A real-time crack extension monitoring device and a crack extension position calculation method

Abstract

The present invention discloses a real-time crack extension monitoring device and a crack extension position solution method, which belongs to the technical field of analysis and testing of civil engineering; the present invention proposes a real-time crack extension monitoring device with an assembled flexible wireless bionic spider web structure, which solves many problems in the current monitoring process of crack extension evolution of solid materials, such as complex operation and wiring, and the inability to directly measure the cracks of solid materials in a wireless long-term dynamic manner, etc., and can realize continuous, fast, wireless transmission of signals, high-precision, and cross-scale monitoring of the evolution path of crack development in solid materials, and can locate the crack extension position of solid materials in real time, understand the dynamic development law of cracks, and the crack monitoring device is a flexible assembled structure, which can be used repeatedly, realizing the miniaturization and integration of the device. The present invention also provides a crack extension position solution method using the real-time crack extension monitoring device, which realizes high-precision, efficient, fast, and accurate positioning of cracks.

Description

Technical Field

[0001] The present invention relates to the technical field of analysis and testing of civil engineering, and in particular to a real-time monitoring device for crack extension and a method for calculating the crack extension position. Background Art

[0002] Studying the failure evolution process of various solid materials under the action of external forces in various states of tension, compression and shear has always been a research hotspot in the fields of civil engineering, materials engineering and solid mechanics. There are countless catastrophic accidents caused by the failure of solid materials. Although science and technology have made great progress, the constitutive theories of various solid materials have been continuously improved, and various new analysis and testing technologies have emerged in an endless stream, people still need to conduct in-depth research on the failure mechanism of solid materials, especially to determine the propagation path of cracks when solid materials break, and track the development trajectory of cracks in real time. It has important theoretical research significance and engineering practical value to reveal the macroscopic and microscopic nonlinear mechanical behavior of the crack propagation process of solid materials, evaluate the safety status of civil engineering, understand the stability of civil engineering structures, and take reasonable crack prevention measures in the future.

[0003] The crack extension tracking technology of solid materials has a wide range of applications in the fields of structural safety monitoring and scientific research. The prior art has disclosed the use of acoustic emission technology to monitor crack extension (CN108548726A), the use of image recognition technology to analyze the crack path (CN113865487A), and a method for monitoring crack extension based on the change characteristics of the tip spectrum during crack extension (CN105954293A). In addition, there is a method based on the electromagnetic induction theory to generate an induced current through electromagnetic induction and then judge the occurrence of cracks (CN114076795A), and a method for measuring the surface crack extension of a metal structure using a micrometer grid (CN104568610A). These methods have studied the crack extension evolution of solid materials based on the basic theories of acoustics, optics, electromagnetism, and mechanics, and have achieved certain research results. However, these methods have complex data analysis, high prices for device components, and cannot achieve high-precision long-term dynamic direct measurement of cracks in solid materials. Therefore, it is necessary to develop a dynamic crack monitoring device with high sensitivity, adjustable monitoring accuracy, simple operation, anti-disturbance, flexible and reusable, and wireless signal transmission, which is helpful to study the evolution law of crack propagation in solid materials and promote the progress of crack simulation and crack prevention and arrest technology of solid materials. In view of this, the present invention proposes a real-time crack propagation monitoring device and a crack propagation position calculation method. Summary of the invention

[0004] The purpose of the present invention is to provide a real-time crack extension monitoring device and a crack extension position solution method to solve the problems of complex operation, low precision and complex wiring in the process of solid material crack extension evolution monitoring in the prior art. It is continuous and fast, wirelessly transmits signals, has adjustable monitoring accuracy, and can monitor the solid material crack development evolution path with low disturbance and cross-scale, so as to realize the miniaturization and integration of the monitoring device, locate the solid material crack extension position through precise theoretical calculation, and understand the dynamic development law of solid material cracks.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A real-time crack extension monitoring device includes a flexible assembled crack extension sensor module and a flexible PCB circuit board, and specifically includes the following structure:

[0007] The flexible assembled crack sensing module includes a spider web structure core crack sensing element and an assembled flexible rubber ring. A circular groove is reserved at the bottom of the assembled flexible rubber ring. The spider web structure core crack sensing element is placed in the circular groove reserved at the bottom of the assembled flexible rubber ring and is bonded to the assembled flexible rubber ring to form a whole.

[0008] Preferably, the core crack sensor element of the spider web structure is in the shape of a bionic spider web composed of multiple unclosed spiral annular wires and multiple radial longitudinal wires, with an external lead wire led out from each of the spiral annular wires and the radial longitudinal wires, and different radial longitudinal wires are individually connected to the longitudinal wires connected to the external lead wires, and the remaining radial longitudinal wires are not directly connected to each other. The advantage of choosing this shape is that the crack propagation state within the entire crack sensor element can be monitored by only two external wires, avoiding complicated internal wiring and improving the overall stability of the crack sensor element and the monitoring device; another major advantage of choosing this shape structure is that this shape structure can accurately determine the crack propagation position through electrical theoretical calculations, without the need for data calibration and fitting, thereby improving the reliability of the monitoring data. The theoretical calculation for accurately determining the crack propagation position is detailed in the subsequent description.

[0009] Preferably, the core crack sensing element of the spider web structure is specifically a conductive micron wire, the material of which can be selected from traditional conductive metals such as gold, silver, and copper, or new polymer conductive materials such as graphene and liquid metal composites. The production of the conductive micron wire can be selected from photolithography, sputtering, spraying, molding, etc. There are no clear regulations on the material type and production method of the conductive micron wire, and it is only necessary to ensure that the material and thickness of the conductive micron wire are uniform and the conductivity is good.

[0010] Preferably, the assembled flexible rubber ring is in the shape of a flat cylinder with a groove reserved at the bottom, and the shape of the reserved groove is circular. The diameter of the circular groove is slightly larger than the core crack sensor element of the spider web structure, ensuring that the core crack sensor element of the spider web structure can be placed in the groove; in addition, the depth of the reserved groove is the same as the diameter of the conductive micron wire of the core crack sensor element of the spider web structure, ensuring that the core crack sensor element of the spider web structure is flush with the outer diameter of the assembled flexible rubber ring after being placed in the groove. The above design ensures the overall integrity of the flexible assembled crack sensor module and avoids disturbance and damage to the sensor element when the conductive micron wire is directly moved. In addition, the diameter of the assembled flexible rubber ring is the same as the diameter of the reserved assembly hole of the flexible PCB circuit board.

[0011] Preferably, the assembled flexible rubber ring is made of an elastic material, and can be made of traditional flexible materials such as silicone or rubber, or new elastic polymer materials such as PDMS and Ecoflex. The production of the assembled flexible rubber ring can be made by molding, photolithography and other methods. There are no clear regulations on the material type and production method of the assembled flexible rubber ring. It is only necessary to ensure that the flexible rubber ring is elastic, has a smooth surface and a uniform material.

[0012] Preferably, the outer ring of the assembled flexible rubber ring has reserved assembly holes, and the shape of the assembly hole is an arc-shaped groove surrounding the outer rubber ring. The function of the arc-shaped groove is to connect the flexible assembled crack extension sensor module with the flexible PCB circuit board. The connection method between the flexible assembled crack extension sensor module and the flexible PCB circuit board is snap-on fixation. The selected snap-on type is a strong-release snap-on, which is commonly used on the bottle caps of daily chemical products. The advantage of using this connection and fixation method is that the strong-release snap-on has a simple structure, is easy to produce, and is easy to disassemble, and is suitable for the connection and fixation of small assembled components.

[0013] The flexible PCB circuit board includes a flexible PCB circuit substrate, a power supply module, a flexible PCB circuit board reserved sensor element assembly holes, wiring contacts, a signal amplifier, an analog-to-digital converter, a CPU, and a low-power Bluetooth signal transmitter; the power supply module, the signal amplifier, the analog-to-digital converter, the CPU, and the low-power Bluetooth signal transmitter are integrated on the flexible PCB circuit board to form a whole; the flexible PCB circuit board reserved sensor element assembly holes are the placement positions of the flexible assembled crack extension sensor module, and the fixing method after placement is the aforementioned strong release buckle fixing; the data transmission contact is the connection position where two data transmission wires are led out from the flexible PCB circuit board and the flexible assembled crack extension sensor module, and the connection method is metal welding, and the welding method can be selected from lap welding, hook welding or wrap welding.

[0014] Preferably, the power supply module provides power for the entire device and is battery-powered. The battery type is button batteries. The button battery type can be a common 3V button battery, such as the smaller CR927 with a capacity of 28mah and a size of 9*2.7mm, or a large-capacity CR123A with a capacity of 1600mah and a size of 17*34.5mm. The power supply module can be adjusted in time according to the device size and battery life requirements to select different types of button batteries, and the flexible PCB circuit board can be adjusted at the same time to match it with the power supply module.

[0015] Preferably, the signal amplifier is a differential amplifier, which measures the output resistance signal in the circuit to provide real-time feedback on the resistance change of the flexible assembled crack extension sensor module, thereby monitoring the extension of the crack in the solid material in real time. The advantage of using a differential signal amplifier is that it can amplify the differential signal input and output in the circuit, suppress the common mode interference of the signal, and improve the sensitivity and anti-interference ability of the signal.

[0016] Preferably, the analog-to-digital converter is selected to support the Bluetooth communication protocol. The main function of the analog-to-digital converter is to convert the analog signal in the circuit into a digital signal. The working principle is to convert the amplitude information of the continuous signal into a discrete value in digital form through a quantization and sampling process, so as to facilitate subsequent CPU digital signal processing, analysis and wireless transmission.

[0017] Preferably, the CPU selects a type that supports the Bluetooth communication protocol, and its main function is to receive the digital signal transmitted by the analog-to-digital converter, analyze and process the digital signal, and transmit the processing result to the low-power Bluetooth signal transmitter.

[0018] Preferably, the low-power Bluetooth signal transmitter is a wireless signal transmission device, and its main function is to wirelessly transmit and feedback the digital signal processing results. Its low power consumption ensures the battery life of the device. In addition, the CPU and low-power Bluetooth can be integrated into one, and the available market models are Nordic Semiconductor nRF52840, Texas Instruments CC2640R2F, Texas Instruments CC2640, Silicon Labs Blue Gecko BGM113 and other models.

[0019] A crack extension position solution method, the main principle of which is to calculate the resistance of multiple series-parallel combined circuits. Through analysis, the core crack sensing element of the spider web structure composed of conductive micron silk threads can be simplified into multiple series-parallel combined circuits. According to the voltage division formula of resistor series and the current shunting formula of resistor parallel, the total circuit resistance of this complex circuit without conductive micron silk thread breakage and different conductive micron silk thread breakage conditions can be accurately calculated. By assembling a flexible assembled crack extension sensing module on a flexible PCB circuit board and wirelessly measuring the change of the resistance signal in the circuit, the fracture of the conductive micron silk thread in the flexible assembled crack extension sensing module can be obtained in real time. The overall crack extension position determination logic is: the change of the circuit resistance value can determine the disconnection state of the conductive micron silk thread at different positions in the circuit, and the disconnection state of the conductive micron silk thread at different positions can locate the crack extension position of the solid material.

[0020] Compared with the prior art, the present invention provides a real-time crack propagation monitoring device and a crack propagation position calculation method, which have the following beneficial effects:

[0021] The present invention proposes a real-time crack extension monitoring device and a crack extension position solution method, which can continuously, quickly, highly accurately and cross-scale monitor the crack development evolution path of solid materials, and realize the whole process monitoring from the initiation of cracks in solid materials to the crack extension evolution.

[0022] The present invention proposes a real-time crack extension monitoring device, the main components of which adopt a flexible assembled structure, which can be applied to both crack extension monitoring of solid materials on planes and crack extension monitoring of solid materials on micro-curved surfaces. In addition, the assembled structure makes the crack extension sensor module replaceable, and the flexible PCB circuit board can be reused, which is economical, environmentally friendly, and cost-saving. At the same time, the present invention integrates a CPU and a low-power Bluetooth signal transmitter in the flexible PCB circuit board, which can analyze and process digital signals and transmit them wirelessly, and can achieve long-term dynamic crack extension monitoring, which is continuous and efficient, saves a lot of manpower and material resources, and has a good use and promotion value. Furthermore, the core sensor element circuit structure designed by the present invention is in the shape of a spider web, and the wiring is simple. The crack extension situation in the plane covered by the entire sensor element module can be located by two lead wires, avoiding complicated wiring measurements, and greatly improving the measurement efficiency and the overall stability of the monitoring device.

[0023] The present invention also proposes a crack propagation position calculation method that matches the above-mentioned device. Through reliable numerical theoretical analysis, there is no need for data fitting approximation and experimental calibration. Only by comparing the measured resistance value with the theoretically calculated resistance value, the disconnection of the conductive micron wire can be accurately located, and then the crack propagation position can be accurately located, thereby achieving high-precision, efficient, fast and accurate positioning of the crack. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the overall structure of the real-time crack monitoring device mentioned in Example 1 of the present invention;

[0025] Figure 2 This is a circuit structure flow chart of the real-time crack monitoring device mentioned in Example 1 of the present invention;

[0026] Figure 3 This is a schematic diagram of the use status mentioned in Example 1 of the present invention;

[0027] Figure 4 This is a schematic diagram of the spider web structure core crack sensing element mentioned in Example 1 of the present invention;

[0028] Figure 5 This is a schematic diagram of the circuit structure of the spider web structure core crack sensor element mentioned in Example 1 of the present invention;

[0029] Figure 6 Schematic diagram of different types of shapes of the spider web structure core crack sensing element mentioned in Example 1 of the present invention;

[0030] Figure 7 This is a side view of the flexible assembled crack extension sensor module package mentioned in Example 1 of the present invention;

[0031] Figure 8 This is a top view of the flexible assembled crack extension sensor module package mentioned in Example 1 of the present invention;

[0032] Fig. 9 This is a schematic diagram of the connection between the flexible assembled crack extension sensor module and the flexible PCB circuit board mentioned in Example 1 of the present invention.

[0033] In the figure: 1. Flexible PCB circuit substrate; 2. Power supply module; 3. Flexible assembled crack extension sensor module; 4. Wiring contacts; 5. Signal amplifier; 6. Analog-to-digital converter; 7. CPU; 8. Low-power Bluetooth signal transmitter; 9. Crack extension material to be monitored; 10. Device body; 11. Spider web structure core crack sensor element; 12. Spiral annular wire; 13. Radial longitudinal wire; 14. External lead one; 15. External lead two; 16. Assembled flexible rubber ring; 17. Assembly buckle; 18. Circular groove. DETAILED DESCRIPTION

[0034] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. It should be particularly pointed out that the crack extension monitoring accuracy of the present invention can be adjusted by only increasing or reducing the spiral annular wires and radial longitudinal wires in the core crack sensing element of the spider web structure. If the conductive micron wire is thin enough and the spiral annular wires and radial longitudinal wires are arranged densely enough, continuous positioning monitoring of crack extension can be achieved in theory. Figure 6 This conclusion can be clearly drawn from the above, therefore, the embodiments of the present invention 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.

[0035] The following is an explanation of a crack propagation real-time monitoring device and a crack propagation position calculation method proposed in the present invention in conjunction with a specific example. The specific contents are as follows.

[0036] Embodiment 1:

[0037] See also Figure 1 The present invention proposes a real-time crack monitoring device of an assembled flexible wireless bionic spider web structure, which is mainly composed of two core parts: a flexible assembled crack extension sensor module 3 and a flexible PCB circuit board, specifically including: a flexible PCB circuit substrate 1, a power supply module 2, a flexible assembled crack extension sensor module 3, wiring contacts 4, a signal amplifier 5, an analog-to-digital converter 6, a CPU 7, and a low-power Bluetooth signal transmitter 8.

[0038] See also Figure 2 , Figure 2 The circuit structure flow chart of the real-time crack monitoring device is shown in the figure, wherein the power supply module 2 provides power supply for the flexible PCB circuit substrate 1, the flexible assembled crack extension sensor module 3 is welded to the wiring contact 4, the signal amplifier 5 receives the resistance analog signal of the flexible assembled crack extension sensor module 3 and amplifies the signal, the analog signal in the circuit is converted into a digital signal through the analog-to-digital converter 6, and the converted digital signal is transmitted to the CPU 7, and finally the low-power Bluetooth signal transmitter 8 transmits the result processed by the CPU 7 to the receiving terminal.

[0039] like Figure 3 As shown, the device body 10 of the present invention is directly attached to the surface of the crack extension material 9 to be monitored, so as to monitor the extension of the surface crack within the range of the flexible assembled crack extension sensor module 3.

[0040] like Figure 4As shown, the shape of the spider web structure core crack sensor element 11 in this embodiment is an unclosed regular octagon, comprising 14 conductive micron wires, including 6 spiral ring wires 12 numbered from ① to ⑥ and 8 spiral ring wires 12 numbered from ⑦ to The radial longitudinal wire 13, and the external lead wire 14 connected to the inflection points of the spiral annular wire 12 No. ① and the radial longitudinal wire 13 No. ⑧, and the external lead wire 2 15 connected to the end of the radial longitudinal wire 13 No. ⑦, the external lead wire 14 and the external lead wire 2 15 are connected to the wiring contact 4 by welding.

[0041] The circuit structure of the spider web core crack sensor element 11 is simplified and analyzed to obtain the following: Figure 5 The multiple series-parallel combination circuit shown has a total of 6 paths.

[0042] like Figure 6 As shown, the crack extension monitoring accuracy of the spider web structure core crack sensor element 11 can be adjusted by simply increasing or decreasing the spiral annular wires 12 and radial longitudinal wires 13 in the spider web structure core crack sensor element 11. If the conductive micron wire is thin enough and the spiral annular wires 12 and radial longitudinal wires 13 are arranged densely enough, continuous positioning monitoring of crack extension can be achieved in theory. Figure 6 This conclusion can be obviously drawn.

[0043] like Figure 7 and Figure 8 As shown, the bottom surface of the assembled flexible rubber ring 16 is provided with a circular groove 18, and the outer ring of the flexible rubber ring 16 is provided with an assembly buckle 17; the spider web structure core crack sensor element 11 is placed in the circular groove 18 and fixedly connected by bonding.

[0044] like Fig. 9 As shown, the flexible assembled crack extension sensor module 3 is connected to the flexible PCB circuit board 1 by means of a snap-fit ​​fixation. The type of the snap-fit ​​is a strong release snap-fit. During installation, push the flexible assembled crack extension sensor module 3 and push the assembly snap-fit ​​17 until it is in full contact with the flexible PCB circuit board 1. At this time, the flexible assembled crack extension sensor module 3 and the flexible PCB circuit board 1 form a fixed whole.

[0045] The present invention further proposes a crack position calculation method, the working principle of which is:

[0046] The basic judgment principle of crack extension monitoring is that according to the change of the resistance value of the core crack sensor element 11 of the spider web structure, it can be judged which of the numbered spiral annular wire 12 and the numbered radial longitudinal wire 13 has broken. The breakage indicates that crack extension has occurred in the solid material within the range of the conductive wire.

[0047] According to the relationship between different conductive wire materials, conductivity, length and thickness, the resistance values ​​of each numbered spiral annular wire 12 and each numbered radial longitudinal wire 13 can be obtained. The resistance value of the spiral annular wire 12 No. ① is R1, the resistance value of the spiral annular wire 12 No. ② is R2, the resistance value of the spiral annular wire 12 No. ③ is R3, the resistance value of the spiral annular wire 12 No. ④ is R4, the resistance value of the spiral annular wire 12 No. ⑤ is R5, the resistance value of the spiral annular wire 12 No. ⑥ is R6, the resistance value of the radial longitudinal wire 13 No. ⑦ is R7, the resistance value of the radial longitudinal wire 13 No. ⑧ is R8, the resistance value of the radial longitudinal wire 13 No. ⑨ is R9, and the resistance value of the radial longitudinal wire 13 No. ⑩ is R 10 , The resistance value of radial longitudinal wire 13 is R 11 , The resistance value of radial longitudinal wire 13 is R 12 , The resistance value of the radial longitudinal wire is R 13 , The resistance value of radial longitudinal wire 13 is R 14 , the total circuit resistance of the core crack sensing element 11 of the entire spider web structure is R.

[0048] Through Figure 5 By analyzing and calculating the circuit structure of the spider web core crack sensor element 11, the following conclusions can be obtained:

[0049] If there is no crack in the coverage of the entire flexible assembled crack extension sensor module 3, then the core crack sensor element 11 of the spider web structure has no conductive wire breakage, and the circuit resistance is the series circuit resistance plus the parallel circuit resistance:

[0050]

[0051] If cracks propagate in the area of ​​the No. ① spiral annular wire 12 within the coverage of the entire flexible assembled crack propagation sensor module 3, the No. ① spiral annular wire 12 breaks, and the circuit resistance is:

[0052] R=R8+R7

[0053] If crack propagation occurs in the area of ​​the No. ② spiral annular wire 12 within the coverage of the entire flexible assembled crack propagation sensor module 3, the No. ② spiral annular wire 12 is broken, and the circuit resistance is:

[0054]

[0055] If crack propagation occurs in the area of ​​the No. ③ spiral annular wire 12 within the coverage of the entire flexible assembled crack propagation sensor module 3, the No. ③ spiral annular wire 12 is broken, and the circuit resistance is:

[0056]

[0057] If crack propagation occurs in the area of ​​the No. ④ spiral annular wire 12 within the coverage of the entire flexible assembled crack propagation sensor module 3, the No. ④ spiral annular wire 12 is broken, and the circuit resistance is:

[0058]

[0059] If crack propagation occurs in the area of ​​the spiral annular wire 12 No. ⑤ within the coverage area of ​​the entire flexible assembled crack propagation sensor module 3, the spiral annular wire 12 No. ⑤ is broken, and the circuit resistance is:

[0060]

[0061] If crack propagation occurs in the area of ​​No. ⑥ spiral annular wire 12 within the coverage of the entire flexible assembled crack propagation sensor module 3, and No. ⑥ spiral annular wire 12 breaks, the circuit voltage is:

[0062]

[0063] If cracks propagate in the radial longitudinal wire area No. ⑦ within the coverage of the entire flexible assembled crack propagation sensor module 3, the radial longitudinal wire No. ⑦ 13 is broken, and the circuit resistance is:

[0064] R=∞

[0065] At this point, there is no conductive path and the resistance is infinite;

[0066] If cracks propagate in the radial longitudinal wire area No. ⑧ within the coverage of the entire flexible assembled crack propagation sensor module 3, the radial longitudinal wire No. ⑧ 13 is broken, and the circuit resistance is:

[0067]

[0068] If cracks propagate in the radial longitudinal wire area No. 9 within the coverage of the entire flexible assembled crack propagation sensor module 3, the radial longitudinal wire No. 9 13 is broken, and the circuit resistance is:

[0069]

[0070] If cracks propagate in the radial longitudinal wire area No. ⑩ within the coverage of the entire flexible assembled crack propagation sensor module 3, the radial longitudinal wire No. ⑩ 13 is broken, and the circuit resistance is:

[0071]

[0072] If the entire flexible assembled crack extension sensor module 3 covers The radial longitudinal wire area produces crack expansion. The radial longitudinal wire 13 is broken, and the circuit resistance is:

[0073]

[0074] If the entire flexible assembled crack extension sensor module 3 covers The radial longitudinal wire area produces crack expansion. The radial longitudinal wire 13 is broken, and the circuit resistance is:

[0075]

[0076] If the entire flexible assembled crack extension sensor module 3 covers The radial longitudinal wire area produces crack expansion. The radial longitudinal wire 13 is broken, and the circuit resistance is:

[0077]

[0078] If the entire flexible assembled crack extension sensor module 3 covers The radial longitudinal wire area produces crack expansion. The radial longitudinal wire 13 is broken, and the circuit resistance is:

[0079]

[0080] According to the above deduction, it can be explained that the breakage of different spiral circumferential wires 12 and radial longitudinal wires 13 will cause the overall resistance value of the spider web structure core crack sensor element 11 to change. Therefore, the breakage of different spiral circumferential wires 12 and radial longitudinal wires 13 in the spider web structure core crack sensor element 11 can be inferred according to the different resistance changes in the circuit, thereby determining the expansion of the crack in the solid material to be tested. The crack solution method of this device has a solid theoretical basis, clear crack discrimination criteria, accurate and reliable data, no calibration is required, and the measurement error caused by fitting approximation is avoided, which has broad prospects for promotion and application.

[0081] The above theory is derived as the crack extension location principle of the embodiment, such as Figure 6 As shown, the shape of the spider web structure core crack sensor element 11 can be changed, and the density of the spiral annular wire 12 and the radial longitudinal wire 13 can be increased or decreased according to different crack extension monitoring accuracy requirements. The specific derivation principle is the same as the above derivation principle, so the similar shape change of the spider web structure core crack sensor element 11 does not constitute a limitation of this patent.

[0082] The method for using the assembled flexible wireless bionic spider web structure crack real-time monitoring device mentioned in the present invention is very convenient, and only needs to be attached to the surface of the solid material to be tested.

[0083] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A real-time monitoring device for crack extension, characterized in that: The device comprises a flexible assembled crack extension sensing module (3) and an integrated flexible PCB circuit board; The flexible assembled crack extension sensor module (3) comprises a spider web structure core crack sensor element (11) and an assembled flexible rubber ring (16), a circular groove (18) is reserved at the bottom of the assembled flexible rubber ring (16), and the spider web structure core crack sensor element (11) is placed in the circular groove (18) reserved at the bottom of the assembled flexible rubber ring (16) and is bonded to the assembled flexible rubber ring (16) to form a whole; The integrated flexible PCB circuit board comprises a flexible PCB circuit substrate (1), a power supply module (2), wiring contacts (4), a signal amplifier (5), an analog-to-digital converter (6), a CPU (7), and a low-power Bluetooth signal transmitter (8); the power supply module (2), the signal amplifier (5), the analog-to-digital converter (6), the CPU (7), and the low-power Bluetooth signal transmitter (8) are integrated on the flexible PCB circuit substrate (1) to form a whole; The flexible assembled crack extension sensor module (3) and the integrated flexible PCB circuit board are fixed by snap fastening to form a detachable and replaceable assembled structure; The device is designed as a bionic spider web structure, consisting of a plurality of unclosed spiral annular wires (12) and a plurality of radial longitudinal wires (13), an external lead wire is led out from each of the spiral annular wires (12) and the radial longitudinal wires (13), different radial longitudinal wires (13) are individually connected to the longitudinal wires connected to the external lead wires, and the remaining radial longitudinal wires (13) are not directly connected to each other; the lead wire is connected to the wiring contact (4) in the integrated flexible PCB circuit board by welding.

2. A real-time crack extension monitoring device according to claim 1, characterized in that: The raw materials of the spiral annular wires (12) and the radial longitudinal wires (13) are conductive micron wires, and the conductive micron wires are made of traditional conductive metals or new polymer conductive materials.

3. A real-time crack extension monitoring device according to claim 1, characterized in that: The assembled flexible rubber ring (16) is made of elastic material, and an assembly buckle (17) is reserved on its outside, and the buckle is a strong release buckle.

4. A real-time crack extension monitoring device according to claim 1, characterized in that: The power supply module (2) of the integrated flexible PCB circuit board is powered by a button battery; the signal amplifier (5) is specifically a differential amplifier; the analog-to-digital converter (6) is a type that supports the Bluetooth communication protocol; the CPU (7) is a type that supports Bluetooth communication; and the low-power Bluetooth signal transmitter (8) is a low-power type.

5. A method for calculating crack extension position implemented by the device according to any one of claims 1 to 4, characterized in that: The additional area encryption submodule implements encryption based on the longest edge binary encryption method. The specific execution process is as follows: The circuit structure of the spider web structure core crack sensor element (11) is analyzed, and the resistance values ​​of multiple series-parallel combined circuits in different disconnection states are calculated. The change in resistance value is used to reflect the disconnection state of different spiral annular wires (12) and radial longitudinal wires (13) in the spider web structure core crack sensor element (11). The resistance value is in one-to-one relationship with the disconnection state of the spider web structure core crack sensor element (11). Thus, by measuring the change in resistance value of the spider web structure core crack sensor element (11), it is determined which spiral annular wire (12) or radial longitudinal wire (13) has broken. The occurrence of a break indicates that a crack has expanded in the solid material within the conductive wire range.

6. The method for calculating the crack extension position according to claim 5, characterized in that: By adjusting the shape of the core crack sensing element (11) of the spider web structure, the spiral annular wires (12) and radial longitudinal wires (13) in the core crack sensing element (11) of the spider web structure are denser or reduced, and based on the same analysis and calculation principle, the monitoring accuracy of the crack monitoring device is regulated.

Images