• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    System (1) for detecting a mechanical tensile / compressive stress of a rail (2) of a track (3), in particular for determining the neutral temperature, comprising a rail vehicle (6), a rail temperature detector (9) arranged thereon and an evaluation device (14). It is provided that the system (1) comprises a heat source (8) for targeted heating of a measuring region (19) of the rail (2), that the rail temperature detector (9) for temperature detection during a heating and / or cooling phase of the measuring range (19 ) is formed and that the evaluation device (14) is arranged to derive the rail voltage from detected temperature data. Moreover, the invention relates to a method for detecting a tensile / compressive stress of a rail (2) of a track (3) by means of the system (1).
    公开号:AT520438A4
    申请号:T67/2018
    申请日:2018-03-12
    公开日:2019-04-15
    发明作者:
    申请人:Plasser & Theurer Export Von Bahnbaumaschinen Gmbh；
    IPC主号:
    专利说明:

    description
    System for detecting a mechanical tensile / compressive stress of a rail
    Technical Field The invention relates to a system for detecting a mechanical tensile / compressive stress of a rail of a track, in particular for determining the neutral temperature, comprising a rail vehicle, a rail temperature detector arranged thereon and an evaluation device. Moreover, the invention relates to a method for detecting a tensile / compressive stress of a rail of a track by means of the system.
    PRIOR ART [02] Temperature fluctuations, starting and braking of rail vehicles and deflections due to load lead in particular to rail fastening means because of the coupling of superstructure and
    Structure to constraints and thus to additional longitudinal stresses in a rail.
    Today, railway tracks are designed so that the thermal forces that would lead to an expansion of the rails, for example, heat, from the superstructure, so the sleepers and the track bed, are included.
    Especially when using rail welding equipment, a precise determination of tensile / compressive stresses of a rail or in consequence a determination of the neutral temperature is necessary in order to ensure a stress-relieved condition of the welded track.
    [05] In order to detect a precise analysis and an actual state of a track, several methods for determining a neutral temperature or a tensile / compressive stress of a rail are already known from the prior art.
    [06] A known method for measuring the neutral temperature is the ultrasonic measurement. This is based on a phenomenon that the speed of sound in a rail is influenced by the state of tension. The speed of sound in the rail is compared with the speed of sound in a rail without thermal stresses. From a difference between these, the tensile / compressive stresses can be derived. This is a fast method, but the need for a reference measurement makes the results inaccurate. The ultrasound method is an indirect method that uses a database that includes the relationships between sound velocity and rail material. Such a method is known, for example, from WO 2013/070455 A1 and WO 2014/124050 A1.
    [07] A likewise known method, the magnetic measurement, is disclosed in WO 96/35947 A1. In this method, non-contact magnetic probes are used to generate an alternating magnetic field in the rail. This alternating field interacts with the properties of a rail microstructure and generates a magnetic Barkhausen noise (magnetic Barkhausen effect). The Barkhausen noise can be made visible via an oscilloscope. An amplitude of Barkhausen noise is related to the longitudinal stress in the rail. As with ultrasonic methods, however, measurements from the loaded rail must be compared with measurements from reference material.
    [08] US 2013/0 070083 A1 discloses a system which has a camera, a temperature detector and a computer control. The images taken by the camera rail connections or rail anchors and the collected data of the temperature detector are used to estimate via a computer control an axial tension of the rail due to the images and rail temperature.
    Summary of the Invention [09] It is an object of the invention to provide improvements over the prior art for a system and method of the type mentioned above.
    [10] According to the invention, these objects are achieved by the features of claims 1 and 11. Advantageous developments of the invention will become apparent from the dependent claims.
    The invention provides that the system comprises a heat source for targeted heating of a measuring range of the rail, that the rail temperature detector for temperature detection during a heating and / or cooling phase of the measuring range is formed and that the evaluation device for deriving the rail voltage from detected temperature data is set up. A temporal evolution of the measured temperature data from the rail temperature detector provides a precise way to determine a thermal thermal conductivity of a rail material in order to derive in consequence the prevailing mechanical tensile / compressive stress in the rail by means of the evaluation.
    [12] Advantageously, the heat source is spaced and in particular guided at a continuous speed along the rail. Contactless heating of the rail makes it possible to detect a mechanical tensile / compressive stress of a rail during a right of way of the rail vehicle.
    [13] In a further improvement, the rail temperature detector is arranged on the rail vehicle by means of a guide device. In order to always maintain a constant distance between rail temperature detector and rail during a work operation of the rail vehicle, the rail temperature detector is slidably mounted in a track transverse direction relative to a machine frame on the guide device. As a result, an exact constant relative distance can be ensured, for example, in a curve and / or a track cant. A shift in a track longitudinal direction is advantageous for a continuous measuring insert.
    [14] In an advantageous embodiment of the invention, the rail temperature detector is designed as a point-like measuring infrared detector. In a relative standstill between rail temperature detector and rail (for example by means of a guide device) during a measurement process, the use of a punctiform infrared detector is particularly suitable. Such a detector is inexpensive and robust in construction.
    In a further advantageous embodiment of the invention, the rail temperature detector is designed as an infrared camera. The use of an infrared camera additionally allows a simultaneous evaluation at different local measuring positions on the rail through a larger detection area.
    In addition, it is advantageous if the heat source is designed as a laser. A big advantage here is the precision of the laser. Thus, a measuring range can be specifically heated on the rail, for example, a point-like action of the laser takes place. A surface heating allows the use of a line or surface laser.
    In a further advantageous embodiment of the invention, the heat source is designed as an induction coil. The induction coil offers a structurally simple, but reliable solution for a heat source.
    [18] In addition, it is advantageous if the heat source and the rail temperature detector are controlled by means of a common control device. In order to ensure a coordinated operation, the rail temperature detector, the heat source and possibly the guide device and all associated drives are controlled via the common control device.
    [19] Conveniently, the heat source and the rail temperature detector are aligned in the same direction to detect temperatures of an illuminated rail surface. As a result, heat source and rail temperature detector can be easily and space-savingly arranged below a rail vehicle. Another advantage is given by a simple retrofitting to existing rail vehicles.
    [20] In a further variant, the heat source and the rail temperature detector are oriented in opposite directions to detect temperatures at a back side of a rail land illuminated on a front side. By a separate, two-sided arrangement of the heat source and the rail temperature detector an even more precise measurement is achieved. Mutual influence of heat source and rail temperature detector is thus excluded.
    [21] In the method according to the invention, it is provided that a measuring region of a rail is heated by means of the heat source and thermal excitation of the measuring region takes place by detecting a heating and / or cooling behavior occurring in the measuring region on the rail by means of the rail temperature detector and by means of the evaluation device is evaluated. Such a measuring method for determining mechanical tensile / compressive stresses in a rail is precise and requires no reference measurements on dead rails.
    [22] A further variant of the method provides that a temporal temperature profile of a measuring range matched to a driving speed is detected during a machine precedence. As a result, a tensile / compressive stress measurement is achieved during a machine approach.
    [23] For a more detailed analysis of the track condition, the measuring range is thermally excited with a modulated energy curve. For example, a laser radiation can be modulated sinusoidally. An evaluation in the frequency domain then also permits, in particular, a determination of phase values. A measurement signal of the rail temperature detector is compared with an excitation by the heat source. This has an advantageous effect on the robustness of the method or on the independence of the measurement signal from external influences such as rail surface condition or laser power.
    [24] It is advantageous if a phase shift between the modulated energy curve and a detected temperature profile is determined. The determination of the phase shift enables a precise comparison of the measured data and a particularly precise evaluation.
    Brief Description of the Drawings [25] The invention will now be described by way of example with reference to the accompanying drawings. In a schematic representation:
    Fig. 1 Side view of a rail vehicle Fig. 2 Cross section of a rail vehicle Fig. 3 Detection area of the rail temperature detector Fig. 4 Arrangement of a rail temperature detector and a heat source
    DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows a system 1 for detecting a mechanical tensile / compressive stress of a rail 2 of a track 3, comprising a rail vehicle 6 which can be moved on the track 3, in a side view. The rail vehicle 6 has a machine frame 5 supported by rail carriages 4. On the machine frame 5, a vehicle cab 7 is arranged. Below the machine frame 5 and between the rail carriages 4, a heat source 8 and a rail temperature detector 9 are positioned per rail 2. Each heat source 8 and optionally also each rail temperature detector 9 is associated with a guide device 10. In addition, the rail vehicle 6 has its own drive 11 and a power supply 12 via a control device 13, the heat sources 8, the rail temperature detectors 9, the displacement devices 10 and any drives are centrally controlled. In order to evaluate the data detected by the rail temperature detectors 9, the system 1 comprises an evaluation device 14.
    [27] In Fig. 2, the rail vehicle 6 is shown in section in a track transverse direction 15. Below the machine frame 5, a heat source 8 and a rail temperature detector 9 are positioned for the respective rail 2. Conveniently, each heat source 8 and each rail temperature detector 9 is slidably mounted on its own guide means 10. To extend the adjustment options, the respective rail temperature detector 9 is additionally assigned a pivot drive 20.
    [28] In the example shown, the respective heat source 9 is designed as a laser. A laser beam 16 separated from the laser is centered on a rail head surface 17. A viewing axis 18 of the associated rail temperature detector 9 is also aligned with the rail head surface 17. In a curve and / or track cant, a lateral tracking of the laser and possibly the rail temperature detectors 9 by a corresponding control of the guide means 10 by means of the common control device 13 in this way, a predefined measuring range 19 of the respective rail 2 is heated and detected.
    [29] In a simple embodiment, the rail temperature detector 9 is formed as a point-type infrared detector. For an accurate detection of a temperature profile in the measuring range 19, the infrared detector is held in position relative to the associated rail 2 for the duration of a measuring operation. Thus, the temporal evolution of a detected temperature signal at a local point is evaluated, whereby frequency analysis methods can be used.
    In another embodiment, the rail temperature detector 9 is designed as an infrared camera (area detector). An infrared camera offers the advantage of an extended detection range 21 in comparison to a point-type infrared detector. A guide device 10 is not necessary if the measuring range 19 does not move out of the detection range 21 of the infrared camera even in cornering and over-track. The measuring area 19 is that area of the rail 2 in which a temperature change caused by the heat source 8 is detected. The use of an infrared camera enables the simultaneous evaluation at different local positions, for example along a local measuring line 22 or distributed over the rail surface.
    [31] FIG. 3 shows the detection area 21 of an infrared camera which moves forward with the rail vehicle 6 in the direction of travel 23 over the rail 2 (camera sensor image). The heat source 8 designed as a laser is centered over the rail head surface 17 and heats the measuring area 19. The heating (thermal excitation) can be punctiform, linear or planar. In the course of time, a pulsed or sinusoidal thermal excitation makes sense.
    [32] In the measuring area 19, a temperature profile is detected at least at one measuring point 24. In this case, the measuring point 24 moves during a measuring process along a horizontally shifted local measuring line 22 in the camera sensor image counter to the direction of travel 23. The temporal temperature profile at the measuring point 24 is detected by the correct, matched to the driving speed assignment of the corresponding signal values along the measuring line 22. For example, a first measured value for the measuring point 24 is detected at a first measuring position 26. With a matched to the driving speed distance to the first measuring position 26, a second measured value for the measuring point 24 is detected at a second measuring position 27. Additional measurements are taken at further measuring positions 28, 29 until the measuring point 24 moves out of the detection area 21.
    In this way, during a measurement process, a recording of temporal temperature profiles (heating or a temporal cooling behavior) takes place through the rail temperature detector 9 designed as an infrared camera. Here, a few measured values suffice to detect meaningful temperature profiles. The system 1 according to the invention thus also enables measurements at high speeds of the rail vehicle 8.
    [34] The thermal conductivity of the rail material depends on the prevailing tensile / compressive forces in the rails 2. The measured temperature profile or the temporal development of the measured thermal amplitude values at the measuring points 24 makes it possible to determine the thermal thermal conductivity (or variables derived therefrom, such as thermal diffusivity or effusivity). Based on the known
    Material properties are derived from this as a consequence of the tensile / compressive forces.
    An improvement of the method provides that a time-modulated heating of the measuring range 19 or the respective measuring point 24 takes place. For example, the laser is driven with a sinusoidal signal so that the emitted radiation energy follows a sine wave. In this case, an evaluation of the measured temperature profile at the respective measuring point 24 in the frequency domain. This evaluation is supported by appropriate frequency analysis methods.
    For a precise evaluation, a phase shift between the modulated course of the introduced energy and the detected temperature profile is determined. In order to be able to determine the phase shift precisely, the detected temperature profile is decomposed by Fourier transformation into a plurality of continuous spectra. Thus, a frequency of the laser can be compared to a frequency of the temperature profile.
    [37] The physical relationships between a temperature curve and a tensile / compressive stress are described in the publication Huiting Huan et al., "Non-destructive and non-contacting stress-strain characterization of aerospace metallic alloys using photo-thermomechanical radiometry, NDT & E International 84 (2016), 47-53, Elsevier Ltd. described.
    In addition, based on known material properties on the temporally modulated heating and an evaluation of the temperature profile in the frequency range alloy compositions of the rail material can be detected.
    [39] FIG. 4 shows a further variant for an arrangement of the heat source 8 and the temperature detector 9. In this case, the heat source 8 acts on one side of the rail 2, while the rail temperature detector 9 is directed to a transverse in the transverse direction 15 side of the rail 2. As a result of this spatial separation of these system components 8, 9, influencing of the components with one another can be ruled out. This causes in particular an improvement of the signal quality.
    [40] In FIG. 1, the respective rail temperature detector 9 is additionally displaceably mounted in a rail longitudinal direction 25. During a machine approach, the rail temperature detector 9 is cyclically moved back and forth. The backward movement is coordinated with the forward travel of the rail vehicle 6 in order to keep the rail temperature detector 9 above a measuring point 24 during a measuring process. At a turning point, the rail temperature detector 9 is again shifted in the direction of travel 23 to its starting position and the measuring cycle starts again. As a result, a longer measurement time can be realized. In addition, this arrangement is suitable for the use of a punctiform infrared detector, wherein the rail vehicle 6 does not have to be stopped during a measurement process.
    权利要求:
    Claims (14)
    [1]
    claims
    A system (1) for detecting a mechanical tensile / compressive stress of a rail (2) of a track (3), in particular for determining the neutral temperature, comprising a rail vehicle (6), a rail temperature detector (9) arranged thereon and an evaluation device (14 ), characterized in that the system (1) comprises a heat source (8) for targeted heating of a measuring region (19) of the rail (2), that the rail temperature detector (9) for temperature detection during a heating and / or cooling phase of the measuring range ( 19) is formed and that the evaluation device (14) is arranged to derive the rail voltage from detected temperature data.
    [2]
    2. System (1) according to claim 1, characterized in that the heat source (8) spaced and in particular at a continuous speed along the rail (2) is guided.
    [3]
    3. System (1) according to claim 1 or 2, characterized in that the rail temperature detector (9) by means of a guide device (10) on the rail vehicle (6) is arranged.
    [4]
    4. System (1) according to any one of claims 1 to 3, characterized in that the rail temperature detector (9) is designed as a punctiform infrared detector.
    [5]
    5. System (1) according to one of claims 1 to 3, characterized in that the rail temperature detector (9) is designed as an infrared camera.
    [6]
    6. System (1) according to one of claims 1 to 5, characterized in that the heat source (8) is designed as a laser.
    [7]
    7. System (1) according to one of claims 1 to 5, characterized in that the heat source (8) is designed as an induction coil.
    [8]
    8. System (1) according to one of claims 1 to 7, characterized in that the heat source (8) and the rail temperature detector (9) by means of a common control device (13) are driven.
    [9]
    9. System (1) according to one of claims 1 to 8, characterized in that the heat source (8) and the rail temperature detector (9) are aligned in the same direction to detect temperatures of an illuminated rail surface.
    [10]
    A system (1) according to any one of claims 1 to 8, characterized in that the heat source (8) and the rail temperature detector (9) are oriented in opposite directions to detect temperatures at a rear side of a rail land illuminated on a front side.
    [11]
    11. A method for detecting a tensile / compressive stress of a rail (2) of a track (3), in particular for determining the neutral temperature, by means of a system (1) according to one of claims 1 to 10, characterized in that a measuring range (19) a rail (2) by means of the heat source (8) is heated and thereby thermal excitation of the measuring range (19) takes place, that in the measuring range (19) on the rail (2) occurring heating and / or cooling behavior by means of the rail temperature detector (9 ) is detected and evaluated by the evaluation device (14).
    [12]
    12. The method according to claim 11, characterized in that during a machine approach, a temporal temperature profile of a tuned to a driving speed measuring range (19) is detected.
    [13]
    13. The method according to claim 11 or 12, characterized in that the measuring range (19) is thermally excited with a modulated energy profile.
    [14]
    14. The method according to claim 13, characterized in that a phase shift between the modulated energy profile and a detected temperature profile is determined.
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    同族专利:
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    WO2019174834A1|2019-09-19|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    WO1979001156A1|1978-05-31|1979-12-27|Sira Institute|Apparatus and method for indicating stress in an object|
    US4541059A|1980-12-05|1985-09-10|Kabushiki Kaisha Komatsu Seisakusho|Stress distribution measuring instrument|
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    US20080201089A1|2007-01-11|2008-08-21|Ensco, Inc.|System and method for determining neutral temperature of a metal|
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    WO2011071432A1|2009-12-07|2011-06-16|Erik Berggren|Method for determining the stress free temperature of the rail and/or the track resistance|
    US20140044146A1|2012-08-13|2014-02-13|Harold Harrison|Method and apparatus for detecting track failure|
    US20150110151A1|2012-10-22|2015-04-23|En'urga Inc.|Method and Apparatus for Measuring Rail Surface Temperature|
    DE10008200A1|2000-02-23|2001-08-30|Christa Reiners|Bending strength measurement device for metallic mast, detects deflection of mast due to bending load, based on output of light receiver mounted on mast, which receives light from stationary light source|
    US20150285688A1|2014-04-03|2015-10-08|General Electric Company|Thermographic route examination system and method|US11186301B1|2021-06-14|2021-11-30|Bnsf Railway Company|System and method for wheel impact load detection compensation|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA67/2018A|AT520438B1|2018-03-12|2018-03-12|System for detecting a mechanical tensile / compressive stress of a rail|ATA67/2018A| AT520438B1|2018-03-12|2018-03-12|System for detecting a mechanical tensile / compressive stress of a rail|
    PCT/EP2019/053371| WO2019174834A1|2018-03-12|2019-02-12|System for capturing a mechanical tensile/compressive stress of a rail|
    EP19704617.0A| EP3765831A1|2018-03-12|2019-02-12|System for capturing a mechanical tensile/compressive stress of a rail|
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