Methods for monitoring a structure, in particular an infrastructure system

Abstract

Method (200) for monitoring a structure, in particular an infrastructure system, which has a measuring area in which a magnetic field sensor system (100) with at least one flexible magnetic field sensor element (110) is arranged on a flexible substrate (120), wherein the method comprises: (a1) Excitation of the measuring range with an alternating electric current (201) and performance of a magnetic field measurement using the magnetic field sensor system (202); or (a2) Performing a magnetic field measurement using the magnetic field sensor system without prior excitation of the measuring range (211); and (b) Evaluation of the magnetic field measurement (220).

Description

TECHNICAL AREA

[0001] The present disclosure relates to a method for monitoring a structure, in particular an infrastructure system, the use of a magnetic field sensor system for monitoring a structure, in particular an infrastructure system, preferably for structural health monitoring, a structure, in particular an infrastructure system, and a system for monitoring a structure, in particular an infrastructure system. TECHNICAL BACKGROUND

[0002] For various applications, an assessment of the condition of a structure may be necessary. One such application is tensile testing. For example, tensile test specimens can be monitored using optical systems, such as cameras, and / or strain gauges permanently attached to the specimen.

[0003] To assess the condition of structures such as buildings, bridges, towers, pipelines, and similar structures, a method for essentially continuous structural monitoring can be used. This method can be referred to as Structural Health Monitoring (SHM). SHM can be used, for example, to record the condition of the structure under investigation, to analyze its condition, and / or to detect damage to the structure caused by stress and applied loads at an early stage.

[0004] Various methods can be used to monitor structures. Some of the techniques commonly used for SHM include modal-based analysis, acoustic emissions, crack detection, acoustic emission analysis, guided waves, fiber optic sensors, wireless sensors, and machine learning for data analysis. Often, particularly vulnerable areas of the structures are not easily accessible and / or not adequately monitored.

[0005] The purpose of this disclosure is to provide a method for monitoring a structure that enables a cost-effective and / or reliable assessment of the condition of a structure. BRIEF DESCRIPTION OF THE INVENTION

[0006] This problem is solved by a method for monitoring a structure, in particular an infrastructure system, according to claim 1, furthermore by the use of a magnetic field sensor system for monitoring a structure, in particular an infrastructure system, preferably for structural health monitoring, according to claim 8, by a structure, in particular an infrastructure system, according to claim 10, and by a system for monitoring a structure, in particular an infrastructure system, according to claim 12. Further embodiments, configurations, and advantages will become apparent from the dependent claims and the following description.

[0007] According to one aspect of the present disclosure, a method for monitoring a structure is provided. The structure has a measuring area in which at least one magnetic field sensor system with at least one magnetic field sensor element is arranged on a flexible substrate. The method comprises: excitation of the measuring area with an alternating electric current and performance of a magnetic field measurement using the magnetic field sensor system; or performance of a magnetic field measurement using the magnetic field sensor system without prior excitation of the measuring area; and evaluation of the magnetic field measurement, for example, with regard to the integrity of the structure. The method can enable a cost-effective and reliable assessment of the condition of a structure.

[0008] According to another aspect of the present disclosure, the use of a magnetic field sensor system comprising at least one magnetic field sensor element on a flexible substrate is provided for monitoring a structure, in particular an infrastructure system, preferably for structural health monitoring.

[0009] According to another aspect of the present disclosure, a structure, in particular an infrastructure system, is provided. The structure comprises at least one magnetic field sensor system with at least one magnetic field sensor element on a flexible substrate and is arranged at a measuring area of ​​the structure. The magnetic field sensor system is configured to excite the measuring area with an alternating electric current and perform a magnetic field measurement; or to perform a magnetic field measurement without prior excitation of the measuring area.

[0010] According to another aspect of the present disclosure, a system for monitoring a structure, in particular an infrastructure system, is provided. The system comprises at least one magnetic field sensor system with at least one magnetic field sensor element on a flexible substrate, the flexible substrate being adapted to be positioned at a measurement area of ​​the structure. The system includes a controller. The controller is configured to excite the measurement area with an alternating electrical current via electrical conductors and to perform, process, and / or evaluate a magnetic field measurement using the magnetic field sensor element; or to perform, process, and / or evaluate a magnetic field measurement using the magnetic field sensor element without prior excitation of the measurement area.

[0011] The details of one or more aspects of the disclosure are set forth in the accompanying figures and the following description. Other features, objects, and advantages of the principles described in this disclosure will become apparent from the description and drawings, as well as from the claims. BRIEF DESCRIPTION OF THE FIGURES

[0012] The invention will now be explained in more detail with reference to embodiments, without these being intended to restrict the scope of protection defined by the claims.

[0013] The accompanying drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention. The elements of the drawings are relative to one another and not necessarily to scale. Identical reference numerals denote similar parts. Fig. Figure 1 schematically shows a top view of a magnetic field sensor system according to embodiments of the present disclosure. Fig. Figure 2 schematically shows a method for monitoring a structure according to embodiments of the present disclosure. DETAILED DESCRIPTION

[0014] The principles described in this disclosure relate to a method for monitoring a structure. At least one flexible magnetic field sensor element can be arranged on a flexible substrate to obtain a magnetic field sensor system. The magnetic field sensor system can be positioned directly adjacent to a measurement area of ​​the structure and perform measurements regarding the structure's integrity. The measurement area can also be referred to as a measurement surface. This allows for a cost-effective and / or reliable assessment of the structure's condition. The more reliable assessment of the structure's condition can, for example, extend maintenance intervals and reduce costs. In some embodiments, the magnetic field sensor system can be located below a protective layer of the structure at the measurement area and is preferably adapted for essentially continuous monitoring of the structure.

[0015] This disclosure describes a method for monitoring a structure, in particular an infrastructure system such as buildings, bridges, towers, pipelines, and the like. In this context, "monitoring" can refer to monitoring the integrity of the structure. For example, critical material changes such as plastic deformation, hardening, cracking, martensite transformations, and others can be monitored. These can each affect the integrity of the structure. The structure, and in particular the measurement area, typically exhibits ferromagnetic properties and / or is conductive.

[0016] To monitor the structure, at least one magnetic field sensor system is provided at a measuring area of ​​the structure. The magnetic field sensor system comprises at least one magnetic field sensor element and a flexible substrate. The magnetic field sensor element is arranged on the flexible substrate and can be designed to be flexible. "Flexible" in the context of this disclosure can be understood as being adaptable to essentially any surface shape. For example, the magnetic field sensor system can be arranged in corners, over edges, and similar features. In this way, a radius of curvature of less than 1 mm or even less than 200 µm can be achieved.

[0017] The measuring area may, for example, be uneven. However, the method according to the present disclosure enables advantageous monitoring of the structure even with flat measuring surfaces. In particular, a measurement can be carried out essentially without an air gap between the substrate and the measuring surface, so that a particularly small distance of, for example, less than 100 µm, particularly less than 30 µm, preferably less than 5 µm, can be achieved between the measuring surface and the at least one magnetic field sensor element.

[0018] The method involves exciting the structure at the measurement area with an alternating electric current and performing a magnetic field measurement using the magnetic field sensor system, and / or performing a magnetic field measurement using the magnetic field sensor system without prior excitation of the measurement area. The magnetic field measurement with excitation can be referred to as an eddy current magnetic field measurement. The magnetic field measurement without prior excitation of the measurement area can be referred to as a leakage flux magnetic field measurement.

[0019] Eddy current magnetic field measurement can, for example, detect conductivity differences over time by exciting eddy currents in the measurement area. These conductivity differences can provide information about stresses, plastic deformations, hardening, cracks, and similar phenomena resulting from compressive and tensile loads on the structure.

[0020] The magnetic field leakage principle can, for example, detect permeability differences via local stray fields at the measurement surface. In particular, a local stray field can emanate from the measurement surface towards the magnetic field sensor system due to permeability differences. Stresses, such as tension, can also generate magnetic fields (magnetostriction, Villari effect, or reverse magnetostriction). These permeability differences can provide information about stresses, plastic deformations, hardening, cracks, and similar phenomena resulting from compressive and tensile loads on the structure.

[0021] The method further includes an evaluation of the magnetic field measurement. For example, the evaluation can include an assessment of the structure's integrity over time. In some embodiments, the evaluation of the magnetic field measurement can include a prediction regarding the structure's integrity at a later time.

[0022] In some embodiments, the magnetic field sensor system can have at least two magnetic field sensor elements, in particular at least three magnetic field sensor elements, preferably a plurality of magnetic field sensor elements. Preferably, the magnetic field sensor system can have nxm uniformly arranged magnetic field sensor elements. Such embodiments can enable the monitoring of an area.

[0023] In some embodiments, the magnetic field sensor system can have a first region and a second region, wherein the magnetic field sensor elements are arranged at a higher density in the first region than in the second region. "Density" can refer to the number of magnetic field sensor elements per unit area. Such embodiments can allow for more targeted monitoring of the measurement area and reduce costs.

[0024] According to some embodiments, the flexible substrate can have a total height in a direction transverse to the measuring surface of 50 µm, in particular of less than 20 µm, preferably less than 2 µm. Such embodiments allow for particularly small distances between the at least one magnetic field sensor element and the measuring surface. Local magnetic fields can thus be detected and evaluated more effectively.

[0025] In some embodiments, the magnetic field sensor system can also be adapted to excite the measuring range with alternating electric current.

[0026] The following section refers in detail to embodiments of the disclosure, some examples of which are illustrated in the figures. Each example serves to illustrate the disclosure, not to limit it. For example, features that are shown or described as part of embodiments can be used with other embodiments to produce further embodiments.

[0027] Fig. Figure 1 schematically shows in a top view a magnetic field sensor system 100 according to embodiments of the present disclosure.

[0028] The magnetic field sensor system 100 comprises at least one magnetic field sensor element 110 on a flexible substrate 120. In the Fig. In the embodiment shown in Figure 1, the magnetic field sensor system 100 has a plurality of magnetic field sensor elements 110. A measuring surface / measuring area of ​​a structure lies, for example, essentially in the plane of the drawing.

[0029] The magnetic field sensor system 100 has a first region 111, a second region 112, and a third region 113. The magnetic field sensor elements 110 in the first region 111 are arranged at a higher density on the flexible substrate 120 than in the second region 112 and in the third region 113.

[0030] Areas 111, 112, and 113 do not necessarily have to be arranged next to each other, but can also be arranged one above the other and / or partially overlapping.

[0031] The multitude of magnetic field sensor elements 110 can, for example, be arranged uniformly, i.e., nxm magnetic field sensor elements 110 can be arranged essentially regularly on the flexible substrate 120.

[0032] The flexible substrate 120 has a total height of 20 µm. In embodiments, the total height can be less than 50 µm, in particular less than 20 µm, preferably less than 2 µm.

[0033] The magnetic field sensor elements 110 can be configured to detect a local magnetic field. This local magnetic field can be, for example, a stray field from a ferromagnetic structure and / or a magnetic field generated by eddy currents in a conductive structure.

[0034] The magnetic field sensor system 100 can, for example, be configured to excite the measuring area with an alternating electric current such that eddy currents are induced in the measuring area by the magnetic field sensor system 100. For this purpose, the magnetic field sensor system 100 can, for example, include an electrical conductor and / or a coil.

[0035] The magnetic field sensor element 110 can output one or more measured values ​​via a measurement output 130. These one or more measured values ​​can, for example, relate to the local magnetic field. With multiple magnetic field sensor elements 110, the output via the measurement output 130 can be configured such that each measured value is assigned a position on the flexible substrate 120. By performing numerous measurements over time, essentially the entire measuring range can be monitored, and impending failures can be predicted.

[0036] The magnetic field sensor system 100 can include a controller for processing and / or evaluating the measured values. The controller can further be configured to perform an eddy current magnetic field measurement using the magnetic field sensor element 110 and / or a leakage flux magnetic field measurement using the magnetic field sensor element 110.

[0037] The magnetic field sensor system 100 can have a communication interface such that measurement data can be queried from the magnetic field sensor system 100. For example, the communication interface can be configured to transmit the measurement data via wireless communication.

[0038] Fig. Figure 2 schematically shows a method 200 for monitoring a structure, in particular an infrastructure system, according to embodiments of the present disclosure.

[0039] A flexible substrate 120 with at least one magnetic field sensor element 110 of a magnetic field sensor system 100 is arranged on a measuring area of ​​the structure. For example, the flexible substrate 120 can be adhesively attached to the measuring area. The flexible substrate 120 can also be arranged on a non-planar measuring surface. The flexible substrate 120 can be in direct contact with the measuring area.

[0040] The magnetic field sensor system 100 can be used in connection with Fig. 1 described magnetic field sensor system 100 correspond.

[0041] For example, the structure can be a tensile test specimen. The tensile test specimen can exhibit ferromagnetic properties. Method 200 involves performing a leakage flux principle magnetic field measurement using the magnetic field sensor system 211.

[0042] For example, a first magnetic field leakage measurement can be performed before the structure is subjected to stress. A second magnetic field leakage measurement can be performed after the structure has been loaded.

[0043] Method 200 comprises the evaluation of the leakage flux magnetic field measurement 220. For example, the method can detect differences between the first and second leakage flux magnetic field measurements. Furthermore, the evaluation can include an assessment of the first and / or second leakage flux magnetic field measurements. In this way, stresses, plastic deformations, hardening, cracks, and similar features can be detected.

[0044] In one example, the structure could be an infrastructure system, particularly a bridge. The infrastructure system could be partially electrically conductive. The magnetic field sensor system 100 could, for example, be positioned below a protective layer of the structure, such as a coating or similar, at the measuring area. The method 200 comprises exciting the measuring area with an alternating electric current 201. The alternating electric current induces eddy currents at the measuring area. The method 200 further comprises an eddy current principle magnetic field measurement using the magnetic field sensor system 202.

[0045] The eddy current principle magnetic field measurement is evaluated 220, for example with regard to the integrity of the infrastructure system.

[0046] The foregoing description presents a method for monitoring a structure, in particular an infrastructure system, a structure, in particular an infrastructure system, and a system for monitoring a structure, in particular an infrastructure system, with reference to specific examples. It should be noted that various aspects and embodiments disclosed herein can be combined in combinations other than those shown in the figures. It is assumed that various modifications to the aforementioned embodiments can be made without deviating from the scope of the disclosure and the following claims. REFERENCE MARK LIST 100 magnetic field sensor system 110 Magnetic field sensor element 111 first area 112 second area 113 third area 120 flexible substrate 130 measuring output 200 procedures 201 Procedure step a1.1 202 Procedure step a1.2 211 Procedure step a2 220 Procedure step 220

Claims

Method (200) for monitoring a structure, in particular an infrastructure system, which has a measuring area in which a magnetic field sensor system (100) with at least one flexible magnetic field sensor element (110) is arranged on a flexible substrate (120), wherein the method comprises: (a1) excitation of the measuring area with an alternating electric current (201) and performance of a magnetic field measurement using the magnetic field sensor system (202); or (a2) performance of a magnetic field measurement using the magnetic field sensor system without prior excitation of the measuring area (211); and (b) evaluation of the magnetic field measurement (220). Method (200) according to claim 1, wherein the at least one magnetic field sensor element (110) and the flexible substrate (120) are arranged below a protective layer of the structure at the measuring area. Method (200) according to one of the preceding claims, wherein the magnetic field sensor system (100) comprises at least two flexible magnetic field sensor elements (110), in particular at least three flexible magnetic field sensor elements (110), preferably a plurality of magnetic field sensor elements (110). Method (200) according to claim 3, wherein the magnetic field sensor system (100) comprises nxm uniformly arranged flexible magnetic field sensor elements (110). Method (200) according to one of the preceding claims, wherein the magnetic field sensor system (100) has a first region (111) and a second region (112), wherein the magnetic field sensor elements (110) are arranged in the first region (111) at a higher density than in the second region (112). Method (200) according to one of the preceding claims, wherein the flexible substrate (120) has a total height of less than 50 µm, in particular less than 20 µm, preferably less than 2 µm. Method according to one of the preceding claims, wherein the magnetic field sensor system (100) is further adapted to excite the measuring range with the alternating electric current. Use of a magnetic field sensor system (100) comprising at least one flexible magnetic field sensor element (110) on a flexible substrate (120) for monitoring a structure, in particular an infrastructure system, preferably for structural health monitoring. Use of a magnetic field sensor system (100) according to claim 8, wherein the structure is a tensile test specimen. Structure, in particular infrastructure system, comprising at least one magnetic field sensor system (100), comprising at least one flexible magnetic field sensor element (110) on a flexible substrate (120), arranged on a measuring area of ​​the structure; wherein the magnetic field sensor system (100) is configured to: (a1) excite the measuring area with an alternating electric current and perform a magnetic field measurement; or (a2) perform a magnetic field measurement without prior excitation of the measuring area. Structure according to claim 10, wherein the structure comprises a plurality of spatially spaced magnetic field sensor systems (100). A system for monitoring a structure, in particular an infrastructure system, comprising: at least one magnetic field sensor system (100) comprising at least one flexible magnetic field sensor element (110) on a flexible substrate (120), wherein the flexible substrate (120) is adapted to be arranged on a measuring area of ​​the structure; a controller, wherein the controller is configured to (a1) excite the measuring area with an alternating electric current via electrical conductors and to perform, process and / or evaluate a magnetic field measurement using the magnetic field sensor element (110); or (a2) to perform, process and / or evaluate a magnetic field measurement using the magnetic field sensor element (110) without prior excitation of the measuring area. System according to claim 12, further comprising a communication interface for querying measurement data.

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