Crack detection device and method

Abstract

The embodiment of the invention provides a crack detection device and method, and relates to the technical field of crack detection. The crack detection device provided by the embodiment of the invention comprises a piezoelectric sensing module, a traction module and a control module, the piezoelectric sensing module comprises a plurality of piezoelectric sensing fiber groups, and the extension directions of two piezoelectric sensing fiber groups are different; the piezoelectric sensing module is connected with the traction module and is used for moving on the surface of the to-be-detected structure under the traction of the traction module; the control module is electrically connected with the piezoelectric sensing module and is used for acquiring sensing electric signals of the at least two piezoelectric sensing fiber groups and determining a setting mode of the crack in the to-be-detected structure according to the sensing electric signals, and the setting mode comprises at least one of crack existence, crack width and crack extension direction. By adopting the technical scheme, the crack detection device can detect whether cracks exist on the surface of the to-be-detected structure according to the piezoelectric signals in the piezoelectric sensing fiber groups with different extension directions and detect the widths and the extension directions of the cracks, and the detection precision is high.

Description

Technical Field

[0001] The present invention relates to the technical field of crack detection, and in particular to a crack detection device and method. Background Art

[0002] In dam projects, crack detection is crucial because the presence of cracks may cause damage to the dam structure, endangering the safety of surrounding areas and even threatening people's lives. After relevant investigations, research and analysis, most of the dam cracks are horizontally penetrating the dam surface and are relatively wide.

[0003] Existing dam crack detection devices are usually sensor networks arranged on the surface or inside the dam, which generally have low measurement accuracy and require external power supply. Some dam crack detection devices also require workers to hand-hold the detection, which is time-consuming, labor-intensive and inefficient. Summary of the invention

[0004] The embodiment of the present invention provides a crack detection device, which can detect whether there are cracks on the surface of a structure to be tested, the width and extension direction of the cracks, and has high detection accuracy.

[0005] In a first aspect, an embodiment of the present invention provides a crack detection device, including a piezoelectric sensing module, a traction module and a control module, wherein the piezoelectric sensing module includes a plurality of piezoelectric sensing fiber groups, and two of the piezoelectric sensing fiber groups have different extension directions;

[0006] The piezoelectric sensing module is connected to the traction module and is used to move on the surface of the structure to be detected under the traction of the traction module;

[0007] The control module is electrically connected to the piezoelectric sensing module, and is used to obtain sensing electrical signals from at least two groups of piezoelectric sensing fiber groups, and determine the setting mode of the crack in the structure to be detected based on the sensing electrical signals, and the setting mode includes at least one of the presence or absence of cracks, crack width and crack extension direction.

[0008] Optionally, any two groups of piezoelectric sensing fibers have different extending directions.

[0009] Optionally, the piezoelectric sensing module further includes a carrier substrate, and the carrier substrate is connected to the traction module;

[0010] A plurality of piezoelectric sensing fiber groups are disposed on the same side of the supporting substrate and arranged along a first direction;

[0011] Along the first direction, the angles between the plurality of piezoelectric sensing fiber groups and the first edge of the supporting substrate gradually change; the first edge extends along the first direction.

[0012] Optionally, the piezoelectric sensing fiber group includes a flexible matrix and a nanofiber group disposed in the flexible matrix;

[0013] The nanofiber group includes a nanofiber layer, a first electrode and a second electrode, the nanofiber layer includes a plurality of nanofibers and a plurality of third electrodes, the third electrode is electrically connected to at least one nanofiber and is disposed on an outer layer of the nanofiber;

[0014] The first electrode is electrically connected to the third electrode, the second electrode is electrically connected to the inner layer of the nanofiber, and the first electrode and the second electrode are electrically connected to the control module respectively, for conducting the sensed charges of opposite polarity to the control module. Optionally, the traction module includes a traction unit and a connection force unit;

[0015] The control module is also electrically connected to the traction unit and is used to determine the travel path of the traction unit according to the preset detection path, so as to control the traction unit to travel according to the travel path;

[0016] The connecting force applying unit is respectively connected to the traction unit and the piezoelectric sensing module, and is used to drive the piezoelectric sensing module to move on the structure to be detected under the traction of the traction unit and apply pressure to the piezoelectric sensing module.

[0017] In a second aspect, an embodiment of the present invention provides a crack detection method, which is used in a crack detection device provided in any embodiment of the present invention, comprising:

[0018] Acquire sensing electrical signals of multiple groups of piezoelectric sensing fibers;

[0019] The setting mode of the crack in the structure to be detected is determined according to the sensed electrical signal, and the setting mode includes at least one of the presence or absence of the crack, the crack width and the crack extension direction.

[0020] Optionally, determining a setting mode of cracks in the structure to be detected according to the sensed electrical signal includes:

[0021] When the sensing electrical signal of at least one group of piezoelectric sensing fibers is smaller than a preset electrical signal, it is determined that there is a crack on the surface of the structure to be detected.

[0022] Optionally, determining a setting mode of cracks in the structure to be detected according to the sensed electrical signal includes:

[0023] Determining the number of piezoelectric sensing fiber groups whose sensing electrical signals are smaller than a preset electrical signal;

[0024] The crack width of the crack in the arrangement direction of the plurality of piezoelectric sensing fiber groups is determined according to the number.

[0025] Optionally, determining a setting mode of cracks in the structure to be detected according to the sensed electrical signal includes:

[0026] Determine the extending direction of the fiber group of the piezoelectric sensing fiber group whose sensing electrical signal is smaller than the preset electrical signal;

[0027] The crack extension direction is determined according to the fiber group extension direction.

[0028] Optionally, acquiring sensing electrical signals of multiple groups of piezoelectric sensing fiber groups includes:

[0029] Obtain detection path information and detection coordinate information;

[0030] The traveling path of the traction module is controlled according to the detection path information, and when the detection coordinate information is reached during the traveling process, the sensing electrical signals of the plurality of piezoelectric sensing fiber groups are obtained.

[0031] The crack detection device provided by the embodiment of the present invention applies pressure to the piezoelectric sensing module through a traction device, so that the piezoelectric sensing fiber groups with different extension directions are subjected to pressure, and the piezoelectric sensing fiber groups thereby output a sensing electrical signal. If the sensing electrical signal becomes smaller, it proves that the surface of the structure to be detected cannot provide support for the piezoelectric sensing module, indicating that there are cracks on the surface of the structure to be detected. Since the extension directions of the piezoelectric sensing fiber groups are different, the degree of overlap between different piezoelectric sensing fiber groups and the cracks is also different. The control module can further calculate the width and extension direction of the crack by comparing the sizes of the sensing electrical signals output by each piezoelectric sensing fiber group. The detection accuracy of the width and extension direction of the crack is high.

[0032] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 is a structural schematic diagram of a crack detection device provided by an embodiment of the present invention;

[0035] Figure 2 is a structural schematic diagram of a piezoelectric sensing module provided by an embodiment of the present invention;

[0036] Figure 3 is a structural schematic diagram of another piezoelectric sensing module provided by an embodiment of the present invention;

[0037] Figure 4 is a structural schematic diagram of another piezoelectric sensing module provided by an embodiment of the present invention;

[0038] Figure 5is a schematic structural diagram of a nanofiber group provided by an embodiment of the present invention;

[0039] Figure 6 is a schematic structural diagram of a nanofiber layer provided by an embodiment of the present invention;

[0040] Figure 7 is a schematic structural diagram of another crack detection device provided by an embodiment of the present invention;

[0041] Figure 8 is a top view of another crack detection device provided by an embodiment of the present invention;

[0042] Fig. 9 is a test diagram of another crack detection device provided by an embodiment of the present invention;

[0043] Fig.10 is a flow chart of a crack detection method provided by an embodiment of the present invention;

[0044] Fig.11 is a flow chart of another crack detection method provided by an embodiment of the present invention;

[0045] Fig.12 is a flow chart of another crack detection method provided by an embodiment of the present invention;

[0046] Fig.13 This is a flow chart of another crack detection method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0048] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0049] The embodiment of the present invention provides a crack detection device. Figure 1 is a structural schematic diagram of a crack detection device provided by an embodiment of the present invention, Figure 2 is a schematic diagram of the structure of a piezoelectric sensing module provided by an embodiment of the present invention, combined with Figure 1 and Figure 2 As shown, the crack detection device includes a piezoelectric sensing module 100, a traction module 200 and a control module 300. The piezoelectric sensing module 100 includes multiple groups of piezoelectric sensing fiber groups 101, and there are two groups of piezoelectric sensing fiber groups 101 with different extension directions; the piezoelectric sensing module 100 is connected to the traction module 200, and is used to move on the surface of the structure to be detected under the traction of the traction module 200; the control module 300 is electrically connected to the piezoelectric sensing module 100, and is used to obtain sensing electrical signals of at least two groups of piezoelectric sensing fiber groups 101, and determine the setting mode of the crack in the structure to be detected according to the sensing electrical signals, and the setting mode includes at least one of the presence or absence of cracks, crack width and crack extension direction.

[0050] Combination Figure 1 and Figure 2 As shown, the piezoelectric sensing module 100 includes at least two groups of piezoelectric sensing fiber groups 101. Due to the piezoelectric effect, when the piezoelectric sensing fiber group 101 is subjected to pressure, a potential difference will be generated inside the piezoelectric sensing fiber group 101. The potential difference is also the sensing electrical signal. The greater the pressure on the piezoelectric sensing fiber group 101, the greater the potential difference generated by the piezoelectric sensing fiber group 101. The piezoelectric sensing module 100 may include multiple groups of piezoelectric sensing fiber groups 101, and the embodiment of the present invention does not impose a specific restriction on the number of piezoelectric sensing fiber groups 101.

[0051] Combination Figure 1 and Figure 2As shown, the control module 300 is electrically connected to each piezoelectric sensing fiber group 101, so that the sensing electrical signals generated by each piezoelectric sensing fiber group 101 can be obtained respectively. By detecting the magnitude of each sensing electrical signal, the magnitude of the pressure on each piezoelectric sensing fiber group 101 can be calculated. When the crack detection device is working, the piezoelectric sensing module 100 is set on the surface of the structure to be tested, and the traction module 200 applies a constant pressure on the piezoelectric sensing module 100. For example, the traction module 200 applies a pressure of 100N on the piezoelectric sensing module 100, so that the piezoelectric sensing module 100 is pressed on the surface of the structure to be tested. Each piezoelectric sensing fiber group 101 in the piezoelectric sensing module 100 is subjected to a certain pressure. When there is no crack on the surface of the structure to be tested, the pressure on each piezoelectric sensing fiber group 101 is the standard pressure, and the sensing electrical signal output by each piezoelectric sensing fiber group 101 is the actual sensing signal. The actual sensing signal can be compared with the preset signal and the comparison result can be used to confirm whether the structure to be tested carrying the piezoelectric sensing fiber group 101 has a crack. The value of the preset electrical signal can be measured in an experimental environment, and the pressure used in the test process is the same as or similar to the pressure used in the actual detection process. When the difference or ratio between the sensing electrical signals output by each piezoelectric sensing fiber group 101 and the preset electrical signal meets the preset comparison result, it means that there is no crack on the surface of the structure to be tested detected by the current crack detection device. The traction device 200 can pull the piezoelectric sensing module 100 to continue to move on the surface of the structure to be tested, and the traction device 200 always applies a constant pressure to the piezoelectric sensing module 100 during the movement. When the difference or ratio between the sensing electrical signals output by one or several piezoelectric sensing fiber groups 101 and the preset signal does not meet the preset comparison result, it means that these piezoelectric sensing fiber groups 101 overlap with the cracks on the surface of the structure to be tested, and the piezoelectric sensing fiber groups 101 on the cracks cannot be subjected to force, so the pressure on these piezoelectric sensing fiber groups 101 becomes smaller, and the sensing electrical signals output by them also become smaller, thereby detecting the position of the cracks on the surface of the structure to be tested.

[0052] It is understandable that, since the pressure applied by the traction device 200 is constant, when the pressure on the piezoelectric sensing fiber group 101 located on the crack decreases, the pressure on other piezoelectric sensing fiber groups 101 will increase. When the area of ​​the overlapping portion between the crack and the piezoelectric sensing fiber group 101 is larger, the sensing electrical signal output by the piezoelectric sensing fiber group 101 is smaller, so the degree of overlap between the piezoelectric sensing fiber group 101 and the crack can be obtained by calculating the ratio between the sensing electrical signal output by the piezoelectric sensing fiber group 101 and the preset electrical signal. Using the built-in algorithm of the control module 300, the extension direction and width of the crack can be obtained according to the degree of overlap between each piezoelectric sensing fiber group 101 and the crack. Exemplarily, the extension direction of the piezoelectric sensing fiber group 101 with the greatest degree of overlap with the crack represents the extension direction of the crack, and the detection accuracy of the crack extension direction is related to the number and extension direction of the piezoelectric sensing fiber group 101.

[0053] The crack detection device provided in the embodiment of the present invention applies pressure to the piezoelectric sensing module through a traction device, so that the piezoelectric sensing fiber groups with different extension directions are subjected to pressure, and the piezoelectric sensing fiber groups output sensing electrical signals. If the sensing electrical signal becomes smaller, it proves that the surface of the structure to be detected cannot provide support for the piezoelectric sensing module, indicating that there are cracks on the surface of the structure to be detected. Since the piezoelectric sensing fiber groups have different extension directions, the degree of overlap between different piezoelectric sensing fiber groups and the cracks is also different. The control module can calculate the width and extension direction of the crack on the surface of the structure to be detected by comparing the sizes of the sensing electrical signals output by each piezoelectric sensing fiber group. The detection accuracy of the crack width and extension direction is high.

[0054] Figure 3 is a schematic diagram of the structure of another piezoelectric sensing module provided by an embodiment of the present invention, referring to Figure 3 , the extension directions of any two groups of piezoelectric sensing fiber groups 101 are different. By setting multiple groups of piezoelectric sensing fiber groups 101 with different extension directions, cracks in various extension directions can be detected. For the same crack, the overlapping degree of multiple groups of piezoelectric sensing fiber groups 101 with different extension directions and the crack is different, and the measured sensing electrical signals are also different. The extension direction and width of the crack calculated by the control module 300 are more accurate. Optionally, the piezoelectric sensing fiber group 101 includes piezoelectric nanofibers, and the detection accuracy of the piezoelectric nanofibers is high, which can improve the detection accuracy of the crack detection device. Optionally, the piezoelectric nanofibers are prepared by an electrospinning method.

[0055] Combination Figure 1 and Figure 3As shown, optionally, the piezoelectric sensing module 100 also includes a supporting substrate 102, which is connected to the traction module 200; multiple groups of piezoelectric sensing fiber groups 101 are arranged on the same side of the supporting substrate 102 and arranged along the first direction X; along the first direction X, the angle between the multiple groups of piezoelectric sensing fiber groups 101 and the first edge 1021 of the supporting substrate 102 gradually changes; the first edge 1021 extends along the first direction X.

[0056] Combination Figure 1 and Figure 3 As shown, the extension directions of the multiple groups of piezoelectric sensing fiber groups 101 gradually change along the first direction X, and the angles between the extension directions of the multiple groups of piezoelectric sensing fiber groups 101 and the first direction X gradually decrease along the first direction X. When detecting cracks, the overlap between each piezoelectric sensing fiber group 101 and the crack is different, and the sensed electrical signals measured are also different, so the extension direction and width of the crack calculated by the control module 300 are more accurate. Figure 4 is a schematic diagram of the structure of another piezoelectric sensing module provided by an embodiment of the present invention, referring to Figure 4 , the electrical detection sensing module 100 may include multiple groups of symmetrically placed piezoelectric sensing fiber groups 101. Optionally, the electrical detection sensing module 100 includes 12 groups of piezoelectric sensing fiber groups 101 with different inclination angles, and the inclination angles of each group of piezoelectric sensing fiber groups 101 relative to the first edge 1021 are 0°, 5°, 15°, 30°, 45°, 60°, 120°, 135°, 150°, 165°, 175° and 180° respectively.

[0057] Figure 5 is a schematic structural diagram of a nanofiber group provided by an embodiment of the present invention, Figure 6 is a schematic diagram of the structure of the nanofiber layer provided by an embodiment of the present invention, combined with Figure 4 , Figure 5 and Figure 6 As shown, the piezoelectric sensing fiber group 101 includes a flexible substrate 1011 and a nanofiber group 1021 arranged in the flexible substrate 1011; the nanofiber group 1021 includes a nanofiber layer 1022, a first electrode 1023 and a second electrode 1024, the nanofiber layer 1022 includes a plurality of nanofibers 1025 and a plurality of third electrodes 1026, the third electrode 1026 is electrically connected to at least one nanofiber 1025, and is arranged on the outer layer of the nanofiber 1025; the first electrode 1023 is electrically connected to the third electrode 1026, the second electrode 1024 is electrically connected to the inner layer of the nanofiber 1025, and the first electrode 1023 and the second electrode 1024 are electrically connected to the control module 300, respectively, for conducting the sensed charges of opposite polarity to the control module 300.

[0058] Combination Figure 4 , Figure 5and Figure 6 As shown, the nanofiber group 1021 is wrapped in a flexible matrix 1011, and the flexible matrix 1011 is in direct contact with the surface of the structure to be tested. The flexible matrix 1011 can protect the nanofiber group 1021 and prevent the charge generated by the nanofiber group 1021 from being transferred to the surface of the structure to be tested. The nanofiber layer 1022 is composed of a plurality of nanofibers 1025, and the nanofibers 1025 are in a ring shape. The plurality of nanofibers 1025 are arranged to form Figure 5 The tubular nanofiber layer 1022 is shown. The outer wall of the nanofiber layer 1022 is the outer layer, and the inner wall of the nanofiber layer 1022 is the inner layer. When the tubular nanofiber layer 1022 is subjected to pressure, charges of opposite polarity will be generated in the inner layer and the outer layer respectively. The inner layer of the nanofiber layer 1022 is electrically connected to the second electrode 1024. The outer layer of the nanofiber layer 1022 is provided with a plurality of third electrodes 1026, and the third electrodes 1026 are used to conduct the charges generated when the nanofiber 1025 is subjected to pressure. The first electrode 1023 is electrically connected to the nanofiber layer 1022 through the third electrode 1026. The first electrode 1023 and the second motor 1024 can respectively conduct the charges of opposite polarity generated when the nanofiber layer 1022 is subjected to pressure to the control module 300. Optionally, the material of the flexible substrate 1011 is epoxy resin.

[0059] Figure 7 is a schematic structural diagram of another crack detection device provided by an embodiment of the present invention, Figure 8 is a top view of another crack detection device provided by an embodiment of the present invention, Fig. 9 is a test diagram of another crack detection device provided by an embodiment of the present invention, combined with Figure 7 , Figure 8 and Fig. 9 As shown, the traction module 200 includes a traction unit 201 and a connection force unit 202; the control module 300 is also electrically connected to the traction unit 201, and is used to determine the travel path of the traction unit 201 according to a preset detection path, so as to control the traction unit 201 to move along the travel path; the connection force unit 202 is respectively connected to the traction unit 201 and the piezoelectric sensing module 100, and is used to drive the piezoelectric sensing module 100 to move on the structure to be detected 400 under the traction of the traction unit 201 and apply pressure to the piezoelectric sensing module 100.

[0060] Combination Figure 7 , Figure 8 and Fig. 9As shown, the traction unit 201 can drive the connection force unit 202 and the piezoelectric sensing module 100 to move, and provide a force point for the connection force unit 202, and the connection force unit 202 applies a constant pressure to the piezoelectric sensing module 100. When the crack detection device is working, the control module 300 controls the traction unit 201 to move along the travel path, and at the same time, the connection force unit 202 applies a constant pressure to the piezoelectric sensing module 100, and the piezoelectric sensing module 100 is in contact with the surface of the structure to be detected 400. Optionally, the control module 300 includes a positioning unit and is connected to the local area network for communication. The control module 300 obtains the terrain of the current position through the positioning unit and the local area network, and designs the travel route according to the terrain to achieve comprehensive detection of the structure to be detected.

[0061] Exemplarily, the connecting force unit 202 includes a robotic arm, the traction module 201 includes a vehicle body, the vehicle body includes four tires 203, the robotic arm is installed on the top of the vehicle body, the robotic arm is connected to a motor and the direction and state are controlled by the control module 300; a 40AH 24V lithium battery is arranged in the vehicle body as a power source, the robotic arm is arranged at the upper end of the vehicle body, each joint of the robotic arm is driven by a motor, and by controlling the rotation of each motor, the robotic arm can complete corresponding movements and posture adjustments, so that the robotic arm can adapt to different shapes and structures of structures to be detected.

[0062] Based on the same inventive concept, an embodiment of the present invention provides a crack detection method, which is used in a crack detection device provided in any embodiment of the present invention. Fig.10 is a flow chart of a crack detection method provided by an embodiment of the present invention, with reference to Fig.10 , crack detection methods include:

[0063] S101, acquiring sensing electrical signals of multiple groups of piezoelectric sensing fibers.

[0064] Combination Figure 1 , Figure 4 , Figure 7 , Figure 8 , Fig. 9 and Fig.10 As shown, specifically, when the crack detection device is working, the piezoelectric sensing module 100 is arranged on the surface of the structure to be tested, and the traction module 200 applies a constant pressure on the piezoelectric sensing module 100, so that the piezoelectric sensing module 100 is pressed on the surface of the structure to be tested, and each piezoelectric sensing fiber group 101 in the piezoelectric sensing module 100 is subjected to a certain pressure, so that each piezoelectric sensing fiber group 101 generates a sensing electrical signal. The control module 300 can obtain the sensing electrical signal generated by each piezoelectric sensing fiber group 101.

[0065] S102, determining a setting mode of cracks in the structure to be detected according to the sensed electrical signal, where the setting mode includes at least one of the presence or absence of cracks, crack width, and crack extension direction.

[0066] Combination Figure 1 , Figure 4 , Figure 7 , Figure 8 , Fig. 9 and Fig.10 As shown, specifically, when there is no crack on the surface of the structure to be tested, the pressure on each piezoelectric sensing fiber group 101 is the standard pressure, and the sensing electrical signal output by each piezoelectric sensing fiber group 101 is a preset electrical signal, and the value of the preset electrical signal can be measured in an experimental environment. When the sensing electrical signal output by each piezoelectric sensing fiber group 101 is a preset electrical signal, it means that there is no crack on the surface of the structure to be tested detected by the current crack detection device, and the traction device 200 can traction the piezoelectric sensing module 100 to move on the surface of the structure to be tested. During the movement, the traction device 200 always applies a constant pressure to the piezoelectric sensing module 100. When the sensing electrical signal output by one or several piezoelectric sensing fiber groups 101 is less than the preset electrical signal, it means that these piezoelectric sensing fiber groups 101 overlap with the cracks on the surface of the structure to be tested, and the piezoelectric sensing fiber groups 101 on the cracks cannot be subjected to force, so the pressure on these piezoelectric sensing fiber groups 101 becomes smaller, and the sensing electrical signal output by them also becomes smaller, thereby detecting the position of the crack on the surface of the structure to be tested. It can be understood that, since the pressure applied by the traction device 200 is constant, when the pressure on the piezoelectric sensing fiber group 101 located on the crack becomes smaller, the pressure on other piezoelectric sensing fiber groups 101 will become larger.

[0067] To summarize, the crack detection method provided by the embodiment of the present invention has different degrees of overlap between the piezoelectric sensing fiber groups with different extension directions and the cracks. Therefore, the sensing electrical signals transmitted by the piezoelectric sensing fiber groups with different extension directions can determine whether there are cracks on the surface of the structure to be detected, as well as the width and extension direction of the cracks. The detection accuracy of the crack width and extension direction is high.

[0068] Based on the above embodiments, how to determine the setting mode of the crack in the structure to be detected according to the sensed electrical signal is described in detail below.

[0069] Specifically, Fig.11 is a flow chart of another crack detection method provided by an embodiment of the present invention, refer to Fig.11 , crack detection methods include:

[0070] S201, obtaining sensing electrical signals of multiple groups of piezoelectric sensing fiber groups.

[0071] S202: When the sensing electrical signal of at least one group of piezoelectric sensing fiber groups is smaller than a preset electrical signal, it is determined that cracks exist on the surface of the structure to be detected.

[0072] Combination Figure 1 , Figure 4 , Figure 7 and Fig.11 As shown, when the sensing electrical signals output by one or several piezoelectric sensing fiber groups 101 are smaller than the preset electrical signals, it means that these piezoelectric sensing fiber groups 101 overlap with the cracks on the surface of the structure to be tested, and the piezoelectric sensing fiber groups 101 on the cracks cannot be subjected to force. Therefore, the pressure on these piezoelectric sensing fiber groups 101 becomes smaller, and the sensing electrical signals output by them also become smaller, thereby determining that there are cracks on the surface of the structure to be tested.

[0073] S203, determining the number of piezoelectric sensing fiber groups whose sensing electrical signals are smaller than a preset electrical signal.

[0074] Combination Figure 1 , Figure 4 and Fig.11 As shown, specifically, when the sensing electrical signal output by one or several piezoelectric sensing fiber groups 101 is smaller than the preset electrical signal, it means that these piezoelectric sensing fiber groups 101 overlap with the cracks on the surface of the structure to be measured, and the piezoelectric sensing fiber groups 101 on the cracks cannot be subjected to force, so the pressure on these piezoelectric sensing fiber groups 101 becomes smaller, and the sensing electrical signal output by them also becomes smaller. Therefore, the number of piezoelectric sensing fiber groups 101 whose sensing electrical signals are smaller than the preset electrical signal is the number of piezoelectric sensing fiber groups 101 that overlap with the cracks.

[0075] S204, determining the crack width of the crack in the arrangement direction of the plurality of piezoelectric sensing fiber groups according to the number.

[0076] Combination Figure 1 , Figure 4 and Fig.11 As shown, specifically, the number of piezoelectric sensing fiber groups 101 that overlap with the crack represents the crack width in the arrangement direction of the piezoelectric sensing fiber group 101. In summary, the crack detection method provided by the embodiment of the present invention can determine that there is a crack on the surface of the structure to be detected when the sensing electrical signal of at least one group of piezoelectric sensing fiber groups is less than the preset electrical signal. And further, the width of the crack is determined based on the number of piezoelectric sensing fiber groups whose sensing electrical signals are less than the preset electrical signals, and the presence or absence of cracks and crack width detection accuracy is high.

[0077] Based on the above embodiments, Fig.12 is a flowchart of another crack detection method provided by an embodiment of the present invention, referring to Fig.12 , crack detection methods include:

[0078] S301, obtaining sensing electrical signals of multiple groups of piezoelectric sensing fibers.

[0079] S302: When the sensing electrical signal of at least one group of piezoelectric sensing fiber groups is smaller than a preset electrical signal, it is determined that cracks exist on the surface of the structure to be detected.

[0080] Combination Figure 1 , Figure 4 , Figure 7 and Fig.11 As shown, when the sensing electrical signals output by one or several piezoelectric sensing fiber groups 101 are smaller than the preset electrical signals, it means that these piezoelectric sensing fiber groups 101 overlap with the cracks on the surface of the structure to be tested, and the piezoelectric sensing fiber groups 101 on the cracks cannot be subjected to force. Therefore, the pressure on these piezoelectric sensing fiber groups 101 becomes smaller, and the sensing electrical signals output by them also become smaller, thereby determining that there are cracks on the surface of the structure to be tested.

[0081] S303, determining the fiber group extension direction of the piezoelectric sensing fiber group whose sensing electrical signal is smaller than the preset electrical signal.

[0082] S304, determining the extension direction of the crack according to the extension direction of the fiber group.

[0083] Combination Figure 1 , Figure 4 and Fig.12 As shown, specifically, when the area of ​​the overlapped portion between the crack and the piezoelectric sensing fiber group 101 is larger, the sensing electrical signal output by the piezoelectric sensing fiber group 101 is smaller, so the overlap degree between the piezoelectric sensing fiber group 101 and the crack can be obtained by calculating the ratio between the sensing electrical signal output by the piezoelectric sensing fiber group 101 and the preset electrical signal. The extension direction of the piezoelectric sensing fiber group 101 where the ratio between the sensing electrical signal output by the piezoelectric sensing fiber group 101 and the preset electrical signal is the smallest is the extension direction of the crack.

[0084] In summary, the crack detection method provided by the embodiment of the present invention can determine that there is a crack on the surface of the structure to be detected when the sensing electrical signal of at least one group of piezoelectric sensing fiber groups is less than the preset electrical signal. And further, the extension direction of the crack is determined according to the extension direction of the fiber group of the piezoelectric sensing fiber group whose sensing electrical signal is less than the preset electrical signal, and the detection accuracy of the presence or absence of cracks and the extension direction of cracks is high.

[0085] Based on the above embodiments, Fig.13 is a flowchart of another crack detection method provided by an embodiment of the present invention, referring to Fig.13 , crack detection methods include:

[0086] S401, obtaining detection path information and detection coordinate information.

[0087] Combination Figure 1 , Figure 7 and Fig.13 As shown, the control module 300 includes a positioning unit, and the control module 300 is connected to the local area network for communication. The control module 300 obtains the terrain of the current position through the positioning unit and the local area network, and designs a travel route according to the terrain to achieve comprehensive detection of the structure to be tested.

[0088] S402, controlling the travel path of the traction module according to the detection path information, and acquiring sensing electrical signals of the plurality of piezoelectric sensing fiber groups when reaching the detection coordinate information during the travel process.

[0089] Combination Figure 1 , Figure 7 and Fig.13 As shown, the control module 300 can obtain the detection path information and the detection coordinate information, and control the travel path of the traction module 200 according to the detection path information. The traction unit 201 can drive the connection force unit 202 and the piezoelectric sensing module 100 to move, and provide a force application point for the connection force unit 202, and the connection force unit 202 applies a constant pressure to the piezoelectric sensing module 100. When the crack detection device is working, the control module 300 controls the traction unit 201 to move along the travel path, and at the same time, the connection force unit 202 applies a constant pressure to the piezoelectric sensing module 100, and the piezoelectric sensing module 100 contacts the surface of the structure 400 to be detected.

[0090] S403, determining a setting mode of the crack in the structure to be detected according to the sensed electrical signal, where the setting mode includes at least one of the presence or absence of cracks, crack width, and crack extension direction.

[0091] In summary, the crack detection method provided by the embodiment of the present invention obtains sensing electrical signals of multiple groups of piezoelectric sensing fiber groups when the detection coordinate information is reached, and repeatedly obtains useless signals, thereby improving detection efficiency.

[0092] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A crack detection device, characterized in that: It includes a piezoelectric sensing module, a traction module and a control module, wherein the piezoelectric sensing module includes a plurality of piezoelectric sensing fiber groups, and two of the piezoelectric sensing fiber groups have different extension directions; The piezoelectric sensing module is connected to the traction module and is used to move on the surface of the structure to be detected under the traction of the traction module; The control module is electrically connected to the piezoelectric sensing module, and is used to obtain sensing electrical signals from at least two groups of the piezoelectric sensing fiber groups, and determine the setting mode of the cracks in the structure to be detected based on the sensing electrical signals, wherein the setting mode includes at least one of the presence or absence of cracks, crack width, and crack extension direction.

2. The crack detection device according to claim 1, characterized in that: Any two groups of the piezoelectric sensing fiber groups have different extending directions.

3. The crack detection device according to claim 2, characterized in that: The piezoelectric sensing module further comprises a carrier substrate, and the carrier substrate is connected to the traction module; A plurality of groups of the piezoelectric sensing fibers are disposed on the same side of the supporting substrate and arranged along a first direction; Along the first direction, the angles between the plurality of piezoelectric sensing fiber groups and the first edge of the supporting substrate gradually change; and the first edge extends along the first direction.

4. The crack detection device according to claim 1, characterized in that: The piezoelectric sensing fiber group includes a flexible substrate and a nanofiber group disposed in the flexible substrate; The nanofiber group includes a nanofiber layer, a first electrode and a second electrode, the nanofiber layer includes a plurality of nanofibers and a plurality of third electrodes, the third electrode is electrically connected to at least one of the nanofibers and is disposed on an outer layer of the nanofiber; The first electrode is electrically connected to the third electrode, the second electrode is electrically connected to the inner layer of the nanofiber, and the first electrode and the second electrode are electrically connected to the control module respectively, for conducting sensed charges of opposite polarity to the control module.

5. The crack detection device according to claim 1, characterized in that: The traction module includes a traction unit and a connection force unit; The control module is also electrically connected to the traction unit, and is used to determine the travel path of the traction unit according to a preset detection path, so as to control the traction unit to travel along the travel path; The connecting force applying unit is connected to the traction unit and the piezoelectric sensing module respectively, and is used to drive the piezoelectric sensing module to move on the structure to be detected and apply pressure to the piezoelectric sensing module under the traction of the traction unit.

6. A crack detection method, used in the crack detection device according to any one of claims 1 to 5, characterized in that: include: Acquiring sensing electrical signals of a plurality of groups of piezoelectric sensing fiber groups; The setting mode of the crack in the structure to be detected is determined according to the sensing electrical signal, and the setting mode includes at least one of the presence or absence of the crack, the crack width and the crack extension direction.

7. The crack detection method according to claim 6, characterized in that: Determining a setting mode of a crack in a structure to be detected according to the sensed electrical signal includes: When the sensing electrical signal of at least one group of the piezoelectric sensing fiber groups is smaller than a preset electrical signal, it is determined that cracks exist on the surface of the structure to be detected.

8. The crack detection method according to claim 7, characterized in that: Determining a setting mode of a crack in a structure to be detected according to the sensed electrical signal includes: Determining the number of the piezoelectric sensing fiber groups whose sensing electrical signals are smaller than a preset electrical signal; The crack width of the crack in the arrangement direction of the plurality of groups of piezoelectric sensing fibers is determined according to the number.

9. The crack detection method according to claim 7, characterized in that: Determining a setting mode of a crack in a structure to be detected according to the sensed electrical signal includes: Determine an extending direction of a fiber group of the piezoelectric sensing fiber group whose sensing electrical signal is smaller than a preset electrical signal; The extension direction of the crack is determined according to the extension direction of the fiber group.

10. The crack detection method according to claim 6, characterized in that: Acquiring sensing electrical signals of the plurality of piezoelectric sensing fiber groups, comprising: Obtain detection path information and detection coordinate information; The traveling path of the traction module is controlled according to the detection path information, and when the detection coordinate information is reached during the traveling process, sensing electrical signals of the plurality of piezoelectric sensing fiber groups are acquired.

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