Sensor device for detecting strains on a linear infrastructure component, in particular a track rail, measuring arrangement, method and application device

Abstract

A sensor device (3) for detecting strains in a linear infrastructure component (12), in particular a track rail, comprises a first sensor unit (16, 16') with a first support (28) and at least one strain sensor mounted on the first support (28) for detecting a strain at the first measuring point (19), a second sensor unit (17) with a second support (29) and at least one strain sensor mounted on the second support (29) for detecting a strain at the second measuring point (20), a coupling means (18) connected to the first support (28) and the second support (29) for defining a measuring distance (d) between the first measuring point (19) and the second measuring point (20) along a longitudinal direction (21) of the linear infrastructure component (12), a measuring arrangement (19) with the sensor device (3), a method, and an application device for applying the sensor device (3).

Description

The invention relates to a sensor device for detecting expansions on a linear infrastructure component, in particular a rail. The invention further relates to a measuring arrangement having such a sensor device. The invention also relates to a method and an application device for applying such a sensor device.WO 2015 / 110 361 A2 discloses fiber-optic strain sensors for detecting strains of a track rail. The elongations are detected in the region of a threshold compartment between two adjacent track thresholds. The strain sensors are individually connected to the track rail and each separately connected to an evaluation device. It is disadvantageous that the installation of the strain sensors on the track rail is complicated and prone to errors, that the complexity of the apparatus is high and that the gain of information and thus the field of application are limited.It is an object of the invention to provide an improved sensor device for detecting expansions on a linear infrastructure component, in particular a track rail, which can be produced and mounted particularly economically and reliably, is robust in operation and can be used in a wide variety of ways.This object is achieved by a sensor device having the features of claim 1. It has been recognized that a sensor device for detecting expansions on a linear infrastructure component, in particular on a rail, having a first sensor unit and a second sensor unit can have a coupling means for defining a measurement distance between the respective measurement points of the sensor units, in order to be particularly economical and reliable to produce and mount and robust in operation and to have an extended field of application. The configuration of the sensor device with the first carrier, the second carrier and the coupling means ensures that the relative position and / or orientation of two or more strain sensors of the different sensor units can be precisely predefined, in particular can already be established during the production of the sensor device. The plurality of strain sensors can be attached to the linear infrastructure component with reduced effort, in particular in only one positioning and alignment step. This prevents each individual strain sensor from having to be positioned and aligned individually precisely on the linear infrastructure component. In particular, fault sources associated with the individual assembly are eliminated. Due to the simplified attachment of the sensor device, its partially or completely automated attachment to the infrastructure component is made possible. The positioning and alignment of the plurality of strain sensors with respect to one another can take place under controllable environmental conditions during the production of the sensor device and thus take place particularly precisely. The reduced assembly effort makes it possible, in particular with the same effort, to equip the linear infrastructure component with a larger number of sensor units, in particular strain sensors, whereby the information gain is increased and the field of application is extended.The linear infrastructure component may generally be an elongate object. Preferably, the linear infrastructure component is a track rail. Alternatively, the linear object can be a pipe, a cable, in particular a carrying cable of a bridge or a cableway, an electrical line, in particular a power line, an engineering structure, such as a bridge, a carrying structure, a fluid line, for example a fuel trunk line, a water line, in particular a drinking water line, a hot water line, a geothermal line and / or a gas line, an above-ground and / or underground installation, a wind turbine tower, a traffic route, in particular a road, a bridge, a track, a high-speed traffic route, in particular a reduced-pressure transport pipe, and / or any other elongated object, the expansion of which is potentially of interest at least at two measurement points along the longitudinal direction of the linear infrastructure component.The at least one strain sensor is preferably connected to the respective carrier in a materially bonded and / or form-fitting and / or force-fitting manner. For example, the at least one strain sensor can be encapsulated by the carrier material by casting and / or injection molding.A measurement contact surface is understood to mean that surface of the sensor device, in particular of the sensor unit, which is provided for contact with the linear infrastructure component and / or via which the sensor unit is attached to the linear infrastructure component or absorbs the strain to be detected.The at least one strain sensor can have a distance to the measurement contact surface of at most 2 mm, in particular at most 1 mm, in particular at most 0.5 mm, in particular at most 0.2 mm, in particular at most 0.1 mm, in particular at most 0.05 mm, and / or at least 0.01 mm. A surface of the at least one strain sensor can form the measurement contact surface at least in sections. The at least one strain sensor can be surrounded completely and / or partially, but not completely, in particular not at the measurement contact surface, by the respective carrier.Preferably, the measurement point can determine the section plane or measurement plane at which the strain is detected in the linear infrastructure component, in particular in the track rail. The sectional plane is preferably oriented perpendicular to the longitudinal direction of the linear infrastructure component. The measurement point can define the position along the longitudinal direction of the linear infrastructure component at which the intersecting forces of the linear infrastructure component are determined.The respective measurement point is preferably the position at which the strain of the linear infrastructure component is determined by means of the respective sensor unit, in particular the at least one strain sensor. In the case of a single strain sensor, the measurement of the strain is preferably carried out directly at the measurement point. In the case of a plurality of strain sensors, these can be arranged grouped at a preferably small distance from the measurement point or around the measurement point. Alternatively, the plurality of strain sensors can overlap one another and the measurement point in a plan view of the measurement point, in particular of the measurement contact surface. In other words, the plurality of strain sensors for detecting the strains can be arranged at the same measurement point in the measurement contact surface and / or at a distance from the measurement point perpendicular thereto. The distance between the at least one strain sensor, in particular all strain sensors, and the associated measurement point is preferably at most 25 mm, in particular at most 10 mm, in particular at most 5 mm, in particular at most 2 mm, in particular at most 1 mm, in particular at most 0.5 mm, in particular at most 0.1 mm, in particular at most 0.01 mm, in particular at most 0.001 mm, and / or at least 0.001 mm.The coupling means preferably establishes, in particular together with the first carrier and / or the second carrier, the measurement distance between the first sensor unit and the second sensor unit, in particular the first measurement point and the second measurement point. The measurement distance is determined in particular in the longitudinal direction of the linear infrastructure component. A straight line between the first and the second measurement point is preferably oriented substantially parallel to the longitudinal direction. This is preferably also understood to mean angle deviations of a maximum of 10°, in particular a maximum of 5°, in particular a maximum of 2°, in particular a maximum of 1°, in particular a maximum of 0.5°, in particular a maximum of 0.1°, in particular a maximum of 0.01 °, with respect to the parallel orientation.Preferably, the coupling means, in particular together with the first and / or the second carrier, is configured to produce a translationally and / or rotationally rigid connection between the first and the second sensor unit, in particular between the two carriers and / or the first and the second measurement point. A connection between the coupling means and the respective sensor unit, in particular the respective carrier, and / or the coupling means itself can be designed to be translationally and / or rotationally rigid. As a result, the measurement points are fixed particularly precisely with respect to one another.The coupling means and the first carrier and / or the second carrier can be formed in multiple parts and / or in one part. For example, the coupling means and the first and / or the second carrier can be connected to one another in a materially bonded manner, in particular bonded and / or welded. The coupling means and the first and / or the second carrier can be produced in one piece, in particular cast and / or injection molded. Alternatively, the coupling means can be designed as a separate component and can be mounted with the first and / or the second carrier, in particular in a materially bonded, force-fit and / or form-fit manner.The first carrier and / or the second carrier and / or the coupling means can comprise, in particular consist of, a plastic material, in particular a thermosetting material and / or an elastic material, for example polyethylene and / or polypropylene and / or polyurethane, and / or a metallic material, in particular aluminum.The coupling means can have at least one signal line running between the first and the second sensor unit, in particular their strain sensors, in particular at least one measurement signal line, in particular an electrical and / or a fiber-optic signal line. Thus, the production of the measurement signal connection to the strain sensors can be effected particularly economically and in a robust manner, in particular bundled for the at least two measurement points.The first strain sensor and / or the second strain sensor, in particular all strain sensors, can be electrical strain sensors, in particular film sensors, and / or optical strain sensors. Such strain sensors are particularly robust and provide precise measurement results.The sensor device, in particular the first and the second sensor unit, can be connected, in particular bonded, to the linear infrastructure component in a materially integral manner. In particular, an adhesive layer can be formed between the linear infrastructure component and the sensor device. The adhesive layer can have a thickness of at most 2 mm, in particular at most 1 mm, in particular at most 0.5 mm, in particular at most 0.1 mm, in particular at most 0.05 mm, and / or at least 0.001 mm. The expansions can thereby be detected particularly precisely.According to one aspect, the sensor device can be designed for application to a rail web of the rail. For this purpose, the sensor device can have dimensions which ensure a suitability for mounting on a rail web. In particular, a height of the sensor device can correspond at most to the height of the track rail, in particular of the track web, and / or lie in a range from 1 cm to 30 cm, in particular from 2 cm to 20 cm, in particular from 4 cm to 16 cm, in particular from 6 cm to 12 cm. The respective sensor unit can have a corresponding height. In particular, the measurement contact surface of the sensor device, in particular of the respective sensor unit, can have a corresponding height. The thickness of the sensor device, in particular of the respective sensor unit, in particular perpendicular to the measurement contact surface, is preferably in a range from 0.01 cm to 10 cm, in particular from 0.1 cm to 5 cm, in particular from 0.2 cm to 4 cm, in particular from 0.5 cm to 3 cm.According to a further aspect, the measurement distance between the first and the second measurement point can be in a range from 5 cm to 200 cm, in particular from 10 cm to 120 cm, in particular from 15 cm to 60 cm, in particular from 20 cm to 40 cm. This advantageously achieves the effect that the two sensor units can be fastened to the track rail along the longitudinal direction within the same sleeper compartment or between two adjacent track sleepers.According to a further aspect, the coupling means and / or the first carrier and / or the second carrier can be designed to be flexurally soft. This advantageously achieves the effect that the respective measurement contact surface can be formed particularly precisely on the surface of the linear infrastructure component. In particular, a substantially constant thickness of adhesive layer between the sensor device and the linear infrastructure component can be ensured. The measurement results are thus particularly precise. Preferably, the coupling means and / or the first and / or the second carrier comprise an elastic material, in particular an elastic plastic, for example polyurethane and / or silicone and / or EPDM, and / or a rubber, in particular NBR, in particular consist thereof.In general, the coupling means and / or the first and / or the second carrier can be designed to be flexible and / or rigid and / or rigid.The hardness of the material of the coupling agent and / or of the first and / or of the second carrier is preferably in a range from 10 Shore A to 100 Shore A, in particular from 20 Shore A to 80 Shore A, in particular from 30 Shore A to 60 Shore A.According to a further aspect, the at least one strain sensor can be a fiber-optic strain sensor, in particular all strain sensors can be fiber-optic strain sensors. The fiber-optic strain sensor can have an optical waveguide, in particular an optical fiber, in particular an optical fiber. The at least one strain sensor, in particular the first and / or the second strain sensor, can be a fiber Bragg grating sensor. Such sensors are particularly precise and robust in operation and are particularly suitable for wide transmission paths of the measurement signal.According to a further aspect, at least one strain sensor of the first sensor unit and at least one strain sensor of the second sensor unit can be connected, in particular formed, by the same optical waveguide. In particular, the fiber Bragg grating of the two strain sensors can be arranged in the same optical waveguide. Preferably, at least three, in particular at least five, in particular at least 10, in particular all, strain sensors of a sensor unit and / or of both sensor units and / or of the sensor device are formed by the same optical waveguide. This can significantly reduce the effort associated with connecting the strain sensors. Securing a corresponding signal connection, in particular when used on the rail, is also significantly simplified.The sensor device can have a plurality of measurement signal lines, in particular optical waveguides, which are formed separately from one another or are provided for separate connection to an evaluation device.According to a further aspect, the coupling means can carry at least one, in particular exactly one or more, measurement signal lines for conducting a measurement signal between the first sensor unit and the second sensor unit. The at least one measurement signal line can be embedded, for example, in the material of the coupling means, in particular completely surrounded by the latter. As a result, the sensor device is particularly robust in operation and easy to handle.According to a further aspect, the coupling means can carry at least two separately formed optical waveguides, in particular measurement signal lines and / or data signal lines. The data signal line preferably transmits, in particular additionally or exclusively, signals other than the measurement signals, for example communication signals. The coupling means can also carry a plurality of measurement signal lines. This enables the number of strain sensors which the sensor device formed in one piece has to be increased. The coupling means preferably carries at least two, in particular at least five, and / or at most twenty, in particular at most ten, separate optical waveguides.According to one aspect, the first sensor unit can have at least two of the strain sensors for detecting a strain at the first measurement point. The second sensor unit can have at least two of the strain sensors for detecting a strain at the second measurement point. The respective sensor unit can have, in particular, at least three, in particular at least four, in particular five, and / or a maximum of ten strain sensors, which are designed, in particular, for detecting a strain at the measurement point of the respective sensor unit.According to a further aspect, the measurement direction of the at least one strain sensor can be aligned obliquely to the longitudinal direction of the linear infrastructure component, in particular at an angle to the longitudinal direction in a range from 20° to 70°, in particular from 30° to 60°, in particular from 40° to 50°, in particular 45°. The above angular ranges can alternatively or additionally be present with respect to a straight line between the first measurement point and the second measurement point. In this way, a shear strain can be determined, in particular when the respective strain sensor is arranged on the rail web.According to a further aspect, the measurement direction of at least one strain sensor of the first and second sensor units can be aligned obliquely to the longitudinal direction and / or obliquely to an orthogonal direction to the longitudinal direction of the linear infrastructure component, in particular obliquely to the vertical direction. In particular, two strain sensors of the respective sensor unit can each have a corresponding orientation.According to a further aspect, at least one, in particular exactly one, strain sensor of the sensor device, in particular one of the sensor units, in particular each sensor unit, can have a measurement direction aligned parallel to the longitudinal direction of the linear infrastructure component. Longitudinal expansions can thereby be detected, in particular a longitudinal expansion of the track rail.According to a further aspect, at least one strain sensor, in particular at least two, in particular exactly two, strain sensors of the sensor device, in particular at least one of the sensor units, in particular each sensor unit, can have a measurement direction oriented perpendicularly to the longitudinal direction of the linear infrastructure component, in particular vertically. As a result, in particular transverse expansions can be detected, in particular a transverse expansions of the track rail, and / or the position of the neutral fiber can be determined precisely and / or the shear expansion can be determined particularly precisely on the basis of the transverse expansions. Transverse expansions above and / or below the neutral fiber and / or the measuring point are preferably detected, in particular at a distance from the neutral fiber in a range from 1 mm to 100 mm, in particular from 5 mm to 70 mm, in particular from 10 mm to 40 mm.According to a further aspect, the sensor device can have at least one temperature sensor, in particular on the first and / or the second carrier and / or on the coupling means. The temperature sensor can be a fiber-optic temperature sensor, in particular a fiber Bragg grating sensor and / or another fiber-optic temperature sensor, for example a distributed temperature sensor (DTS=distributed temperature sensing), in particular for temperature determination based on a fiber-optic Raman backscatter method, and / or an electrical sensor, in particular a film sensor.The at least one temperature sensor preferably ensures that temperature influences, in particular expansions, in particular of the sensor and / or of the linear infrastructure component, can be determined and / or compensated or eliminated by calculation on the basis of temperature influences, in particular by means of the evaluation device. For example, the at least one temperature sensor or the evaluation device connected thereto can be designed to determine and / or compensate for the temperature-dependent measurement behavior of at least one strain sensor and / or the dependence of the measurement signal of at least one strain sensor on the thermal expansion of the linear infrastructure component, in particular of the track rail.According to a further aspect, the at least one temperature sensor and at least one, in particular at least two, of the strain sensors, in particular all strain sensors of the same sensor unit, in particular of the same sensor device, can be formed by the same light-conducting fiber.According to a further aspect, the sensor device, in particular the first sensor unit and / or the second sensor unit, in particular the first carrier and / or the second carrier, comprises a positioning stop for reversibly releasable form-locking fixing of the position and orientation of the sensor device relative to an application device and / or to the linear infrastructure component, in particular the track rail. The positioning stop can have one or more stop elements, in particular made of a rigid material, for example a rigid plastic and / or metal. The stop elements can be arranged circumferentially on at least one of the sensor units or on the coupling means.According to one aspect, the sensor device can have at least one, in particular at least two, in particular at least five, in particular at least 10, in particular at least 20, and / or at most 500, in particular at most 100, in particular at most 50, further sensor units which are connected to one another in particular in a structurally and / or signal-transmitting manner. The aspect of securing a plurality of sensor units in a predefined position and / or orientation with respect to one another via a coupling means can thereby be extended to further sensor units. The at least one further sensor unit preferably has in each case a further carrier and at least one strain sensor, which is recorded by the further carrier, for detecting a strain at a further measurement point.Preferably, the sensor device, in particular each further sensor unit, comprises a further coupling means for connecting the further sensor unit to an adjacent sensor unit, in particular an adjacent further sensor unit and / or the first sensor unit and / or the second sensor unit. The at least one further coupling means can be configured to define a measurement distance between the further measurement point and the adjacent measurement point or the measurement point of the adjacent sensor unit, in particular in the longitudinal direction of the linear infrastructure component. Alternatively, the further coupling means can be flexible, in particular flexurally soft and / or stretch-soft, in particular ensure a displacement of the further measurement point to the adjacent measurement point. For example, the further coupling means can be configured cable-shaped, in particular band-shaped, in order to ensure longitudinal flexibility by forming a loop, for example.Particularly preferably, two of the sensor units are connected to a coupling means, which establishes the measurement distance between their measurement points, in particular in the longitudinal direction of the linear infrastructure component. Two such sensor units are also referred to as sensor unit pairs. Between adjacent sensor unit pairs, a flexible coupling means, in particular a flexible coupling means, can be arranged.According to one aspect, at least two of the measuring units and / or the measuring points of the sensor device can have a distance of at least 0.6 m, in particular at least 1 m, in particular at least 2 m, in particular 4 m, in particular at least 10 m, and / or a maximum of 250 m, in particular a maximum of 100 m. In particular, the total length of the sensor device can be in the above-mentioned range. As a result, the sensor device can detect the stress on the linear infrastructure component over a long length, in particular over a plurality of threshold compartments. Preferably, at least one sensor unit, in particular two sensor units, is provided per threshold compartment. A measurement signal line, in particular an optical waveguide of the sensor device, preferably extends over the entire length between the measurement points, in particular over the entire length of the sensor device.According to a further aspect, the sensor device can be designed to be windable and / or foldable. In particular, the sensor device can be wound onto a reel, in particular for transport to the linear infrastructure component. This significantly simplifies the handling of the sensor device, in particular before the installation of the linear infrastructure component.A further object of the invention is to provide an improved measuring arrangement which can be produced particularly economically and reliably and is robust and flexible in use.This object is achieved by a measuring arrangement having a linear infrastructure component, in particular a track rail and a sensor device attached thereto in a materially bonded manner, according to the above description, wherein the first and the second measurement point on the linear infrastructure component are arranged at the measurement distance determined by the coupling means. The measuring arrangement can be further developed with at least one of the features described above in connection with the sensor device. The advantages of the measuring arrangement preferably correspond to the advantages of the sensor device.The materially bonded connection between the linear infrastructure component and the sensor device is preferably effected by welding and / or bonding, in particular by means of a cyanoacrylate adhesive and / or an epoxy adhesive.An adhesive layer can be continuous or uninterrupted between the first sensor unit and the second sensor unit or interrupted, in particular separately for the first and the second sensor unit. Preferably, the sensor unit pairs are attached, in particular glued or welded, separately, in particular one after the other, to the linear infrastructure component.According to one aspect, the first and the second measurement point are arranged, in particular attached, in particular glued, on a rail web of the rail rail.At least one, in particular exactly one, expansion sensor, in particular per sensor unit, can be arranged on the rail foot, in particular on the upper side, a side surface and / or the lower side of the rail foot and / or on a rail head, in particular on the lower side and / or a side surface of the rail head. On the rail foot and / or on the rail head, a strain sensor arranged longitudinally or perpendicularly to the longitudinal direction of the rail rail can be arranged.The first and the second measuring point are preferably arranged in the neutral fiber of the track rail. The neutral fiber is determined in that, in the case of pure bending, in particular about a horizontal transverse direction of the track, no longitudinal forces occur there. The measurements of the neutral fiber ensure a particularly precise determination of the load on the infrastructure component, in particular of shear expansions.According to a further aspect, the measuring arrangement can have a covering means which, together with the linear infrastructure component, in particular the track rail, encloses or seals the first and / or the second sensor unit in a liquid-tight manner, in particular in a moisture-tight manner. The covering means can comprise a plastic material, for example polyurethane and / or bitumen, in particular consist thereof. The covering means can be designed to be rigid or elastic. The covering means can comprise a housing, in particular comprising a plastic material and / or a metallic material.According to a further aspect, the first and the second measurement point can be arranged in the longitudinal direction between two adjacent track sleepers, in particular in a so-called sleeper compartment. By determining the expansions of the track rail at at least two measurement points along the longitudinal direction, influences of the supports, in particular of the ballast bed, can be identified and / or compensated. The expansions can be determined particularly precisely or allow particularly precise conclusions to be drawn about the actually present stress on the track rail.The invention also relates to a measurement system, having a sensor device, in particular a measurement arrangement, according to the above description and an evaluation device for evaluating measurement signals of the at least two strain sensors. The evaluation device preferably comprises at least one processor for processing digital data. The evaluation device can have at least one, in particular three, in particular at least five, in particular at least 10, and / or a maximum of 50 measurement signal line inputs. The measuring system can be further developed with at least one of the features described above in connection with the sensor device and / or the measuring arrangement.A further object of the invention is to provide an improved method for applying a sensor device to a linear infrastructure component, in particular to a rail, which is particularly economical and robust in its design.This object is achieved by a method for applying a sensor device to a linear infrastructure component, in particular a rail, comprising the steps of: providing a sensor device, in particular according to the above description, and attaching the sensor device to the linear infrastructure component in such a way that the two measurement points on the linear infrastructure component are arranged at the measurement distance determined by the coupling means. The method can be further developed with at least one of the features described above in connection with the sensor device and / or the measuring arrangement and / or the measuring system. The advantages of the method preferably correspond to the advantages of the sensor device and / or of the measuring arrangement and / or of the measuring system.The method preferably comprises the cleaning and / or the grinding and / or the sandblasting and / or the laser beam and / or the water jetting and / or the brushing and / or the plasma treatment of the infrastructure component and / or the unwinding of the sensor device, in particular from a reel, and / or the unfolding of the sensor device and / or the application of adhesive, in particular onto the sensor device and / or the infrastructure component, and / or the feeding of the sensor device to the infrastructure component, in particular in contact with the infrastructure component, and / or the pressing of the sensor device onto the infrastructure component and / or the curing of the adhesive and / or the covering of at least one, in particular all, of the sensor units, in particular with the covering means, and / or the laying and / or the securing of at least one measurement signal line and / or the connection of the measurement signal line to the evaluation device.According to one aspect, the positioning and / or alignment of the sensor device with respect to the infrastructure component can be effected by means of an application device which preferably interacts in a form-fitting manner with a positioning stop of the sensor device. By means of the application device, the sensor device can preferably be pressed onto the infrastructure component. The attachment can thus be effected in a particularly time-efficient, economical and reliable manner.According to a further aspect, the sensor device is calibrated by travelling on the rail with a rail vehicle, in particular a calibration car, having a known weight. This allows a defined load on the track rail to be applied. Based on this, the transfer function, in particular the calibration curve, of the respective strain sensor attached to the track rail can be determined. The rail is preferably traveled on by rail vehicles of different, known weights. As a result, the transfer function of the strain sensors can be determined particularly precisely, in particular for different points of the transfer function.A further object is to provide an improved application apparatus for applying a sensor device to a linear infrastructure component, in particular a track rail, which in particular ensures particularly economic and reliable mounting of the sensor device on the infrastructure component.This is achieved by an application device for applying a sensor device to a linear infrastructure component, in particular a rail, having a fastening means for reversibly releasable form-locking fixing of the position and orientation of the application device relative to the linear infrastructure component and a counter-positioning stop for reversibly releasable form-locking fixing of the position and orientation of the sensor device, in particular at least one sensor unit, relative to the application device. The application device can be further developed with at least one of the features described above in connection with the sensor device and / or the measuring arrangement and / or the measuring system and / or the method. The advantages of the application device preferably correspond to the advantages of the sensor device and / or of the measuring arrangement and / or of the measuring system and / or of the method.The fastening means can be designed for a form-fit and / or force-fit connection to the infrastructure component, in particular to the track rail. The fastening means can have two fastening elements which are connected to one another in an articulated manner.The application device can have a pressing plunger for exerting a, in particular adjustable, pressing force on the at least one sensor unit. For example, the pressing punch can be connected to the fastening means via a pressing force means, in particular a thread. The counter-positioning stop can be formed complementary to the positioning stop of the sensor device.The application device can have at least one magnet, preferably a permanent magnet, alternatively an electromagnet, for fastening the sensor device, in particular at least one, in particular the first and the second sensor unit, to the linear infrastructure component, in particular the track rail, in particular for bringing about the contact pressure on the sensor units. By means of the magnetic force acting between the linear infrastructure component and the application device, the sensor device arranged therebetween, in particular the at least one sensor unit, can be pressed onto the linear infrastructure component. The magnet can be a component of a pressing punch.The application device preferably comprises a layer of an elastic material, in particular on the pressing die, via which the pressing force is transmitted to the sensor device, in particular the at least one sensor unit. As a result, unevennesses in the contact region between the application device and the sensor device can be compensated for.The invention also relates to a method for operating a measuring system, in particular according to the above description, comprising the steps of: detecting measuring signals by means of the sensor device, in particular on the track rail, determining, on the basis of the measuring signals, at least one item of information from the group comprising a property of the track vehicle, in particular its length, weight, number of cars, number of axles, quality condition, in particular wheel runout, running quality, in particular tendency to derailment, in particular derailment coefficient, in particular Y / Q value (=rad guidance force / wheel contact force or horizontal / vertical track transverse force), lateral acceleration, bogie integrity and / or weight distribution, and / or a property of the track, in particular longitudinal extension and / or curvature, in particular local, in particular lateral and / or vertical, The displacement from a target arrangement, the compaction state of the track blocker and / or the structural integrity of the track rail, in particular crack formation, and / or the integrity of the rail fastening and / or the temperature of the track rail and / or of at least one sensor and / or of the environment, and / or a property of the rail traffic, for example the position of a rail vehicle and / or the number and / or the time of rail vehicles passing over.Further features, advantages and details of the invention are evident from the following description of a plurality of exemplary embodiments with reference to the figures. The following are shown: FIG. 1 shows a schematic illustration of a measuring arrangement with a linear infrastructure component in the form of a track rail and a sensor device attached thereto for detecting expansions at a plurality of measurement points, FIG. 2 shows a schematic detailed illustration of the measuring arrangement in FIG. 1, wherein two measuring units are held at a measurement distance from one another by a coupling means, FIG. 3 shows a sectional illustration of the measuring arrangement along the section line III-III in FIG. 2, wherein a respective sensor device is attached to both sides of a rail web of the track rail, FIG. 4 shows a rear view of one of the sensor units of the measuring arrangement in FIG. 1, strain sensors of the sensor unit being designed as fiber-optic strain sensors, FIGS. 5A-5F are schematic representations of sensor units according to further embodiments; and. FIGS. 6A-6F are schematic sectional views through measuring arrangements according to further embodiments.With reference to FIGS. 1, 2, 3 to 4, a first embodiment of a measuring arrangement 1 is described. The measuring arrangement 1 comprises a linear infrastructure component 2, in particular a track rail, and a sensor device 3 attached thereto in a materially bonded manner for detecting expansions.The sensor device 3 is preferably in signal communication with an evaluation device 5. In particular, the sensor device 3 and the evaluation device 5 are components of a measurement system 6. the evaluation device 5 is preferably designed to process the sensor signals of the sensor device 3, in particular to evaluate the sensor signals of a plurality of sensors in combination, in particular in order to determine therefrom findings about the stress and / or the load on the rail 2 and / or a state of quality of a rail vehicle 9 and / or of the track 10 running thereon. The evaluation device 5 can have a wired signal connection to the sensor device 3.The evaluation device 5 can be in signal connection with a central processing unit 7, in particular a control station and / or a signal box 8, in particular for transmitting the measurement signals or information determined therefrom. The signal connection can be configured to be wired and / or wireless, in particular as a radio connection, in particular as a mobile radio connection. The evaluation of the measurement signals can alternatively or additionally be carried out by means of the central processing unit 7.The track 10 comprises track sleepers 11 which are arranged on a track floor 12, in particular a ballast bed, and two track rails 2 fastened on the track sleepers 11.The sensor device 3 has a first sensor unit 16, a second sensor unit 17 and a coupling means 18. The respective sensor unit 16, 17 is designed to detect an extension at a measurement point 19, 20. The respective measuring point 19, 20 is located on the rail web 14. The coupling means 18 connects the first and the second sensor unit 16, 17 in such a way that the measuring points 19, 20 are arranged at a fixed measuring distance d from one another.The measurement distance d is preferably measured along a longitudinal direction 21 of the track 10, in particular of the track rail 2.The two measuring units 16, 17, in particular furthermore the coupling means 18, are arranged, in particular along the longitudinal direction 21, between two adjacent track sleepers 11, in particular in the same sleeper compartment 22. The distance x between two adjacent railway sleepers 11 is preferably in a range from 0.4 m to 1 m, in particular from 0.5 m to 0.8 m, in particular this is 0.6 m.The measurement distance d is preferably in a range from 0.1 m to 0.6 m, in particular from 0.2 m to 0.4 m, and can be 0.3 m in particular. A ratio between the distance x of adjacent track sleepers 11 and the measurement distance d can be in a range from 1.2:1 to 5:1, in particular from 1.5:1 to 4:1, in particular from 1.8:1 to 3:1.The sensor device 3 can have at least one further sensor unit 23 for detecting expansions at at least one further measurement point 24. The further sensor unit 23 can be connected to the respectively adjacent sensor unit 16, 17, 23 via a further coupling means 25. The further coupling means 25 can be configured to connect the further sensor unit 23 to an adjacent sensor unit 16, 17, 23, in particular to connect it in a signal-transmitting manner and / or to connect it structurally, in particular in such a way that the further measurement point 24 is arranged at a fixed, further measurement distance d from an adjacent measurement point 19, 20, 24. The further measurement distance d can correspond to the measurement distance d or deviate therefrom.Two of the sensor units 16, 17, 23 can form a sensor unit pair 26, in particular together with the coupling means 18 connecting them, in particular with a coupling means 18 defining the measurement distance d. Preferably, each threshold compartment 22 over which the sensor device 3 extends is assigned exactly one sensor unit pair 26.Adjacent sensor unit pairs 26 are preferably connected to one another in a signal-transmitting manner, in particular to the further coupling means 25. The relative position of two adjacent sensor unit pairs 26 is preferably variable, in particular in the longitudinal direction 21 of the track rail 2.The sensor device 3 preferably comprises at least two, in particular at least four, in particular at least eight, in particular at least 10 and / or a maximum of 500, in particular a maximum of 200, in particular a maximum of 100, in particular a maximum of 50, of the sensor units 16, 17, 23.An overall length L of the sensor device 3, in particular along the track rail 2 or along a straight line, can be in a range from 1 m to 1 km, in particular from 2 m to 200 m, in particular from 5 m to 100 m, in particular from 10 m to 50 m.With reference to FIG. 2, one of the sensor unit pairs 26 is illustrated in further detail. The coupling means 18 is designed to be rigid in shape, in particular as a strip, for example made of a metallic material, in particular of aluminum.The respective sensor unit 16, 17 comprises a carrier 28, 29. In particular, the respective carrier 28, 29 comprises an elastic material, in particular a plastic, for example silicone and / or polyurethane and / or a rubber material, for example NBR. Due to the flexibility of the carrier, the latter, in particular the respective sensor unit 16, 17, can be attached to the surface of the track rail 2, in particular of the track web 14, precisely, in particular in a closely fitting manner.The first sensor unit 16 has at least one strain sensor 30 received by the first carrier 28 for detecting a strain at the first measurement point 19. The second sensor unit 17 has at least one second strain sensor 31 received by the second carrier 29 for detecting a strain at the second measurement point 20. In particular, each sensor unit 16, 17 comprises two of the strain sensors 30.1, 30.2, 31.1, 31.2. The strain sensors 30.1, 30.2, 31.1, 31.2 are designed as fiber-optic strain sensors, in particular as fiber Bragg grating sensors. The light-conducting fiber 32, into which corresponding fiber Bragg gratings are introduced, is preferably a glass fiber.The strain sensors 30.1, 30.2, 31.1, 31.2 are each arranged at an angle α 1.1, α 1.2, α 2.1, α 2.2 of 45° to the longitudinal direction 21 of the linear infrastructure component 2. As a result, the strain sensors 30.1, 30.2, 31.1, 31.2 can precisely detect shear strains, in particular in the rail web 14.The two measuring points 19, 20 are preferably arranged in the region of the neutral fiber 33 of the track rail 2. In the neutral fiber 33, the longitudinal extension of the track rail 2 is zero under pure bending load, in particular about a horizontal transverse direction of the track.A width b of the respective sensor units 16, 17 is preferably in a range from 1 cm to 15 cm, in particular from 2 cm to 10 cm, in particular from 4 cm to 8 cm, and is in particular 5 cm. A height h of the respective sensor unit 16, 17 can lie in a range from 2 cm to 20 cm, in particular from 4 cm to 15 cm, in particular from 6 cm to 10 cm, and is in particular 8 cm. The protruding dimensions relate in particular to a portion of the respective sensor unit 16, 17 protruding from the coupling means 18 or protruding therefrom.FIG. 3 illustrates the arrangement of the sensor unit 16 on the track rail 2. the first carrier 28 is attached, in particular bonded, to the track rail 2, in particular to the rail web 14. An adhesive layer 34 preferably extends over the full surface between the track rail 2 and the first sensor unit 16, in particular the first carrier 28.The second sensor unit 17 is mounted on the track rail 2 preferably according to the first sensor unit 16.The adhesive forming the adhesive layer 34 preferably comprises cyanoacrylate and / or epoxy, in particular consists thereof.Because the first carrier 28 is designed to be flexurally soft, it, in particular the first sensor unit 16, can adapt precisely to the shape of the track rail 2, in particular to a curved shape of the track web 14.According to the embodiment shown in FIG. 3, a sensor unit 16, 16', in particular symmetrically, is arranged on each of the two sides of the rail web 14. The symmetrical configuration of corresponding sensor units 16, 16' on the track rail 2 enables comprehensive analysis of expansions, in particular of the stress and / or the load. The symmetrical arrangement is advantageous, but optional.The two sensor units 16, 16' can be components of the same sensor device 3 or belong to separate sensor devices 3, 3'. Sensor units 16, 16' are associated with the same sensor device 3 if they are structurally and / or signal-transmittingly connected and / or are connected to the evaluation device 5 via a common connection, in particular via a single signal line.The sensor unit 16 is described in more detail with reference to FIG. 4. FIG. 4 shows the side of the sensor unit 16 facing the track rail 2. In the region of the first support 28, this forms the two strain sensors 30.1, 31.2, the respective measurement direction 35.1, 35.2 of which is arranged obliquely to the longitudinal direction 21 and to a vertical direction 36.For a particularly precise arrangement of the light-conducting fiber 32 in the region of the strain sensors 30.1, 30.2, the latter is fastened to support elements 37. The respective support element 37 can comprise a metallic material and / or a plastic, in particular consist thereof.To form the respective strain sensor 30.1, 30.2, a section in each case preferably extends in the light-conducting fiber 32 between two of the support elements 37.The strain sensors 30.1, 30.2 are arranged at a small distance from the first measuring point 19 or directly at the measuring point 19. A distance can be present in particular if one sensor unit 16, 17, 23 has a plurality of strain sensors 30.1, 30.2, 31.1, 31.2. However, the distance is preferably so small, or the arrangement of the strain sensors 30.1, 30.2, 31.1, 31.2 is selected such that displacement effects due to the distance are small and / or can be compensated or can be eliminated by calculation.The sensor device 3, in particular the respective sensor unit 16, 17, 23, can have a positioning stop 38, in particular in the form of peripheral recesses, which are designed for the reversibly releasable, form-fitting fixing of the position and orientation of the sensor device 3, in particular of the respective sensor unit 16, 17, 23, in particular relative to an application device 39.The support elements 37 and / or the light-conducting fiber 32 can be arranged on a surface of the sensor unit 16, 17, 23. As a result, the transmission of expansions between the track rail 2 and the respective expansion sensor 30.1, 30.2 is particularly direct and precise.The plurality of strain sensors 30.1, 30.2, 31.1, 31.2 are preferably formed by the same or a single light-conducting fiber 32. Between the sensor units 16, 17 the light-conducting fiber 32 is preferably guided or supported by the coupling means 18.Between two sensor unit pairs 26, a measurement signal line 40, in particular a cable- and / or belt-shaped measurement signal line, can be formed, which has the light-conducting fiber 32. The measurement signal line 40 can form the loop 27.The sensor device 3, in particular the coupling means 18, 25, preferably comprises a plurality of, in particular at least two, in particular at least three, in particular at least five, measurement signal lines 40.The sensor device 3, 3', in particular the coupling means 18, 25, can have a temperature sensor, not shown. The temperature sensor can be designed as a fiber-optic temperature sensor and / or as a film sensor. Temperature influences can be determined and / or compensated for thereby.The sensor device 3 is preferably designed to be flexurally soft, in particular to be foldable and / or wound up or able to be unwound.The method of operation of the measuring system 6, the measuring arrangement 1 or the sensor device 3 is as follows:First, the track 10 can be ready for operation, but without the sensor device 3, 3'. To produce the measuring arrangement 1, the sensor device 3, 3' is attached to the track rail 2. The sensor device 3, 3' is preferably transported to the track 10 in a folded and / or wound-up transport state, in particular wound up on a reel, because of its large length.The surface of the track rail 2, in particular in the region of the rail web 14, can be ground on and / or degreased and / or cleaned.Adhesive can be applied to the track rail 2 and / or the sensor device 3, 3', in particular the respective carrier 28, 29, in order to form the adhesive layer 34.The sensor device 3, 3', in particular the sensor units 16, 17, 23, can be pressed and / or glued onto the track rail 2, preferably one after the other. For this purpose, the application device 39 described in more detail below can be used.The arrangement of the sensor device 3, 3', in particular of the sensor unit pairs 36, in particular of the sensor units 16, 17, 23, takes place according to the above description, in particular as explained with reference to FIGS. 1, 2, 3 to 4.To protect the sensor device 3, 3', in particular the sensor units 16, 17, 23 and / or the adhesive layer 34, the sensor units 16, 17, 23 and / or the coupling means 18, 25 are preferably sealed with a covering means 41. The sensor units 16, 17, 23 are preferably enclosed by the covering means 41 and the track rail 2 in a liquid-tight manner, in particular in a moisture-tight manner.The sensor device 3, 3' is connected to the evaluation device 5 in a signal-transmitting manner. A signal connection can be established between the evaluation device 5 and the signal box 8.The measuring system 6, the measuring arrangement 1 and the sensor device 3, 3' are completed.The calibration of the sensor device 3, 3' can be carried out by means of a measurement run. For this purpose, a rail vehicle 9 with a known weight m can be moved over the track 10. The measurement signals detected by the sensor device 3, 3', in particular the strain sensors 30.1, 30.2, 31.1, 31.2, can be unambiguously assigned to the known mass of a rail vehicle 9 passing ahead. If necessary, the calibration takes place by means of a plurality of measurement runs, in particular with rail vehicles 9 of different, known weights m. The precision of the calibration can thereby be increased once again.The measuring system 6, the measuring arrangement 1 or the sensor device 3, 3' are operational.The measurement signals of the sensor device 3, 3' can be evaluated by means of the evaluation device 5 in order, for example, to determine the stress and / or the load on the track 10, in particular on the track rail 2, and / or to determine a property of the track vehicle 9, in particular its weight and / or quality condition, in particular the runout of wheels of the track vehicle 9, and / or the quality condition of the track 10, in particular for detecting defects and / or cracks in the track rail 2 and / or the track sleepers 11, and / or for detecting the compaction condition of the ballast bed 12, in particular for detecting cavities in the ballast bed 12, in particular below the track sleepers 11.The evaluation of the sensor signals furthermore ensures the precise determination of the position of a rail vehicle 9, a train completion control and / or a speed detection.The measuring system 6, the measuring arrangement 1 or the sensor device 3, 3' ensure a comprehensive, flexible and precise detection of the stresses acting on the track rail 2. These can be used to infer in detail the loads acting on the track 10, in particular the quality state of the track 10 and rail vehicles 9. The measuring system 6, the measuring system 1 or the sensor device 3 increase the operational reliability, the economic efficiency and the reliability of a rail traffic system formed therewith.With reference to FIGS. 5A to 6F, further embodiments of different sensor units 16, 16', 17, 23 are described:The sensor unit 16 shown in FIG. 5A differs from the sensor unit 16 described above in that only one strain sensor 30.1, instead of two of the strain sensors 30.1, 30.2, is provided. In this way, too, shear expansions can be detected with sufficient accuracy, at least for certain application cases.The sensor unit 16 shown in FIG. 5B additionally comprises a strain sensor 30.3, the measurement direction 35.3 of which is oriented parallel to the longitudinal direction 21. The additional strain sensor 30.3 ensures the detection of longitudinal strains of the track rail 2.In addition to the sensor unit 16 described above, the sensor unit 16 illustrated in FIG. 5C comprises two strain sensors 30.4, 30.5, the measurement directions 35.4, 35.5 of which are oriented vertically, in particular perpendicularly to the longitudinal direction 21.In FIG. 5D, the two sensor units 16, 16' described above are shown as a reference. The sensor units 16, 16' are components of separate sensor devices 3, 3'.FIG. 5E shows two sensor units 16, 16' which are structurally and / or signal-transmittingly connected via a coupling means 25. The sensor units 16, 16' and the coupling means 25 are components of the same sensor device 3.FIG. 5F shows two sensor units 16, 16' which are connected to one another by a coupling means 25, in particular structurally and / or signal-transmitting, and are constituent parts of the same sensor device 3. In contrast to the embodiment described above, a further strain sensor 30.6 is arranged on the coupling means 25. A measurement direction 35.6 of the strain sensor 30.6 is oriented parallel to the longitudinal direction 21. The strain sensor 30.6 is arranged on the coupling means in such a way that it can be attached to the rail foot 15. The coupling means 25 ensures a precise positioning of the strain sensor 30.6 relative to the strain sensors 30.1, 30.2 of the sensor unit 16.The production of the measuring arrangement 1 is described in more detail with reference to FIG. 6A. The application device 39 is attached to the track rail 2. This is supported on the rail foot 15 and on the rail head 13. For this purpose, the application device 39 has corresponding fastening means 42.1, 42.2 for connecting to the rail head 13 and the rail foot 15. These can be articulated to one another. A pressing ram 43 can clamp the sensor unit 16 against the track rail 2. Preferably, the pressing punch 43 comprises a thread 44 for effecting the clamping force. The pressing die 43 can have a layer 43 aof an elastic material, in particular for compensating unevennesses between the application device 39 and the sensor unit 16.The application device 39, in particular the pressing plunger 43, can have a counter-positioning stop 45 for precise positioning and / or alignment of the sensor unit 16 relative to the track rail 2.FIG. 6B shows the sensor unit 16 with an additional strain sensor 30.6 for the rail foot 15. The sensor unit 16 is enclosed by the covering means 41, together with the track rail 2, in a liquid-tight manner, in particular in a moisture-tight manner. The covering means 41 can comprise a plastic, in particular consist thereof.The sensor units 16, 16' according to FIG. 6C largely correspond to those according to FIG. 3. A rigid, in particular rigid, structure for connecting the two sensor units 16, 17 of a sensor pair 26 is not provided.Furthermore, an alternative embodiment of an application device 46 is described with reference to FIG. 6C. This can be used with any sensor units 16, 16'. The application device 46 comprises at least one magnet 47, preferably a permanent magnet, alternatively an electromagnet, for fastening to the linear infrastructure component 2, in particular to the track rail, in particular for bringing about a contact pressure force on the sensor units 16, 16'. The pressing punch 43 can otherwise be designed like that of the application device 39.FIG. 6D shows an asymmetrical arrangement of the sensor units 16, 16'.FIG. 6E shows an embodiment largely corresponding to FIG. 5E.FIG. 6F shows an embodiment according to which the sensor device 3 has a symmetrical structure with strain sensors 30.1, 30.2 on the rail web 14 and strain sensors 30.6 on the rail foot 15.

Claims

Sensor device (3, 3') for detecting expansions on a linear infrastructure component (2), in particular a rail, having 1.1 a first sensor unit (16, 16'), having 1.1.1 a first carrier (28), and 1.1.2 at least one expansion sensor (30.1 to 30.6) recorded by the first carrier for detecting an expansion at the first measurement point (19), 1.2 a second sensor unit (17), having 1.2.1 a second carrier (29), and 1.2.2 at least one expansion sensor (31.1, 31.2) recorded by the second carrier (29) for detecting an expansion at the second measurement point (20), 1.3 a coupling means (18) connected to the first carrier (28) and the second carrier (29) for defining a measurement distance (d) between the first measurement point (19) and the second measurement point (20) along a longitudinal direction (21) of the linear infrastructure component (2).Sensor device (3, 3') according to claim 1, characterised in that it is designed for application to a rail web (14) of the rail (2).Sensor device (3, 3') according to claim 1 or 2, characterised in that the measurement distance (d) between the first measurement point (19) and the second measurement point (20) is in a range from 10 cm to 120 cm.Sensor device (3, 3') according to one of the preceding claims, characterized in that the coupling means (18) and / or the first carrier (28) and / or the second carrier (29) are designed to be flexurally soft.Sensor device (3, 3') according to one of the preceding claims, characterized in that the at least one strain sensor (30.1 to 30.6, 31.1, 31.2) is a fibre-optic strain sensor, in particular a fibre Bragg grating sensor.Sensor device (3, 3') according to claim 5, characterised in that the at least one strain sensor (30.1 to 30.6, 31.1, 31.2) is a fibre Bragg grating sensor.Sensor device (3, 3') according to claim 5 or 6, characterised in that at least one strain sensor (30.1 to 30.6) of the first sensor unit (16, 16') and at least one strain sensor (31.1, 31.2) of the second sensor unit (17) are constructed as fibre-optic strain sensors of the same optical fibre (32).Sensor device (3, 3') according to one of the preceding claims, characterized in that the coupling means (18) carries at least one measurement signal line (40) for conducting a measurement signal between the first sensor unit (16, 16') and the second sensor unit (17).Sensor device (3, 3') according to one of the preceding claims, characterized in that the coupling means (18) carries at least two separate optical waveguides (32).Sensor device (3, 3') according to one of the preceding claims, characterized in that the first sensor unit (16, 16') of the at least two of the strain sensors (30.1 to 30.6) has for detecting a strain at the first measurement point (19).Sensor device (3, 3') according to one of the preceding claims, characterized in that the measurement direction (35.1 to 35.6) of the at least one strain sensor (30.1 to 30.6, 31.1, 31.2) is aligned obliquely to the longitudinal direction (21) of the linear infrastructure component (2).Sensor device (3, 3') according to claim 11, characterised in that the measurement direction (35.1 to 35.6) of at least one strain sensor (30.1 to 30.6, 31.1, 31.2) of the first and the second sensor units (16, 16', 17) is aligned obliquely to the longitudinal direction (21) and obliquely to the vertical direction (36) of the linear infrastructure component (2).Sensor device (3, 3') according to one of the preceding claims, characterized byat least one strain sensor (30.3), the measurement direction (35.3) of which is oriented parallel to the longitudinal direction (21) of the linear infrastructure component (2).Sensor device (3, 3') according to one of the preceding claims, characterized byat least one strain sensor (30.3), the measurement direction (35.3) of which is oriented perpendicular to the longitudinal direction (21) of the linear infrastructure component (2), in particular vertically.Sensor device (3, 3') according to one of the preceding claims, characterized byat least one temperature sensor, in particular on the first and / or the second carrier (28, 29) and / or on the coupling means (18).Sensor device (3, 3') according to claim 15, characterised in that the at least one temperature sensor is a fibre-optic strain sensor, in particular a fibre Bragg grating sensor.Sensor device (3, 3') according to claim 15 or 16, characterised in that the at least one temperature sensor and at least one of the strain sensors (30.1 to 30.6, 31.1, 31.2) are formed by the same light-conducting fibre (32).Sensor device (3, 3') according to one of the preceding claims, characterized bya positioning stop (38) for reversibly releasable form-locking fixing of the position and orientation of the sensor device (3, 3') relative to an application device (39) and / or to the linear infrastructure component (2).Sensor device (3, 3') according to one of the preceding claims, characterized byat least one further sensor unit (23), each having a further carrier (23a) and at least one strain sensor accommodated on the further carrier (23a) for detecting a strain at a further measurement point (24), and by a further coupling means (25) for connecting the further sensor unit (23) to an adjacent sensor unit (16, 16', 17, 23).Sensor device (3, 3') according to one of the preceding claims, characterized in that at least two of the measurement points (19, 20) have a distance of at least 0.6 m, in particular at least 2 m, in particular at least 4 m, in particular at least 10 m.Sensor device (3, 3') according to one of the preceding claims, characterized in that it is designed such that it can be wound up and / or folded.Measuring arrangement (1), comprising 22.1 a linear infrastructure component (2), in particular a rail, and 22.2 a sensor device (3, 3') according to one of the preceding claims, 22.3 which is attached to the linear infrastructure component (2) in a materially bonded manner, wherein the two measurement points (19, 20) on the linear infrastructure component (2) are arranged at the measurement distance (d) defined by the coupling means (18).Measuring arrangement (1) according to Claim 22, characterized in that the first and the second measuring point (19, 20) are arranged on a rail web (14) of the rail (2).Measuring arrangement (1) according to Claim 22 or 23, characterized in that the first and the second measuring point (19, 20) are arranged in the neutral fibre (33) of the track rail (2).Measuring arrangement (1) according to one of Claims 22 to 24, characterized bya covering means (41) which, together with the linear infrastructure component (2), seals the first and the second sensor unit (16, 16', 17) in a liquid-tight manner, in particular in a moisture-tight manner.Measuring arrangement (1) according to one of Claims 22 to 25, characterized in that the first and the second measuring point (19, 20) are arranged between two adjacent track sleepers (11) in the longitudinal direction (21).Method for applying a sensor device (3, 3') to a linear infrastructure component (2), in particular a rail, comprising the steps: 27.1 providing a sensor device (3, 3') according to one of Claims 1 to 21, 27.2 attaching the sensor device (3, 3') to the linear infrastructure component (2) in such a way that the two measurement points (19, 20) on the linear infrastructure component (2) are arranged at the measurement distance (d) determined by the coupling means (18).Method according to claim 27, characterised bythe fact that the sensor device (3, 3') is adjusted and aligned by means of an application device (39), which cooperates in a form-fitting manner with a positioning stop (38) of the sensor device (3, 3').Method according to Claim 27 or 28, characterized bycomprising the sensor device (3, 3'), wherein the expansions are detected when the rail (2) is being traveled on by a rail vehicle (9) having a known weight (m).

Images