possibility of crack initiation are determined; based on which, the 3D orientations/angles of the possible squat cracks are estimated. Numerical estimations are compared with sample results of experimental observations on a rail specimen with squat from the site. The findings suggest a proper agreement between results of modelling and experiment. It is observed that squat cracks initiate at an in-plane angle around 13°-22° relative to the rail surface. The initiation angle seen on surface plane is calculated around 29°-48°, while the crack tend to initiate in angles around 25°-31° in the rail cross-section.

  17. A microstructure sensitive study of rolling contact fatigue in bearing steels: A numerical and experimental approach

    NASA Astrophysics Data System (ADS)

    Pandkar, Anup Surendra

    Bearings are an integral part of machine components that transmit rotary power such as cars, motors, engines etc. Safe bearing operation is essential to avoid serious failures and accidents, which necessitates their timely replacement. This calls for an accurate bearing life prediction methods. Based on the Lundberg-Palmgen (LP) model, current life models consistently under predict bearings lives. Improvement in life prediction requires understanding of the bearing failure mechanism i.e. Rolling Contact Fatigue (RCF). The goal of this research is to develop a mechanistic framework required for an improved bearing life prediction model. Such model should account for metal plasticity, influence of microstructural features and cyclically evolving stressstrain fields induced during RCF. To achieve this, elastic-plastic finite element (FE) study is undertaken to investigate the response of M50-NiL bearing steel during RCF. Specifically, a microstructure sensitive study of the influence of non-metallic inclusions on RCF response of bearings is presented. M50-NiL microstructure consists of carbides which are orders of magnitude smaller than bearing dimensions. To account for this size difference, a multi-scale FE modeling approach is employed. The FE results reveal that hard carbide particles act as local stress risers, alter surrounding stressstrain fields and cause micro-scale yielding of steel matrix. Moreover, they introduce a shear stress cycle with non-zero mean stress, which promotes micro-plastic strain accumulation via ratcheting mechanism. Localized ratcheting is primarily responsible for cyclic hardening within the RCF affected region. Such evolution of subsurface hardness can be used to quantify RCF induced damage. To investigate this further, cyclic hardening response of the RCF affected region is simulated. The results show good agreement with the experimental observations. The cyclic stress-strain fields obtained from these simulations and the knowledge of

  18. Finite Element and Experimental Analysis of Closure and Contact Bonding of Pores During Hot Rolling of Steel

    NASA Astrophysics Data System (ADS)

    Joo, Soo-Hyun; Jung, Jaimyun; Chun, Myung Sik; Moon, Chang Ho; Lee, Sunghak; Kim, Hyoung Seop

    2014-08-01

    The closure and contact bonding behavior of internal pores in steel slabs during hot rolling was studied using experiments and the finite element method (FEM). Effects of pore size and shape were investigated, and three different cases of pore closure results were observed: no closure, partial closure, and full closure. The FEM results well reproduced various closure events. Bonding strengths of unsuccessfully closed pores, measured by tensile tests, showed critical effects. Also, there was a difference in bonding strengths of several fully closed pores. Fracture surfaces showed that welded regions could be divided into three (not, partially, and perfectly) welded regions. The pressure-time curves obtained from the FEM results indicate that pore surface contact time and deformed surface length are important parameters in pore welding. Pore size, pore shape, time of pressure contact, and deformed surface length should be considered to completely eliminate pores in final products.

  19. Evolution of mechanical properties of M50 bearing steel due to rolling contact fatigue

    NASA Astrophysics Data System (ADS)

    Allison, Bryan D.

    Current bearing life models significantly under predict the life of bearings made of modern ultra-clean steels. New life models that include the constitutive response of the material are needed. However, the constitutive response of bearing steel is known to change during bearing operation. In the current study, the evolution of the mechanical properties of M50 bearing steel due to rolling contact fatigue (RCF) was investigated. A combination of M50 balls and rods were subjected to RCF testing under various conditions (e.g. number of RCF cycles, applied Hertzian stress, and interacting material). Additionally, some of the balls tested went through a proprietary mechanical process to induce compressive residual stresses over the first several hundred microns into the depth of the ball prior to RCF testing. After RCF testing, the specimens were subjected to a number of tests. First, the residual stresses within the subsurface RCF affected region were measured via x-ray diffraction. The residual stresses within the mechanically processed (MP) balls were found to not significantly change due to RCF, while a linear relationship was found between the maximum residual stress with the RCF affected zone and the Hertzian stress for the unprocessed balls. Then, the specimens were sectioned, polished, and chemically etched to study the evolution of the microstructure due to RCF. A similar relationship was found between the size of the dark etching region (DER) and the Hertzian stress. Formation of a light etching region (LER) is demonstrated to not correlate with a decrease in material strength and hardness, but it does serve as a predictor for failure due to spall. Micro-indentation was performed within subsurface to estimate the local yield stress. Micro-indentation is not able to provide information about the stress-strain response, only the yield strength. Hence, a novel method to extract and test miniature compression specimens from within the RCF affected regions of

  20. Effect of sulfur on rolling contact fatigue life of high-manganese precipitation-hardening austenitic steel

    SciTech Connect

    Haruna, Y.; Yamamoto, A.; Tsubakino, H.

    1998-10-05

    For mechanical components used in high magnetic flux such as bearings and shafts that undergo cyclic stress, materials require low permeability with high strength, hardness, appropriate machinability, and good fatigue properties. Although it is implied that low permeability and machinability will be achieved by a selection of sulfurized austenitic ({gamma}) steel grades, effect of manganese sulfide (MnS) on fatigue properties of such grades especially for bearing applications is not clarified. For high-carbon chromium bearing steels, the effect of MnS on rolling contact fatigue life of the steels containing sulfur less than 0.03% are discussed. In these studies, the effect of MnS is not clearly determined whether it is beneficial or harmful to contact fatigue lives of the steels. However, effect of MnS under higher sulfur content, i.e., 0.10%, on the fatigue properties of {gamma} steel has not been studied. In this paper, the effect of sulfur on rolling contact fatigue properties of vanadium added {gamma} steel, 10Cr-6Ni-8Mn-1.6V-0.6C, was investigated focusing on microstructural change in connection with MnS particles.

  1. The role of surface roughness and slide-roll ratio on the decomposition of MoDTC in tribological contacts

    NASA Astrophysics Data System (ADS)

    Khaemba, Doris N.; Jarnias, Frederic; Thiebaut, Benoit; Neville, Anne; Morina, Ardian

    2017-03-01

    In this study, the role of surface roughness and slide-roll ratio in the decomposition and friction performance of molybdenum dialkyldithiocarbamate (MoDTC) has been investigated. Tribotests were carried out in a minitraction machine (MTM) using steel discs of varying roughness rubbing against smooth steel balls in a sliding/rolling contact. Tests were conducted at slide-roll ratio (SRR) values of SRR  =  100% and 200%. Raman spectroscopy was used to perform chemical characterisation on the resulting wear scars. The friction performance of rough discs was not affected by the SRR. On the other hand, increasing the SRR from 100% to 200% in tests with smooth discs resulted in higher friction with large instabilities. Raman analysis showed significant differences in chemical composition of the wear scars generated after tests with smooth and rough discs. Wear scars generated using rough discs were mainly composed of MoS2 indicating complete MoDTC decomposition while those generated using smooth discs were composed of a mixture of MoS2, MoS x (x  >  2) and FeMoO4 indicating partial MoDTC decomposition. Numerical simulation of the contact revealed that under similar loading conditions rough surfaces have higher local pressures than smoother surfaces. It is proposed that higher local pressures in rough surfaces promoted complete MoDTC decomposition. The novel finding from results presented in this study is that at similar temperature and MoDTC concentration, the degradation of MoDTC within tribocontacts is highly dependent on the roughness of the tribopair. This is because surface roughness determines the local pressure at the asperity–asperity contact.

  2. Effects of service condition on rolling contact fatigue failure mechanism and lifetime of thermal spray coatings—A review

    NASA Astrophysics Data System (ADS)

    Cui, Huawei; Cui, Xiufang; Wang, Haidou; Xing, Zhiguo; Jin, Guo

    2015-01-01

    The service condition determines the Rolling Contact Fatigue(RCF) failure mechanism and lifetime under ascertain material structure integrity parameter of thermal spray coating. The available literature on the RCF testing of thermal spray coatings under various condition services is considerable; it is generally difficult to synthesize all of the result to obtain a comprehensive understanding of the parameters which has a great effect on a thermal spray coating's resistance of RCF. The effects of service conditions(lubrication states, contact stresses, revolve speed, and slip ratio) on the changing of thermal spray coatings' contact fatigue lifetime is introduced systematically. The effects of different service condition on RCF failure mechanism of thermal spray coating from the change of material structure integrity are also summarized. Moreover, In order to enhance the RCF performance, the parameter optimal design formula of service condition and material structure integrity is proposed based on the effect of service condition on thermal spray coatings' contact fatigue lifetime and RCF failure mechanism. The shortage of available literature and the forecast focus in future researches are discussed based on available research. The explicit result of RCF lifetime law and parameter optimal design formula in term of lubrication states, contact stresses, revolve speed, and slip ratio, is significant to improve the RCF performance on the engineering application.

  3. Acoustic Emission Investigation of Rolling/Sliding Contact Fatigue Failure of NiCr-Cr3C2 Coating

    NASA Astrophysics Data System (ADS)

    Guolu, Li; Zhonglin, Xu; Tianshun, Dong; Haidou, Wang; Jinhai, Liu; Jiajie, Kang

    2016-10-01

    NiCr-Cr3C2 coating was fabricated using supersonic plasma spraying technology. Subsequently, rolling/sliding contact fatigue (R/SCF) testing was carried out, using acoustic emission (AE) technology to monitor the failure process. The results showed that R/SCF consists of three failure modes, namely abrasion, spalling, and delamination. Abrasion is the main failure mode, but delamination is the most severe. The AE monitoring results indicated that the R/SCF failure process is composed of normal contact, crack initiation, crack propagation, and material removal stages. The frequency of each stage was analyzed by fast Fourier transform, revealing a peak frequency for each stage mainly distributed from 200 to 250 kHz.

  4. KENNEDY SPACE CENTER, FLA. - The camera installed on the aft skirt of a solid rocket booster is seen here, framed by the railing. The installation is in preparation for a vibration test of the Mobile Launcher Platform with SRBs and external tank mounted. The MLP will roll from one bay to another in the Vehicle Assembly Building.

    NASA Image and Video Library

    2003-11-06

    KENNEDY SPACE CENTER, FLA. - The camera installed on the aft skirt of a solid rocket booster is seen here, framed by the railing. The installation is in preparation for a vibration test of the Mobile Launcher Platform with SRBs and external tank mounted. The MLP will roll from one bay to another in the Vehicle Assembly Building.

  5. A simple running model with rolling contact and its role as a template for dynamic locomotion on a hexapod robot.

    PubMed

    Huang, Ke-Jung; Huang, Chun-Kai; Lin, Pei-Chun

    2014-10-07

    We report on the development of a robot's dynamic locomotion based on a template which fits the robot's natural dynamics. The developed template is a low degree-of-freedom planar model for running with rolling contact, which we call rolling spring loaded inverted pendulum (R-SLIP). Originating from a reduced-order model of the RHex-style robot with compliant circular legs, the R-SLIP model also acts as the template for general dynamic running. The model has a torsional spring and a large circular arc as the distributed foot, so during locomotion it rolls on the ground with varied equivalent linear stiffness. This differs from the well-known spring loaded inverted pendulum (SLIP) model with fixed stiffness and ground contact points. Through dimensionless steps-to-fall and return map analysis, within a wide range of parameter spaces, the R-SLIP model is revealed to have self-stable gaits and a larger stability region than that of the SLIP model. The R-SLIP model is then embedded as the reduced-order 'template' in a more complex 'anchor', the RHex-style robot, via various mapping definitions between the template and the anchor. Experimental validation confirms that by merely deploying the stable running gaits of the R-SLIP model on the empirical robot with simple open-loop control strategy, the robot can easily initiate its dynamic running behaviors with a flight phase and can move with similar body state profiles to those of the model, in all five testing speeds. The robot, embedded with the SLIP model but performing walking locomotion, further confirms the importance of finding an adequate template of the robot for dynamic locomotion.

  6. Rolling Reloaded

    ERIC Educational Resources Information Center

    Jones, Simon A.; Nieminen, John M.

    2008-01-01

    Not so long ago a new observation about rolling motion was described: for a rolling wheel, there is a set of points with instantaneous velocities directed at or away from the centre of the wheel; these points form a circle whose diameter connects the centre of the wheel to the wheel's point of contact with the ground (Sharma 1996 "Eur. J. Phys."…

  7. The Role of Thermoelastic Effects in the Scuffing Failure of Rolling/Sliding EHD Contacts

    DTIC Science & Technology

    1988-08-15

    Avsi i)!or TABLE OF CONTENTS FACE ABSTRACT INTRODUCTION ........... ............................ I SUMMARY AND FUTURE WORK... Table 1. Figure 3a indicates that the peak surface temperature for pure rolling occurs in the inlet zone near the point of maximum pressure gradient...CO Iq r4,) N~ 0 0 0 d 0 0 o 0 Q 0 14 Table 1. Disk and lubriant properties Material of both disks steel Lubricart, synthetic paraffinic hydrocarbon

  8. Impact of the rail-pad multi-discrete model upon the prediction of the rail response

    NASA Astrophysics Data System (ADS)

    Mazilu, T.; Leu, M.

    2017-08-01

    Wheel/rail vibration has many technical effects such as wear of the rolling surfaces, rolling noise, settlement of the ballast and subgrade etc. This vibration is depending on the rail pad characteristic and subsequently, it is important to have an accurate overview on the relation between the rail pad characteristic and the level of the wheel/rail vibration. To this end, much theoretical and experimental research has been developed in the past, and for the theoretical approach the track model, in general, and, particularly, the rail pad model is of crucial importance. Usually, the rail pad model is discrete model one, neglecting the length of the rail pad. This fact is questionable because the sleepers span is only 4 times the rail pad length. Using the rail pad discrete model, the rail response is overestimated when the frequency of the excitation equals the pinned-pinned resonance frequency. In this paper, a multi-discrete model for the rail pad, consisting in many Kelvin-Voigt parallel systems, is inserted into an analytical model of the track. The track model is reduced to a rail taken as infinite Timoshenko beam, discretely supported via rail pad, sleeper and ballast. The influence of the number of Kelvin-Voigt systems of the rail pad model on the rail response is analysed.

  9. Optical interferometry study of film formation in lubrication of sliding and/or rolling contacts

    NASA Technical Reports Server (NTRS)

    Stejskal, E. O.; Cameron, A.

    1972-01-01

    Seventeen fluids of widely varying physical properties and molecular structure were chosen for study. Film thickness and traction were measured simultaneously in point contacts by interferometry, from which a new theory of traction was proposed. Film thickness was measured in line contacts by interferometry and electrical capacitance to establish correlation between these two methods. An interferometric method for the absolute determination of refractive index in the contact zone was developed and applied to point contact fluid entrapments. Electrical capacitance was used to study the thickness and properties of the soft surface film which sometimes forms near a metal-fluid interface.

  10. Surface Strength of Silicon Nitride in Relation to Rolling Contact Performance Measured on Ball-on-Rod and Modified Four-Ball Tests

    SciTech Connect

    Wang, Wei; Hadfield, M.; Wereszczak, Andrew A

    2010-01-01

    Silicon nitride (Si{sub 3}N{sub 4}) has been used in various rolling contact applications in turbomachinery, automotive and power industry. It is favoured to replace conventional steel due to its low density, low friction, corrosion resistance and good performance under extreme condition. However, a major limitation of its wider application is its high material and machining cost, especially the cost associated with the finishing process. In the present study, a low cost sintered and reaction bonded silicon nitride (SRBSN) is used to study the surface machining effects on its rolling contact performance. Attempt has been made to link the surface strengths of Si{sub 3}N{sub 4} derived from half-rod and C-sphere flexure strength specimens to the rolling contact lifetimes of Si{sub 3}N{sub 4} rod and ball specimens. The rolling contact fatigue tests are carried out on ball-on-rod and modified four ball machines. Three types of surfaces with coarse, fine and conventional finishing conditions are examined. Flexure strength tests on half-rod and C-sphere show an increasing surface strength from specimens with coarse, fine to conventionally machined conditions. During rolling contact fatigue test of as-machined specimens, there are no failures observed on both ball-on-rod and four ball tests after 100 million stress cycles. However, there is a trend of decreasing wear volumes measured on the contact path of rods and balls with coarse, fine and conventional conditions. In four ball test, spall failures are observed on pre-crack specimens. There is a trend of increasing rolling contact fatigue lifetime from pre-cracked specimens with coarse, fine to conventional machining conditions.

  11. Microstructural and Material Quality Effects on Rolling Contact Fatigue of Highly Elastic Intermetallic NiTi Ball Bearings

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Howard, S. Adam; Thomas, Fransua; Stanford, Malcolm K.

    2017-01-01

    Rolling element bearings made from highly-elastic intermetallic materials (HIM)s, such as 60NiTi, are under development for applications that require superior corrosion and shock resistance. Compared to steel, intermetallics have been shown to have much lower rolling contact fatigue (RCF) stress capability in simplified 3-ball on rod (ASTM STP 771) fatigue tests. In the 3-ball tests, poor material quality and microstructural flaws negatively affect fatigue life but such relationships have not been established for full-scale 60NiTi bearings. In this paper, 3-ball-on-rod fatigue behavior of two quality grades of 60NiTi are compared to the fatigue life of full-scale 50mm bore ball bearings made from the same materials. 60NiTi RCF rods with material or microstructural flaws suffered from infant mortality failures at all tested stress levels while high quality 60NiTi rods exhibited no failures at lower stress levels. Similarly, tests of full-scale bearings made from flawed materials exhibited early surface fatigue and through crack type failures while bearings made from high quality material did not fail even in long-term tests. Though the full-scale bearing test data is yet preliminary, the results suggest that the simplified RCF test is a good qualitative predictor of bearing performance. These results provide guidance for materials development and to establish minimum quality levels required for successful bearing operation and life.

  12. Selection and Calculation of Optimum Generatrix of Rolling contacts for Roller Bearings,

    DTIC Science & Technology

    the rollers. The reason for the concentration of contact stresses at the edges of cylindrical rollers is the edge effect , a sharp increase in...inaccuracy in bearing manufacture. A new form of generatrix is suggested produced with large radius camber and elements decreasing the influence of the edge ... effect , considering the actual operating conditions of circles and rollers and providing increased bearing durability in bearings with rollers having rectangular generatrix.

  13. Influence of typical faults over the dynamic behavior of pantograph-catenary contact force in electric rail transport

    NASA Astrophysics Data System (ADS)

    Rusu-Anghel, S.; Ene, A.

    2017-05-01

    The quality of electric energy capture and also the equipment operational safety depend essentially of the technical state of the contact line (CL). The present method for determining the technical state of CL based on advance programming is no longer efficient, due to the faults which can occur into the not programmed areas. Therefore, they cannot be remediated. It is expected another management method for the repairing and maintenance of CL based on its real state which must be very well known. In this paper a new method for determining the faults in CL is described. It is based on the analysis of the variation of pantograph-CL contact force in dynamical regime. Using mathematical modelling and also experimental tests, it was established that each type of fault is able to generate ‘signatures’ into the contact force diagram. The identification of these signatures can be accomplished by an informatics system which will provide the fault location, its type and also in the future, the probable evolution of the CL technical state. The measuring of the contact force is realized in optical manner using a railway inspection trolley which has appropriate equipment. The analysis of the desired parameters can be accomplished in real time by a data acquisition system, based on dedicated software.

  14. A 3D Contact Smoothing Method based on Quasi-C1 Interpolation and Normal voting —Application to 3D Forging and Rolling

    NASA Astrophysics Data System (ADS)

    Hachani, Maha; Fourment, Lionel

    2010-06-01

    This paper describes the effect of tool discretization accuracy on the simulation of forming processes, especially for processes where the contact area is quite small with respect to the component size. For smoothing contact surface discretized by linear triangles, an algorithm is followed to develop a higher order quadratic interpolation of the curved surface from the positions and normal vectors of the nodes, as proposed by Nagata. Normal vectors are calculated at each node from the existing discretized surface by considering a patch of surrounding elements. This is accomplished by the mean of normal voting strategy. The efficiency and reliability of the resulting contact model are checked through several examples like indenting and ironing a bulk parallelepiped. It is also applied to complex ring rolling, form rolling and extrusion problems.

  15. Reducing rail side wear on heavy-haul railway curves based on wheel-rail dynamic interaction

    NASA Astrophysics Data System (ADS)

    Zhai, Wanming; Gao, Jianmin; Liu, Pengfei; Wang, Kaiyun

    2014-05-01

    This article investigates an optimisation strategy for the design of rail-grinding profiles to be used on heavy-haul railway curves, aiming to reduce the rail side wear on curves. A design methodology of rail asymmetric-grinding profiles is put forward based on the principle of low wheel-rail dynamic interaction. The implementing procedure is illustrated in detail. As a case study, the rail asymmetric-grinding profiles were designed for a curve with 600 m radius on Chinese Shuohuang heavy-haul railway. The characteristics of wheel-rail contact geometry and wheel-rail dynamic interaction were analysed and compared between the original standard rail profiles and the designed rail-grinding profiles. The rails on a test curve were ground according to the designed profiles. Before and after rail grinding, both the wheel-rail dynamics indexes and the rail side wear were measured in the field. The theoretical and experimental results show that the wheel-rail dynamic interaction is clearly improved and the rail side wear is alleviated by 30-40% after rail grinding, which validates the effectiveness of the design methodology of rail asymmetric-grinding profiles on curves.

  16. Rolling-contact fatigue resistance of hard coatings on bearing steels.

    SciTech Connect

    Erdemir, A.

    1999-08-18

    Ball- and roller-bearings of the 21st Century are expected to perform better and last longer while operating under more stringent conditions than before. To meet these great expectations, researchers have been constantly exploring new bearing designs or refining existing ones, optimizing microstructure and chemistry of bearing materials, and alternatively, they have been considering the use of thin hard coatings for improved bearing performance and durability. Already, some laboratory tests have demonstrated that hard nitride, carbide (such as TiN, TiC, etc.) and diamondlike carbon (DLC) coatings can be very effective in prolonging the fatigue lives of bearing steels. This paper provides an overview of the recent developments in hard coatings for bearing applications. Previous studies have demonstrated that thin, hard coatings can effectively prolong the fatigue lives of bearing steel substrates. In particular, thinner hard coatings (i.e., 0.2 - 1 {micro}m thick) provide exceptional improvements in the fatigue lives of bearing steel substrates. In contrast, thicker hard coatings suffer micro fracture and delamination when tested under high contact stresses, hence are ineffective and may even have a negative effect on bearing life. Overall, it was concluded that thin hard coatings may offer new possibilities for bearing industry in meeting the performance and durability needs of the 21st Century.

  17. Hydrodynamic lubrication of rigid nonconformal contacts in combined rolling and normal motion

    NASA Technical Reports Server (NTRS)

    Ghosh, M. K.; Hamrock, B. J.; Brewe, D. E.

    1984-01-01

    A numerical solution to the problem of hydrodynamic lubrication of rigid point contacts with an isoviscous, incompressible lubricant was obtained. The hydrodynamic load-carrying capacity under unsteady (or dynamic) conditions arising from the combined effects of squeeze motion superposed upon the entraining motion was determined for both normal approach and separation. Superposed normal motion considerably increases net load-carrying capacity during normal approach and substantially reduces net load-carrying capacity during separation. Geometry was also found to have a significant influence on the dynamic load-carrying capacity. The ratio of dynamic to steady state load-carrying capacity increases with increasing geometry parameter for normal approach and decreases during separation. The cavitation (film rupture) boundary is also influenced significantly by the normal motion, moving downstream during approach and upstream during separation. For sufficiently high normal separation velocity the rupture boundary may even move upstream of the minimum-film-thickness position. Sixty-three cases were used to derive a functional relationship for the ratio of the dynamic to steady state load-carrying capacity in terms of the dimensionless normal velocity parameter (incorporating normal velocity, entraining velocity, and film thickness) and the geometry parameter.

  18. Effect of discrete track support by sleepers on rail corrugation at a curved track

    NASA Astrophysics Data System (ADS)

    Jin, X. S.; Wen, Z. F.

    2008-08-01

    The paper investigates into the effect of discrete track support by sleepers on the initiation and development of rail corrugation at a curved track when a railway vehicle passes through using a numerical method. The numerical method considers a combination of Kalker's rolling contact theory with non-Hertzian form, a linear frictional work model and a dynamics model of a half railway vehicle coupled with the curved track. The half-vehicle has a two-axle bogie and doubled suspension systems. It is treated as a full dynamic rigid multi-body model. In the track model, an Euler beam is used to model the rail, and the discrete track support by sleepers moving backward with respect to the vehicle running direction is considered to simulate the effect of the discrete sleeper support on the wheels/rails in rolling contact when the vehicle moves on the track. The sleeper is treated as a rigid body and the ballast bed is replaced with equivalent mass bodies. The numerical analysis exams in detail the variations of wheel/rail normal loads, the creepages, and the rail wear volume along the curved track. Their variations are much concerned with the discrete track support. The numerical results show that the discrete track support causes the fluctuating of the normal loads and creepages at a few frequencies. These frequencies comprise the passing frequency of the sleepers and the excited track resonant frequencies, which are higher than the sleeper passing frequency. Consequently, rail corrugation with several wavelengths initiates and develops. Also the results show that the contact vibrating between the curved rails and the four wheels of the same bogie has different frequencies. In this way, the different key frequencies to be excited play an important role in the initiation and development of curved rail corrugation. Therefore, the corrugations caused by the four wheels of the same bogie present different wavelengths. The paper shows and discusses the depths of the initial

  19. Investigation of Wear and Friction Properties Under Sliding Conditions of Some Materials Suitable for Cages of Rolling-Contact Bearings

    NASA Technical Reports Server (NTRS)

    Johnson, Robert L; Swikert, Max A; Bisson, Edmond E

    1952-01-01

    An investigation of wear and friction properties of a number of materials sliding against SAE 52100 steel was conducted. These materials included brass, bronze, beryllium copper, monel, nichrome v, 24s-t aluminum, nodular iron, and gray cast iron. The metals investigated may be useful as possible cage (separator or retainer) materials for rolling-contact bearings of high-speed turbine engines. The ability of materials to form surface films that prevent welding is a most important factor in both dry friction and boundary lubrication. On the basis of wear and resistance to welding only, the cast irons were the most promising materials investigated; they showed the least wear and the least tendency to surface failure when run dry, and when boundary lubricated they showed the highest load capacity. On the basis of mechanical properties, nodular iron is superior to gray cast iron. Bronze had the lowest friction coefficient under dry sliding conditions. The results with brass, beryllium copper, and aluminum were poor and these materials do not appear, with regard to friction and wear, to be suitable for cages.

  20. Simulation of contact stresses and forces during hot rolling of thin wide strips with allowance for a stick zone and elastic regions in the deformation zone

    NASA Astrophysics Data System (ADS)

    Garber, E. A.; Kozhevnikova, I. A.; Tarasov, P. A.; Zavrazhnov, A. A.; Traino, A. I.

    2007-04-01

    A new procedure for the calculation of contact stresses and hot-rolling forces for wide strips 0.8 1.5 mm thick has been developed and tested. This procedure takes into account the presence of a stick zone in the deformation zone and stress distributions in both elastic and plastic regions in the deformation zone. The average error in the force calculation according to the new procedure is 5%, which is more than two times smaller than the calculation error of well-known force calculation procedures. The developed procedure is used to simulate the contact stresses in the deformation zones of working stands in a six-stand 1700 mill during rolling of strips thinner than 1.0 mm. A number of new relations for the state of stress in a strip have been revealed upon simulation. Some of these relations are as follows: in the last stands, the length of elastic regions accounts for 10 17% of the total deformation-zone length; the maximum normal contact stresses are 1300 1400 MPa, which corresponds to the stresses in the deformation zones of cold-rolling mills; the stick-zone length accounts for 85 99% of the deformation-zone length; and the contact stresses in the stick zone are virtually independent of the friction coefficient. The developed calculation procedure can be used to optimize the technological regimes of wide-strip mills.

  1. Surface fatigue life of carburized and hardened M50NiL and AISI 9310 spur gears and rolling-contact test bars

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Bamberger, Eric N.

    1989-01-01

    Spur gear endurance tests and rolling-element surface tests were conducted to investigate vacuum-induction-melted, vacuum-arc-melted (VIM-VAR) M50NiL steel for use as a gear steel in advanced aircraft applications, to determine its endurance characteristics, and to compare the results with those for standard VAR and VIM-VAR AISI 9310 gear material. Tests were conducted with spur gears and rolling-contact bars manufactured from VIM-VAR M50NiL and VAR and VIM-VAR AISI 9310. The gear pitch diameter was 8.9 cm (3.5 in.). Gear test conditions were an inlet oil temperature of 320 K (116 F), and outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. Bench rolling-element fatigue tests were conducted at ambient temperatures with a bar speed of 12,500 rpm and a maximum Hertz stress of 4.83 GPA (700 ksi). The VIM-VAR M50NiL gears had a surface fatigue life that was 4.5 and 11.5 times that for VIM-VAR and VAR AISI 9310 gears, respectively. The surface fatigue life of the VIM-VAR M50NiL rolling-contact bars was 13.2 and 21.6 times that for the VIM-VAR and VAR AISI 9310, respectively. The VIM-VAR M50NiL material was shown to have good resistance to fracture through a fatigue spall and to have fatigue life far superior to that of both VIM-VAR and VAR AISI 9310 gears and rolling-contact bars.

  2. Surface fatigue life of carburized and hardened M50NiL and AISI 9310 spur gears and rolling-contact test bars

    NASA Technical Reports Server (NTRS)

    Townsend, Dennis P.; Bamberger, Eric N.

    1989-01-01

    Spur gear endurance tests and rolling-element surface tests were conducted to investigate vacuum-induction-melted, vacuum-arc-melted (VIM-VAR) M50NiL steel for use as a gear steel in advanced aircraft applications, to determine its endurance characteristics, and to compare the results with those for standard VAR and VIM-VAR AISI 9310 gear material. Tests were conducted with spur gears and rolling-contact bars manufactured from VIM-VAR M50NiL and VAR and VIM-VAR AISI 9310. The gear pitch diameter was 8.9 cm (3.5 in.). Gear test conditions were an inlet oil temperature of 320 K (116 F), and outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. Bench rolling-element fatigue tests were conducted at ambient temperatures with a bar speed of 12,500 rpm and a maximum Hertz stress of 4.83 GPA (700 ksi). The VIM-VAR M50NiL gears had a surface fatigue life that was 4.5 and 11.5 times that for VIM-VAR and VAR AISI 9310 gears, respectively. The surface fatigue life of the VIM-VAR M50NiL rolling-contact bars was 13.2 and 21.6 times that for the VIM-VAR and VAR AISI 9310, respectively. The VIM-VAR M50NiL material was shown to have good resistance to fracture through a fatigue spall and to have fatigue life far superior to that of both VIM-VAR and VAR AISI 9310 gears and rolling-contact bars.

  3. Niobium in Microalloyed Rail Steels

    NASA Astrophysics Data System (ADS)

    Ray, A.; Bhadeshia, H. K. D. H.

    Rails generally do not have a homogeneous austenite grain structure across their sections because the degree of plastic strain achieved during hot-rolling depends on location. Here we explore a philosophy in which niobium microalloying may be introduced in order to thermomechanically process the material so that pancaked and refined austenite grains may eventually be achieved in the critical regions of the rail. The essential principle in alloy design involves the avoidance of coarse niobium carbide precipitates in the regions of the steel that contain chemical segregation caused by non-equilibrium solidification. Both pearlitic and cementite-free bainitic rails have been studied. The work is of generic value to the design of high-carbon microalloyed steels.

  4. 12. DETAIL VIEW OF INTERLOCKING RAIL CONNECTION AT FREE END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. DETAIL VIEW OF INTERLOCKING RAIL CONNECTION AT FREE END OF MOVING LEAF - Seddon Island Scherzer Rolling Lift Bridge, Spanning Garrison Channel from Tampa to Seddon Island, Tampa, Hillsborough County, FL

  5. Influence of process parameters on rolling-contact-fatigue life of ion plated nickel-copper-silver lubrication

    SciTech Connect

    Danyluk, Mike; Dhingra, Anoop

    2012-05-15

    In this paper, we present a connection between argon ion flux, element-mixing, and rolling contact fatigue (RCF) life of a thin film nickel-copper-silver lubricant on ball bearings. The film is deposited on the balls using an ion plating process and tested for RCF in high vacuum. The ion flux is measured using a Langmuir probe and the plane stress within the film during deposition is calculated using a thin film model. Experiments reveal that there is an inverse relationship between ion flux and RCF life for most deposition voltage and pressure combinations tested, specifically, 15.5-18.5 mTorr and 1.5-3.5 kV. For voltages up to 2.5 kV, RCF life decreases as ion flux increases due to increased compressive stress within the film, reaching as high as 2.6 GPa. For voltages between 2.5 and 3.5 kV, interlayer mixing of nickel and copper with the silver layer reduces RCF life due to contamination, even as ion flux and corresponding film compressive stress are reduced. A Monte Carlo-based simulation tool, SRIM is used to track collision cascades of the argon ions and metal atoms within the coating layers. At process voltages above 2.5 kV we observe elemental mixing of copper and nickel with the silver layer using Auger electron spectroscopy of coated steel and Si{sub 3}N{sub 4} balls. The authors conclude that an ion flux greater than 5.0 x 10{sup 14} cm{sup -2} s{sup -1} leads to reduced RCF life due to high film stress. In addition, process voltages greater than 2.5 kV also reduce RCF life due to contamination and interlayer mixing of nickel and copper within the silver layer.

  6. Investigation of the Influence of Shapes-Texture on Surface Deformation of UHMWPE as a Bearing Material in Static Normal Load and Rolling Contact

    NASA Astrophysics Data System (ADS)

    Lestari, W. D.; Ismail, R.; Jamari, J.; Bayuseno, A. P.

    2017-05-01

    Surface texture is a common method for improving wear properties of a tribo-pair of soft and hard bearing material. The reduction of wear rates on the contacting surface material is becoming important issues. In the present study, analysis of the contact pressure on the flat surface of UHMWPE (Ultra High Molecular Weight Polyethylene) under the static- and rolling motion with the surface of steel ball used the 3D finite element method (FEM) (the ABAQUS software version 6.12). Five shaped-texture models (square, circle, ellipse, triangle, and chevron) were presented on the flat surface for analysis. The normal load of 17, 30 and 50 N was deliberately set-up for static and rolling contact analysis. The contact pressure was determined to predict the wear behavior of the shaped-texture on the flat surface of UHMWPE. The results have shown that the static normal load yielded the lowest von-Mises stress distribution on the shaped-texture of the ellipse for all values applied a load, while the square shape experienced the highest stress distribution. Under rolling contact, however, the increasing load yielded the increasing von Mises stress distribution for the texture with a triangle shape. Moreover, the texture shapes for circle, ellipse, and chevron respectively, may undergo the lowest stress distribution for all load. The wear calculation provided that the circle and square shape may undergo the highest wear rates. Obviously, the surface texture of circle, ellipse, and chevron may experience the lowest wear rates and is potential for use in the surface engineering of bearing materials.

  7. Evaluation of Non-Ozone-Depleting-Chemical Cleaning Methods for Space Mechanisms Using a Vacuum Spiral Orbit Rolling Contact Tribometer

    NASA Technical Reports Server (NTRS)

    Jansen, Mark J.; Jones, William R., Jr.; Wheeler, Donald R.; Keller, Dennis J.

    2000-01-01

    Because CFC 113, an ozone depleting chemical (ODC), can no longer be produced, alternative bearing cleaning methods must be studied. The objective of this work was to study the effect of the new cleaning methods on lubricant lifetime using a vacuum bearing simulator (spiral orbit rolling contact tribometer). Four alternative cleaning methods were studied: ultra-violet (UV) ozone, aqueous levigated alumina slurry (ALAS), super critical fluid (SCF) CO2 and aqueous Brulin 815GD. Baseline tests were done using CFC 113. Test conditions were the following: a vacuum of at least 1.3 x 10(exp -6) Pa, 440C steel components, a rotational speed of 10 RPM, a lubricant charge of between 60-75 micrograms, a perfluoropolyalkylether lubricant (Z-25), and a load of 200N (44.6 lbs., a mean Hertzian stress of 1.5 GPa). Normalized lubricant lifetime was determined by dividing the total number of ball orbits by the amount of lubricant. The failure condition was a friction coefficient of 0.38. Post-test XPS analysis was also performed, showing slight variations in post-cleaning surface chemistry. Statistical analysis of the resultant data was conducted and it was determined that the data sets were most directly comparable when subjected to a natural log transformation. The natural log life (NL-Life) data for each cleaning method were reasonably normally (statistically) distributed and yielded standard deviations that were not significantly different among the five cleaning methods investigated. This made comparison of their NL-Life means very straightforward using a Bonferroni multiple comparison of means procedure. This procedure showed that the ALAS, UV-ozone and CFC 113 methods were not statistically significantly different from one another with respect to mean NL-Life. It also found that the SCF CO2 method yielded a significantly higher mean NL-Life than the mean NL-Lives of the ALAS, UV-ozone and CFC 113 methods. It also determined that the aqueous Brulin 815GD method yielded a mean

  8. Cyclic hardening properties of hard-drawn copper and rail steel

    NASA Astrophysics Data System (ADS)

    Bower, A. F.

    A CYCLIC hardening law due to ARMSTRONG and FREDERICK (CEGB Report RD/B/N731, 1966) has been extended to describe plastic strain accumulation (ratchetting) in hard-drawn copper and rail steel. The four parameters of the theoretical model were determined from a single uniaxial test on each material, in which unequal tension and compression were applied. Using these parameters the model was found to give good predictions of the ratchetting rate measured in non-proportional cycles of tension-torsion-compression, which are representative of the stress cycles experienced by surface elements in rolling and sliding contact.

  9. Assessment of rail long-pitch corrugation

    NASA Astrophysics Data System (ADS)

    Valehrach, Jan; Guziur, Petr; Riha, Tomas; Plasek, Otto

    2017-09-01

    The paper focuses on defects of the running surface of the rail, namely the rail corrugation defect and specifically long-pitch corrugation in curves of small radii. These defects cause a shorter life of the rails, greater maintenance costs and increase the noise and vibration pollution. Therefore, it is very important to understand the formation and development of the imperfection of the rails. In the paper, various sections of railway tracks in the Czech Republic are listed, each of them completed with comparison of defect development, the particular track superstructure, rolling stock, axle load, traffic load etc. Based on performed measurements, defect development has been proved as different on sections with similar (or even same) parameters. The paper assumes that a train velocity is the significant circumstance for defect development rates. Assessment of track section with under sleeper pads, which are expected to be the one of the possible ways to suppress the corrugation defect development, is included in evaluation.

  10. Transient rolling friction model for discrete element simulations of sphere assemblies

    NASA Astrophysics Data System (ADS)

    Kuhn, Matthew R.

    2014-03-01

    The rolling resistance between a pair of contacting particles can be modeled with two mechanisms. The first mechanism, already widely addressed in the DEM literature, involves a contact moment between the particles. The second mechanism involves a reduction of the tangential contact force, but without a contact moment. This type of rotational resistance, termed creep-friction, is the subject of the paper. Within the creep-friction literature, the term “creep” does not mean a viscous mechanism, but rather connotes a slight slip that accompanies rolling. Two extremes of particle motions bound the range of creep-friction behaviors: a pure tangential translation is modeled as a Cattaneo-Mindlin interaction, whereas prolonged steady-state rolling corresponds to the traditional wheel-rail problem described by Carter, Poritsky, and others. DEM simulations, however, are dominated by the transient creep-friction rolling conditions that lie between these two extremes. A simplified model is proposed for the three-dimensional transient creep-friction rolling of two spheres. The model is an extension of the work of Dahlberg and Alfredsson, who studied the two-dimensional interactions of disks. The proposed model is applied to two different systems: a pair of spheres and a large dense assembly of spheres. Although creep-friction can reduce the tangential contact force that would otherwise be predicted with Cattaneo-Mindlin theory, a significant force reduction occurs only when the rate of rolling is much greater than the rate of translational sliding and only after a sustained period of rolling. When applied to the deviatoric loading of an assembly of spheres, the proposed creep-friction model has minimal effect on macroscopic strength or stiffness. At the micro-scale of individual contacts, creep-friction does have a modest influence on the incremental contact behavior, although the aggregate effect on the assembly's behavior is minimal.

  11. Development of the electromagnetic technology for broken rail detection from a mobil platform

    NASA Astrophysics Data System (ADS)

    Plotnikov, Yuri; Raghunathan, Arun; Kumar, Ajith; Noffsinger, Joseph; Fries, Jeffrey; Ehret, Steven; Frangieh, Tannous; Palanganda, Samhitha

    2016-02-01

    Timely detection of breaks in running rails remains a topic of significant importance for the railroad industry. GE has been investigating new ideas of the Rail Integrity Monitoring or RIM technology that can be implemented on a wide range of the rolling stock platforms including locomotives, passenger and freight cars. The focus of the project is to establish a simple, non-contact, and inexpensive means of nondestructive inspection by fusion of known solutions with new technology development that can result in detection with high reliability. A scaled down model of a typical locomotive-track system has been developed at GE Global research for detailed study of the detection process. In addition, a finite element model has been established and used to understand distribution of the magnetic field and currents in such a system. Both models have been using the rails and wheel-axles geometry to establish a realistic model that would provide the electric current and magnetic field distribution close to the real world phenomenon. Initial magnetic field maps were obtained by scanning a 1:15 model constructed of steel bars using a 3D scanner and an inductive coil. Sensitivity to a broken rail located between two locomotive axles simulated by an opening in this metallic frame was demonstrated. Further investigation and optimization was conducted on a larger, 1:3 scale, physical model and by running mathematical simulations. Special attention was paid to consistency between the finite element and physical model results. The obtained results allowed establishment of a working frequency range, inductive current injection into the rail-wheel-axle loop and measuring the electromagnetic response to a broken rail. The verification and full scale system prototype tests are following the laboratory experiments and mathematical simulations.

  12. Elasto-plastic coupled temperature-displacement finite element analysis of two-dimensional rolling-sliding contact with a translating heat source

    NASA Technical Reports Server (NTRS)

    Rubin, C. A.; Hahn, G. T.; Kulkarni, S. M.

    1991-01-01

    The present paper describes a transient translating elastoplastic thermomechanical finite element model to study two-dimensional frictional rolling contact. Frictional two-dimensional contact is simulated by repeatedly translating a nonuniform thermomechanical distribution across the surface of an elastoplastic half space. The half space is represented by a two-dimensional finite element mesh with appropriate boundaries. Calculations are for an elastic-perfectly plastic material and the selected thermophysical properties are assumed to be temperature independent. The paper presents temperature variations, stress and plastic strain distributions and deformations. Residual tensile stresses are observed. The magnitude and depth of these stresses depends on (1) the temperature gradients and (2) the magnitudes of the normal and tangential tractions.

  13. Modelling pressure rolling of asymmetric rolling process

    NASA Astrophysics Data System (ADS)

    Alexa, V.; Ratiu, S. A.; Kiss, I.; Cioata, V. G.

    2017-05-01

    The paper presents a comparative analysis between experimental results and modelling in order to interpret the value of the contact pressure on the asymmetric longitudinal rolling. It is also intended action and the different behaviour of upper cylinder compared to the lower cylinder action in situations when both are driven, or only one operates. In the modelling will be presented on the basis of boundary conditions imposed rolling pressure variation in the degree of reduction and also re size arc length of contact. Determining a curve is also important to determine the locus of points which characterize symmetry conditions partial rolling process between unequal diameters cylinders.

  14. Dragline roller track improvement. Volume I. Evaluation of low hardness dragline track materials in rolling contact. Final report, September 30, 1976-July 30, 1980

    SciTech Connect

    Dunfee, J.; Leonard, L.; Rumbarger, J.

    1980-01-01

    The Franklin Research Center (FRC), a Division of the Franklin Institute, was contracted by the Bureau of Mines to improve walking dragline roller tracks. The contract was subsequently transferred to the Department of Energy. The period from September 1977 to September 1978 covered laboratory rolling contact rig tests to evaluate typical low hardness dragline track materials. The results of this work are covered by DOE/ET/9121-1 Final Report, Volume I. The period from September 1978 to July 1980 covered field measurements of dragline roller circle loadings. The results of this work are covered by DOE/ET/9121-2 Final Report, Volume II. The laboratory rolling contact rig test results indicate that forged vacuum degassed air melt steel materials are recommended over air-melt cast materials for rollers and tracks. The steels tested exhibited good freedom from sensitivity to stress raisers like brinell marks and small holes or discontinuities (Volume I). The largest unknown in a recommended method for life testing roller tracks is the condition of the upper rotating frame structure and the lower tub supporting structure.

  15. Stress dependence of guided waves in rails

    NASA Astrophysics Data System (ADS)

    Bartoli, Ivan; Coccia, Stefano; Phillips, Robert; Srivastava, Ankit; Lanza di Scalea, Francesco; Salamone, Salvatore; Fateh, Mahmood; Carr, Gary

    2010-03-01

    This paper presents numerical results on the dynamic behavior of continuously welded rails (CWR) subjected to a static axial stress. The results quantify the sensitivity of guided waves to stress variations and could be potentially used to estimate the stress level in CWR or alternatively the rail Neutral Temperature (stress free rail temperature). This work represents the initial concept phase of a research and development study funded by the Federal Railroad Administration. The ultimate objective of this study is to develop and test a prototype system that uses non-contact dynamic sensing to measure in-situ rail stress in motion, to determine rail Neutral Temperatures (NT) and the related Incipient Buckling Risks in CWR.

  16. Dynamic vehicle-track interaction in switches and crossings and the influence of rail pad stiffness - field measurements and validation of a simulation model

    NASA Astrophysics Data System (ADS)

    Pålsson, Björn A.; Nielsen, Jens C. O.

    2015-06-01

    A model for simulation of dynamic interaction between a railway vehicle and a turnout (switch and crossing, S&C) is validated versus field measurements. In particular, the implementation and accuracy of viscously damped track models with different complexities are assessed. The validation data come from full-scale field measurements of dynamic track stiffness and wheel-rail contact forces in a demonstrator turnout that was installed as part of the INNOTRACK project with funding from the European Union Sixth Framework Programme. Vertical track stiffness at nominal wheel loads, in the frequency range up to 20 Hz, was measured using a rolling stiffness measurement vehicle (RSMV). Vertical and lateral wheel-rail contact forces were measured by an instrumented wheel set mounted in a freight car featuring Y25 bogies. The measurements were performed for traffic in both the through and diverging routes, and in the facing and trailing moves. The full set of test runs was repeated with different types of rail pad to investigate the influence of rail pad stiffness on track stiffness and contact forces. It is concluded that impact loads on the crossing can be reduced by using more resilient rail pads. To allow for vehicle dynamics simulations at low computational cost, the track models are discretised space-variant mass-spring-damper models that are moving with each wheel set of the vehicle model. Acceptable agreement between simulated and measured vertical contact forces at the crossing can be obtained when the standard GENSYS track model is extended with one ballast/subgrade mass under each rail. This model can be tuned to capture the large phase delay in dynamic track stiffness at low frequencies, as measured by the RSMV, while remaining sufficiently resilient at higher frequencies.

  17. On dynamic effects of wheel-rail interaction in the case of Polygonalisation

    NASA Astrophysics Data System (ADS)

    Bogacz, R.; Frischmuth, K.

    2016-10-01

    Following earlier work of the authors [1], we study here the influence of surface imperfections of a certain type on the vertical loading, in particular in the form of fluctuations in the progressive speed of a moving force. The problem is partly associated with another line of work, where we analyzed configurations of regions in the parameter space with qualitatively different solutions for supported beams under moving loads [2]. In this paper, we study the rolling motion of a polygonalised railway wheel on the rail. For uniform guiding motion, the trajectory of the contact point and vertical accelerations are evaluated first in the rigid case, then in the case of elastic and visco-elastic contact. It will be pointed out that a wavy form of the wheel changes considerably the longitudinal velocity of contact points, even for constant speed of the wheel center which can be are as on for instability.

  18. Research in bus and rail transit operations

    SciTech Connect

    Chatterjee, A.; Wegmann, F.J.; Ceder, A.; Levinson, H.S.; Hollander, A.

    1989-01-01

    The 10 papers in the report deal with the following areas: Private Sector Involvement in Sponsoring Sunday Bus Service; Optimal Design of Transit Short-Turn Trips; New York City's Unfranchised Buses: Case Study in Deregulation; Critical Factors in Planning Multimodal Passenger Terminals; Use of Travelers' Attitudes in Rail Service Design; Driven, Attended, and Fully Automated Transit; Qualitative Comparison; Impact on Transit Patronage of Cessation or Inauguration of Rail Service; Use of Productivity Factors in Estimating LRT Operating Costs; Simulation Study To Evaluate Spare Ratios in Bus Transit Systems; Statistical Evaluation of Spare Ratio in Transit Rolling Stock.

  19. 77 FR 2077 - Intent To Request Renewal From OMB of One Current Public Collection of Information: Rail...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-13

    ... railroad carriers, and rail mass transit systems to designate and submit contact information for a Rail... receiver facilities, passenger railroad carriers, and rail mass transit systems to report to TSA... Collection of Information: Rail Transportation Security AGENCY: Transportation Security Administration, DHS...

  20. Guided Wave Inspection for Bottom Edge of Rails

    NASA Astrophysics Data System (ADS)

    Hayashi, T.; Miyazaki, Y.; Murase, M.; Abe, T.

    2007-03-01

    Defects in a railhead and web can be detected with rail inspection cars and rail inspection tools equipped with special transducers such as wheel probes. However, bottom edges of rails, easily damaged regions due to contact to soil and fastening, are blind zones for the conventional ultrasonic inspection technique in which signals are input from a railhead. In this paper, inspection technique for defects in bottom edges of rails using guided waves were described. Dispersion curves for a rail obtained by a semi analytical finite element calculation show that a lot of propagating modes exist in a frequency region used for guided wave inspection, eg. 10kHz - 200kHz. Guided wave modes mainly vibrating a bottom edge of a rail were selected among the many modes in dispersion curves, and then defect detection tests were done using the selected modes. Good reflections from an artificial defect and a rail end were obtained with a vertically vibrating mode.

  1. Analysis of the main trends in the development of rail production in Russia and abroad

    NASA Astrophysics Data System (ADS)

    Golovatenko, A. V.; Umansky, A. A.; Dorofeev, V. V.

    2016-09-01

    The present analysis reveals the main directions in the development of rail production in the world: the transition to rolling of rail sections using continuous group of universal stands, increase of the rails length, application of differentiated hardening of rails in different media. It is shown that the technological gap between the Russian metallurgical industry and the world's leading rail manufactures of the last decades was closed in 2013 -2014 when the new universal rolling mills at JSC “EVRAZ Consolidated West Siberian Metallurgical Plant” (“EVRAZ ZSMK”) and OJSC “Chelyabinsk Metallurgical Plant” (company “Mechel”) were launched. Currently, these steel enterprises provide complete import substitution of long rails with increased wear resistance for the construction of high-speed networks.

  2. Numerical analysis of some problems related to the mechanics of pneumatic tires: Finite deformation/rolling contact of a viscoelastic cylinder and finite deformation of cord-reinforced rubber composites

    NASA Technical Reports Server (NTRS)

    Oden, J. T.; Becker, E. B.; Lin, T. L.; Hsieh, K. T.

    1984-01-01

    The formulation and numerical analysis of several problems related to the behavior of pneumatic tires are considered. These problems include the general rolling contact problem of a rubber-like viscoelastic cylinder undergoing finite deformations and the finite deformation of cord-reinforced rubber composites. New finite element models are developed for these problems. Numerical results obtained for several representative cases are presented.

  3. Development of a vehicle-track model assembly and numerical method for simulation of wheel-rail dynamic interaction due to unsupported sleepers

    NASA Astrophysics Data System (ADS)

    Zhu, Jian Jun; Ahmed, A. K. W.; Rakheja, Subhash; Khajepour, Amir

    2010-12-01

    In practice, it is not very uncommon to find railway track systems with unsupported sleepers due to the uneven settlement of a ballasted track system. These unsupported sleepers are among the major vibration excitations for a train and track system when a train moves forwards on a track. The vibration induced by unsupported sleepers can cause a large dynamic contact force between wheels and rails. For heavily loaded high-speed trains, the deteriorated sleeper support may lead to accelerated degradation of the railway track and vehicle components, and may thus impose safety risk to the operation. This paper presents analyses of a coupled vehicle-track assembly consisting of a roll plane vehicle model, a continuous track system model and an adaptive wheel-rail contact model. In order to improve the simulation efficiency, a numerical approach based on the central finite difference method is proposed in this investigation. The developed model assembly and proposed simulation method are utilised to simulate the vehicle-track dynamic interaction in the presence of unsupported sleepers. The dynamic response in terms of the dynamic wheel-rail interaction force due to one or multiple unsupported sleepers is studied. Important factors influencing the dynamic wheel-rail interaction force in the presence of sleeper voids are also investigated. The results show that the vehicle speed, the gap size and the number of unsupported sleepers primarily dictate the magnitude of impact load which can be significant.

  4. Myosin heavy chain-like localizes at cell contact sites during Drosophila myoblast fusion and interacts in vitro with Rolling pebbles 7

    SciTech Connect

    Bonn, Bettina R.; Rudolf, Anja; Hornbruch-Freitag, Christina; Daum, Gabor; Kuckwa, Jessica; Kastl, Lena; Buttgereit, Detlev; Renkawitz-Pohl, Renate

    2013-02-15

    Besides representing the sarcomeric thick filaments, myosins are involved in many cellular transport and motility processes. Myosin heavy chains are grouped into 18 classes. Here we show that in Drosophila, the unconventional group XVIII myosin heavy chain-like (Mhcl) is transcribed in the mesoderm of embryos, most prominently in founder cells (FCs). An ectopically expressed GFP-tagged Mhcl localizes in the growing muscle at cell–cell contacts towards the attached fusion competent myoblast (FCM). We further show that Mhcl interacts in vitro with the essential fusion protein Rolling pebbles 7 (Rols7), which is part of a protein complex established at cell contact sites (Fusion-restricted Myogenic-Adhesive Structure or FuRMAS). Here, branched F-actin is likely needed to widen the fusion pore and to integrate the myoblast into the growing muscle. We show that the localization of Mhcl is dependent on the presence of Rols7, and we postulate that Mhcl acts at the FuRMAS as an actin motor protein. We further show that Mhcl deficient embryos develop a wild-type musculature. We thus propose that Mhcl functions redundantly to other myosin heavy chains in myoblasts. Lastly, we found that the protein is detectable adjacent to the sarcomeric Z-discs, suggesting an additional function in mature muscles. - Highlights: ► The class XVIII myosin encoding gene Mhcl is transcribed in the mesoderm. ► Mhcl localization at contact sites of fusing myoblasts depends on Rols7. ► Mhcl interacts in vitro with Rols7 which is essential for myogenesis. ► Functional redundancy with other myosins is likely as mutants show no muscle defects. ► Mhcl localizes adjacent to Z-discs of sarcomeres and might support muscle integrity.

  5. Improving fatigue performance of rail thermite welds

    NASA Astrophysics Data System (ADS)

    Jezzini-Aouad, M.; Flahaut, P.; Hariri, S.; Winiar, L.

    2010-06-01

    Rail transport development offers economic and ecological interests. Nevertheless, it requires heavy investments in rolling material and infrastructure. To be competitive, this transportation means must rely on safe and reliable infrastructure, which requires optimization of all implemented techniques and structure. Rail thermite (or aluminothermic) welding is widely used within the railway industry for in-track welding during re-rail and defect replacement. The process provides numerous advantages against other welding technology commonly used. Obviously, future demands on train traffic are heavier axle loads, higher train speeds and increased traffic density. Thus, a new enhanced weld should be developed to prevent accidents due to fracture of welds and to lower maintenance costs. In order to improve such assembly process, a detailed metallurgical study coupled to a thermomechanical modelling of the phenomena involved in the thermite welding process is carried out. Obtained data enables us to develop a new improved thermite weld (type A). This joint is made by modifying the routinely specified procedure (type B) used in a railway rail by a standard gap alumino-thermic weld. Joints of type A and B are tested and compared. Based on experimental temperature measurements, a finite element analysis is used to calculate the thermal residual stresses induced. In the vicinity of the weld, the residual stress patterns depend on the thermal conditions during welding as it also shown by litterature [1, 2]. In parallel, X-Ray diffraction has been used to map the residual stress field that is generated in welded rail of types A and B. Their effect on fatigue crack growth in rail welds is studied. An experimental study based on fatigue tests of rails welded by conventional and improved processes adjudicates on the new advances and results will be shown.

  6. Three-dimensional rail-current distribution near the armature of simple, square-bore, two-rail railguns

    SciTech Connect

    Beno, J.H. )

    1991-01-01

    In this paper vector potential is solved as a three dimensional, boundary value problem for a conductor geometry consisting of square-bore railgun rails and a stationary armature. Conductors are infinitely conducting and perfect contact is assumed between rails and the armature. From the vector potential solution, surface current distribution is inferred.

  7. The Effect of Stress and TiC Coated Balls on Lubricant Lifetimes Using a Vacuum Ball-on-Plate Rolling Contact Tribometer

    NASA Technical Reports Server (NTRS)

    Jones, William R., Jr.; Jansen, Mark J.; Helmick, Larry H.; Nguyen, QuynhGiao; Wheeler, Donald R.; Voving, Hans J.

    1999-01-01

    A vacuum ball-on-plate rolling contact tribometer was used to determine the relative lifetimes of a perfluoropolyether (Krytox 143 AC) on 440C stainless steel. The effect of mean Hertzian stresses (0.75, 1.0, 1.5 and 2.0 GPa) and the use of TiC coated balls on lubricant lifetime was studied. Other conditions included: approximately 100 rpm, approximately 50 micrograms of lubricant, an initial vacuum level of less than 1.0 x 1O(exp -8) Torr, and room temperature (approximately 23 C). increasing the mean Hertzian stress from 0.75 to 2.0 GPa results in an exponential decrease in lubricant lifetime for both material combinations. However. substituting a TiC ball for the 440C ball quadrupled lifetime at low stress levels (0.75 and 1.0 GPa) and doubled life at higher stresses (1.5 and 2.0 GPa). The reduced reactivity of the TiC surface with the PFPE lubricant is considered to be the reason for this enhancement. Decreasing lifetime with increasing stress levels correlated well with energy dissipation calculations.

  8. The Effect of Stress and TiC Coated Balls on Lubricant Lifetimes Using a Vacuum Ball-on-Plate Rolling Contact Tribometer

    NASA Technical Reports Server (NTRS)

    Jones, William R., Jr.; Jansen, Mark J.; Helmick, Larry H.; Nguyen, QuynhGiao; Wheeler, Donald R.; Boving, Hans J.

    1999-01-01

    A vacuum ball-on-plate rolling contact tribometer was used to determine the relative lifetimes of a perfluoropolyether (Krytox 143 AC) on 440C stainless steel. The effect of mean Hertzian stresses (0.75, 1.0, 1.5, and 2.0 GPa) and the use of TiC-coated balls on lubricant lifetime was studied. Other conditions included: 100 rpm, 50 micro-g of lubricant, an initial vacuum level of less than 1.0 x 10(exp -8) Torr, and room temperature (23 C). Increasing the mean Hertzian stress from 0.75 to 2.0 GPa results in an exponential decrease in lubricant lifetime for both material combinations. However, substituting a TiC ball for the 440C ball quadrupled lifetime at low stress levels (0.75 and 1.0 GPa) and doubled life at higher stresses (1.5 and 2.0 GPa). The reduced reactivity of the TiC surface with the PFPE lubricant is considered to be the reason for this enhancement. Decreasing lifetime with increasing stress levels correlated well with energy dissipation calculations.

  9. The Effect of Stress and TiC Coated Balls on Lubricant Lifetimes Using a Vacuum Ball-on-Plate Rolling Contact Tribometer

    NASA Technical Reports Server (NTRS)

    Jones, William R., Jr.; Jansen, Mark J.; Helmick, Larry H.; Nguyen, QuynhGiao; Wheeler, Donald R.; Boving, Hans J.

    1999-01-01

    A vacuum ball-on-plate rolling contact tribometer was used to determine the relative lifetimes of a perfluoropolyether (Krytox 143 AC) on 440C stainless steel. The effect of mean Hertzian stresses (0.75, 1.0, 1.5, and 2.0 GPa) and the use of TiC-coated balls on lubricant lifetime was studied. Other conditions included: 100 rpm, 50 micro-g of lubricant, an initial vacuum level of less than 1.0 x 10(exp -8) Torr, and room temperature (23 C). Increasing the mean Hertzian stress from 0.75 to 2.0 GPa results in an exponential decrease in lubricant lifetime for both material combinations. However, substituting a TiC ball for the 440C ball quadrupled lifetime at low stress levels (0.75 and 1.0 GPa) and doubled life at higher stresses (1.5 and 2.0 GPa). The reduced reactivity of the TiC surface with the PFPE lubricant is considered to be the reason for this enhancement. Decreasing lifetime with increasing stress levels correlated well with energy dissipation calculations.

  10. Optimal Placement Method of RFID Readers in Industrial Rail Transport for Uneven Rail Traflc Volume Management

    NASA Astrophysics Data System (ADS)

    Rakhmangulov, Aleksandr; Muravev, Dmitri; Mishkurov, Pavel

    2016-11-01

    The issue of operative data reception on location and movement of railcars is significant the constantly growing requirements of the provision of timely and safe transportation. The technical solution for efficiency improvement of data collection on rail rolling stock is the implementation of an identification system. Nowadays, there are several such systems, distinguished in working principle. In the authors' opinion, the most promising for rail transportation is the RFID technology, proposing the equipping of the railway tracks by the stationary points of data reading (RFID readers) from the onboard sensors on the railcars. However, regardless of a specific type and manufacturer of these systems, their implementation is affiliated with the significant financing costs for large, industrial, rail transport systems, owning the extensive network of special railway tracks with a large number of stations and loading areas. To reduce the investment costs for creation, the identification system of rolling stock on the special railway tracks of industrial enterprises has developed the method based on the idea of priority installation of the RFID readers on railway hauls, where rail traffic volumes are uneven in structure and power, parameters of which is difficult or impossible to predict on the basis of existing data in an information system. To select the optimal locations of RFID readers, the mathematical model of the staged installation of such readers has developed depending on the non-uniformity value of rail traffic volumes, passing through the specific railway hauls. As a result of that approach, installation of the numerous RFID readers at all station tracks and loading areas of industrial railway stations might be not necessary,which reduces the total cost of the rolling stock identification and the implementation of the method for optimal management of transportation process.

  11. Radial arm strike rail

    DOEpatents

    McKeown, Mark H.; Beason, Steven C.

    1991-01-01

    The radial arm strike rail assembly is a system for measurement of bearings, directions, and stereophotography for geologic mapping, particularly where magnetic compasses are not appropriate. The radial arm, pivoting around a shaft axis, provides a reference direction determination for geologic mapping and bearing or direction determination. The centerable and levelable pedestal provide a base for the radial arm strike rail and the telescoping camera pedestal. The telescoping feature of the radial arm strike rail allows positioning the end of the rail for strike direction or bearing measurement with a goniometer.

  12. The Rail Gun.

    ERIC Educational Resources Information Center

    Stewart, Gay B.

    1996-01-01

    Presents a rail gun demonstration that addresses a broad group of educational goals in introductory electricity and magnetism. Uses a battery-powered circuit consisting of a movable conductor placed across two conducting rails in a magnetic field to review mechanics, foster approximate reasoning and lateral class discussion, and demonstrate the…

  13. Fence Posts and Rails

    ERIC Educational Resources Information Center

    Turton, Roger

    2016-01-01

    "Mathematical Lens" uses photographs as a springboard for mathematical inquiry and appears in every issue of "Mathematics Teacher." Recently while dismantling an old wooden post-and-rail fence, Roger Turton noticed something very interesting when he piled up the posts and rails together in the shape of a prism. The total number…

  14. Fence Posts and Rails

    ERIC Educational Resources Information Center

    Turton, Roger

    2016-01-01

    "Mathematical Lens" uses photographs as a springboard for mathematical inquiry and appears in every issue of "Mathematics Teacher." Recently while dismantling an old wooden post-and-rail fence, Roger Turton noticed something very interesting when he piled up the posts and rails together in the shape of a prism. The total number…

  15. Swing-out rail system separates overhead crane rails

    NASA Technical Reports Server (NTRS)

    Pitkin, R. G.

    1966-01-01

    Swing-out rail system separates and reconnects the overhead traveling crane rails of a building to provide for the passage of a thick concrete radiation shield sliding door through the rails. In the swing-out position, the rail cantilevered from an axial shaft.

  16. Investigation of thermomechanical behavior of a work roll and of roll life in hot strip rolling

    NASA Astrophysics Data System (ADS)

    Sun, C. G.; Hwang, S. M.; Yun, C. S.; Chung, J. S.

    1998-09-01

    An integrated finite element-based model is presented for the prediction of the steady-state thermomechanical behavior of the roll-strip system and of roll life in hot strip rolling. The model is comprised of basic finite-element models, which are incorporated into an iterative-solution procedure to deal with the interdependence between the thermomechanical behavior of the strip and that of the work roll, which arises from roll-strip contact, as well as with the interdependence between the thermal and mechanical behavior. Comparison is made between the predictions and the measurements to assess solution accuracy. Then, the effect of various process parameters on the detailed aspects of thermomechanical behavior of the work roll and on roll life is investigated via a series of process simulations.

  17. ORNL RAIL BARGE DB

    SciTech Connect

    Johnson, P. )

    1991-07-01

    The Oak Ridge National Laboratory (ORNL) Rail and Barge Network Database is a representation of the rail and barge system of the United States. The network is derived from the Federal Rail Administration (FRA) rail database. The database consists of 96 subnetworks. Each of the subnetworks represent an individual railroad, a waterway system, or a composite group of small railroads. Two subnetworks represent waterways; one being barge/intercoastal, and the other coastal merchant marine with access through the Great Lakes/Saint Lawrence Seaway, Atlantic and Gulf Coasts, the Panama Canal, and Pacific Coast. Two other subnetworks represent small shortline railroads and terminal railroad operations. One subnetwork is maintained for the representation of Amtrak operations. The remaining 91 subnetworks represent individual or corporate groups of railroads. Coordinate locations are included as part of the database. The rail portion of the database is similar to the original FRA rail network. The waterway coordinates are greatly enhanced in the current release. Inland waterway representation was extracted from the 1:2,000,000 United States Geological Survey data. An important aspect of the database is the transfer file. This file identifies where two railroads interline traffic between their systems. Also included are locations where rail/waterway intermodal transfers could occur. Other files in the database include a translation table between Association of American Railroad (AAR) codes to the 96 subnetworks in the database, a list of names of the 96 subnetworks, and a file of names for a large proportion of the nodes in the network.

  18. Rolling Contact Fatigue Life and Spall Propagation Characteristics of AISI M50, M50 NiL, and AISI 52100. Part 3. Metallurgical Examination (Preprint)

    DTIC Science & Technology

    2009-10-01

    life of 52100 compared to M50 based on ‘ cleanliness ’ of the steel. Additional studies of metal ball vs. silicon nitride should be conducted on both...52100 bearings have different internal geometry and metal balls compared to silicon nitride balls used in the M50 and M50 NiL bearings. The mass...difference between a steel rolling element and silicon nitride rolling element will alter the impact stress and it is expected this will affect the

  19. Structural health condition monitoring of rails using acoustic emission techniques

    NASA Astrophysics Data System (ADS)

    Yilmazer, Pinar

    In-service rails can develop several types of structural defects due to fatigue and wear caused by rolling stock passing over them. Most rail defects will develop gradually over time thus permitting inspection engineers to detect them in time before final failure occurs. In the UK, certain types of severe rail defects such as tache ovales, require the fitting of emergency clamps and the imposing of an Emergency Speed Restriction (ESR) until the defects are removed. Acoustic emission (AE) techniques can be applied for the detection and continuous monitoring of defect growth therefore removing the need of imposing strict ESRs. The work reported herewith aims to develop a sound methodology for the application of AE in order to detect and subsequently monitor damage evolution in rails. To validate the potential of the AE technique, tests have been carried out under laboratory conditions on three and four-point bending samples manufactured from 260 grade rail steel. Further tests, simulating the background noise conditions caused by passing rolling stock have been carried out using special experimental setups. The crack growth events have been simulated using a pencil tip break..

  20. Rolling Stitch Welder For Foil

    NASA Technical Reports Server (NTRS)

    Gilbert, Jeffery L.; Morgan, Gene E.

    1992-01-01

    Hand-operated rolling spotwelder stitch-welds foil faster and more consistently than single-spotwelding gun without damaging it. Internal spring reacts against roller frame, exerting force on welding wheel when rollers contact workpiece.

  1. Railway ground vibrations induced by wheel and rail singular defects

    NASA Astrophysics Data System (ADS)

    Kouroussis, Georges; Connolly, David P.; Alexandrou, Georgios; Vogiatzis, Konstantinos

    2015-10-01

    Railway local irregularities are a growing source of ground-borne vibration and can cause negative environmental impacts, particularly in urban areas. Therefore, this paper analyses the effect of railway track singular defects (discontinuities) on ground vibration generation and propagation. A vehicle/track/soil numerical railway model is presented, capable of accurately predicting vibration levels. The prediction model is composed of a multibody vehicle model, a flexible track model and a finite/infinite element soil model. Firstly, analysis is undertaken to assess the ability of wheel/rail contact models to accurately simulate the force generation at the wheel/rail contact, in the presence of a singular defect. It is found that, although linear contact models are sufficient for modelling ground vibration on smooth tracks, when singular defects are present higher accuracy wheel/rail models are required. Furthermore, it is found that the variation in wheel/rail force during the singular defect contact depends on the track flexibility, and thus requires a fully coupled vehicle/track/foundation model. Next, a parametric study of ground vibrations generated by singular rail and wheel defects is undertaken. Six shapes of discontinuity are modelled, representing various defect types such as transition zones, switches, crossings, rail joints and wheel flats. The vehicle is modelled as an AM96 train set and it is found that ground vibration levels are highly sensitive to defect height, length and shape.

  2. 75 FR 43611 - U S Rail Corporation-Construction and Operation Exemption-Brookhaven Rail Terminal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-26

    ...-- Brookhaven Rail Terminal On August 7, 2008, U S Rail Corporation (U S Rail), an existing class III short line...) of new rail line at a 28-acre site (the Brookhaven Rail Terminal or BRT) located in the Town...

  3. Kalker's algorithm Fastsim solves tangential contact problems with slip-dependent friction and friction anisotropy

    NASA Astrophysics Data System (ADS)

    Piotrowski, J.

    2010-07-01

    This paper presents two extensions of Kalker's algorithm Fastsim of the simplified theory of rolling contact. The first extension is for solving tangential contact problems with the coefficient of friction depending on slip velocity. Two friction laws have been considered: with and without recuperation of the static friction. According to the tribological hypothesis for metallic bodies shear failure, the friction law without recuperation of static friction is more suitable for wheel and rail than the other one. Sample results present local quantities inside the contact area (division to slip and adhesion, traction) as well as global ones (creep forces as functions of creepages and rolling velocity). For the coefficient of friction diminishing with slip, the creep forces decay after reaching the maximum and they depend on the rolling velocity. The second extension is for solving tangential contact problems with friction anisotropy characterised by a convex set of the permissible tangential tractions. The effect of the anisotropy has been shown on examples of rolling without spin and in the presence of pure spin for the elliptical set. The friction anisotropy influences tangential tractions and creep forces. Sample results present local and global quantities. Both extensions have been described with the same language of formulation and they may be merged into one, joint algorithm.

  4. Wheel-rail profile matching based on finite element method for Beijing metro

    NASA Astrophysics Data System (ADS)

    Liu, Jia-huan; Zhang, Jun; Liu, Xiao-dong; Zhu, Huang-shi; Zhang, Lin; Shang, Weipeng

    2017-09-01

    An instrument that measures wheel-rail appearance is used to measure the size of the wheel and rail in the section of the Baishiqiao South Station of Beijing Metro Line 6 to develop a finite element entity. Different working conditions such as axle load and traction are considered. The results show that: Under axle load, the matching performance of wheel I/rail II is improved, its contact area is the largest, and its equivalent stress and contact force are minimal; Under traction force, the matching performance of wheel I/rail II is improved, and the shear stress and equivalent stress are minimal, and thus is ideal.

  5. Critical rolling angle of microparticles

    NASA Astrophysics Data System (ADS)

    Farzi, Bahman; Vallabh, Chaitanya K. P.; Stephens, James D.; Cetinkaya, Cetin

    2016-03-01

    At the micrometer-scale and below, particle adhesion becomes particularly relevant as van der Waals force often dominates volume and surface proportional forces. The rolling resistance of microparticles and their critical rolling angles prior to the initiation of free-rolling and/or complete detachment are critical in numerous industrial processes and natural phenomenon involving particle adhesion and granular dynamics. The current work describes a non-contact measurement approach for determining the critical rolling angle of a single microparticle under the influence of a contact-point base-excitation generated by a transient displacement field of a prescribed surface acoustic wave pulse and reports the critical rolling angle data for a set of polystyrene latex microparticles.

  6. Electromagnetic configurations of rail guns

    NASA Astrophysics Data System (ADS)

    Fat'yanov, O. V.; Ostashev, V. E.; Lopyrev, A. N.; Ul'Yanov, A. V.

    1993-06-01

    Some problems associated with the electromagnetic acceleration of macrobodies in a rail gun are examined. An approach to the design of rail gun configurations is proposed, and some basic rail gun schemes are synthesized. The alternative rail gun schemes are compared in terms of electrode potential and stability of the electrode gap with respect to parasitic current shunting. The effect of the ohmic resistance of the electrodes and of the additional magnetization field on the spatial structure of the discharge in the rail gun channel is discussed. A classification of rail gun modifications is presented.

  7. A 3D model for rubber tyres contact, based on Kalker's methods through the STRIPES model

    NASA Astrophysics Data System (ADS)

    Chollet, Hugues

    2012-01-01

    A project on the pavement-rutting evolution under the effect of a tram on tyre, led the author to make a link between road and railway approaches to the problem of rolling contact. A simplified model is proposed with a fine description of the contact patch between a tyre and the road, and a more realistic pressure and shear stresses distribution than that available from basic models previously available. Experimental measurements are used to identify some characteristics of the force description, while the geometric shape of the tyre-road section are used, like in the traditional rail-wheel contact models, to build the 3D model. The last part validates a plausible contact pressure shape from self-aligning torque measurements and from Kalker's contact stresses gradient applied to the real tyre used in the project. The final result is a brush model extended from the wheel-rail STRIPES one, applicable to dynamics or contact studies of real tyres, with a physical coupling between longitudinal, lateral and spin effects, and a relatively fine description of the contact stresses along each strip of each tyre of the vehicle on an uneven road.

  8. Western end of ATSF rail yard with remnant of rail ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Western end of ATSF rail yard with remnant of rail spur and dumping location. Concrete vault foundation in foreground. Stone foundation and wood foundation in background. - Grand Canyon Village Utilities, Grand Canyon National Park, Grand Canyon Village, Coconino County, AZ

  9. House, south side, west railing on stoop (note: east railing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    House, south side, west railing on stoop (note: east railing the same, CA. 1935, made from iron fencing that was removed and replaced by a brick wall - Colonel John Stuart House, 106 Tradd Street, Charleston, Charleston County, SC

  10. Curve squeal of urban rolling stock—Part 1: State of the art and field measurements

    NASA Astrophysics Data System (ADS)

    Vincent, N.; Koch, J. R.; Chollet, H.; Guerder, J. Y.

    2006-06-01

    This is the first part of a series of three papers dealing with curve squeal of urban rolling stock such as metros and trams. After a brief review of the present state of the art, the key parameters involved in curve squeal generation are discussed. Then, some results of field measurement campaigns, on metro and on tramway systems, are presented. A specific measurement methodology is applied for both campaigns in order to record the main key parameters: rolling speed, axle angle of attack, wheel/rail lateral position and modal damping of relevant wheel modes. On-board microphones are mounted close to each wheel of the instrumented bogies in order to locate the squealing wheels. No squeal occurs on the outer wheel of the leading axle in flange contact with the rail. The highest squeal levels are generally found on the front inner wheel. Pure tone frequencies are related to wheel axial modes for metro (undamped steel wheel) and for tramway (resilient wheels). Squeal occurrence is also observed on a bogie with independent wheels.

  11. Multi-point contact of the high-speed vehicle-turnout system dynamics

    NASA Astrophysics Data System (ADS)

    Ren, Zunsong

    2013-05-01

    The wheel-rail contact problems, such as the number, location and the track of contact patches, are very important for optimizing the spatial structure of the rails and lowering the vehicle-turnout system dynamics. However, the above problems are not well solved currently because of having the difficulties in how to determine the multi-contact, to preciously present the changeable profiles of the rails and to establish an accurate spatial turnout system dynamics model. Based on a high-speed vehicle-turnout coupled model in which the track is modeled as flexible with rails and sleepers represented by beams, the line tracing extreme point method is introduced to investigate the wheel-rail multiple contact conditions and the key sections of the blade rail, longer nose rail, shorter rail in the switch and nose rail area are discretized to represent the varying profiles of rails in the turnout. The dynamic interaction between the vehicle and turnout is simulated for cases of the vehicle divergently passing the turnout and the multi-point contact is obtained. The tracks of the contact patches on the top of the rails are presented and the wheel-rail impact forces are offered in comparison with the contact patches transference on the rails. The numerical simulation results indicate that the length of two-point contact occurrence of a worn wheel profile and rails is longer than that of the new wheel profile and rails; The two-point contact definitely occurs in the switch and crossing area. Generally, three-point contact doesn't occur for the new rail profile, which is testified by the wheel-rails interpolation distance and the first order derivative function of the tracing line extreme points. The presented research is not only helpful to optimize the structure of the turnout, but also useful to lower the dynamics of the high speed vehicle-turnout system.

  12. Do Steel Bridges Prevent Rail Corrugations?

    NASA Astrophysics Data System (ADS)

    Meinke, Peter; Stephanides, Johannes

    2010-03-01

    Rail corrugations (germ. "Schlupfwellen") are wear pattern, which emerge during the transits of railway vehicles at narrow railway curves (R ≤ 250 m) and they are a menace to railway operators, especially if their railroad network exists in mountains. Therefore ÖBB started recently a research program "OBO" (Optimierter Bogenoberbau) for better understanding and avoidance of "Schlupfwellen", which is mainly experimentally oriented. As a representative test track was the extended famous narrow curve at the valley of Brixen close to Kitzbühl chosen, and two Measurement sites where there established, one embedded in the ballasted track bed and another one on a steel bridge, situated in this curve. Measuring the passing trains, a rearly astonishing fact was discovered: Whereas in the ballasted track all well known typical features occur (vibration, bending and torsion of the rail,…), which produce the wear created Schlupfwellen and the dedicated grumbling noise, the wheelsets run properly on the steel bridge track and pass "friendly" the associated curve segment! Dicussing the ascertained fact, it was realized that on many European steel bridges such phenomena happens! The paper ends assuming that a broad-band vibration of the rail heads upon the steel bridge reduces the friction coefficient in the wheel/rail contact area ("Flange oilers"). This can be the reason for the smooth travel at the bridge. This may also be the basis for a technical application to overcome the generation of Schlupfwellen?

  13. Fundamental phenomena governing heat transfer during rolling

    NASA Astrophysics Data System (ADS)

    Chen, W. C.; Samarasekera, I. V.; Hawbolt, E. B.

    1993-06-01

    To quantify the effect of roll chilling on the thermal history of a slab during hot rolling, tests were conducted at the Canada Center for Mineral and Energy Technology (CANMET) and at the University of British Columbia (UBC). In these tests, the surface and the interior temperatures of specimens were recorded during rolling using a data acquisition system. The corresponding heat-transfer coefficients in the roll bite were back-calculated by a trial-and-error method using a heat-transfer model. The heat-transfer coefficient was found to increase along the arc of contact and reach a maximum, followed by a decrease, until the exit of the roll bite. Its value was influenced by rolling parameters, such as percent reduction, rolling speed, rolling temperature, material type, etc. It was shown that the heat-transfer coefficient in the roll gap was strongly dependent on the roll pressure, and the effect of different variables on the interfacial heat-transfer coefficient can be related to their influence on pressure. At low mean roll pressure, such as in the case of rolling plain carbon steels at elevated temperature, the maximum heat-transfer coefficient in the roll bite was in the 25 to 35 kW/m2 °C range. As the roll pressure increased with lower rolling temperature and higher deformation resistance of stainless steel and microalloyed grades, the maximum heat-transfer coefficient reached a value of 620 kW/m2 °C. Obviously, the high pressure improved the contact between the roll and the slab surface, thereby reducing the resistance to heat flow. The mean roll-gap heat-transfer coefficient at the interface was shown to be linearly related to mean roll pressure. This finding is important because it permitted a determination of heat-transfer coefficients applicable to industrial rolling from pilot mill data. Thus, the thermal history of a slab during rough rolling was computed using a model in which the mean heat-transfer coefficient between the roll and the slab was

  14. Creep force modelling for rail traction vehicles based on the Fastsim algorithm

    NASA Astrophysics Data System (ADS)

    Spiryagin, Maksym; Polach, Oldrich; Cole, Colin

    2013-11-01

    The evaluation of creep forces is a complex task and their calculation is a time-consuming process for multibody simulation (MBS). A methodology of creep forces modelling at large traction creepages has been proposed by Polach [Creep forces in simulations of traction vehicles running on adhesion limit. Wear. 2005;258:992-1000; Influence of locomotive tractive effort on the forces between wheel and rail. Veh Syst Dyn. 2001(Suppl);35:7-22] adapting his previously published algorithm [Polach O. A fast wheel-rail forces calculation computer code. Veh Syst Dyn. 1999(Suppl);33:728-739]. The most common method for creep force modelling used by software packages for MBS of running dynamics is the Fastsim algorithm by Kalker [A fast algorithm for the simplified theory of rolling contact. Veh Syst Dyn. 1982;11:1-13]. However, the Fastsim code has some limitations which do not allow modelling the creep force - creep characteristic in agreement with measurements for locomotives and other high-power traction vehicles, mainly for large traction creep at low-adhesion conditions. This paper describes a newly developed methodology based on a variable contact flexibility increasing with the ratio of the slip area to the area of adhesion. This variable contact flexibility is introduced in a modification of Kalker's code Fastsim by replacing the constant Kalker's reduction factor, widely used in MBS, by a variable reduction factor together with a slip-velocity-dependent friction coefficient decreasing with increasing global creepage. The proposed methodology is presented in this work and compared with measurements for different locomotives. The modification allows use of the well recognised Fastsim code for simulation of creep forces at large creepages in agreement with measurements without modifying the proven modelling methodology at small creepages.

  15. Model development of work roll wear in hot strip mill

    NASA Astrophysics Data System (ADS)

    Liu, Ziying; Guan, Yingping; Wang, Fengqin

    2017-06-01

    This paper, based on the analysis of the main factors(specific roll force, mean roll surface temperature, irregular edge wear and contact arc length) affecting roll wear, designed a new work roll wear model, the test data shows that the model can more accurately reflect the work roll wear, can be on-line prediction of work roll wear. The roll wear curve, including constant wear and irregular edge wear, presents a box shape, and the reasons also are showed in this paper. The top roll wear and bottom roll wear in the same mill are inconsistent, and the reasons are also analysed in this paper. Results show that the construction of the work roll mathematical model accords with the general law of work roll wear and tear; it can more accurately forecast roll wear online.

  16. Rolling Ribbons

    NASA Astrophysics Data System (ADS)

    Raux, P. S.; Reis, P. M.; Bush, J. W. M.; Clanet, C.

    2010-07-01

    We present the results of a combined experimental and theoretical investigation of rolling elastic ribbons. Particular attention is given to characterizing the steady shapes that arise in static and dynamic rolling configurations. In both cases, above a critical value of the forcing (either gravitational or centrifugal), the ribbon assumes a two-lobed, peanut shape similar to that assumed by rolling droplets. Our theoretical model allows us to rationalize the observed shapes through consideration of the ribbon’s bending and stretching in response to the applied forcing.

  17. Rail safety and rail privatisation in Japan.

    PubMed

    Evans, Andrew W

    2010-07-01

    Over the period from 1980 to the present, the economic status of the main line railway systems in many developed countries has changed, by privatisation or economic deregulation or both. The principal aims of such changes have been to improve the economic performance of the railways, and not to change the safety performance. Nevertheless, it is recognised that changing the organisational structure of railways might affect safety. The empirical evidence of the effect of restructuring on safety is limited, both in railways and in other industries. This paper adds to the empirical evidence by analysing train accidents in Japan before and after the privatisation of the Japanese National Railways (JNR) in 1987. The paper finds that the JNR achieved downward trends in the mean number of train accidents per train-kilometre in the 16 years 1971-1986, and the paper takes the extrapolation of these favourable trends as the yardstick by which to judge the safety performance of the privatised railways. The paper finds that the privatised railway had fewer train accidents in total than this yardstick in 1987-2006. This finding applies whether or not the high-speed Shinkansen train operations are included. Thus there is no evidence that rail privatisation in Japan had an adverse effect on train accidents. The methods adopted and the results are similar to those previously found by the author for rail privatisation in Great Britain. Copyright 2010 Elsevier Ltd. All rights reserved.

  18. Friction induced rail vibrations

    NASA Astrophysics Data System (ADS)

    Kralov, Ivan; Sinapov, Petko; Nedelchev, Krasimir; Ignatov, Ignat

    2012-11-01

    A model of rail, considered as multiple supported beam, subjected on friction induced vibration is studied in this work using FEM. The model is presented as continuous system and the mass and elastic properties of a real object are taken into account. The friction forces are nonlinear functions of the relative velocity during slipping. The problem is solved using Matlab Simulink.

  19. Rolling Robot

    NASA Technical Reports Server (NTRS)

    Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.

    1990-01-01

    Proposed rolling robot routinely traverses rough terrain, clearing rocks as high as 1 m. Climbs steps 1 m high and spans ditches 2.3 m wide. Simple but rugged semiautonomous rover has large wheels and articulated body. With combined yaw, roll, and four-wheel drive, robot crawls slowly to pass over soft or sandy terrain. Senses terrain along corridor, chooses path to avoid insurmountable obstacles, and monitors state of vehicle for unexpected hazards.

  20. Multiple pole electromagnetic propulsion system with separated ballistic guidance and electrical current contact surfaces

    DOEpatents

    Sims, Jr., James R.

    2008-07-15

    An electromagnetic propulsion system is disclosed having separate rails for ballistic guidance and for carrying current. In this system, one or more pairs of ballistic guidance rails are provided, with each ballistic guidance rail having a pair of current carrying rails joined to it to form a combined rail. Each combined rail is separated electrically from adjacent combined rails by electrically insulating blocks. Each of the current carrying rails in a given combined rail pair have the same electrical polarity, and the polarities alternate between adjacent combined rails. Armatures contact current carrying rails to complete the circuit to generate the accelerating Lorentz force on the armatures. Bore riders on the sabot and/or projectile are in contact with the ballistic guide rails. Separation of the current carrying and ballistic guidance functions increases resistance of the system to rail movement and bending, as well as reduced wear/damage to the rails. In further embodiments, a circumferential over wrap providing compressive force on the rails further increases resistance of the system to rail movement and bending.

  1. 3D shape reconstruction of rail and surface defect detection based on PMP

    NASA Astrophysics Data System (ADS)

    Duan, Fan; Lee, Jinlong; Luo, Lin; Gao, Xiaorong

    2016-09-01

    With the rapid development of high-speed and heavy-load in modern rail transit, the abrasion and surface defect of rail are getting serious, and the demand of measuring the rail shape and surface defect has been rising. Phase Measuring Profilometry (PMP), due to the good characters of non-contact, high precision, easy to control automatically etc., is often used for precise 3D shape reconstruction. In this paper, PMP technology and Stoilov phase shift algorithm are adopted, three deformed fringe patterns of rail are collected with fixed phase shift between them, and branch cut phase unwrapping algorithm is used, based on which the three-dimensional surface shape of the rail is reconstructed and the artificial surface flaws are restored and measured. This method provides a good reference for the precise online detection of the rail abrasion and surface defect.

  2. Investigation of rail irregularity effects on wheel/rail dynamic force in slab track: Comparison of two and three dimensional models

    NASA Astrophysics Data System (ADS)

    Sadeghi, Javad; Khajehdezfuly, Amin; Esmaeili, Morteza; Poorveis, Davood

    2016-07-01

    Rail irregularity is one of the most significant load amplification factors in railway track systems. In this paper, the capability and effectiveness of the two main railway slab tracks modeling techniques in prediction of the influences of rail irregularities on the Wheel/Rail Dynamic Force (WRDF) were investigated. For this purpose, two 2D and 3D numerical models of vehicle/discontinuous slab track interaction were developed. The validation of the numerical models was made by comparing the results of the models with those obtained from comprehensive field tests carried out in this research. The effects of the harmonic and non-harmonic rail irregularities on the WRDF obtained from 3D and 2D models were investigated. The results indicate that the difference between WRDF obtained from 2D and 3D models is negligible when the irregularities on the right and left rails are the same. However, as the difference between irregularities of the right and left rails increases, the results obtained from 2D and 3D models are considerably different. The results indicate that 2D models have limitations in prediction of WRDF; that is, a 3D modeling technique is required to predict WRDF when there is uneven or non-harmonic irregularity with large amplitudes. The size and extent of the influences of rail irregularities on the wheel/rail forces were discussed leading to provide a better understanding of the rail-wheel contact behavior and the required techniques for predicting WRDF.

  3. A Semianalytic Model of Leukocyte Rolling

    PubMed Central

    Krasik, Ellen F.; Hammer, Daniel A.

    2004-01-01

    Rolling allows leukocytes to maintain adhesion to vascular endothelium and to molecularly coated surfaces in flow chambers. Using insights from adhesive dynamics, a computational method for simulating leukocyte rolling and firm adhesion, we have developed a semianalytic model for the steady-state rolling of a leukocyte. After formation in a force-free region of the contact zone, receptor-ligand bonds are transported into the trailing edge of the contact zone. Rolling velocity results from a balance of the convective flux of bonds and the rate of dissociation at the back edge of the contact zone. We compare the model's results to that of adhesive dynamics and to experimental data on the rolling of leukocytes, with good agreement. We calculate the dependence of rolling velocity on shear rate, intrinsic forward and reverse reaction rates, bond stiffness, and reactive compliance, and use the model to calculate a state diagram relating molecular parameters and the dynamic state of adhesion. A dimensionless form of the analytic model permits exploration of the parameters that control rolling. The chemical affinity of a receptor-ligand pair does not uniquely determine rolling velocity. We elucidate a fundamental relationship between off-rate, ligand density, and reactive compliance at the transition between firm and rolling adhesion. The model provides a rapid method for screening system parameters for the potential to mediate rolling. PMID:15315955

  4. A numerical study of the derailment caused by collision of a rail vehicle using a virtual testing model

    NASA Astrophysics Data System (ADS)

    Cho, Hyun Jik; Koo, Jeong Seo

    2012-01-01

    This study investigated the wheel-lift and roll-over derailment mechanisms caused by train collisions using a precise virtual testing model (VTM) of a Korean high-speed train. The VTM was a complex, nonlinear finite element model composed of the shell, beam, solid, spring, and surface contact elements for the car body, bogies, suspensions, and wheel-rail interfaces. The VTM was validated by checking the errors in the total energy and the dynamic responses of the spring elements. To achieve a quick, dynamic relaxation of the dead weight of the VTM before the collision analysis, the artificial damping method and the artificial force method were introduced and numerically evaluated. The surface-to-surface contact model from commercial software, Ls-Dyna, was applied to the VTM in order to simulate the derailment mechanisms caused by collision accidents. The numerical analyses of the VTM colliding with a large deformable obstacle or a rigid wall revealed for the first time that a mixed slip/roll-over-type derailment mechanism generally occurs. Furthermore, the simulation results were consistent with the results from a simplified theoretical derailment model of a wheel set.

  5. Stochastic disks that roll.

    PubMed

    Holmes-Cerfon, Miranda

    2016-11-01

    We study a model of rolling particles subject to stochastic fluctuations, which may be relevant in systems of nano- or microscale particles where rolling is an approximation for strong static friction. We consider the simplest possible nontrivial system: a linear polymer of three disks constrained to remain in contact and immersed in an equilibrium heat bath so the internal angle of the polymer changes due to stochastic fluctuations. We compare two cases: one where the disks can slide relative to each other and the other where they are constrained to roll, like gears. Starting from the Langevin equations with arbitrary linear velocity constraints, we use formal homogenization theory to derive the overdamped equations that describe the process in configuration space only. The resulting dynamics have the formal structure of a Brownian motion on a Riemannian or sub-Riemannian manifold, depending on if the velocity constraints are holonomic or nonholonomic. We use this to compute the trimer's equilibrium distribution with and without the rolling constraints. Surprisingly, the two distributions are different. We suggest two possible interpretations of this result: either (i) dry friction (or other dissipative, nonequilibrium forces) changes basic thermodynamic quantities like the free energy of a system, a statement that could be tested experimentally, or (ii) as a lesson in modeling rolling or friction more generally as a velocity constraint when stochastic fluctuations are present. In the latter case, we speculate there could be a "roughness" entropy whose inclusion as an effective force could compensate the constraint and preserve classical Boltzmann statistics. Regardless of the interpretation, our calculation shows the word "rolling" must be used with care when stochastic fluctuations are present.

  6. Stochastic disks that roll

    NASA Astrophysics Data System (ADS)

    Holmes-Cerfon, Miranda

    2016-11-01

    We study a model of rolling particles subject to stochastic fluctuations, which may be relevant in systems of nano- or microscale particles where rolling is an approximation for strong static friction. We consider the simplest possible nontrivial system: a linear polymer of three disks constrained to remain in contact and immersed in an equilibrium heat bath so the internal angle of the polymer changes due to stochastic fluctuations. We compare two cases: one where the disks can slide relative to each other and the other where they are constrained to roll, like gears. Starting from the Langevin equations with arbitrary linear velocity constraints, we use formal homogenization theory to derive the overdamped equations that describe the process in configuration space only. The resulting dynamics have the formal structure of a Brownian motion on a Riemannian or sub-Riemannian manifold, depending on if the velocity constraints are holonomic or nonholonomic. We use this to compute the trimer's equilibrium distribution with and without the rolling constraints. Surprisingly, the two distributions are different. We suggest two possible interpretations of this result: either (i) dry friction (or other dissipative, nonequilibrium forces) changes basic thermodynamic quantities like the free energy of a system, a statement that could be tested experimentally, or (ii) as a lesson in modeling rolling or friction more generally as a velocity constraint when stochastic fluctuations are present. In the latter case, we speculate there could be a "roughness" entropy whose inclusion as an effective force could compensate the constraint and preserve classical Boltzmann statistics. Regardless of the interpretation, our calculation shows the word "rolling" must be used with care when stochastic fluctuations are present.

  7. Experimental Study of the Rolling-Sliding Contact Conditions in a PA66/STEEL Gear Using Twin-Disc Test Rig: Friction and Wear Analysis

    NASA Astrophysics Data System (ADS)

    Mbarek, Meftah; Rhaiem, Sadok; Kharrat, Mohamed; Dammak, Maher

    2015-09-01

    This study investigates the effects of sliding ratio on the tribological response of the contact between the teeth of a metal/polymer gear in the regions close to the pitch point. For this purpose, a new twin-disc test rig was developed on the basis of two discs of different diameters rotating one above the other at the same angular speed. Two different materials were used: non-alloyed structural steel (C45) and polyamide (PA66). The effect of the slip ratio (4%, 12%, 20% and 28%) was studied at a constant pressure of 34 MPa and a constant angular speed of 300 rpm. In addition, the contact conditions were controlled with measurements of the two discs surface temperatures. The results indicate that the wear and the friction are closely related to the contact temperature generated by the sliding phenomenon. At low slip ratio (4% and 12%), the coefficient of friction and the temperature are characterized by a quasi-linear increase with time, and the wear increases slowly. At higher slip ratio (20% and 28%), the coefficient of friction and the temperature presents a steady state, and the wear increases dramatically. During the test, a film of transferred PA66 is formed on the steel surface causing the development of adhesive interactions between the contacting discs which increase the friction coefficient and the contact temperature. The high thermal conductivity of steel as compared to that of the polymer can reduce enormously the contact temperature generated by the sliding process.

  8. Rail Track Detection and Modelling in Mobile Laser Scanner Data

    NASA Astrophysics Data System (ADS)

    Oude Elberink, S.; Khoshelham, K.; Arastounia, M.; Diaz Benito, D.

    2013-10-01

    We present a method for detecting and modelling rails in mobile laser scanner data. The detection is based on the properties of the rail tracks and contact wires such as relative height, linearity and relative position with respect to other objects. Points classified as rail track are used in a 3D modelling algorithm. The modelling is done by first fitting a parametric model of a rail piece to the points along each track, and estimating the position and orientation parameters of each piece model. For each position and orientation parameter a smooth low-order Fourier curve is interpolated. Using all interpolated parameters a mesh model of the rail is reconstructed. The method is explained using two areas from a dataset acquired by a LYNX mobile mapping system in a mountainous area. Residuals between railway laser points and 3D models are in the range of 2 cm. It is concluded that a curve fitting algorithm is essential to reliably and accurately model the rail tracks by using the knowledge that railways are following a continuous and smooth path.

  9. Friction in rail guns

    NASA Technical Reports Server (NTRS)

    Kay, P. K.

    1984-01-01

    The influence of friction is included in the present equations describing the performance of an inductively driven rail gun. These equations, which have their basis in an empirical formulation, are applied to results from two different experiments. Only an approximate physical description of the problem is attempted, in view of the complexity of details in the interaction among forces of this magnitude over time periods of the order of milisecs.

  10. Friction in rail guns

    NASA Technical Reports Server (NTRS)

    Kay, P. K.

    1984-01-01

    The influence of friction is included in the present equations describing the performance of an inductively driven rail gun. These equations, which have their basis in an empirical formulation, are applied to results from two different experiments. Only an approximate physical description of the problem is attempted, in view of the complexity of details in the interaction among forces of this magnitude over time periods of the order of milisecs.

  11. Design and optimisation of wheel-rail profiles for adhesion improvement

    NASA Astrophysics Data System (ADS)

    Liu, B.; Mei, T. X.; Bruni, S.

    2016-03-01

    This paper describes a study for the optimisation of the wheel profile in the wheel-rail system to increase the overall level of adhesion available at the contact interface, in particular to investigate how the wheel and rail profile combination may be designed to ensure the improved delivery of tractive/braking forces even in poor contact conditions. The research focuses on the geometric combination of both wheel and rail profiles to establish how the contact interface may be optimised to increase the adhesion level, but also to investigate how the change in the property of the contact mechanics at the wheel-rail interface may also lead to changes in the vehicle dynamic behaviour.

  12. Using Plasticine (TM) to Measure the Rolling Friction Coefficient.

    ERIC Educational Resources Information Center

    Castellvi, Francesc; And Others

    1995-01-01

    Presents an experiment that makes manifest the energy lost to friction of an iron ball moving along an inclined iron rail, which allows students to compute the rolling friction coefficient. Uses a method based on measurement of deformation produced in a piece of Plasticine by an inelastic collision with the ball and combines mechanical concepts…

  13. Foucault Dissipation in a Rolling Cylinder: A Webcam Quantitative Study

    ERIC Educational Resources Information Center

    Bonanno, A.; Bozzo, G.; Camarca, M.; Sapia, P.

    2011-01-01

    In this paper we present an experimental strategy to measure the micro power dissipation due to Foucault "eddy" currents in a copper cylinder rolling on two parallel conductive rails in the presence of a magnetic field. Foucault power dissipation is obtained from kinematical measurements carried out by using a common PC webcam and video analysis…

  14. Foucault Dissipation in a Rolling Cylinder: A Webcam Quantitative Study

    ERIC Educational Resources Information Center

    Bonanno, A.; Bozzo, G.; Camarca, M.; Sapia, P.

    2011-01-01

    In this paper we present an experimental strategy to measure the micro power dissipation due to Foucault "eddy" currents in a copper cylinder rolling on two parallel conductive rails in the presence of a magnetic field. Foucault power dissipation is obtained from kinematical measurements carried out by using a common PC webcam and video analysis…

  15. Investigation of the effect of a diamine-based friction modifier on micropitting and the properties of tribofilms in rolling-sliding contacts

    NASA Astrophysics Data System (ADS)

    Soltanahmadi, Siavash; Morina, Ardian; van Eijk, Marcel C. P.; Nedelcu, Ileana; Neville, Anne

    2016-12-01

    The effect of N-tallow-1,3-diaminopropane (TDP) on friction, rolling wear and micropitting has been investigated with the ultimate objective of developing lubricants with no or minimal environmental impact. A mini traction machine (MTM-SLIM) has been utilised in order to generate tribofilms and observe the effect of TDP on anti-wear tribofilm formation and friction. Micropitting was induced on the surface of specimens using a micropitting rig (MPR). The x-ray photoelectron spectroscopy (XPS) surface analytical technique has been employed to investigate the effect of TDP on the chemical composition of the tribofilm while atomic force microscopy (AFM) was used to generate high resolution topographical images of the tribofilms formed on the MTM discs. Experimental and analytical results showed that TDP delays the zinc dialkyldithiophosphate (ZDDP) anti-wear tribofilm formation. TDP in combination with ZDDP induces a thinner and smoother anti-wear tribofilm with a modified chemical structure composed of mixed Fe/Zn (poly)phosphates. The sulphide contribution to the tribofilm and oxygen-to-phosphorous atomic concentration ratio are greater in the bulk of the tribofilm derived from a combination of TDP and ZDDP compared to a tribofilm derived from ZDDP alone. Surface analyses showed that utilising TDP effectively mitigates micropitting wear in the test conditions used in this study. Reduction of micropitting, relevant to rolling bearing applications, can be attributed to the improved running-in procedure, reduced friction, formation of a smoother tribofilm and modification of the tribofilm composition induced by TDP.

  16. Prediction of the interaction between a simple moving vehicle and an infinite periodically supported rail - Green's functions approach

    NASA Astrophysics Data System (ADS)

    Mazilu, Traian

    2010-09-01

    This paper herein describes the interaction between a simple moving vehicle and an infinite periodically supported rail, in order to signalise the basic features of the vehicle/track vibration behaviour in general, and wheel/rail vibration, in particular. The rail is modelled as an infinite Timoshenko beam resting on semi-sleepers via three-directional rail pads and ballast. The time-domain analysis was performed applying Green's matrix of the track method. This method allows taking into account the nonlinearities of the wheel/rail contact and the Doppler effect. The numerical analysis is dedicated to the wheel/rail response due to two types of excitation: the steady-state interaction and rail irregularities. The study points out to certain aspects regarding the parametric resonance, the amplitude-modulated vibration due to corrugation and the Doppler effect.

  17. Development of mathematical models and methods for calculation of rail steel deformation resistance of various chemical composition

    NASA Astrophysics Data System (ADS)

    Umansky, A. A.; Golovatenko, A. V.; Kadykov, V. N.; Dumova, L. V.

    2016-09-01

    Using the device of the complex “Gleeble System 3800” the physical experimental studies of deformation resistance of chrome rail steel at different thermo-mechanical deformation parameters were carried out. On the basis of mathematical processing of experimental data the statistical model of dependence of the rail steel deformation resistance on the simultaneous influence of deformation degree, rate and temperature, as well as the steel chemical composition, was developed. The nature of influence of deformation parameters and the content of chemical elements in steel on its resistance to plastic deformation is scientifically substantiated. Verification of the adequacy of the proposed model by the comparative analysis of the calculated and actual rolling forces during passes in the universal rail-and-structural steel mill JSC “EVRAZ Consolidated West Siberian Metallurgical Plant” (“EVRAZ ZSMK”) showed the possibility of its use for development and improvement of new modes of rails rolling.

  18. Rolling Uphill

    ERIC Educational Resources Information Center

    Cross, Rod

    2017-01-01

    In a recent letter to this journal, Mungan noted that translational energy can be converted into gravitational potential energy when an object is projected vertically, but rotational energy is not usually converted in this manner. As an exception, he gave an example where "a ball initially rolling without slipping will travel higher up a…

  19. 46 CFR 127.320 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and at...

  20. 46 CFR 108.221 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the following...

  1. 46 CFR 177.920 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must be...

  2. 46 CFR 169.329 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...

  3. 77 FR 48591 - State Rail Plan Guidance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-14

    ... Federal Railroad Administration State Rail Plan Guidance AGENCY: Federal Railroad Administration (FRA), Department of Transportation (DOT). ACTION: Request for Public Comment on Proposed State Rail Plan Guidance..., submission, and acceptance of State rail plans. State rail plans are documents that are required...

  4. 77 FR 17121 - RailAmerica, Inc., Palm Beach Rail Holding, Inc., RailAmerica Transportation Corp., RailTex, Inc...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-23

    ... Corp., RailTex, Inc., Fortress Investment Group, LLC, and RR Acquisition Holding, LLC--Control.... (Palm Beach), RailAmerica Transportation Corp. (RTC), RailTex, Inc. (RailTex), Fortress Investment Group....), have filed a verified notice of exemption to acquire indirect control of the Wellsboro & Corning...

  5. 46 CFR 127.320 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and at...

  6. 46 CFR 127.320 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and at...

  7. 46 CFR 177.920 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must be...

  8. 46 CFR 177.920 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must be...

  9. 46 CFR 169.329 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...

  10. 46 CFR 108.221 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the following...

  11. 46 CFR 177.920 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must be...

  12. 46 CFR 108.221 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the following...

  13. 46 CFR 108.221 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the following...

  14. 46 CFR 169.329 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...

  15. 46 CFR 169.329 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...

  16. 46 CFR 127.320 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and at...

  17. 46 CFR 127.320 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and at...

  18. 46 CFR 108.221 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the following...

  19. 46 CFR 177.920 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must be...

  20. 46 CFR 169.329 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...

  1. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Rail joints. 213.351 Section 213.351... Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for the rail on which it is applied. (b) If a joint bar is cracked, broken...

  2. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Rail joints. 213.351 Section 213.351... Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for the rail on which it is applied. (b) If a joint bar is cracked, broken...

  3. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Rail joints. 213.351 Section 213.351... Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for the rail on which it is applied. (b) If a joint bar is cracked, broken...

  4. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Rail joints. 213.351 Section 213.351... Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for the rail on which it is applied. (b) If a joint bar is cracked, broken...

  5. 49 CFR 213.351 - Rail joints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Rail joints. 213.351 Section 213.351... Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for the rail on which it is applied. (b) If a joint bar is cracked, broken...

  6. Natal plumage characters in rails

    USGS Publications Warehouse

    Wetherbee, D.K.; Meanley, B.

    1965-01-01

    The downy young of the Clapper Rail (Rallus longirostris), King Rail (Rallus elegans), and Virginia Rail (Rallus limicola) are described as totally black in all literature examined by us. Wetherbee (Bird-Banding, 32: 141-159, 1961) noted that some neonates of Virginia Rail from Storrs, Connecticut, had patches of white down below the wings. "Neonatal" pertains to the developmental condition or characters at hatching distinct from the much abused term "natal" which in ornithology pertains to the condition or characters from hatching to acquisition of teleoptile plumage. The presence of similar patches of white down was observed by us in the Clapper Rails at Chincoteague, Virginia (Figure 1). An examination of many hundreds of specimens from the ranges of most of the subspecies of Clapper Rails, including the strongly contrasting R. longirostris saturatus from Louisiana, revealed the almost invariable presence of at least 1 and sometimes as many as 30 white neossoptiles in the anterior abdominal regions of the ventral pterylae. Conversely, no King Rail neonate examined by us has shown a white neossoptile.

  7. CONTROL FOR ROLLING MILL

    DOEpatents

    Shuck, A.B.; Shaw, W.C.

    1961-06-20

    A plutonium-rolling apparatus is patented that has two sets of feed rolls, shaping rolls between the feed rolls, and grippers beyond the feed rolls, which ready a workpiece for a new pass through the shaping rolls by angularly shifting the workpiece about its axis or transversely moving it on a line parallel to the axes of the shaping rolls. Actuation of each gripper for gripping or releasing the workpiece is produced by the relative positions assumed by the feed rolls adjacent to the gripper as the workpiece enters or leaves the feed rolls.

  8. Rolling Uphill

    NASA Astrophysics Data System (ADS)

    Cross, Rod

    2017-04-01

    In a recent letter to this journal, Mungan noted that translational energy can be converted into gravitational potential energy when an object is projected vertically, but rotational energy is not usually converted in this manner. As an exception, he gave an example where "a ball initially rolling without slipping will travel higher up a rough ramp than it will up a frictionless ramp." However, such a result is unlikely to be observed in practice. A better example would be a ball spinning rapidly forwards as it slides up the ramp, since the friction force on the ball then acts in a direction up the ramp.

  9. Theoretical Optimization of Track Components to Reduce Rolling Noise

    NASA Astrophysics Data System (ADS)

    Vincent, N.; Bouvet, P.; Thompson, D. J.; Gautier, P. E.

    1996-05-01

    The control of railway rolling noise requires a reduction in wheel and track noise emission. In this paper, a parametric study of the possible minimization of the track sound power is presented. In an initial global approach, a number of potential variations in track parameters are assessed in terms of their likely effect on rolling noise. from this, two main themes are selected for deeper study by use of TWINS model. The first parameter considered is the stiffness and damping of the rail-pad. By reducing the pad stiffness, the noise radiation from the sleeper is reduced but that from the rail is increased, and vice versa. An optimum is found when the rail and sleeper components are equal, for which the track radiation is a minimum. Starting from one existing track design, this optimum pad stiffness has been derived for an example wheel. The second area investigated is the increase of the attenuation rate of rail vibrations by the addition of damping measures. The implementation of dynamic absorbers with a mass of 5 kg every sleeper bay (0.6 m) leads to predicted reductions of track radiation of 2 dB(A) if the rail-pad stiffness is already optimal. For softer pads a larger reduction has been found, but the total effect is less than the combined effect of first changing to the optimum pad stiffness and then adding absorbers. Globally, for ballasted track with bibloc concrete sleepers, a 2-6 dB(A) reduction in track sound power can be expected through a rail-pad optimization and/or the implementation of dynamic absorbers on the rail.

  10. Environmental issues: noise, rail noise, and high-speed rail

    SciTech Connect

    Hall, F.L.; Welland, J.D.; Bragdon, C.R.; Houtman, J.W.; Immers, B.H.

    1987-01-01

    The six papers in the report deal with the following areas: the effect of noise barriers on the market value of adjacent residential properties; control of airport- and aircraft-related noise in the United States; a traffic-assignment model to reduce noise annoyance in urban networks; a survey of railroad occupational noise sources; a prediction procedure for rail transportation ground-borne noise and vibration; and high-speed rail in California: the dream, the process, and the reality.

  11. Ruby on Rails Applications

    NASA Technical Reports Server (NTRS)

    Hochstadt, Jake

    2011-01-01

    Ruby on Rails is an open source web application framework for the Ruby programming language. The first application I built was a web application to manage and authenticate other applications. One of the main requirements for this application was a single sign-on service. This allowed authentication to be built in one location and be implemented in many different applications. For example, users would be able to login using their existing credentials, and be able to access other NASA applications without authenticating again. The second application I worked on was an internal qualification plan app. Previously, the viewing of employee qualifications was managed through Excel spread sheets. I built a database driven application to streamline the process of managing qualifications. Employees would be able to login securely to view, edit and update their personal qualifications.

  12. Segmented rail linear induction motor

    DOEpatents

    Cowan, Jr., Maynard; Marder, Barry M.

    1996-01-01

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces.

  13. Segmented rail linear induction motor

    DOEpatents

    Cowan, M. Jr.; Marder, B.M.

    1996-09-03

    A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces. 6 figs.

  14. Non-contact measurement of contact wire

    NASA Astrophysics Data System (ADS)

    Yi, Yaxing; Ye, Xuemei; Li, Zhongke; Yue, Kaiduan

    2008-12-01

    The overhead contact system is the power supply unit of the electric locomotive. This article is to introduce our newly developed method to measure the height and pull out value of the contact wire. A carema dolly which can move on railway is applied to bear the weight of the measure equipment; two linear CCD cameras are installed on the dolly symmetrically about the midline of two rails. While the dolly move along the railway, two CCD cameras grasp the image synchronously, and a computer real-time process the images, the height and pull out value can be calculate out from the images.

  15. Simulation of the evolution of rail corrugation using a rotating flexible wheelset model

    NASA Astrophysics Data System (ADS)

    Vila, Paloma; Fayos, Juan; Baeza, Luis

    2011-11-01

    This paper presents a simulation tool designed for predicting the wear pattern on the running surface of the rails and for studying the evolution of rail corrugation after thousands of wheelset passages. This simulation tool implements a cyclic track model, a rotating flexible wheelset model, a wheel-rail contact model and a wear model. The vehicle-track system is modelled by using a substructuring technique, by which the vehicle, the rails and the sleepers are treated independently of each other and are coupled by the forces transmitted through the wheel-rail contact and the railpad. The vehicle model takes only account of the wheelset since the sprung masses of the vehicle are not relevant in the frequency range analysed. The wheelset model considers the flexibility of the wheelset and the effects associated with rotation. By using the Campbell diagram, two cases have been identified in which the combined effect of two different modes may give rise to higher wheel-rail contact forces and wear.

  16. Simulation of rolling friction in the working stands of wide-strip mills

    NASA Astrophysics Data System (ADS)

    Garber, E. A.; Samarin, S. N.; Traino, A. I.; Ermilov, V. V.

    2007-04-01

    The energy consumed for rolling friction in the interroll contact area in the working stands of cold-rolling and pinch-pass mils intended for the production of wide steel strips has been analyzed. The coefficients and power of rolling friction are obtained for the first time using the databases of the process control systems of operating mills and simulating these quantities. A statistically reliable regression relation is obtained between the coefficient of rolling friction and the significant parameters of rolling and skin rolling (i.e., the interroll force, the roll speed, and the roll body roughness). The power fraction consumed for rolling friction is found to reach 60 80% of the total power of the main drive of working stands for skin rolling and 30 50% for cold rolling. Therefore, it is necessary to take into account these power losses in designing mills and developing technological cold-rolling conditions.

  17. Rail Defect Detection Using Ultrasonic Surface Waves

    NASA Astrophysics Data System (ADS)

    Edwards, R. S.; Jian, X.; Fan, Y.; Dixon, S.

    2006-03-01

    Current testing of the rail network is limited in terms of both speed of testing and accuracy of detecting surface defects such as gauge corner cracking. By using ultrasonic surface waves generated and detected in a pitch-catch manner we can detect such defects with a much higher accuracy. We use electro-magnetic acoustic transducers (EMATs) to generate and detect the ultrasound. These have the advantage of being non-contact and require no couplant. It is not sufficient to merely detect the presence of a defect; hence accurate calibration of the system is required. We present measurements on calibration samples giving the response of the system to defects of different depths. Further experiments have been performed on rail samples containing real and manufactured defects, both longitudinal and transverse. Using the change in signal amplitude and frequency content we are able to give a depth and position for these defects, and these are compared with more established measurement methods. An enhancement of the signal when the receive EMAT is close to the defect is also discussed.

  18. 75 FR 53734 - Patriot Rail, LLC, Patriot Rail Holdings LLC, and Patriot Rail Corp.-Continuance in Control...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-01

    ... Exemption--Piedmont & Northern Railway, Inc. Patriot Rail, LLC (PRL) and its subsidiaries, Patriot Rail... carrier.\\1\\ \\1\\ PRL is a noncarrier limited liability company that owns not less than 51% of the...

  19. 78 FR 10581 - Rail Vehicles Access Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-14

    ... TRANSPORTATION BARRIERS COMPLIANCE BOARD 36 CFR Part 1192 RIN 3014-AA42 Rail Vehicles Access Advisory Committee... Disabilities Act for transportation vehicles that operate on fixed guideway systems (e.g., rapid rail, light rail, commuter rail, and intercity rail). We are establishing a Rail Vehicles Access Advisory...

  20. 46 CFR 28.410 - Deck rails, lifelines, storm rails, and hand grabs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Deck rails, lifelines, storm rails, and hand grabs. 28..., lifelines, storm rails, and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section... with a bulwark, chain link fencing, wire mesh, or an equivalent. (f) A suitable storm rail or hand grab...

  1. 46 CFR 28.410 - Deck rails, lifelines, storm rails, and hand grabs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Deck rails, lifelines, storm rails, and hand grabs. 28..., lifelines, storm rails, and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section... weather decks accessible to individuals. Where space limitations make deck rails impractical, hand grabs...

  2. 46 CFR 28.810 - Deck rails, lifelines, storm rails and hand grabs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Deck rails, lifelines, storm rails and hand grabs. 28..., storm rails and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section, deck... weather decks accessible to individuals. Where space limitations make deck rails impractical, hand grabs...

  3. 46 CFR 28.410 - Deck rails, lifelines, storm rails, and hand grabs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Deck rails, lifelines, storm rails, and hand grabs. 28..., lifelines, storm rails, and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section... weather decks accessible to individuals. Where space limitations make deck rails impractical, hand grabs...

  4. 46 CFR 28.810 - Deck rails, lifelines, storm rails and hand grabs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Deck rails, lifelines, storm rails and hand grabs. 28..., storm rails and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section, deck... weather decks accessible to individuals. Where space limitations make deck rails impractical, hand grabs...

  5. 46 CFR 28.810 - Deck rails, lifelines, storm rails and hand grabs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Deck rails, lifelines, storm rails and hand grabs. 28..., storm rails and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section, deck... weather decks accessible to individuals. Where space limitations make deck rails impractical, hand grabs...

  6. 46 CFR 28.810 - Deck rails, lifelines, storm rails and hand grabs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Deck rails, lifelines, storm rails and hand grabs. 28..., storm rails and hand grabs. (a) Except as otherwise provided in paragraph (d) of this section, deck... weather decks accessible to individuals. Where space limitations make deck rails impractical, hand grabs...

  7. 76 FR 22747 - RailAmerica, Inc., Palm Beach Holdings, Inc., RailAmerica Transportation Corp., RailTex, Inc...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-22

    ...., RailTex, Inc., Fortress Investment Group, LLC, and RR Acquisition Holding, LLC--Continuance in Control.... (RTC), RailTex, Inc. (RailTex), Fortress Investment Group, LLC (Fortress), and RR Acquisition Holding... continue in control, through RTC, of Conecuh Valley Railway, LLC (CVR), Three Notch Railway, LLC (TNRW...

  8. 77 FR 12107 - RailAmerica, Inc., Palm Beach Holding, Inc., RailAmerica Transportation Corp., RailTex, Inc...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-28

    ...., RailTex, Inc., Fortress Investment Group, LLC, and RR Acquisition Holding, LLC--Control Exemption...), RailAmerica Transportation Corp. (RTC), RailTex, Inc., Fortress Investment Group, LLC (Fortress), and... U.S.C. 10502 from the prior approval requirements of 49 U.S.C. 11323-25 to acquire control of...

  9. Rolling-Element Bearings

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Anderson, W. J.

    1983-01-01

    Rolling element bearings are a precision, yet simple, machine element of great utility. A brief history of rolling element bearings is reviewed and the type of rolling element bearings, their geometry and kinematics, as well as the materials they are made from and the manufacturing processes they involve are described. Unloaded and unlubricated rolling element bearings, loaded but unlubricated rolling element bearings and loaded and lubricated rolling element bearings are considered. The recognition and understanding of elastohydrodynamic lubrication covered, represents one of the major development in rolling element bearings.

  10. Rail Access to Yucca Mountain: Critical Issues

    SciTech Connect

    Halstead, R. J.; Dilger, F.; Moore, R. C.

    2003-02-25

    The proposed Yucca Mountain repository site currently lacks rail access. The nearest mainline railroad is almost 100 miles away. Absence of rail access could result in many thousands of truck shipments of spent nuclear fuel and high-level radioactive waste. Direct rail access to the repository could significantly reduce the number of truck shipments and total shipments. The U.S. Department of Energy (DOE) identified five potential rail access corridors, ranging in length from 98 miles to 323 miles, in the Final Environmental Impact Statement (FEIS) for Yucca Mountain. The FEIS also considers an alternative to rail spur construction, heavy-haul truck (HHT) delivery of rail casks from one of three potential intermodal transfer stations. The authors examine the feasibility and cost of the five rail corridors, and DOE's alternative proposal for HHT transport. The authors also address the potential for rail shipments through the Las Vegas metropolitan area.

  11. 49 CFR 213.337 - Defective rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... progressing on a path either inclined upward toward the rail head or inclined downward toward the base. Fully... rail head area individually or 10 percent in the aggregate, oriented in or near the transverse...

  12. 49 CFR 213.337 - Defective rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... progressing on a path either inclined upward toward the rail head or inclined downward toward the base. Fully... rail head area individually or 10 percent in the aggregate, oriented in or near the transverse...

  13. 49 CFR 213.337 - Defective rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... progressing on a path either inclined upward toward the rail head or inclined downward toward the base. Fully... rail head area individually or 10 percent in the aggregate, oriented in or near the transverse...

  14. 49 CFR 213.337 - Defective rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... progressing on a path either inclined upward toward the rail head or inclined downward toward the base. Fully... rail head area individually or 10 percent in the aggregate, oriented in or near the transverse...

  15. 49 CFR 213.337 - Defective rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... progressing on a path either inclined upward toward the rail head or inclined downward toward the base. Fully... rail head area individually or 10 percent in the aggregate, oriented in or near the transverse...

  16. 78 FR 57450 - State Rail Plan Guidance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-18

    ... provides for enhanced State involvement in rail policy, planning, and development efforts, including... planning organization (MPO), eleven (11) trade organizations, five (5) national stakeholder organizations... offered by commenters for preparing State rail plans as part of a comprehensive, coordinated...

  17. 78 FR 71724 - Rail Depreciation Studies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-29

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Surface Transportation Board Rail Depreciation Studies AGENCY: Surface Transportation Board, DOT. ACTION... Surface Transportation Board has obtained OMB approval for its information collection, Rail...

  18. Railway wheel-flat and rail surface defect modelling and analysis by time-frequency techniques

    NASA Astrophysics Data System (ADS)

    Liang, B.; Iwnicki, S. D.; Zhao, Y.; Crosbee, D.

    2013-09-01

    Damage to the surface of railway wheels and rails commonly occurs in most railways. If not detected, it can result in the rapid deterioration and possible failure of rolling stock and infrastructure components causing higher maintenance costs. This paper presents an investigation into the modelling and simulation of wheel-flat and rail surface defects. A simplified mathematical model was developed and a series of experiments were carried out on a roller rig. The time-frequency analysis is a useful tool for identifying the content of a signal in the frequency domain without losing information about its time domain characteristics. Because of this, it is widely used for dynamic system analysis and condition monitoring and has been used in this paper for the detection of wheel flats and rail surface defects. Three commonly used time-frequency analysis techniques: Short-Time Fourier Transform, Wigner-Ville transform and wavelet transform were investigated in this work.

  19. 77 FR 13483 - Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-07

    ... Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, England, DE248BJ; phone: 011-44-1332..., contact Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, England, DE248BJ; phone:...

  20. 78 FR 11976 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-21

    ... information identified in this AD, contact Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby... Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, England, DE248BJ; phone:...

  1. Signal and power roll ring testing update

    NASA Technical Reports Server (NTRS)

    Smith, Dennis W.

    1989-01-01

    The development of the roll ring as a long-life, low-torque alternative to the slip ring is discussed. A roll ring consists of one or more circular flexures captured by their own spring force in the annular space between two concentric conductors or contact rings. The advantages of roll rings over other types of electrical transfer devices are: extremely low drag torque, high transfer efficiencies in high-power configurations, extremely low wear debris generation, long life, and low weight for high-power applications.

  2. Rail accelerator technology and applications

    NASA Technical Reports Server (NTRS)

    Zana, L. M.; Kerslake, W. R.

    1985-01-01

    Rail accelerators offer a viable means of launching ton-size payloads from the Earth's surface to space. The results of two mission studies which indicate that an Earth-to-Space Rail Launcher (ESRL) system is not only technically feasible but also economically beneficial, particularly when large amounts of bulk cago are to be delivered to space are given. An in-house experimental program at the Lewis Research Center (LeRC) was conducted in parallel with the mission studies with the objective of examining technical feasibility issues. A 1 m long - 12.5 by 12.5 mm bore rail accelerator as designed with clear polycarbonate sidewalls to visually observe the plasma armature acceleration. The general character of plasma/projectile dynamics is described for a typical test firing.

  3. Green light on the rails

    SciTech Connect

    Not Available

    1980-02-25

    It is speculated that a freight-rail revival may be at hand. The reasons for the optimism stem partly from America's energy imperative, i.e., as part of the effort to reduce dependence on foreign oil, domestic coal is getting more attention. Federal regulators are attempting to apply some economic logic to the freight-rail system. Regulations are now in place for railroads to liquidate or cut service. Congress is considering deregulation bills that would give railroads more freedom in setting freight rates and abandoning little-used routes. The ICC is promoting cost-saving merges and rail stocks are becoming a popular investment. Problems remain and these are discussed.

  4. 46 CFR 116.920 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Storm rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must be installed where necessary...

  5. 49 CFR 234.233 - Rail joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Rail joints. 234.233 Section 234.233... joints. Each non-insulated rail joint located within the limits of a highway-rail grade crossing train detection circuit shall be bonded by means other than joint bars and the bonds shall be maintained in...

  6. 46 CFR 116.920 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Storm rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must be installed where necessary...

  7. 46 CFR 116.920 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Storm rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must be installed where necessary...

  8. 46 CFR 116.920 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Storm rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must be installed where necessary...

  9. 46 CFR 116.920 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Storm rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must be installed where necessary...

  10. 49 CFR 234.233 - Rail joints.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Rail joints. 234.233 Section 234.233... joints. Each non-insulated rail joint located within the limits of a highway-rail grade crossing train detection circuit shall be bonded by means other than joint bars and the bonds shall be maintained in such...

  11. 49 CFR 234.233 - Rail joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Rail joints. 234.233 Section 234.233..., Inspection, and Testing Maintenance Standards § 234.233 Rail joints. Each non-insulated rail joint located... than joint bars and the bonds shall be maintained in such condition to ensure electrical conductivity. ...

  12. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Rail joints. 213.121 Section 213.121..., DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for...

  13. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Rail joints. 213.121 Section 213.121..., DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for...

  14. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Rail joints. 213.121 Section 213.121..., DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for...

  15. 49 CFR 234.233 - Rail joints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Rail joints. 234.233 Section 234.233... joints. Each non-insulated rail joint located within the limits of a highway-rail grade crossing train detection circuit shall be bonded by means other than joint bars and the bonds shall be maintained in such...

  16. 49 CFR 234.233 - Rail joints.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Rail joints. 234.233 Section 234.233..., Inspection, and Testing Maintenance Standards § 234.233 Rail joints. Each non-insulated rail joint located... than joint bars and the bonds shall be maintained in such condition to ensure electrical conductivity. ...

  17. 49 CFR 213.121 - Rail joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Rail joints. 213.121 Section 213.121..., DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise joint shall be of a structurally sound design and dimensions for...

  18. 46 CFR 177.900 - Deck rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... simultaneously. (c) Where space limitations make deck rails impractical for areas designed for crew use only.... (2) Rails on a vessel subject to the 1966 International Convention on Load Lines must be at least 1... installed between a top rail required by paragraph (a) of this section, and the deck so that no open space...

  19. Wheel/rail noise generation due to nonlinear effects and parametric excitation.

    PubMed

    Nordborg, Anders

    2002-04-01

    Two models are developed, one in the time domain and another in the frequency domain, to explain when a wheel/rail noise generation model requires the inclusion of discrete supports, parametric excitation, and the nonlinear contact spring. Numerical simulations indicate the inclusion of discrete supports to describe low frequency response, and also at higher frequencies, especially where the rail is very smooth or has a corrugation/wavelength corresponding to the pinned-pinned frequency. With a corrugation, it may become essential to include the nonlinear contact spring, as contact loss occurs at high corrugation amplitudes. As nonlinearity causes force generation over a broad frequency range, some contributions excite wheel resonances, resulting in high radiation levels, that require the inclusion of wheel/rail nonlinear effects and parametric excitation for accurate prediction.

  20. Rolling Element Bearing Stiffness Matrix Determination (Presentation)

    SciTech Connect

    Guo, Y.; Parker, R.

    2014-01-01

    Current theoretical bearing models differ in their stiffness estimates because of different model assumptions. In this study, a finite element/contact mechanics model is developed for rolling element bearings with the focus of obtaining accurate bearing stiffness for a wide range of bearing types and parameters. A combined surface integral and finite element method is used to solve for the contact mechanics between the rolling elements and races. This model captures the time-dependent characteristics of the bearing contact due to the orbital motion of the rolling elements. A numerical method is developed to determine the full bearing stiffness matrix corresponding to two radial, one axial, and two angular coordinates; the rotation about the shaft axis is free by design. This proposed stiffness determination method is validated against experiments in the literature and compared to existing analytical models and widely used advanced computational methods. The fully-populated stiffness matrix demonstrates the coupling between bearing radial, axial, and tilting bearing deflections.

  1. Indirect method for wheel-rail force measurement and derailment evaluation

    NASA Astrophysics Data System (ADS)

    Wei, Lai; Zeng, Jing; Wu, Pingbo; Gao, Hao

    2014-12-01

    Wheel set flange derailment criteria for railway vehicles are derived and the influence of wheel-rail contact parameters is studied. An indirect method for wheel-rail force measurement based on these derailment evaluation criteria is proposed. Laboratory tests for the calibration of strain-force devices on the bearing box are carried out to determine the relationship between the applied force and the measured strain. The simulation package, SIMPACK, is used to develop a passenger car model to generate wheel-rail forces and vibration signals. Different cases are considered in this model to provide an accurate validation of the identified wheel-rail forces. A feasibility test is conducted in the Beijing Loop test line using a passenger car equipped with a set of strain gauges on the wheel set. The comparison of the force time history applied to the instrumented wheel set and that obtained using the indirect method is presented.

  2. Rail accelerator research at Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Kerslake, W. R.; Cybyk, B. Z.

    1982-01-01

    A rail accelerator was chosen for study as an electromagnetic space propulsion device because of its simplicity and existing technology base. The results of a mission feasibility study using a large rail accelerator for direct launch of ton-size payloads from the Earth's surface to space, and the results of initial tests with a small, laboratory rail accelerator are presented. The laboratory rail accelerator has a bore of 3 by 3 mm and has accelerated 60 mg projectiles to velocities of 300 to 1000 m/s. Rail materials of Cu, W, and Mo were tested for efficiency and erosion rate.

  3. A field calibration method to eliminate the error caused by relative tilt on roll angle measurement

    NASA Astrophysics Data System (ADS)

    Qi, Jingya; Wang, Zhao; Huang, Junhui; Yu, Bao; Gao, Jianmin

    2016-11-01

    The roll angle measurement method based on a heterodyne interferometer is an efficient technique for its high precision and environmental noise immunity. The optical layout bases on a polarization-assisted conversion of the roll angle into an optical phase shift, read by a beam passing through the objective plate actuated by the roll rotation. The measurement sensitivity or the gain coefficient G is calibrated before. However, a relative tilt between the laser and objective plate always exist due to the tilt of the laser and the roll of the guide in the field long rail measurement. The relative tilt affect the value of G, thus result in the roll angle measurement error. In this paper, a method for field calibration of G is presented to eliminate the measurement error above. The field calibration layout turns the roll angle into an optical path change (OPC) by a rotary table. Thus, the roll angle can be obtained from the OPC read by a two-frequency interferometer. Together with the phase shift, an accurate G in field measurement can be obtained and the measurement error can be corrected. The optical system of the field calibration method is set up and the experiment results are given. Contrasted with the Renishaw XL-80 for calibration, the proposed field calibration method can obtain the accurate G in the field rail roll angle measurement.

  4. Grading Practices: The Third Rail

    ERIC Educational Resources Information Center

    Erickson, Jeffrey A.

    2010-01-01

    Although Social Security funds are in decline and no solution is evident, few politicians have the temerity to try to change the system. Why? Because Social Security is the third rail in politics: if one touches it, he or she will die. The field of education has an issue that is equally as lethal: grading. Grading is one of the most private…

  5. Crashworthy railing for timber bridges

    Treesearch

    Michael A. Ritter; Ronald K. Faller; Sheila Rimal. Duwadi

    1999-01-01

    Bridge railing systems in the United States have historically beers designed based on static load criteria given in the American Association of State Highway and Transportation 0fficials (AASHTO) Standard Specifications for Highway Bridges. In the past decade, full-scale vehicle crash testing has been recognized as a more appropriate and reliable method of evaluating...

  6. PRB rail loadings shatter record

    SciTech Connect

    Buchsbaum, L.

    2008-09-15

    Rail transport of coal in the Powder River Basin has expanded, with a record 2,197 trains loaded in a month. Arch Coal's Thunder basin mining complex has expanded by literally bridging the joint line railway. The dry fork mine has also celebrated its safety achievements. 4 photos.

  7. Grading Practices: The Third Rail

    ERIC Educational Resources Information Center

    Erickson, Jeffrey A.

    2010-01-01

    Although Social Security funds are in decline and no solution is evident, few politicians have the temerity to try to change the system. Why? Because Social Security is the third rail in politics: if one touches it, he or she will die. The field of education has an issue that is equally as lethal: grading. Grading is one of the most private…

  8. A streetcar named light rail

    SciTech Connect

    Mora, J. )

    1991-02-01

    In this paper, the author discusses the increasing use of light rail vehicles (LRVs) in North America. According to the author, LRVs are being utilized because of concerns about automotive traffic congestion and air pollution. Vehicle technology and economics are assessed.

  9. Scale economies in rail transit systems

    SciTech Connect

    Savage, I.

    1994-06-01

    The research uses Federal Transit Administration Section 15 data to investigate the operating costs of 13 heavy-rail and 13 light-rail urban mass transit systems for the period 1985-91. A Cobb-Douglas technology is used to investigate various types of economies of scale. The principal findings are: (1) Adding additional passenges to an existing network and schedule of services involves zero marginal cost for heavy-rail systems, and small additional costs for light-rail systems. (2) Adding additional trains, and passengers, to an existing network leads to a less than proportionate increase in costs. (3) An expanded route network results in mild increases in unit costs for the large heavy-rail systems. The smaller light-rail systems display reduced unit costs with an expanded network. The research suggests that the minimum efficient scale for rail operation is approximately 25 route miles.

  10. Multi-rail barrel design and performance

    NASA Astrophysics Data System (ADS)

    Maas, Brian L.; Bauer, David P.; Challita, Antonios

    1993-01-01

    Railgun barrels containing multiple isolated rail pairs can be used to control armature current distribution and/or to obtain independent circuits for use with specialized power supplies. Armature current control can be used to effectively distribute acceleration forces for improved projectile launch. Independent rail 'load' circuits are attractive for use with some power supplies such as a polyphase compulsator. We have built and tested a 30 mm barrel containing three distinct rail pairs. These three rail pairs were powered by separate power supplies. This paper describes issues associated with multi-rail barrel design and our band design and performance. Rail alignment, isolation, and construction are described. The effect of multiple rail pairs on the effective inductance gradient of the band is described and test results are provided.

  11. Light rail: where the action is

    SciTech Connect

    Kizzia, T.; Middleton, W.D.

    1980-09-29

    Light rail transit provides the operating benefits of fixed guideway transportation without the high capital cost of heavy rapid transit. The basic light rail concept can be modified to meet a particular city's circumstances. Light rail projects in Pittsburgh, Buffalo, Portland, and San Diego are examined. The status of the light rail proposal for the Denver area is discussed. Denver's Regional Transportation District recently demonstrated that a 73 mi at-grade light rail network would satisfy Denver's need for more cost-effective, less polluting transportation. Various light rail vehicles are described. Advantages and limitations, possible variations, and significant advancements in light rail vehicle technology are discussed. (1 drawing, 1 map, 12 photos)

  12. Optimization of Resilient Wheels for Rolling Noise Control

    NASA Astrophysics Data System (ADS)

    BOUVET, PASCAL; VINCENT, NICOLAS; COBLENTZ, ARNAUD; DEMILLY, FRANÇOIS

    2000-03-01

    Resilient wheels are currently used on light rail systems such as tramways to prevent squealing noise and to reduce impact noise. On the other hand, they are rarely found on main lines (passenger rolling stock and freight rolling stock). Although manufacturers often claim that resilient wheels are favourable for rolling noise control, no extensive theoretical investigation confirming this statement has been published to date. In this paper, it is shown how resilient wheels can be effectively optimised in order to reduce rolling noise emission, compared to a conventional monobloc wheel. A preliminary analysis of the physical phenomena accounting for rolling noise generation emphasizes the key design parameters affecting both wheel and radiation. These parameters are the radial dynamic stiffness and damping loss factor of the rubber layer. The tread mass is also relevant. The influence of these design parameters is then qualified by a parametric study performed with the TWINS software. An optimum radial dynamic stiffness of the resilient layer is found which depends on operating conditions. Reductions in overall rolling noise up to 3 dB(A) are calculated for the configurations investigated. However, poor selection of the design parameters can lead to a noise increase compared to a standard monobloc wheel. It is also shown that a proper design for rolling noise control will not affect wheel efficiency with regard to squeal noise.

  13. Bedside safety rails: assessment of strength requirements and the appropriateness of current designs.

    PubMed

    Boocock, M G; Weyman, A K; McIlroy, R

    2006-06-10

    Bedside safety rails are used extensively throughout hospitals and residential care environments as a safety device to protect people against the risk of falling out of bed. However, several adverse incidents involving body entrapment have been linked to their use, which have resulted in serious injury to the bed occupants and, in more extreme cases, fatalities. Internationally agreed standards (i.e. European Committee for Standardisation (CEN) standards) for the design and testing of bed rails have recently been developed and are targeted at improved safety requirements (European Committee for Standardisation 19972000). The purpose of the present study was to: 1) determine whether the CEN test procedure for assessing bed rail strength and rigidity requirements is consistent with human force exertions to which bed rails may be exposed; 2) carry out loading tests on bed rails currently in use throughout the UK to determine whether they comply with the current safety recommendations proposed by the CEN standards.A laboratory study was conducted to determine the force exertions of 20 participants performing seven tasks (including activities of both bed occupants and care providers), which were considered representative of the forces to which bed rails could be exposed during normal use. Forces exerted by participants were measured using a force platform and distortions of the bed rails leading to potential entrapment zones were measured using linear displacement transducers. Static load tests were then conducted, in which incremental point loading was applied at the most adverse points on each of nine different bed rails (commonly used in UK nursing and residential care homes) in accordance with the test procedure detailed in the current CEN standards. Maximum static forces exerted by participants were found to range between 250 N and 350 N, which were within the 500 N force tolerance requirements set by the standards. Dynamic tasks involving 'rolling aggressively

  14. Numerical prediction of rail roughness growth on tangent railway tracks

    NASA Astrophysics Data System (ADS)

    Nielsen, J. C. O.

    2003-10-01

    Growth of railhead roughness (irregularities, waviness) is predicted through numerical simulation of dynamic train-track interaction on tangent track. The hypothesis is that wear is caused by longitudinal slip due to driven wheelsets, and that wear is proportional to the longitudinal frictional power in the contact patch. Emanating from an initial roughness spectrum corresponding to a new or a recent ground rail, an initial roughness profile is determined. Wheel-rail contact forces, creepages and wear for one wheelset passage are calculated in relation to location along a discretely supported track model. The calculated wear is scaled by a chosen number of wheelset passages, and is then added to the initial roughness profile. Field observations of rail corrugation on a Dutch track are used to validate the simulation model. Results from the simulations predict a large roughness growth rate for wavelengths around 30-40 mm. The large growth in this wavelength interval is explained by a low track receptance near the sleepers around the pinned-pinned resonance frequency, in combination with a large number of driven passenger wheelset passages at uniform speed. The agreement between simulations and field measurements is good with respect to dominating roughness wavelength and annual wear rate. Remedies for reducing roughness growth are discussed.

  15. Hardening Roll Surface by Plasma Nitriding with Subsequent Hardfacing

    NASA Astrophysics Data System (ADS)

    Pesin, A.; Pustovoytov, D.; Vafin, R.; Yagafarov, I.; Vardanyan, E.

    2017-05-01

    The wear of the surface layer of rolls after ion nitriding in glow discharge, followed by a coating of TiN -TiAlN plasma arc are studied and simulated. stress-strain state of the material rolls under asymmetric rolling with ultra-high shear deformations is simulated. The effect of thermal fields, formed upon contact of the tool and a deformable sheet, the structure of aluminum alloys, are considered.

  16. 4. ROLL LATHE OF THE MAIN ROLL SHOP. THE LATHE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. ROLL LATHE OF THE MAIN ROLL SHOP. THE LATHE WAS CLOSED WITH TWO ROLLS IN PLACE, AND THE LOWER ROLL WAS TURNED TO MATCH THE UPPER ROLL. - U.S. Steel Homestead Works, Main Roll Shop, Along Monongahela River, Homestead, Allegheny County, PA

  17. Friction control using ultrasonic oscillation for rolling-element linear-motion guide

    SciTech Connect

    Oiwa, Takaaki

    2006-01-15

    This article reports a friction-control method for rolling-element linear-motion guides used for precision positioning. In general, static friction greater than dynamic friction generates stick-slip motion and diminishes the positioning accuracy. Two ultrasonic actuators excite both the rail and the carriage of the guide to give relative displacements to bearing surfaces. In order to effectively propagate the vibration over the entire rail without damping, the actuator drives at that frequency with a half wavelength corresponding to the distances between the rail mounting bolts. This also minimizes undesirable vibration of the machine structure. Moreover, the bearing surfaces of the carriage are resonated by a second ultrasonic actuator. The experiments using a force sensor showed that the static and dynamic friction forces were reduced by approximately 25% at any place on the 600-mm-long rail. Moreover, excitation only at very low velocity decreased the static friction peak.

  18. Internal roll compression system

    DOEpatents

    Anderson, Graydon E.

    1985-01-01

    This invention is a machine for squeezing water out of peat or other material of low tensile strength; the machine including an inner roll eccentrically positioned inside a tubular outer roll, so as to form a gradually increasing pinch area at one point therebetween, so that, as the rolls rotate, the material is placed between the rolls, and gets wrung out when passing through the pinch area.

  19. Interaction between moving tandem wheels and an infinite rail with periodic supports - Green's matrices of the track method in stationary reference frame

    NASA Astrophysics Data System (ADS)

    Mazilu, Traian

    2017-08-01

    This paper approaches the issue of the interaction between moving tandem wheels and an infinite periodically supported rail and points out at the basic characteristics in the steady-state interaction behaviour and in the interaction in the presence of the rail random irregularity. The rail is modelled as an infinite Timoshenko beam resting on supports which are discretely modelling the inertia of the sleepers and ballast and also the viscoelastic features of the rail pads, the ballast and the subgrade. Green‧s matrices of the track method in stationary reference frame were applied so as to conduct the time-domain analysis. This method allows to consider the nonlinearities of the wheel/rail contact and the Doppler effect. The study highlights certain aspects regarding the influence of the wheel base on the wheels/rail contact forces, particularly at the parametric resonance, due to the coincidence between the wheel/rail natural frequency and the passing frequency and also when the rail surface exhibits random irregularity. It has been shown that the wheel/rail dynamic behaviour is less intense when the wheel base equals integer multiple of the sleeper bay.

  20. Rail electrodynamics in a plasma armature railgun

    SciTech Connect

    Rolader, G.E.; Jamison, K.A.; Villecco, R.A.; Graham, F.R. )

    1991-08-01

    A model is developed to investigate rail electrodynamics in a plasma armature railgun. This model describes the rail motion in response to the transitory Lorentz force and the compressive restoration force from the material which is between the rails and the containment structure. In this model the distance between the rails is found to oscillate with a frequency of {beta}. The magnetic field and the dynamic behavior of the rails induce local electric fields. We investigate the significance of these electric fields in the laboratory frame and in the projectile frame. In the lab frame, rail electrodynamics induces local electric fields which have maximums spaced behind the projectile at locations where {beta}{ital t}{sub {ital p}} is an odd multiple of {pi}, where {ital t}{sub {ital p}} is the time since the projectile has passed an axial location on the rails. When the projectile is accelerating, rail dynamics induce electric fields in the projectile frame which have maximums where {beta}{ital t}{sub {ital p}} is an even multiple of {pi}. As the projectile velocity increases, the locations of the peak voltages move farther behind the projectile. For the CHECMATE railgun, calculations indicate that the rail displacement is on the order of 2 mm, the rail velocity is on the order of 50 m/s, and the voltages induced in the projectile frame are on the order of 20--40 V.

  1. 40 CFR 201.13 - Standard for rail car operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Standard for rail car operations. 201... Interstate Rail Carrier Operations Standards § 201.13 Standard for rail car operations. Effective December 31, 1976, no carrier subject to this regulation shall operate any rail car or combination of rail cars...

  2. 49 CFR 214.523 - Hi-rail vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Hi-rail vehicles. 214.523 Section 214.523..., DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.523 Hi-rail vehicles. (a) The hi-rail gear of all hi-rail vehicles shall be inspected...

  3. 49 CFR 214.523 - Hi-rail vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Hi-rail vehicles. 214.523 Section 214.523..., DEPARTMENT OF TRANSPORTATION RAILROAD WORKPLACE SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.523 Hi-rail vehicles. (a) The hi-rail gear of all hi-rail vehicles shall be inspected...

  4. 40 CFR 201.13 - Standard for rail car operations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Standard for rail car operations. 201... Interstate Rail Carrier Operations Standards § 201.13 Standard for rail car operations. Effective December 31, 1976, no carrier subject to this regulation shall operate any rail car or combination of rail...

  5. 40 CFR 201.13 - Standard for rail car operations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Standard for rail car operations. 201... Interstate Rail Carrier Operations Standards § 201.13 Standard for rail car operations. Effective December 31, 1976, no carrier subject to this regulation shall operate any rail car or combination of rail...

  6. 40 CFR 201.13 - Standard for rail car operations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Standard for rail car operations. 201... Interstate Rail Carrier Operations Standards § 201.13 Standard for rail car operations. Effective December 31, 1976, no carrier subject to this regulation shall operate any rail car or combination of rail...

  7. 40 CFR 201.13 - Standard for rail car operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Standard for rail car operations. 201... Interstate Rail Carrier Operations Standards § 201.13 Standard for rail car operations. Effective December 31, 1976, no carrier subject to this regulation shall operate any rail car or combination of rail...

  8. Rail Damage in a Solid Armature Rail Gun

    DTIC Science & Technology

    1987-12-01

    includes a substantial plasma pressure as well as the electro- magnetic or Lorentz force. Unfortunately, severe rail damage occurs primarily P (CONTID ON...conducting metal armature. Since the plasma arcing is reduced or eliminated, the projectiles are accelerated mainly by the Lorentz force. Thus, solid...developments in barrel technology, such as superconducting augmentation, are presented in this report. UNCLASSIFIED SECURITY CLASSIFICATION OFr THIS PAGE

  9. Silicon nitride used as a rolling-element bearing material

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Zaretsky, E. V.

    1975-01-01

    Rolling-element fatigue tests were conducted with hot-pressed silicon nitride to determine its ability to withstand concentrated contacts in rolling-element bearings. If hot-pressed silicon nitride is used for both balls and races, attention must be paid to fitting both shaft and bearing housing.

  10. 75 FR 55631 - U. S. Rail Corporation-Construction and Operation Exemption-Brookhaven Rail Terminal

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-13

    ... Rail Terminal AGENCY: Surface Transportation Board. ACTION: Notice of Board Action. SUMMARY: Subject to... line of railroad at a 28-acre site to be known as the Brookhaven Rail Terminal (BRT), in...

  11. Non-Contact Ultrasonic Characterization of Angled Surface Defects

    NASA Astrophysics Data System (ADS)

    Edwards, R. S.; Dutton, B.; Rosli, M. H.; Clough, A. R.

    2011-06-01

    Surface ultrasonic waves have been shown to have many uses in non-destructive testing, in particular for gauging the depth of surface defects. Much of the previous work has assumed that these defects are oriented normal to the surface. However, this is not always the case; for example, rolling contact fatigue in rails propagates at an angle of around 25° to the surface, and this angle may affect the characterisation. We present results using non-contact ultrasonic methods to generate and detect ultrasound on samples with a range of defect angles, and compare these with finite element method (FEM) models. We use both electromagnetic acoustic transducers (EMATs) and laser ultrasound. The depth calibration when measuring ultrasound transmission is considered, and what affect the angle of a defect has. Several other methods of characterising crack depth and angle are also discussed, including the arrival times of reflected and mode-converted waves, the delay in the transmission of the high-frequency Rayleigh wave, and the enhancement of the signal at the defect in both the in-plane and out-of-plane components.

  12. Rail-to-rail differential input amplification stage with main and surrogate differential pairs

    DOEpatents

    Britton, Jr., Charles Lanier; Smith, Stephen Fulton

    2007-03-06

    An operational amplifier input stage provides a symmetrical rail-to-rail input common-mode voltage without turning off either pair of complementary differential input transistors. Secondary, or surrogate, transistor pairs assume the function of the complementary differential transistors. The circuit also maintains essentially constant transconductance, constant slew rate, and constant signal-path supply current as it provides rail-to-rail operation.

  13. Theoretical development of a simplified wheelset model to evaluate collision-induced derailments of rolling stock

    NASA Astrophysics Data System (ADS)

    Koo, Jeong Seo; Choi, Se Young

    2012-06-01

    A theoretical method is proposed to predict and evaluate collision-induced derailments of rolling stock by using a simplified wheelset model and is verified with dynamic simulations. Because the impact forces occurring during collision are transmitted from the car body to the bogies and axles through suspensions, rolling stock leads to derailment as a result of the combination of horizontal and vertical impact forces applied to the axle and a simplified wheelset model enforced at the axle can be used to theoretically formulate derailment behaviors. The derailment type depends on the combination of the horizontal and vertical forces, the flange angle and the friction coefficient. According to collision conditions, wheel-climb, wheel-lift or roll-over derailment can occur between the wheel and the rail. In this theoretical derailment model of a simplified wheelset, the derailment types are classified as Slip-up, Slip/roll-over, Climb-up, Climb/roll-over and pure Roll-over according to the derailment mechanisms between the wheel and the rail and the theoretical conditions needed to generate each derailment mechanism are proposed. The theoretical wheelset model is verified by dynamic simulation and its applicability is demonstrated by comparing the simulation results of the theoretical wheelset model with those of an actual wheelset model. The theoretical derailment wheelset model is in good agreement with the virtual testing model simulation for a collision-induced derailment of rolling stock.

  14. Top-of-Rail lubricant

    SciTech Connect

    Alzoubi, M. F.; Fenske, G. R.; Erck, R. A.; Boparai, A. S.

    2000-07-14

    Analysis of the volatile and semivolatile fractions collected after use of the TOR lubricant indicated that other than contaminants in the collection laboratory, no compounds on the EPA's Target Compound Lists (Tables 2 and 5) were detected in these fractions. The data of these qualitative analyses, given in the various tables in the text, indicate only the relative amounts of the tentatively identified compounds. The authors recommend that quantitative analysis be performed on the volatile and semivolatile fractions to allow confirmation of the tentatively identified compounds and to obtain absolute amounts of the detected compounds. Additionally, the semivolatile fraction should be analyzed by liquid chromatography/mass spectrometry to identify compounds that are not chromatographable under the temperature program used for determination of semivolatile compounds. Introducing the top-of-rail (TOR) lubricant into the wheel/rail interface results in a reduction of almost 60% of lateral friction force over the forces encountered under dry conditions. This reveals good potential for energy savings, as well as wear reduction, for railroad companies. In TOR lubrication, an increase in the angle of attack and axle load results in increased lateral friction and rate of lubricant consumption. The most efficient TOR lubricant quantity to be used in the wheel/rail interface must be calculated precisely according to the number of cars, axle loads, train speed, and angle of attack.

  15. Rail-modernization study. Final report

    SciTech Connect

    Not Available

    1987-04-01

    The purposes of the study were to: (1) assess the costs for a ten-year period of aesthetics for new rail systems and for rehabilitating and modernizing existing rail systems to levels consistent with current standards of safety and reliability, and (2) provide an initial cost/ benefit assessment of the proposed improvements and associated costs. The study deals with 34 rapid, light and commuter rail systems and was based on an earlier study design effort.

  16. 78 FR 18676 - Information Collection Activities; Rail Depreciation Studies

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-27

    ... Surface Transportation Board Information Collection Activities; Rail Depreciation Studies ACTION: 30-day...) approval of the information collection--Rail Depreciation Studies-- further described below. The Board... notice the Board is requesting comments on the following information collection: Title: Rail...

  17. 23. CONTEXTUAL, RAIL CARS IN MU SHED Delaware, Lackawanna ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. CONTEXTUAL, RAIL CARS IN MU SHED - Delaware, Lackawanna & Western Railroad Freight & Rail Yard, Multiple Unit Light Inspection Shed, New Jersey Transit Hoboken Terminal Rail Yard, Hoboken, Hudson County, NJ

  18. Land rolling increases broadleaf weed emergence

    USDA-ARS?s Scientific Manuscript database

    In the northern Great Plains, annual forage and pulse crops typically are land rolled after planting to push rocks back into the soil to prevent damage to harvest equipment. Packer wheels commonly are used at planting to improve soil-seed contact for more uniform crop emergence and subsequent matur...

  19. 46 CFR 28.810 - Deck rails, lifelines, storm rails and hand grabs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Deck rails, lifelines, storm rails and hand grabs. 28.810 Section 28.810 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Aleutian Trade Act Vessels § 28.810 Deck rails, lifelines...

  20. 75 FR 70076 - Tennessee Southern Railroad Company, Patriot Rail, LLC, Patriot Rail Holdings LLC, and Patriot...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-16

    ... TRANSPORTATION Surface Transportation Board Tennessee Southern Railroad Company, Patriot Rail, LLC, Patriot Rail Holdings LLC, and Patriot Rail Corp.--Continuance in Control Exemption--Columbia & Cowlitz Railway, LLC, DeQueen and Eastern Railroad, LLC, Golden Triangle Railroad, LLC, Mississippi & Skuna Valley Railroad, LLC...

  1. 75 FR 66057 - Waybill Data Released in Three-Benchmark Rail Rate Proceedings

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-27

    ... be posted to the Board's Web site. ] FOR FURTHER INFORMATION CONTACT: Valerie Quinn at (202) 245-0382. (Assistance for the hearing impaired is available through the Federal Information Relay Service (FIRS) at 1-800-877-8339.) SUPPLEMENTARY INFORMATION: In Simplified Standards for Rail Rate Cases...

  2. The study of sliding contact in railgun with metal armature

    SciTech Connect

    Kondratenko, A.K.; Bykov, M.A.; Schastnykh, B.S.; Glinov, A.P.; Poltanov, A.E.

    1997-01-01

    An experimental technique for the study of the current distribution in the rails and a moving metal armature is developed. The work was carried out on a special experimental railgun with a capacitor power supply. The set of small dB/dt probes as well as wire contact probes were arranged in close vicinity of the rail and armature contact surface. For interpretation of dB/dt measurements the computation technique and program of restoration of current density distribution along the armature was developed. The size and the location of the current concentration zone in the contact area are obtained for several combinations of rail and armature materials; bronze and copper rails, Al and Ti alloy armature. A stationary armature tests with resistive stainless steel and graphite layers were also made to estimate the influence of the layer material resistivity on the current distribution.

  3. On the rolling noise generation due to wheel/track parametric excitation

    NASA Astrophysics Data System (ADS)

    Wu, T. X.; Thompson, D. J.

    2006-06-01

    As a discretely supported railway track is essentially periodic, when a wheel rolls over the rail, it experiences the varying dynamic stiffness in a sleeper bay of the track, and thus the wheel and rail is periodically excited at the sleeper-passing frequency. The parametric excitation due to the varying track stiffness, in addition to the roughness or discontinuities on the wheel and rail rolling surfaces, also causes vibration and noise emission. A frequency-time domain methodology is applied for simulation of the wheel/rail interaction due to the parametric excitation. The wheel/rail interaction forces are calculated and Track-Wheel Interaction Noise Software (TWINS) is used to predict the noise radiation due to the parametric excitation at various train speeds. The results are compared with those from a moving irregularity model where no parametric excitation is generated. It is found that the components due to the parametric excitation are not significant at lower speeds compared with those due to the roughness excitation. Use of a moving irregularity model without considering the wheel/track parametric excitation may under-estimate the noise emission level at high speeds.

  4. Rolling resistance of articular cartilage due to interstitial fluid flow.

    PubMed

    Ateshian, G A; Wang, H

    1997-01-01

    A mechanism which may contribute to the frictional coefficient of diarthrodial joints is the rolling resistance due to hysteretic energy loss of viscoelastic cartilage resulting from interstitial fluid flow. The hypothesis of this study is that rolling resistance contributes significantly to the measured friction coefficient of articular cartilage. Due to the difficulty of testing this hypothesis experimentally, theoretical predictions of the rolling resistance are obtained using the solution for rolling contact of biphasic cylindrical cartilage layers [Ateshian and Wang]. Over a range of rolling velocities, tissue properties and dimensions, it is found that the coefficient of rolling resistance microR varies in magnitude from 10(-6) to 10(-2); thus, it is generally negligible in comparison with experimental measurements of the cartilage friction coefficient (10(-3)-10(-1)) except, possibly, when the tissue is arthritic. Hence, the hypothesis of this study is rejected on the basis of these results.

  5. Strip edge cracking simulation in cold rolling

    SciTech Connect

    Hubert, C.; Dubar, L.; Dubar, M.; Dubois, A.

    2011-01-17

    This research work focuses on a specific defect which occurs during cold rolling of steel strips: edge-serration. Investigations on the industrial processes have led to the conclusion that this defect is the result of the edge-trimming and cold rolling sequences. The aim of this research work is to analyze the effect of the cutting process and the cold rolling on cracks occurrence, especially on strip edges.This study is performed using an experimental testing stand called Upsetting Rolling Test (URT). It allows to reproduce cold rolling contact parameters such as forward slip, reduction ratio and friction coefficients. Specimens sampled near trimmed industrial strip edges are deformed using the URT stand. Two sets of specimens with different stress states, obtained by annealing, are submitted to two reduction passes with extreme forward slips.Scanning electron microscopy observations added to 3D optical surface profiler topographies show that on one hand, forward slip has a major effect on cracks opening. On the other hand, cracks opening decreases according to high roll strip speed gradient. Concerning the heat-treated specimens, no crack appeared after all reduction passes, showing a large influence of the cutting process and consequently of the local stress state in the vicinity of the burnish and fracture regions.

  6. Strip edge cracking simulation in cold rolling

    NASA Astrophysics Data System (ADS)

    Hubert, C.; Dubar, L.; Dubar, M.; Dubois, A.

    2011-01-01

    This research work focuses on a specific defect which occurs during cold rolling of steel strips: edge-serration. Investigations on the industrial processes have led to the conclusion that this defect is the result of the edge-trimming and cold rolling sequences. The aim of this research work is to analyze the effect of the cutting process and the cold rolling on cracks occurrence, especially on strip edges. This study is performed using an experimental testing stand called Upsetting Rolling Test (URT). It allows to reproduce cold rolling contact parameters such as forward slip, reduction ratio and friction coefficients. Specimens sampled near trimmed industrial strip edges are deformed using the URT stand. Two sets of specimens with different stress states, obtained by annealing, are submitted to two reduction passes with extreme forward slips. Scanning electron microscopy observations added to 3D optical surface profiler topographies show that on one hand, forward slip has a major effect on cracks opening. On the other hand, cracks opening decreases according to high roll strip speed gradient. Concerning the heat-treated specimens, no crack appeared after all reduction passes, showing a large influence of the cutting process and consequently of the local stress state in the vicinity of the burnish and fracture regions.

  7. Origins of rolling friction

    NASA Astrophysics Data System (ADS)

    Cross, Rod

    2017-09-01

    When a hard object rolls on a soft surface, or vice versa, rolling friction arises from deformation of the soft object or the soft surface. The friction force can be described in terms of an offset in the normal reaction force or in terms of energy loss arising from the deformation. The origin of the friction force itself is not entirely clear. It is investigated qualitatively in this paper by rolling a steel ball on soft foam and by rolling a foam cylinder on a hard surface. The deformation of the foam was observed visually, providing simple insights into the origin of the friction force.

  8. Rail vs truck transport of biomass.

    PubMed

    Mahmudi, Hamed; Flynn, Peter C

    2006-01-01

    This study analyzes the economics of transshipping biomass from truck to train in a North American setting. Transshipment will only be economic when the cost per unit distance of a second transportation mode is less than the original mode. There is an optimum number of transshipment terminals which is related to biomass yield. Transshipment incurs incremental fixed costs, and hence there is a minimum shipping distance for rail transport above which lower costs/km offset the incremental fixed costs. For transport by dedicated unit train with an optimum number of terminals, the minimum economic rail shipping distance for straw is 170 km, and for boreal forest harvest residue wood chips is 145 km. The minimum economic shipping distance for straw exceeds the biomass draw distance for economically sized centrally located power plants, and hence the prospects for rail transport are limited to cases in which traffic congestion from truck transport would otherwise preclude project development. Ideally, wood chip transport costs would be lowered by rail transshipment for an economically sized centrally located power plant, but in a specific case in Alberta, Canada, the layout of existing rail lines precludes a centrally located plant supplied by rail, whereas a more versatile road system enables it by truck. Hence for wood chips as well as straw the economic incentive for rail transport to centrally located processing plants is limited. Rail transshipment may still be preferred in cases in which road congestion precludes truck delivery, for example as result of community objections.

  9. Assessment of rail flaw inspection data

    NASA Astrophysics Data System (ADS)

    Peterson, M. L.; Jeffrey, Brandon D.; Gutkowski, R. M.

    2000-05-01

    This project is an analysis of rail flaw data from commercial inspection systems. The experimental test work was performed at the facilities of the Transportation Technology Center Inc. (TTCI). Six major railroads provided defective rail which had been removed from service. The rail, which contained a variety of defects was placed into a gauntlet track. The gauntlet track is known as the Railflaw Detection Test Facility and is a railroad industry tool, in cooperation with the Federal Railroad Administration, to evaluate rail flaw detection technology. TTCI inspected the rail, catalogued the defects, and installed the rail in the RDTF. This series of defects was then used to test the comparative performance of commercial rail flaw detection systems. Each system had a maximum of 49 defects which had to be detected for a perfect record. To date there have been six evaluations performed at the RDTF. Preliminary data is shown which indicates the probability of detection for the flaws in the test configurations which can then form a basis for a needs assessment for rail flaw detection.

  10. 46 CFR 177.900 - Deck rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... installed between a top rail required by paragraph (a) of this section, and the deck so that no open space... installed so that there is not an open space higher than 230 millimeters (9 inches) from the deck to the... simultaneously. (c) Where space limitations make deck rails impractical for areas designed for crew use...

  11. 46 CFR 177.900 - Deck rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... installed between a top rail required by paragraph (a) of this section, and the deck so that no open space... installed so that there is not an open space higher than 230 millimeters (9 inches) from the deck to the... simultaneously. (c) Where space limitations make deck rails impractical for areas designed for crew use...

  12. 46 CFR 177.900 - Deck rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... installed between a top rail required by paragraph (a) of this section, and the deck so that no open space... installed so that there is not an open space higher than 230 millimeters (9 inches) from the deck to the... simultaneously. (c) Where space limitations make deck rails impractical for areas designed for crew use...

  13. 46 CFR 177.900 - Deck rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... installed between a top rail required by paragraph (a) of this section, and the deck so that no open space... installed so that there is not an open space higher than 230 millimeters (9 inches) from the deck to the... simultaneously. (c) Where space limitations make deck rails impractical for areas designed for crew use...

  14. Dynamic responses of railroad car models to vertical and lateral rail inputs

    NASA Technical Reports Server (NTRS)

    Sewall, J. L.; Parrish, R. V.; Durling, B. J.

    1971-01-01

    Simplified dynamic models were applied in a study of vibration in a high-speed railroad car. The mathematical models used were a four-degree-of-freedom model for vertical responses to vertical rail inputs and a ten-degree-of-freedom model for lateral response to lateral or rolling (cross-level) inputs from the rails. Elastic properties of the passenger car body were represented by bending and torsion of a uniform beam. Rail-to-car (truck) suspensions were modeled as spring-mass-dashpot oscillators. Lateral spring nonlinearities approximating certain complicated truck mechanisms were introduced. The models were excited by displacement and, in some cases, velocity inputs from the rails by both deterministic (including sinusoidal) and random input functions. Results were obtained both in the frequency and time domains. Solutions in the time domain for the lateral model were obtained for a wide variety of transient and random inputs generated on-line by an analog computer. Variations in one of the damping properties of the lateral car suspension gave large fluctuations in response over a range of car speeds for a given input. This damping coefficient was significant in reducing lateral car responses that were higher for nonlinear springs for three different inputs.

  15. Analytical study on web deformation by tension in roll-to-roll printing process

    NASA Astrophysics Data System (ADS)

    Kang, Y. S.; Hong, M. S.; Lee, S. H.; Jeon, Y. H.; Kang, D.; Lee, N. K.; Lee, M. G.

    2017-08-01

    Recently, flexible devices have gained high intentions for flexible display, Radio Frequency Identification (RFID), bio-sensor and so on. For manufacturing of the flexible devices, roll-to-roll process is a good candidate because of its low production cost and high productivity. Flexible substrate has a non-uniform deformation distribution by tension. Because the roll-to-roll process carries out a number of overlay printing processes, the deformation affect overlay printing precision and printable areas. In this study, the deformation of flexible substrate was analyzed by using finite element analysis and it was verified through experiments. More deformation occurred in the middle region in the direction parallel to rolling of the flexible substrate. It is confirmed through experiments and analysis that deformation occurs less at the both ends than in the middle region. Based on these results, a hourglass roll is proposed as a mechanical design of the roll to compensate the non-uniform deformation of the flexible substrate. In the hourglass roll, high stiffness material is used in the core and low stiffness material such as an elastic material is wrapped. The diameter of the core roll was designed to be the minimum at the middle and the maximum at both ends. We tried to compensate the non-uniform deformation distribution of the flexible substrate by using the variation of the contact stiffness between the roll and the flexible substrate. Deformation distribution of flexible substrates was confirmed by finite element analysis by applying hourglass roll shape. In the analysis when using the hourglass roll, it is confirmed that the stress distribution is compensated by about 70% and the strain distribution is compensated by about 67% compared to the case using the hourglass roll. To verify the compensation of the non-uniform deformation distribution due to the tension, deformation measurement experiment when using the proposed hourglass roll was carried out

  16. Support system for generating statistics of existing railway rolling stock

    NASA Astrophysics Data System (ADS)

    Wróbel, A.; Płaczek, M.; Buchacz, A.

    2016-11-01

    Rail transport is a very important element of the transport system in European countries. Assumptions of rail transport has become more and more attractive in both passenger and freight transport. An example of this may be just noisy action "lorries on track", the promotion of intermodal transport. The principal factors affecting the condition of railway traffic safety are: the technical condition of the railway infrastructure, the technical condition of the rolling stock, the operation of crossings. The main purpose of this article is to present a tool to assist generate statistics operation railway wagons. As part of the project telemetric module allows the location of the freight wagon and the state of its load. Computer program supports GPS module will enable the location of a wagon with an accuracy of 1 meter, generate graphs of speed, road grade and load freight wagon.sheet".

  17. The time domain moving Green function of a railway track and its application to wheel-rail interactions

    NASA Astrophysics Data System (ADS)

    Sheng, X.; Xiao, X.; Zhang, S.

    2016-09-01

    When dealing with wheel-rail interactions for a high-speed train using the time domain Green function of a railway track, it would be more reasonable to use the moving Green function associated with a reference frame moving with the train, since observed from this frame wheel/rail forces are stationary. In this paper, the time domain moving Green function of a railway track as an infinitely long periodic structure is defined, derived, discussed and applied. The moving Green function is defined as the Fourier transform, from the load frequency domain to the time domain, of the response of the rail due to a moving harmonic load. The response of the rail due to a moving harmonic load is calculated using the Fourier transform-based method. A relationship is established between the moving Green function and the conventional impulse response function of the track. Properties of the moving Green function are then explored which can largely simplify the calculation of the Green function. And finally, the moving Green function is applied to deal with interactions between wheels and a track with or without rail dampers, allowing non-linearity in wheel-rail contact and demonstrating the effect of the rail dampers.

  18. Impact and Injury Patterns in Between-Rails Frontal Crashes of Vehicles with Good Ratings for Frontal Crash Protection

    PubMed Central

    Morgan, Richard M.; Cui, Chongzhen; Digges, Kennerly H.; Cao, Libo; Kan, Cing-Dao (Steve)

    2012-01-01

    This research investigated (1) what are the key attributes of the between-rail, frontal crash, (2) what are the types of object contacted, and (3) what is the type of resulting trauma. The method was to study with both weighted and in-depth case reviews of NASS-CDS crash data with direct damage between the longitudinal rails in frontal crashes. Individual case selection was limited to belted occupants in between-rail, frontal impacts of good-rated, late-model vehicles equipped with air bags. This paper evaluates the risk of trauma for drivers in cars and LTVs in between-rail, frontal crashes, and suggests the between-rail impact is more dangerous to car drivers. Using weighted data—representing 227,305 tow-away crashes—the resulting trauma to various body regions was analyzed to suggest greatest injury is to the chest, pelvis/thigh/knee/leg, and foot/ankle. This study analyzed the type of object that caused the direct damage between the rails, including small tree or post, large tree or pole, and another vehicle; and found that the struck object was most often another vehicle or a large tree/pole. Both the extent of damage and the occupant compartment intrusion were explored, and suggest that 64% of the serious injuries are associated with increasing intrusion. Individual NASS cases were reviewed to gain a deeper understanding of the mechanical particulars in the between-rail crash. PMID:23169135

  19. Impact and injury patterns in between-rails frontal crashes of vehicles with good ratings for frontal crash protection.

    PubMed

    Morgan, Richard M; Cui, Chongzhen; Digges, Kennerly H; Cao, Libo; Kan, Cing-Dao Steve

    2012-01-01

    This research investigated (1) what are the key attributes of the between-rail, frontal crash, (2) what are the types of object contacted, and (3) what is the type of resulting trauma. The method was to study with both weighted and in-depth case reviews of NASS-CDS crash data with direct damage between the longitudinal rails in frontal crashes. Individual case selection was limited to belted occupants in between-rail, frontal impacts of good-rated, late-model vehicles equipped with air bags.This paper evaluates the risk of trauma for drivers in cars and LTVs in between-rail, frontal crashes, and suggests the between-rail impact is more dangerous to car drivers. Using weighted data-representing 227,305 tow-away crashes-the resulting trauma to various body regions was analyzed to suggest greatest injury is to the chest, pelvis/thigh/knee/leg, and foot/ankle. This study analyzed the type of object that caused the direct damage between the rails, including small tree or post, large tree or pole, and another vehicle; and found that the struck object was most often another vehicle or a large tree/pole. Both the extent of damage and the occupant compartment intrusion were explored, and suggest that 64% of the serious injuries are associated with increasing intrusion. Individual NASS cases were reviewed to gain a deeper understanding of the mechanical particulars in the between-rail crash.

  20. Diesel developments for rail traction

    SciTech Connect

    Albrecht, A.

    1995-03-01

    The latest developments in diesel rail traction systems are playing an important role in providing economical passenger transportation, especially in Europe. A new generation of diesel-hydraulic and diesel-electric traction systems - featuring reduced weight and using electronic control systems for easier operation, lower engine emissions and reduced fuel consumption - are being introduced into public and private railway networks worldwide. This paper reviews the specifications of diesel based locomotives and trains being currently supplied in Germany, China, Netherlands, Switzerland, and USA. 6 figs.

  1. Rail electrodynamics in a plasma armature railgun

    NASA Astrophysics Data System (ADS)

    Rolander, Glenn E.; Jamison, Keith A.; Villecco, Roger A.; Graham, Floyd R.

    1991-08-01

    Rail electrodynamics are investigated analytically by means of a model which relates rail motion to a transitory Lorentz force and the compressive restoration force. Local electric fields - generated by the magnetic field and the oscillation of the distance separating the rails - are examined to determine the extent of their influence on the laboratory frame and the projectile frame. When the projectile is accelerating, local voltage extremes are found to be related to the value of beta(t)p, with the maximums and minimums corresponding to even and odd multiples of pi, respectively. Based on these findings, rail displacements of about 2 mm are predicted for a railgun with a constant current of 2 MA. Certain criteria are proposed to minimize rail displacement and velocity and maximize the oscillation frequency. However, the model does not consider important effects such as deformation beyond the elastic regime.

  2. Damage mitigation in roll-to-roll transfer of CVD-graphene to flexible substrates

    NASA Astrophysics Data System (ADS)

    Jang, Bongkyun; Kim, Chang-Hyun; Choi, Seung Tae; Kim, Kyung-Shik; Kim, Kwang-Seop; Lee, Hak-Joo; Cho, Seungmin; Ahn, Jong-Hyun; Kim, Jae-Hyun

    2017-06-01

    Roll-to-roll (R2R) transfer of a chemical vapor deposition (CVD) graphene is an inevitable step for large scale and high throughput manufacturing of graphene transparent electrodes on flexible substrates. The damages on graphene induced by high contact pressure of nip rolls during the roll transfer degrade the electrical properties of the transferred graphene on flexible substrates. In this study, we developed a damage mitigation method for the roll transfer of graphene. By analyzing scanning electron microscope (SEM) images of the damages on the transferred graphene, three types of failure modes were classified, and the corresponding failure mechanisms were revealed using the surface morphology and the finite element analyses. Based on the understanding of the failure mechanisms, the graphene transfer with a width of 400 mm was realized at a speed of 1000 mm min-1 using an R2R transfer machine with the capability of nip force control. The high electrical conductivity and uniformity of the roll-transferred graphene demonstrates the scalability and the productivity of the developed roll transfer technology.

  3. Rail transportation of Fernald remediation waste

    SciTech Connect

    Fellman, R.T.; Lojek, D.A.; Motl, G.P.; Weddendorf, W.K.

    1995-01-24

    Remediation of the Department of Energy (DOE) Fernald site located north of Cincinnati will generate large quantities of low-level radwaste. This volume includes approximately 1,050,000 tons of material to be removed from eight waste pits comprising Operable Unit 1 (OU-1). The remedial alternative selected includes waste material excavation, drying and transportation by rail to a burial site in the arid west for disposal. Rail transportation was selected not only because rail transportation is safer than truck transportation, but also because of the sheer magnitude of the project and the availability of bulk rail car unloading facilities at a representative disposal site. Based upon current waste quantity estimates as presented in the Feasibility Study for OUI, a fully-loaded 47-car unit train would depart the Fernald site weekly for five years. This paper illustrates the steps taken to obtain agency and public acceptance of the Record of Decision for the remedy which hinged on rail transportation. A preliminary, but detailed, rail transportation plan was prepared for the project to support a series of CERCLA public meetings conducted in late 1994. Some of the major issues addressed in the plan included the following: (1) Scope of project leading to selection of rail transportation; (2) Waste classification; (3) Rail Company overview; (4) Train configuration and rail car selection; (5) Routing; (6) Safety; (7) Prior Notification Requirements (8) Emergency Response. A series of three public meetings identified a number of issues of prime concern to Fernald stakeholders. Following resolution of these issues during the public comment period, a Record of Decision (ROD) approving implementation of the rail transportation strategy was approved pending incorporation of EPA and State of Ohio comments on December 22, 1994.

  4. 78 FR 60658 - Airworthiness Directives; Rolls-Royce plc Turbofan Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-02

    ..., contact Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, England, DE248BJ; phone: 011-44.... (ii) None. (3) For service information identified in this AD, contact Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, England, DE248BJ; phone: 011-44-1332-242424; fax: 011-44-1332- 249936;...

  5. 78 FR 12255 - Airworthiness Directives; Rolls-Royce (1971) Limited, Bristol Engine Division Turbojet Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ...: (202) 493-2251. For service information identified in this AD, contact Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, England, DE248BJ; phone: 011-44-1332-242424; fax: 011-44-1332-249936; or... information. (3) For service information identified in this AD, contact Rolls-Royce plc,...

  6. Analysis of structure and phase composition of rails subjected to differential hardening at different regimes

    SciTech Connect

    Gromov, V. E. Morozov, K. V. Konovalov, S. V.; Alsaraeva, K. V.; Semina, O. A.; Ivanov, Yu. F.; Volkov, K. V.

    2014-11-14

    Differential hardening of rails by compressed air in different regimes is accompanied by formation of morphologically different structure, being formed according to the diffusion mechanism of γ↔α transformation and consisting of grains of lamellar pearlite, free ferrite and grains of ferrite-carbide mixture. By methods of transmission electron microscopy the layer by layer analysis of differentially hardened rails has been carried out, the quantitative parameters of the structure, phase composition and dislocation substructure have been established and their comparison has been made for different regimes of hardening. It has been found that the structure-phase states being formed have gradient character, defined by the hardening regime, direction of study from the surface of rolling and by depth of location of layer under study.

  7. Understanding Rolle's Theorem

    ERIC Educational Resources Information Center

    Parameswaran, Revathy

    2009-01-01

    This paper reports on an experiment studying twelfth grade students' understanding of Rolle's Theorem. In particular, we study the influence of different concept images that students employ when solving reasoning tasks related to Rolle's Theorem. We argue that students' "container schema" and "motion schema" allow for rich…

  8. 76 FR 55335 - Alternate Passenger Rail Service Pilot Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-07

    ... that own infrastructure over which Amtrak operates certain passenger rail service routes to petition FRA to be considered as a passenger rail service provider over such a route in lieu of Amtrak for a... develop a pilot program that permits a rail carrier or rail carriers that own infrastructure over...

  9. 46 CFR 190.25-10 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  10. 46 CFR 72.40-10 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...

  11. 46 CFR 92.25-10 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Storm rails. 92.25-10 Section 92.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 92.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  12. 49 CFR 213.352 - Torch cut rail.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  13. 49 CFR 213.352 - Torch cut rail.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  14. 49 CFR 213.352 - Torch cut rail.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  15. 49 CFR 213.352 - Torch cut rail.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  16. 49 CFR 213.352 - Torch cut rail.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Torch cut rail. 213.352 Section 213.352... Torch cut rail. (a) Except as a temporary repair in emergency situations no rail having a torch cut end shall be used. When a rail end with a torch cut is used in emergency situations, train speed over that...

  17. 49 CFR 1580.201 - Rail security coordinator.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SECURITY Passenger Rail Including Passenger Railroad Carriers, Rail Transit Systems, Tourist, Scenic... rail or heavy rail transit service on track that is part of the general railroad system of...), and each public authority operating passenger train service. (2) Each passenger railroad carrier...

  18. 49 CFR 1580.201 - Rail security coordinator.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SECURITY Passenger Rail Including Passenger Railroad Carriers, Rail Transit Systems, Tourist, Scenic... rail or heavy rail transit service on track that is part of the general railroad system of...), and each public authority operating passenger train service. (2) Each passenger railroad carrier...

  19. 49 CFR 1580.201 - Rail security coordinator.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SECURITY Passenger Rail Including Passenger Railroad Carriers, Rail Transit Systems, Tourist, Scenic... rail or heavy rail transit service on track that is part of the general railroad system of...), and each public authority operating passenger train service. (2) Each passenger railroad carrier...

  20. 49 CFR 229.79 - Third rail shoes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Third rail shoes. 229.79 Section 229.79....79 Third rail shoes. When locomotives are equipped with both third rail and overhead collectors, third-rail shoes shall be deenergized while in yards and at stations when current collection...

  1. 49 CFR 229.79 - Third rail shoes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Third rail shoes. 229.79 Section 229.79....79 Third rail shoes. When locomotives are equipped with both third rail and overhead collectors, third-rail shoes shall be deenergized while in yards and at stations when current collection...

  2. 49 CFR 229.79 - Third rail shoes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Third rail shoes. 229.79 Section 229.79....79 Third rail shoes. When locomotives are equipped with both third rail and overhead collectors, third-rail shoes shall be deenergized while in yards and at stations when current collection...

  3. 49 CFR 229.79 - Third rail shoes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Third rail shoes. 229.79 Section 229.79....79 Third rail shoes. When locomotives are equipped with both third rail and overhead collectors, third-rail shoes shall be deenergized while in yards and at stations when current collection...

  4. 49 CFR 229.79 - Third rail shoes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Third rail shoes. 229.79 Section 229.79....79 Third rail shoes. When locomotives are equipped with both third rail and overhead collectors, third-rail shoes shall be deenergized while in yards and at stations when current collection...

  5. 46 CFR 190.25-10 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  6. 46 CFR 190.25-10 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  7. 46 CFR 72.40-10 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...

  8. 46 CFR 72.40-10 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...

  9. 46 CFR 92.25-10 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Storm rails. 92.25-10 Section 92.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 92.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  10. 46 CFR 190.25-10 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  11. 46 CFR 92.25-10 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Storm rails. 92.25-10 Section 92.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 92.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  12. 46 CFR 92.25-10 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Storm rails. 92.25-10 Section 92.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 92.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  13. 46 CFR 72.40-10 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...

  14. 46 CFR 72.40-10 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...

  15. 46 CFR 92.25-10 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Storm rails. 92.25-10 Section 92.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 92.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  16. 46 CFR 190.25-10 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Storm rails. 190.25-10 Section 190.25-10 Shipping COAST... ARRANGEMENT Rails and Guards § 190.25-10 Storm rails. (a) On vessels in ocean and coastwise service, suitable storm rails shall be installed in all passageways and at the deckhouse sides where persons on board...

  17. 49 CFR 234.235 - Insulated rail joints.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Insulated rail joints. 234.235 Section 234.235 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Insulated rail joints. Each insulated rail joint used to separate train detection circuits of a highway-rail...

  18. 49 CFR 234.235 - Insulated rail joints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Insulated rail joints. 234.235 Section 234.235 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Insulated rail joints. Each insulated rail joint used to separate train detection circuits of a highway-rail...

  19. Effect of Flaw Removal on Billets in Rolling

    NASA Astrophysics Data System (ADS)

    Yoshida, Kazunari; Shinohara, Tetsuo

    2007-05-01

    High-quality wires, which are used for components such as valve springs of automobiles, are fabricated by rolling and drawing. Even a minute flaw on the surface of the wire leads to a significant decrease in fatigue strength. It is possible to decrease the number of surface flaws during some of the rolling processes; however in most cases, it is difficult to remove flaws. Under such circumstances, high-quality wires are fabricated, at many wire manufacturing factories, by rolling and drawing after removing surface flaws on the raw material. However, the flaw removal process is carried out relying on the experience of onsite workers; many of the mechanisms underlying flaw removal have not been clarified. In this study, billet and wire that have traces formed during flaw removal were subjected to rolling to investigate the behavior of deformation and the recovery of the flaw-removal traces. When flaw-removal traces exist on a billet surface that comes into contact with the roll used in rolling, the traces are removed without difficulty. However, when the flaw-removal traces exist on a surface that does not come into contact with the roll, the traces tend to become wrinkles due to compression from the upper and lower directions. Therefore, when removing the surface flaw on billet before rolling, it is important to remove flaw part thinly.

  20. A rational fraction polynomials model to study vertical dynamic wheel-rail interaction

    NASA Astrophysics Data System (ADS)

    Correa, N.; Vadillo, E. G.; Santamaria, J.; Gómez, J.

    2012-04-01

    This paper presents a model designed to study vertical interactions between wheel and rail when the wheel moves over a rail welding. The model focuses on the spatial domain, and is drawn up in a simple fashion from track receptances. The paper obtains the receptances from a full track model in the frequency domain already developed by the authors, which includes deformation of the rail section and propagation of bending, elongation and torsional waves along an infinite track. Transformation between domains was secured by applying a modified rational fraction polynomials method. This obtains a track model with very few degrees of freedom, and thus with minimum time consumption for integration, with a good match to the original model over a sufficiently broad range of frequencies. Wheel-rail interaction is modelled on a non-linear Hertzian spring, and consideration is given to parametric excitation caused by the wheel moving over a sleeper, since this is a moving wheel model and not a moving irregularity model. The model is used to study the dynamic loads and displacements emerging at the wheel-rail contact passing over a welding defect at different speeds.

  1. Phased-Array Method for the Ut-Inspection of French Rail Repairs

    NASA Astrophysics Data System (ADS)

    Brédif, P.; Plu, J.; Pouligny, P.; Poidevin, C.

    2008-02-01

    The SNCF (French National Railways) is repairing rails that have suffered surface damage. Gas inclusions present in repairs may induce cracking, which could affect the rail integrity. This paper presents a NDT phased-array method developed to detect and characterize small gas inclusions in the bulk of the repair. The method is based on the implementation of a contact phased-array transducer associated with a specific processing. The transducer is articulated to conform as much as possible to the nominal rail section. The use of a phased-array probe allows limitation of mechanical displacements to only one axis (along the longitudinal plane of the rail). Inspection in the plane perpendicular to the axis of the rail is performed through electronic commutation and beam steering. The data analysis is done using CIVA-Software. A processing based on ultrasonic field computation was developed. The method was experimentally assessed on real repairs in laboratory conditions. Experiments proved the capability of the method to detect, locate and categorize gas inclusions according to several ranges of size.

  2. ORNL RAIL & BARGE DB. Network Database

    SciTech Connect

    Johnson, P.

    1991-07-01

    The Oak Ridge National Laboratory (ORNL) Rail and Barge Network Database is a representation of the rail and barge system of the United States. The network is derived from the Federal Rail Administration (FRA) rail database. The database consists of 96 subnetworks. Each of the subnetworks represent an individual railroad, a waterway system, or a composite group of small railroads. Two subnetworks represent waterways; one being barge/intercoastal, and the other coastal merchant marine with access through the Great Lakes/Saint Lawrence Seaway, Atlantic and Gulf Coasts, the Panama Canal, and Pacific Coast. Two other subnetworks represent small shortline railroads and terminal railroad operations. One subnetwork is maintained for the representation of Amtrak operations. The remaining 91 subnetworks represent individual or corporate groups of railroads. Coordinate locations are included as part of the database. The rail portion of the database is similar to the original FRA rail network. The waterway coordinates are greatly enhanced in the current release. Inland waterway representation was extracted from the 1:2,000,000 United States Geological Survey data. An important aspect of the database is the transfer file. This file identifies where two railroads interline traffic between their systems. Also included are locations where rail/waterway intermodal transfers could occur. Other files in the database include a translation table between Association of American Railroad (AAR) codes to the 96 subnetworks in the database, a list of names of the 96 subnetworks, and a file of names for a large proportion of the nodes in the network.

  3. ORNL RAIL & BARGE DB. Network Database

    SciTech Connect

    Johnson, P.

    1992-03-16

    The Oak Ridge National Laboratory (ORNL) Rail and Barge Network Database is a representation of the rail and barge system of the United States. The network is derived from the Federal Rail Administration (FRA) rail database. The database consists of 96 subnetworks. Each of the subnetworks represent an individual railroad, a waterway system, or a composite group of small railroads. Two subnetworks represent waterways; one being barge/intercoastal, and the other coastal merchant marine with access through the Great Lakes/Saint Lawrence Seaway, Atlantic and Gulf Coasts, the Panama Canal, and Pacific Coast. Two other subnetworks represent small shortline railroads and terminal railroad operations. One subnetwork is maintained for the representation of Amtrak operations. The remaining 91 subnetworks represent individual or corporate groups of railroads. Coordinate locations are included as part of the database. The rail portion of the database is similar to the original FRA rail network. The waterway coordinates are greatly enhanced in the current release. Inland waterway representation was extracted from the 1:2,000,000 United States Geological Survey data. An important aspect of the database is the transfer file. This file identifies where two railroads interline traffic between their systems. Also included are locations where rail/waterway intermodal transfers could occur. Other files in the database include a translation table between Association of American Railroad (AAR) codes to the 96 subnetworks in the database, a list of names of the 96 subnetworks, and a file of names for a large proportion of the nodes in the network.

  4. 49 CFR 37.83 - Remanufacture of rail vehicles and purchase or lease of remanufactured rail vehicles by public...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... lease of remanufactured rail vehicles by public entities operating rapid or light rail systems. 37.83... operating rapid or light rail systems. (a) This section applies to any public entity operating a rapid or... operates a rapid or light rail system any segment of which is included on the National Register of Historic...

  5. 49 CFR 37.83 - Remanufacture of rail vehicles and purchase or lease of remanufactured rail vehicles by public...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... lease of remanufactured rail vehicles by public entities operating rapid or light rail systems. 37.83... operating rapid or light rail systems. (a) This section applies to any public entity operating a rapid or... operates a rapid or light rail system any segment of which is included on the National Register of Historic...

  6. Electromagnetic acceleration studies with augmented rails

    SciTech Connect

    Maruo, T.; Fujioka, K.; Nagaoka, K.; Okamoto, A.; Ikuta, K.; Nemoto, K. )

    1991-01-01

    A comparative study of electromagnetic acceleration in the rail-type accelerators with two kinds of rail geometry was carried out experimentally. The accelerators were energized by 200kJ capacitor bank and the weight of loaded projectiles was about 1.3 grams with 10mm {times} 10mm square bore. The attained velocity was 4.3km/s in the augmented accelerator, while it was 3.8km/s in the classical device. In this paper these differences in attained velocity are briefly discussed. A theoretical understanding of the rail erosion is also described.

  7. 76 FR 65941 - Airworthiness Directives; Rolls-Royce plc RB211-524 Series, RB211-Trent 700 Series, and RB211...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-25

    ... Corporate Communications at Rolls-Royce plc, PO Box 31, Derby, DE24 8BJ, United Kingdom, phone: 011-44-1331... including. We changed paragraph (k) of the AD to state ``* * * contact Corporate Communications at Rolls... service information identified in this AD, contact Corporate Communications at Rolls-Royce plc, PO Box...

  8. Ruby on Rails Issue Tracker

    NASA Technical Reports Server (NTRS)

    Rodriguez, Juan Jared

    2014-01-01

    The purpose of this report is to detail the tasks accomplished as a NASA NIFS intern for the summer 2014 session. This internship opportunity is to develop an issue tracker Ruby on Rails web application to improve the communication of developmental anomalies between the Support Software Computer Software Configuration Item (CSCI) teams, System Build and Information Architecture. As many may know software development is an arduous, time consuming, collaborative effort. It involves nearly as much work designing, planning, collaborating, discussing, and resolving issues as effort expended in actual development. This internship opportunity was put in place to help alleviate the amount of time spent discussing issues such as bugs, missing tests, new requirements, and usability concerns that arise during development and throughout the life cycle of software applications once in production.

  9. Effect of Roll Material on Surface Quality of Rolled Aluminum

    NASA Astrophysics Data System (ADS)

    Zhao, Qi

    The surface defects of aluminum alloys that have undergone hot rolling were studied. The effects of different roll materials, of the number of rolling passes and of lubrication on surface defects of hot rolled aluminum alloys were investigated by laboratory hot rolling. Two different aluminum alloys, Al-Mn and Al-Mg, were each rolled against three different steel alloy rolls, AISI 52100, AISI 440C and AISI D2. The results showed that different roll materials do affect the morphology of the mating aluminum alloy surface with apparent surface defects, which included magnesium and oxygen rich dark regions on both alloys. The carbide protrusions in 440C and D2 steel rolls are confirmed to be responsible for the dark, rich magnesium and oxygen regions on both the rolled Al-Mn and Al-Mg alloy surfaces. As the number of passes increases, Mg and O deposit in the form of patches and grain boundaries near the surface area.

  10. Contact dermatitis

    MedlinePlus

    Dermatitis - contact; Allergic dermatitis; Dermatitis - allergic; Irritant contact dermatitis; Skin rash - contact dermatitis ... There are 2 types of contact dermatitis. Irritant dermatitis: This ... can be by contact with acids, alkaline materials such as soaps ...

  11. Laser direct write system for fabricating seamless roll-to-roll lithography tools

    NASA Astrophysics Data System (ADS)

    Petrzelka, Joseph E.; Hardt, David E.

    2013-03-01

    Implementations of roll to roll contact lithography require new approaches towards manufacturing tooling, including stamps for roll to roll nanoimprint lithography (NIL) and soft lithography. Suitable roll based tools must have seamless micro- or nano-scale patterns and must be scalable to roll widths of one meter. The authors have developed a new centrifugal stamp casting process that can produce uniform cylindrical polymer stamps in a scalable manner. The pattern on the resulting polymer tool is replicated against a corresponding master pattern on the inner diameter of a centrifuge drum. This master pattern is created in photoresist using a UV laser direct write system. This paper discusses the design and implementation of a laser direct write system targeting the internal diameter of a rotating drum. The design uses flying optics to focus a laser beam along the axis of the centrifuge drum and to redirect the beam towards the drum surface. Experimental patterning results show uniform coatings of negative photoresist in the centrifuge drum that are effectively patterned with a 405 nm laser diode. Seamless patterns are shown to be replicated in a 50 mm diameter, 60 mm long cylindrical stamp made from polydimethylsiloxane (PDMS). Direct write results show gratings with line widths of 10 microns in negative photoresist. Using an FPGA, the laser can be accurately timed against the centrifuge encoder to create complex patterns.

  12. Rail human factors: Past, present and future.

    PubMed

    Wilson, John R; Norris, Beverley J

    2005-11-01

    Rail human factors research has grown rapidly in both quantity and quality of output over the past few years. There was an early base of work at a few institutions carried out over the 1960s and 1970s, followed by a lull in the 1980s and early 1990s. The continual influences of safety concerns, new technical system opportunities, reorganisation of the business, needs to increase effective, reliable and safe use of capacity, and increased society, media and government interest have now accelerated rail human factors research programmes in several countries. In this paper we review the literature on rail human factors research, covering driving, signalling and control, maintenance, reporting systems, passenger interests, planning and technical systems change. Current major rail human factors programmes are summarised and future research needs proposed. It is asserted that general human factors models and methods are being re-assessed, and new ones developed, to meet the requirements of the railways.

  13. Arc-driven rail gun research

    NASA Technical Reports Server (NTRS)

    Ray, P. K.

    1984-01-01

    The equations describing the performance of an inductively-driven rail gun are analyzed numerically. Friction between the projectile and rails is included through an empirical formulation. The equations are applied to the experiment of Rashleigh and Marshall to obtain an estimate of energy distribution in rail guns as a function of time. The effect of frictional heat dissipation on the bore of the gun is calculated. The mechanism of plasma and projectile acceleration in a dc rail gun is described from a microscopic point of view through the establishment of the Hall field. The plasma conductivity is shown to be a tensor indicating that there is a small component of current parallel to the direction of acceleration. The plasma characteristics are evaluated as a function of plasma mass through a simple fluid mechanical analysis of the plasma. By equating the energy dissipated in the plasma with the radiation heat loss, the properties of the plasma are determined.

  14. Electron emission at the rail surface

    SciTech Connect

    Thornhill, L.; Battech, J. )

    1991-01-01

    In this paper the authors examine the processes by which current is transferred from the cathode rail to the plasma armature in an arc-driven railgun. Three electron emission mechanisms are considered, namely thermionic emission, field-enhanced thermionic emission (or Schottky emission), and photoemission. The author's calculations show that the dominant electron emission mechanism depends, to a great extent, on the work function of the rail surface, the rail surface temperature, the electric field at the rail surface, and the effective radiation temperature of the plasma. For conditions that are considered to be typical of a railgun armature, Schottky emission is the dominant electron emission mechanism, providing current densities on the order of 10{sup 9} A/m{sup 2}.

  15. The electric rail gun for space propulsion

    NASA Technical Reports Server (NTRS)

    Bauer, D. P.; Barber, J. P.; Vahlberg, C. J.

    1981-01-01

    An analytic feasibility investigation of an electric propulsion concept for space application is described. In this concept, quasistatic thrust due to inertial reaction to repetitively accelerated pellets by an electric rail gun is used to propel a spacecraft. The study encompasses the major subsystems required in an electric rail gun propulsion system. The mass, performance, and configuration of each subsystem are described. Based on an analytic model of the system mass and performance, the electric rail gun mission performance as a reusable orbital transfer vehicle (OTV) is analyzed and compared to a 30 cm ion thruster system (BIMOD) and a chemical propulsion system (IUS) for payloads with masses of 1150 kg and 2300 kg. For system power levels in the range from 25 kW(e) to 100 kW(e) an electric rail gun OTV is more attractive than a BIMOD system for low Earth orbit to geosynchronous orbit transfer durations in the range from 20 to 120 days.

  16. Natural history of the King Rail

    USGS Publications Warehouse

    Meanley, Brooke

    1969-01-01

    The King Rail (Rallus elegans Audubon), largest of North American rails, is indeed an elegant bird, as its Latin name implies. Its striking appearance (fig. I), secretive nature, and association with a variety of wetland habitats make it a favorite of bird students and rail hunters. The King Rail is found in most of the eastern half of North America, from the Atlantic coast to the Great Plains and from the Gulf of Mexico to southern Canada. It is most abundant in the fresh and brackish tidal marshes of the Atlantic and Gulf Coastal Plain, the domestic ricefields of Arkansas, Louisiana, and Texas, and the marshes of southern Florida. It is fairly common in parts of the Midwest Prairie and Great Lakes region.I began my studies of this interesting bird in 1950 in the Arkansas ricefields, and have continued them until 1967, both in the field and in the laboratory.

  17. Thermal analysis of electromagnetic launcher rails

    SciTech Connect

    Schnurr, N.M.

    1987-10-01

    A numerical technique has been developed to analyze the combined thermal and electric field diffusion in electromagnetic launcher rails. TOPAZ2D, a two-dimensional finite-element thermal analysis code, has been adapted for this purpose. The resulting code, TOPAZRG, was used to predict the temperature field in the rails of the Lethality Test System being constructed at Los Alamos. Results of those calculations indicate the possibility of localized melting at the rail corners under full-power conditions. A parametric study was made to determine the effect of using tungsten coatings to prevent the melting of rail surfaces. The results of those computations show that the time to melt for a given surface heat flux can be increased by a factor of 2.8. Optimum coating thicknesses were determined for a range of heat fluxes. 11 refs.

  18. Exceptional transport property in a rolled-up germanium tube

    NASA Astrophysics Data System (ADS)

    Guo, Qinglei; Wang, Gang; Chen, Da; Li, Gongjin; Huang, Gaoshan; Zhang, Miao; Wang, Xi; Mei, Yongfeng; Di, Zengfeng

    2017-03-01

    Tubular germanium (Ge) resistors are demonstrated by rolling-up thin Ge nanomembranes (NMs, 50 nm in thickness) with electrical contacts. The strain distribution of rolled-up Ge microtubes along the radial direction is investigated and predicted by utilizing micro-Raman scattering spectroscopy with two different excitation lasers. Electrical properties are characterized for both unreleased GeNMs and released/rolled-up Ge microtubes. The conductivities of GeNMs significantly decrease after rolling-up into tubular structures, which can be attributed to surface charging states on the conductance, band bending, and piezo-resistance effect. When illuminated with a light source, facilitated by the suppressed dark current of rolled-up Ge tubes, the corresponding signal-to-noise ratio can be dramatically enhanced compared with that of planar GeNMs.

  19. Analysis of Strip Profile in Flat Rolling by the Finite Element Method

    NASA Astrophysics Data System (ADS)

    Kim, T. H.; Lee, W. H.; Hwang, S. M.

    2004-06-01

    A full, finite element (FE)-based approach is presented for the precision analysis of the strip profile in flat rolling. Basic FE models for the analysis of the mechanical behavior of the strip and of the rolls are described in detail. Also described is an iterative strategy for a rigorous treatment of the mechanical contact occurring at the roll-strip interface and at the roll-roll interface. Then, presented is an integrated FE process model for the coupled analysis of the mechanical behavior of the strip, work roll, and backup roll in four-high mill. A series of process simulation are conducted and the results are compared with the measurements made in hot and cold rolling experiments.

  20. 75 FR 63727 - Airworthiness Directives; Rolls-Royce plc (RR) RB211-524 Series Turbofan Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-18

    ... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Rolls-Royce plc (RR...-2251. Contact Rolls-Royce plc, P.O. Box 31, Derby, DE24 8BJ, United Kingdom; telephone: 011-44-1332...: Rolls-Royce plc: Docket No. FAA-2009-0162; Directorate Identifier 2004-NE-19-AD. Comments Due Date...

  1. 75 FR 801 - Airworthiness Directives; Rolls-Royce plc RB211-Trent 500, 700, and 800 Series Turbofan Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-06

    ... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Rolls-Royce plc... airworthiness directive (AD) for Rolls-Royce plc RB211-Trent 800 series turbofan engines. That AD currently... through Friday, except Federal holidays. Fax: (202) 493-2251. Contact Rolls-Royce plc, P.O. Box 31,...

  2. 76 FR 72650 - Airworthiness Directives; Rolls-Royce plc (RR) RB211 Trent 800 Series Turbofan Engines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-25

    ... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Rolls-Royce plc (RR.... Fax: (202) 493-2251. Contact Rolls-Royce plc, P.O. Box 31, Derby, DE24 8BJ, United Kingdom; phone: 011... airplane. Relevant Service Information Rolls-Royce plc has issued Alert Service Bulletin...

  3. Sexing California Clapper Rails using morphological measurements

    USGS Publications Warehouse

    Overton, Cory T.; Casazza, Michael L.; Takekawa, John Y.; Rohmer, Tobias M.

    2009-01-01

    California Clapper Rails (Rallus longirostris obsoletus) have monomorphic plumage, a trait that makes identification of sex difficult without extensive behavioral observation or genetic testing. Using 31 Clapper Rails (22 females, 9 males), caught in south San Francisco Bay, CA, and using easily measurable morphological characteristics, we developed a discriminant function to distinguish sex. We then validated this function on 33 additional rails. Seven morphological measurements were considered, resulting in three which were selected in the discriminate function: culmen length, tarsometatarsus length, and flat wing length. We had no classification errors for the development or testing datasets either with resubstitution or cross-validation procedures. Male California Clapper Rails were 6-22% larger than females for individual morphological traits, and the largest difference was in body mass.  Variables in our discriminant function closely match variables developed for sexing Clapper Rails of Gulf Coast populations. However, a universal discriminant function to sex all Clapper Rail subspecies is not likely because of large and inconsistent differences in morphological traits among subspecies. 

  4. Rail profile control using laser triangulation scanners

    NASA Astrophysics Data System (ADS)

    Boronahin, Ð. ńlexandr M.; Larionov, Daniil Yu.; Podgornaya, Liudmila N.; Shalymov, Roman V.; Filatov, Yuri V.; Bokhman, Evgueny D.

    2016-11-01

    Rail track geometric parameters measurement requires knowledge of left and right rail head location in each section. First of all displacement in transverse plane of rail head point located at a distance of 14 mm below the running surface, must be controlled [1]. It is carried out by detecting of each rail profile using triangulation laser scanners. Optical image recognition is carried out successfully in the laboratory, approaches used for this purpose are widely known. However, laser scanners operation has several features on railways leading to necessity of traditional approaches adaptation for solving these particular problems. The most significant problem is images noisiness due to the solar flashes and the effect of "Moon path" on the smooth rail surface. Using of optical filters gives inadequate result, because scanner laser diodes radiation frequency varies with temperature changes that forbid the use of narrow-band filters. Consideration of these features requires additional constructive and algorithmic solutions, including involvement of information from other sensors of the system. The specific usage of optical scanners for rail profiles control is the subject of the paper.

  5. The rail abandonment process: A southern perspective

    SciTech Connect

    Not Available

    1988-12-01

    One factor in evaluating the desirability of rail transport for high-level radioactive wastes or spent fuels is the frequency, or lack thereof, with which railroad and railroad lines have been, and are, abandoned. If DOE makes a decision to use the rail option and a line is subsequently abandoned, the choice results in increased cost, time delays and possibly safety problems: Information is therefore needed prior to the decision-making process to evaluate the desirability of the rail shipping option. One result of the abandonments mentioned herein, as well as other later abandonments, is the creation of a US rail system undergoing an evolutionary process in the 1980s as far-reaching as the changes that occurred when the industry was in its infancy a century and-a-half ago. The purpose of this paper is to examine the factors leading to some of these changes by tracing the historical development of the rail abandonment process, with particular emphasis on the rise of regional railroads, their problems in the modern era and current trends in rail abandonments as well as their effects on the southeastern United States.

  6. Biomechanics of leukocyte rolling

    PubMed Central

    Sundd, Prithu; Pospieszalska, Maria K.; Cheung, Luthur Siu-Lun; Konstantopoulos, Konstantinos; Ley, Klaus

    2011-01-01

    Leukocyte rolling on endothelial cells and other P-selectin substrates is mediated by P-selectin binding to P-selectin glycoprotein ligand-1 expressed on the tips of leukocyte microvilli. Leukocyte rolling is a result of rapid, yet balanced formation and dissociation of selectin-ligand bonds in the presence of hydrodynamic shear forces. The hydrodynamic forces acting on the bonds may either increase (catch bonds) or decrease (slip-bonds) their lifetimes. The force-dependent ‘catch-slip’ bond kinetics are explained using the ‘two pathway model’ for bond dissociation. Both the ‘sliding-rebinding’ and the ‘allosteric’ mechanisms attribute ‘catch-slip’ bond behavior to the force-induced conformational changes in the lectin-EGF domain hinge of selectins. Below a threshold shear stress, selectins cannot mediate rolling. This ‘shear-threshold’ phenomenon is a consequence of shear-enhanced tethering and catch-bond enhanced rolling. Quantitative dynamic footprinting microscopy has revealed that leukocytes rolling at venular shear stresses (> 0.6 Pa) undergo cellular deformation (large footprint) and form long tethers. The hydrodynamic shear force and torque acting on the rolling cell are thought to be synergistically balanced by the forces acting on tethers and stressed microvilli, however, their relative contribution remains to be determined. Thus, improvement beyond the current understanding requires in silico models that can predict both cellular and microvillus deformation and experiments that allow measurement of forces acting on individual microvilli and tethers. PMID:21515934

  7. Rolling the "Black Pearl" over: Analyzing the Physics of a Movie Clip

    ERIC Educational Resources Information Center

    Mungan, Carl E.; Emery, John D.

    2011-01-01

    In the third movie ("At World's End") in the "Pirates of the Caribbean" series, Jack Sparrow and his crew need to roll their ship (the "Black Pearl") over in order to bring it back to the living world during a green flash at sunset. They do so by running back and forth from one side railing to the other on the top deck. In addition, Captain…

  8. Experiments on composites meant for making brake pads for the rolling stock

    NASA Astrophysics Data System (ADS)

    Socalici, A.; Pascu, L.; Ardelean, E.; Putan, V.

    2017-01-01

    For noise rail decrease and observance of the limits in UE rolling stock must be equipped with silent brake blocks of composite material to replace the conventional cast-iron blocks. For testing composite materials test pieces have been produced according to the characteristics of the experimental installation. The paper presents the laboratory experimentation phase on obtaining composite materials for brake blocks and wear behavior of the experimental test pieces.

  9. Rolling the "Black Pearl" over: Analyzing the Physics of a Movie Clip

    ERIC Educational Resources Information Center

    Mungan, Carl E.; Emery, John D.

    2011-01-01

    In the third movie ("At World's End") in the "Pirates of the Caribbean" series, Jack Sparrow and his crew need to roll their ship (the "Black Pearl") over in order to bring it back to the living world during a green flash at sunset. They do so by running back and forth from one side railing to the other on the top deck. In addition, Captain…

  10. 75 FR 76520 - Tennessee Southern Railroad Company, Patriot Rail, LLC, Patriot Rail Holdings LLC, and Patriot...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-08

    ... (PRL) and its subsidiaries, Patriot Rail Holdings LLC (PRH) and Patriot Rail Corp. (Patriot... within a corporate family. PRL proposes to restructure its corporate family by converting two of its...) will become Piedmont & Northern Railway, LLC (PNRLLC). PRL directly controls noncarrier PRH, which...

  11. Spray Rolling Aluminum Strip

    SciTech Connect

    Lavernia, E.J.; Delplanque, J-P; McHugh, K.M.

    2006-05-10

    Spray forming is a competitive low-cost alternative to ingot metallurgy for manufacturing ferrous and non-ferrous alloy shapes. It produces materials with a reduced number of processing steps, while maintaining materials properties, with the possibility of near-net-shape manufacturing. However, there are several hurdles to large-scale commercial adoption of spray forming: 1) ensuring strip is consistently flat, 2) eliminating porosity, particularly at the deposit/substrate interface, and 3) improving material yield. Through this program, a new strip/sheet casting process, termed spray rolling, has been developed, which is an innovative manufacturing technique to produce aluminum net-shape products. Spray rolling combines the benefits of twin-roll casting and conventional spray forming, showing a promising potential to overcome the above hurdles associated with spray forming. Spray rolling requires less energy and generates less scrap than conventional processes and, consequently, enables the development of materials with lower environmental impacts in both processing and final products. Spray Rolling was developed as a collaborative project between the University of California-Davis, the Colorado School of Mines, the Idaho National Engineering and Environmental Laboratory, and an industry team. The following objectives of this project were achieved: (1) Demonstration of the feasibility of the spray rolling process at the bench-scale level and evaluation of the materials properties of spray rolled aluminum strip alloys; and (2) Demonstration of 2X scalability of the process and documentation of technical hurdles to further scale up and initiate technology transfer to industry for eventual commercialization of the process.

  12. Adaptation of model parameters of a rail model at measured rail compliances

    NASA Astrophysics Data System (ADS)

    Ripke, B.

    1992-01-01

    A method for calculation of unknown parameters of a rail model is presented. Measurements were carried out on a test rail of a locomotive factory by means of pulse excitation. Accelerations of the rail head in the vertical and laterial directions were measured with an accelerometer and dilatations were measured as a function of rail flexion with a piezo film. Input and transfer compliances were measured. The obtained data were controlled by means of a fast Fourier transformation analyzer and recorded on magnetic tapes. A model was developed with the finite element method by considering the rail as a Timoshinko beam. Stiffness and damping of bulkhead and tiebar were obtained. A variable threshold mass was introduced for model adaptation to the experiment results in low frequency area.

  13. Wheel-Sleeper Impact Model in Rail Vehicles Analysis

    NASA Astrophysics Data System (ADS)

    Brabie, Dan

    The current paper establishes the necessary prerequisites for studying post-derailment dynamic behavior of high-speed rail vehicles by means of multi-body system (MBS) software. A finite-element (FE) model of one rail vehicle wheel impacting a limited concrete sleeper volume is built in LS-DYNA. A novel simulation scheme is employed for obtaining the necessary wheel-sleeper impact data, transferred to the MBS code as pre-defined look-up tables of the wheel's impulse variation during impact. The FE model is tentatively validated successfully by comparing the indentation marks with one photograph from an authentic derailment for a continuous impact sequence over three subsequent sleepers. A post-derailment module is developed and implemented in the MBS simulation tool GENSYS, which detects the wheel contact with sleepers and applies valid longitudinal, lateral and vertical force resultants based on the existing impact conditions. The accuracy of the MBS code in terms of the wheels three-dimensional trajectory over 24 consecutive sleepers is successfully compared with its FE counterpart for an arbitrary impact scenario. An axle mounted brake disc is tested as an alternative substitute guidance mechanism after flange climbing derailments at 100 and 200 km/h on the Swedish high-speed tilting train X 2000. Certain combinations of brake disc geometrical parameters manage to stop the lateral deviation of the wheelsets in circular curve sections at high lateral track plane acceleration.

  14. Health monitoring of light-rail aerial-structural system

    NASA Astrophysics Data System (ADS)

    Yuan, Robert L.; Bourland, Mark; Ugarte, Eduardo

    2002-06-01

    This paper describes health monitoring of concrete aerial structures for a light-rail train system. The purpose of the study is to perform structural diagnostics and in-situ inspection for 8 line sections under various climate conditions, and with incremental static loading during construction, and dynamic loading due to moving trains. The field diagnostics include instrumentation on piers, pier caps, bridge girders and decks with electrical strain gages and tilt meters. Initial gage-installation efforts are focused on in-situ temperature developed in bridge decks and rail pads. Some tilt plates are installed early prior to deck construction on piers and beams to study the effects of deck placement such as changes in camber and pier rotation. Temperature gages to measure surface temperatures are installed next to every gage type. A non-contact infrared sensor is also being used to measure surface temperature. Air and wet bulb temperature are recorded with other measurements along with time and weather conditions. At this time, the in-situ temperature gages provide two datums: information about cement heat of hydration, and information about diurnal deck temperatures. Tilt-meter measurements record de-camber of pre-stressed concrete I-beams. Graphs of these measurements show miscellaneous events such as beam replacements on pads, pouring of decks, diaphragms, etc. Material properties and structural behavior are discussed for several aerial structural components.

  15. Rail-dbGaP: analyzing dbGaP-protected data in the cloud with Amazon Elastic MapReduce

    PubMed Central

    Nellore, Abhinav; Wilks, Christopher; Hansen, Kasper D.; Leek, Jeffrey T.; Langmead, Ben

    2016-01-01

    Motivation: Public archives contain thousands of trillions of bases of valuable sequencing data. More than 40% of the Sequence Read Archive is human data protected by provisions such as dbGaP. To analyse dbGaP-protected data, researchers must typically work with IT administrators and signing officials to ensure all levels of security are implemented at their institution. This is a major obstacle, impeding reproducibility and reducing the utility of archived data. Results: We present a protocol and software tool for analyzing protected data in a commercial cloud. The protocol, Rail-dbGaP, is applicable to any tool running on Amazon Web Services Elastic MapReduce. The tool, Rail-RNA v0.2, is a spliced aligner for RNA-seq data, which we demonstrate by running on 9662 samples from the dbGaP-protected GTEx consortium dataset. The Rail-dbGaP protocol makes explicit for the first time the steps an investigator must take to develop Elastic MapReduce pipelines that analyse dbGaP-protected data in a manner compliant with NIH guidelines. Rail-RNA automates implementation of the protocol, making it easy for typical biomedical investigators to study protected RNA-seq data, regardless of their local IT resources or expertise. Availability and Implementation: Rail-RNA is available from http://rail.bio. Technical details on the Rail-dbGaP protocol as well as an implementation walkthrough are available at https://github.com/nellore/rail-dbgap. Detailed instructions on running Rail-RNA on dbGaP-protected data using Amazon Web Services are available at http://docs.rail.bio/dbgap/. Contacts: anellore@gmail.com or langmea@cs.jhu.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27153614

  16. Ride performance of a high speed rail vehicle using controlled semi active suspension system

    NASA Astrophysics Data System (ADS)

    Sharma, Sunil Kumar; Kumar, Anil

    2017-05-01

    The rail-wheel interaction in a rail vehicle running at high speed results in large amplitude vibration of carbody that deteriorates the ride comfort of travellers. The role of suspension system is crucial to provide an acceptable level of ride performance. In this context, an existing rail vehicle is modelled in vertical, pitch and roll motions of carbody and bogies. Additionally, nonlinear stiffness and damping parameters of passive suspension system are defined based on experimental data. In the secondary vertical suspension system, a magneto-rheological (MR) damper is included to improve the ride quality and comfort. The parameters of MR damper depend on the current, amplitude and frequency of excitations. At different running speeds, three semi-active suspension strategies with MR damper are analysed for periodic track irregularity and the resulting performance indices are juxtaposed with the nonlinear passive suspension system. The disturbance rejection and force tracking damper controller algorithms are applied to control the desired force of MR damper. This study reveals that the vertical vibrations of a vehicle can be reduced significantly by using the proposed semi-active suspension strategies. Moreover, it naturally results in improved ride quality and passenger’s comfort in comparison to the existing passive system.

  17. Roll cooling and its relationship to roll life

    NASA Astrophysics Data System (ADS)

    Tseng, A. A.; Lin, F. H.; Gunderia, A. S.; Ni, D. S.

    1989-11-01

    Combined experimental and numerical research has been conducted to investigate the roll cooling system used in steel rolling mills and its relationship to roll life. Roll cooling has been identified as a critical factor in the problems of excessive roll wear or spalling, which cause shortened roll life. A special laboratory apparatus resembling the cooling systems used in the steel mills has been developed to evaluate the corresponding heat transfer coefficients. These coefficients have then been utilized for numerical simulation of the rolling processes. In simulation, the thermal behavior of both the roll and the strip have been considered with emphasis on roll temperature and the induced cyclic thermal stresses. An understanding of the cyclic stress can be utilized to evaluate roll wear, and leads to reduction of the roll spalling, or to extension of the roll life by minimizing the cyclic stress or the resultant fatigue stress. As indicated by the present study, in order to minimize the cyclic or fatigue stresses, the roll should be subjected to uniform cooling, as the sharper the heat transfer coefficient distribution, the higher the thermal stress induced.

  18. Wear of hot rolling mill rolls: An overview

    NASA Astrophysics Data System (ADS)

    Spuzic, S.; Strafford, K. N.; Subramanian, C.; Savage, G.

    1994-08-01

    Rolling is today one of the most important industrial processes because a greater volume of material is worked by rolling than by any other technique. Roll wear is a multiplex process where mechanical and thermal fatigue combines with impact, abrasion, adhesion and corrosion, which all depend on system interactions rather than material characteristics only. The situation is more complicated in section rolling because of the intricacy of roll geometry. Wear variables and modes are reviewed along with published methods and models used in the study and testing of roll wear. This paper reviews key aspects of roll wear control - roll material properties, roll pass design, and system factors such as temperature, loads and sliding velocity. An overview of roll materials is given including adamites, high Cr materials, high speed tool steels and compound rolls. Non-uniform wear, recognized as the most detrimental phenomenon in section rolling, can be controlled by roll pass design. This can be achieved by computer-aided graphical and statistical analyses of various pass series. Preliminary results obtained from pilot tests conducted using a two-disc hot wear rig and a scratch tester are discussed.

  19. The literature of the California black rail

    USGS Publications Warehouse

    Wilbur, Sanford R.

    1974-01-01

    Few birds have remained so little known as the California black rail (Laterallus jamaicensis coturniculus). Although first collected in 1859 or before and reported in 1874 (Ridgway 1874), its life history, distribution, and status have remained so obscure that even a sight record of the bird is deemed worthy of a report in some ornithological publications. Because degradation and loss of freshwater and saltwater marshlands in California may be detrimentally affecting the black rail, both the U.S. Bureau of Sport Fisheries and Wildlife (1973) and the California Department of Fish and Game (1972) have classified it as rare and worthy of further study. The 84 papers and notes both summarized in this report and included in its bibliography include essentially all that is currently known about the California black rail. Only 11 of these papers consider the life history of this rail in any detail. The rest are distribution notes and some of the more important papers on the closely related eastern black rail (L. j. jamaicensis). The latter are included for comparative purposes, or because they may lend clues to currently unknown facets of the life history of the western race.

  20. The structural response of a rail acceleration

    NASA Technical Reports Server (NTRS)

    Wang, S. Y.

    1984-01-01

    The transient response of a 0.4 by 0.6 cm rectangular bore rail accelerator was analyzed by a three dimensional finite element code. The copper rail deflected to a peak value of 0.08 mm in compression and then oscillated at an amplitude of 0.02 mm. Simultaneously the insulating side wall of glass fabric base, epoxy resin laminate (G-10) was compressed to a peak value of 0.13 mm and rebounded to a steady state in extension. Projectile pinch or blowby due to the rail extension or compression, respectively, can be identified by examining the time history of the rail displacement. The effect of blowby was most significant at the side wall characterized by mm size displacement in compression. Dynamic stress calculations indicate that the G-10 supporting material behind the rail is subjected to over 21 MPa at which the G-10 could fail if the laminate was not carefully oriented. Results for a polycarbonate resin (Lexan) side wall show much larger displacements and stresses than for G-10. The tradeoff between the transparency of Lexan and the mechanical strength of G-10 for sidewall material is obvious. Displacement calculations from the modal method are smaller than the results from the direct integration method by almost an order of magnitude, because the high frequency effect is neglected. Previously announced in STAR as N83-35412

  1. The structural response of a rail acceleration

    NASA Technical Reports Server (NTRS)

    Wang, S. Y.

    1984-01-01

    The transient response of a 0.4 by 0.6 cm rectangular bore rail accelerator was analyzed by a three dimensional finite element code. The copper rail deflected to a peak value of 0.08 mm in compression and then oscillated at an amplitude of 0.02 mm. Simultaneously the insulating side wall of glass fabric base, epoxy resin laminate (G-10) was compressed to a peak value of 0.13 mm and rebounded to a steady state in extension. Projectile pinch or blowby due to the rail extension or compression, respectively, can be identified by examining the time history of the rail displacement. The effect of blowby was most significant at the side wall characterized by mm size displacement in compression. Dynamic stress calculations indicate that the G-10 supporting material behind the rail is subjected to over 21 MPa at which the G-10 could fail if the laminate was not carefully oriented. Results for a polycarbonate resin (Lexan) side wall show much larger displacements and stresses than for G-10. The tradeoff between the transparency of Lexan and the mechanical strength of G-10 for sidewall material is obvious. Displacement calculations from the modal method are smaller than the results from the direct integration method by almost an order of magnitude, because the high frequency effect is neglected. Previously announced in STAR as N83-35412

  2. The structural response of a rail accelerator

    NASA Technical Reports Server (NTRS)

    Wang, S. Y.

    1983-01-01

    The transient response of a 0.4 by 0.6 cm rectangular bore rail accelerator was analyzed by a three dimensional finite element code. The copper rail deflected to a peak value of 0.08 mm in compression and then oscillated at an amplitude of 0.02 mm. Simultaneously the insulating side wall of glass fabric base, epoxy resin laminate (G-1o) was compressed to a peak value of 0.13 mm and rebounded to a steady state in extension. Projectile pinch or blowby due to the rail extension or compression, respectively, can be identified by examining the time history of the rail displacement. The effect of blowby was most significant at the side wall characterized by mm size displacement in compression. Dynamic stress calculations indicate that the G-10 supporting material behind the rail is subjected to over 21 MPa at which the G-10 could fail if the laminate was not carefully oriented. Results for a polycarbonate resin (Lexan) side wall show much larger displacements and stresses than for G-10. The tradeoff between the transparency of Lexan and the mechanical strength of G-10 for sidewall material is obvious. Displacement calculations from the modal method are smaller than the results from the direct integration method by almost an order of magnitude, because the high frequency effect is neglected.

  3. Characterization of deformed pearlitic rail steel

    NASA Astrophysics Data System (ADS)

    Nikas, Dimitrios; Meyer, Knut Andreas; Ahlström, Johan

    2017-07-01

    Pearlitic steels are commonly used for railway rails because they combine good strength and wear properties. During service, the passage of trains results in a large accumulation of shear strains in the surface layer of the rail, leading to crack initiation. Knowledge of the material properties in this region is therefore important for fatigue life prediction. As the strain is limited to a thin surface layer, very large strain gradients can be found. This makes it very difficult to quantify changes in material behavior. In this study hardness measurements were performed close to the surface using the Knoop hardness test method. The orientation of the pearlitic lamellas was measured to give an overview of the deformed microstructure in the surface of the rail. Microstructural characterization of the material was done by optical microscopy and scanning electron microscopy to evaluate the changes in the microstructure due to the large deformation. A strong gradient can be observed in the top 50 μm of the rail, while deeper into the rail the microstructure of the base material is preserved.

  4. 13. DETAIL OF RAIL SHOWING SIMILARITY OF DESIGN BETWEEN THE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. DETAIL OF RAIL SHOWING SIMILARITY OF DESIGN BETWEEN THE GOTHIC OPENINGS IN THE RAIL AND THE WINDOWS OF THE POWERHOUSE, VIEW NORTH - Menominee River Bridge, Spanning Menominee River at County Truck Higway "K", Amberg, Marinette County, WI

  5. 15. MEREDITH AVENUE, VIEW WITH LOG RAIL AND BARN. PERHAPS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. MEREDITH AVENUE, VIEW WITH LOG RAIL AND BARN. PERHAPS THE LAST REMAINING EXAMPLE OF CCC BUILT "RUSTIC STYLE" GUARD RAIL IN PARK. VIEW NE. - Gettysburg National Military Park Tour Roads, Gettysburg, Adams County, PA

  6. View of ATSF rail yard from top of El Tovar, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of ATSF rail yard from top of El Tovar, view east. Note superindent's house (distant left) and Grand Canyon rail station (center). - Grand Canyon Village Utilities, Grand Canyon National Park, Grand Canyon Village, Coconino County, AZ

  7. 5. Historic American Buildings Survey, April, 1960 WROUGHT IRON RAIL, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Historic American Buildings Survey, April, 1960 WROUGHT IRON RAIL, MAIN FLOOR ON BULL STREET CAST IRON RAIL, SECOND FLOOR. - Crawford-Clarkson House, Bull & Blanding Streets, Columbia, Richland County, SC

  8. 46 CFR 32.02-10 - Rails-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... storm rails installed in all passageways and at the deckhouse sides on weather decks where persons on board might have normal access. Storm rails must be installed on both sides of passageways which are six...

  9. 8. Detail view of pierced arch concrete rails and recessed ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Detail view of pierced arch concrete rails and recessed panel railing piers at the west pedestrian alcove, north side of the bridge. - Yellow Mill Bridge, Spanning Yellow Mill Channel at Stratford Avenue, Bridgeport, Fairfield County, CT

  10. Extended slow-roll conditions and rapid-roll conditions

    SciTech Connect

    Chiba, Takeshi; Yamaguchi, Masahide E-mail: gucci@phys.aoyama.ac.jp

    2008-10-15

    We derive slow-roll conditions for a scalar field which is non-minimally coupled with gravity in a consistent manner and express spectral indices of scalar/tensor perturbations in terms of the slow-roll parameters. The conformal invariance of the curvature perturbation is proved without linear approximations. Rapid-roll conditions are also derived, and the relation with the slow-roll conditions is discussed.

  11. Rolling through a vacuum

    NASA Astrophysics Data System (ADS)

    van der Schaar, Jan Pieter; Yang, I.-Sheng

    2013-12-01

    We clarify under what conditions slow-roll inflation can continue almost undisturbed, while briefly evolving through a (semi-classically) metastable false vacuum. Furthermore, we look at potential signatures in the primordial power spectrum that could point towards the existence of traversed metastable false vacua. Interestingly, the theoretical constraints for the existence of traversable metastable vacua imply that Planck should be able to detect the resulting features in the primordial power spectrum. In other words, if Planck does not see features this immediately implies the non-existence of metastable false vacua rolled through during the inflationary epoch.

  12. METHOD OF ROLLING URANIUM

    DOEpatents

    Smith, C.S.

    1959-08-01

    A method is described for rolling uranium metal at relatively low temperatures and under non-oxidizing conditions. The method involves the steps of heating the uranium to 200 deg C in an oil bath, withdrawing the uranium and permitting the oil to drain so that only a thin protective coating remains and rolling the oil coated uranium at a temperature of 200 deg C to give about a 15% reduction in thickness at each pass. The operation may be repeated to accomplish about a 90% reduction without edge cracking, checking or any appreciable increase in brittleness.

  13. Electronic BAR Gauge: a customized optical rail profile measurement system for rail-grinding applications

    NASA Astrophysics Data System (ADS)

    Bachinsky, Gordon S.

    1995-06-01

    The dynamic interaction that occurs at the rail/wheel interface of any rail system is significantly influenced by rail and wheel profiles. In an effort to enhance this interaction, railways and transit systems often employ rail grinding as a means to maintain a defined rail profile. The cost to perform this procedure can be very high, sometimes exceeding $DLR25,000 per day for the use of a large grinding machine (with up to 128 grinding motors-each motor being 20 hp or more). Because of this, it is imperative that the work be done efficiently and accurately. In recent years there has been substantial research into the optimization of rail profiles. The National Research Council (NRC) of Canada is one research facility that has generated a unique, precise set of specified profiles for use in heavy-haul railway operations. To implement these profiles in a consistent manner, during rail grinding operations, requires some type of measurement system that provides feedback to the field staff. Up until recently, this has been accomplished with a manual BAR gauge that is fitted with a set of accurate profile templates. The BAR gauge, which initially was fitted with four specified templates, is now equipped with ten such templates. To obtain the full potential of benefits from these profiles requires more precise grinding than that which has been achieved in the past. The other problem with the current manual profile measurement (BAR) method is that it is somewhat slow and cumbersome and the differences between profiles is quite small (i.e. 0.020 inch or less). In order to enhance their rail grinding management support, ARM pursued an automated system that would optically measure rail profiles very fast and accurately from a hy-rail vehicle and compare them with the NRC profiles. Another important feature that was desired in this system was the ability to measure the relative position of one profile with respect to the other (i.e. left versus right rail). Such a system

  14. Rail damage in a solid-armature rail gun. Final report

    SciTech Connect

    Brassard, T.; Homan, C.G.

    1987-12-01

    Plasma-arc-drive rail guns operate by forming a high-temperature plasma behind the projectile using a thin metal fuze. These systems achieve the highest projectile velocities (about 12 km /sec), since the driving force includes a substantial plasma pressure as well as the electromagnetic or Lorentz force. Unfortunately, severe rail damage occurs primarily from the intense temperatures generated by the plasma arc and the wiping motion of the armature itself. The solid-armature gun replaces the plasma armature with a conducting metal armature. Since the plasma arcing is reduced or eliminated, the projectiles are accelerated mainly by the Lorentz force. Thus, solid armature rail guns operate at lower projectile velocities. The important tradeoff is that there is a substantial reduction in rail damage for metal armature projectiles. The elimination of the plasma force limits projectile velocities in the metal-armature rail guns. A more-subtle limit is the speed at which the commutation process can take place. Although the latter limit is still not well understood, experimental evidence indicates a commutation limit may occur near 6 to 7 km/sec. This velocity limit is still attractive for Army tactical missions for rail guns. The actual rail damage occurring with two types of metal armatures, wire brush contactors and monolithic metal contactors, and new developments in barrel technology, such as superconducting augmentation, are presented in this report.

  15. Roll-to-roll light directed electrophoretic deposition system and method

    DOEpatents

    Pascall, Andrew J.; Kuntz, Joshua

    2017-06-06

    A roll-to-roll light directed electrophoretic deposition system and method advances a roll of a flexible electrode web substrate along a roll-to-roll process path, where a material source is positioned to provide on the flexible electrode web substrate a thin film colloidal dispersion of electrically charged colloidal material dispersed in a fluid. A counter electrode is also positioned to come in contact with the thin film colloidal dispersion opposite the flexible electrode web substrate, where one of the counter electrode and the flexible electrode web substrate is a photoconductive electrode. A voltage source is connected to produce an electric potential between the counter electrode and the flexible electrode web substrate to induce electrophoretic deposition on the flexible electrode web substrate when the photoconductive electrode is rendered conductive, and a patterned light source is arranged to illuminate the photoconductive electrode with a light pattern and render conductive illuminated areas of the photoconductive electrode so that a patterned deposit of the electrically charged colloidal material is formed on the flexible electrode web substrate.

  16. Modernization of the nation's rail transit systems: A status report

    SciTech Connect

    Not Available

    1992-08-01

    The report is a review and update on the progress the major urban transit authorities have made in rail modernization since 1984. The first Rail Modernization Study (published in April 1987) projected a cost of $17.8 billion (in 1983 dollars) to upgrade the nation's rail system to a good condition over the ten year period from 1984 through 1993. Rail system conditions range from poor to excellent, with good defined as the desirable level over the long term.

  17. The response of a high-speed train wheel to a harmonic wheel-rail force

    NASA Astrophysics Data System (ADS)

    Sheng, Xiaozhen; Liu, Yuxia; Zhou, Xin

    2016-09-01

    The maximum speed of China's high-speed trains currently is 300km/h and expected to increase to 350-400km/h. As a wheel travels along the rail at such a high speed, it is subject to a force rotating at the same speed along its periphery. This fast moving force contains not only the axle load component, but also many components of high frequencies generated from wheel-rail interactions. Rotation of the wheel also introduces centrifugal and gyroscopic effects. How the wheel responds is fundamental to many issues, including wheel-rail contact, traction, wear and noise. In this paper, by making use of its axial symmetry, a special finite element scheme is developed for responses of a train wheel subject to a vertical and harmonic wheel-rail force. This FE scheme only requires a 2D mesh over a cross-section containing the wheel axis but includes all the effects induced by wheel rotation. Nodal displacements, as a periodic function of the cross-section angle 6, can be decomposed, using Fourier series, into a number of components at different circumferential orders. The derived FE equation is solved for each circumferential order. The sum of responses at all circumferential orders gives the actual response of the wheel.

  18. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  19. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  20. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...