Passive resonant color-changing flexible vibration sensor and preparation and measurement method thereof

Abstract

The application provides a passive resonant color-changing flexible vibration sensor and a preparation and measurement method thereof. The sensor comprises a flexible main body, a cantilever beam array, a nitrogen gas chamber and a flexible sticker. The cantilever beam array comprises a plurality of cantilever beams arranged in different regions and having different thicknesses and lengths. Each cantilever beam has a unique natural frequency. The cantilever beam produces structural color change when it receives vibration of the corresponding natural frequency. The nitrogen gas chamber wraps all the cantilever beams. The structural color-changing material is used to passively collect vibration signals. The cantilever beam array is arranged to arrange cantilever beams with different natural frequencies, so as to collect vibration signals of different frequencies. Then, the vibration frequency can be determined according to the color-changing region. The nitrogen gas chamber is used to wrap the cantilever beam to realize undamped vibration of the cantilever beam, so as to improve the accuracy of vibration collection. In addition, the flexible main body and the flexible sticker can be applied to measured objects with different shapes and surfaces, so as to improve the application range of vibration measurement.

Description

Technical Field

[0001] This application relates to the field of vibration sensor technology, specifically to a passive resonant color-changing flexible vibration sensor and its preparation and measurement methods. Background Technology

[0002] In fields such as machinery manufacturing, construction engineering, and industrial automation, vibration monitoring of metal structures is one of the key technologies for achieving equipment condition assessment, fault early warning, and health management. By monitoring vibration signals in real time, abnormal operating conditions of equipment can be effectively identified, potential faults can be predicted, thereby avoiding sudden downtime, reducing maintenance costs, and improving operational safety. Therefore, developing reliable, efficient, and adaptable vibration sensing technologies has significant engineering application value.

[0003] Currently, commonly used vibration sensors mainly fall into two categories: contact sensors and passive sensors. However, both have certain limitations in practical applications. Traditional contact sensors (such as piezoelectric, capacitive, or electromagnetic sensors) typically require an external power supply and a wired data transmission system. These sensors often face challenges during installation, such as complex wiring and the need for signal conditioning circuits. Installation and maintenance are extremely difficult, especially in confined environments with strict space requirements or on high-speed rotating or reciprocating components. Furthermore, wired connections are susceptible to electromagnetic interference and are unsuitable for harsh working conditions or long-term unattended monitoring scenarios. Passive sensors (such as those based on surface acoustic waves, optical principles, or radio frequency identification) do not require local power, but they mostly rely on accompanying acoustic, optical, or wireless receiving equipment for signal acquisition and demodulation. These solutions typically have complex system configurations, high costs, and certain environmental requirements (such as avoiding obstructions and requiring specific signal transmission paths). In practice, they are often cumbersome to deploy, making it difficult to achieve large-scale, low-cost distributed monitoring.

[0004] Furthermore, with the development of flexible electronics technology, some studies have proposed vibration sensors fabricated using flexible substrates to better fit irregular surfaces. However, existing flexible sensors still have significant shortcomings when used for vibration monitoring of metal structures: firstly, their structure has limited adaptability to metal surfaces, making it difficult to achieve tight and firm bonding on complex curved surfaces or microstructures, affecting the accuracy of signal transmission; secondly, most flexible sensing units still require connecting wires or regular calibration and maintenance, resulting in insufficient long-term stability; and thirdly, under low-frequency or low-amplitude vibration conditions, their response sensitivity is often insufficient, making it difficult to detect weak vibration signals.

[0005] Therefore, there is an urgent need to develop a new vibration sensing solution that requires no external power supply or wired connection, can closely fit the curved surface of metal, has high sensitivity, and requires almost no maintenance, in order to meet the pressing needs of intelligent monitoring of modern industrial equipment. Summary of the Invention

[0006] To address the aforementioned technical problems, this application is proposed. Embodiments of this application provide a passive resonant color-changing flexible vibration sensor and its fabrication and measurement methods.

[0007] According to one aspect of this application, a passive resonant color-changing flexible vibration sensor is provided, comprising: a flexible body, the flexible body including a flexible substrate and a flexible encapsulation layer, the flexible substrate and the flexible encapsulation layer forming a closed cavity; a cantilever beam array, the cantilever beam array being arranged within the closed cavity, the cantilever beam array including multiple cantilever beams disposed in different regions and having different thicknesses and lengths, each cantilever beam having a unique natural frequency, and the cantilever beam generating structural color change when receiving vibration at the corresponding natural frequency; a nitrogen chamber, the nitrogen chamber filling the closed cavity, the nitrogen chamber enveloping all the cantilever beams, for providing undamped vibration space for the cantilever beams; and a flexible sticker, the flexible body being embedded in the flexible sticker, the bottom surface of the flexible sticker having an adhesive layer for attaching to the metal surface being measured.

[0008] In one embodiment, the thickness of the cantilever beam is in the range of 0.1-0.5 mm, and / or the length of the cantilever beam is in the range of 1-5 mm, and / or the natural frequency range of the cantilever beam is 10-1000 Hz.

[0009] In one embodiment, the nitrogen concentration in the nitrogen chamber is greater than 99.5%, and the difference between the pressure inside the nitrogen chamber and the standard atmospheric pressure is less than a preset value.

[0010] In one embodiment, the flexible body is a thin cuboid structure with a square base.

[0011] According to another aspect of this application, a method for fabricating a passive resonant color-changing flexible vibration sensor is provided, comprising: casting a flexible substrate in a mold; casting partitions on the flexible substrate to form multiple regional grooves to obtain a sandwich structure; embedding one end of multiple cantilever beams into the multiple regional grooves to obtain a cantilever beam array; casting a flexible encapsulation layer above the sandwich structure to form a closed cavity with the flexible substrate, and reserving a gas injection channel on the flexible encapsulation layer; extracting air from the closed cavity and injecting nitrogen gas, and then sealing the gas injection channel to form a nitrogen gas chamber; and arranging a flexible sticker on the outer surface of the flexible substrate.

[0012] In one embodiment, casting the flexible substrate in the mold includes: casting a flexible material in the mold and controlling the casting temperature to be 25°C-30°C, and after curing, forming a square sheet-like substrate to obtain the flexible substrate.

[0013] In one embodiment, embedding one end of each of the multiple cantilever beams into the multiple region grooves includes: cutting the structural color-changing flexible film into cantilever beams according to preset different sizes, and fixing one end of the cantilever beam to the sidewall of the region groove using a flexible adhesive.

[0014] In one embodiment, the step of extracting air from the closed cavity, injecting nitrogen, and then sealing the gas injection channel to form a nitrogen chamber includes: evacuating the closed cavity to a pressure less than 10 Pa through the gas injection channel, maintaining this pressure for 5 minutes, then injecting nitrogen to standard atmospheric pressure. After repeating the evacuation and nitrogen injection operations multiple times, the gas injection channel is sealed using a local high temperature of 200℃-250℃ to form the nitrogen chamber.

[0015] In one embodiment, the step of distributing a flexible sticker on the outer surface of the flexible substrate includes: coating an adhesive layer on the outer surface of the flexible substrate and attaching a flexible protective sticker to the outer surface of the adhesive layer.

[0016] According to another aspect of this application, a measurement method for a passive resonant color-changing flexible vibration sensor is provided, comprising: attaching a vibration sensor to a metal surface to be measured via an adhesive layer of a flexible sticker; wherein the vibration sensor is a passive resonant color-changing flexible vibration sensor as described in any of the above claims; when the metal surface to be measured vibrates, the cantilever beam array collects vibration signals; if the vibration frequency of the vibration signal is consistent with the natural frequency of the cantilever beams in the cantilever beam array, the cantilever beams in the corresponding region exhibit structural color change; and determining the vibration frequency value of the metal surface to be measured based on the natural frequency corresponding to the cantilever beam at the location of the structural color-changing region.

[0017] This application provides a passive resonant color-changing flexible vibration sensor and its fabrication and measurement methods. The sensor comprises a flexible body, a cantilever beam array, a nitrogen chamber, and a flexible sticker. The flexible body includes a flexible substrate and a flexible encapsulation layer, forming a closed cavity. The cantilever beam array is disposed within the closed cavity and includes multiple cantilever beams of varying thickness and length located in different areas. Each cantilever beam has a unique natural frequency. When a cantilever beam receives vibration at its corresponding natural frequency, it undergoes structural color change. The nitrogen chamber fills the closed cavity, enveloping all the cantilever beams and providing them with a passive resonant color-changing sensor. The damped vibration space consists of a flexible main body embedded in a flexible sticker. The bottom surface of the flexible sticker has an adhesive layer for attaching to the metal surface being measured. Passive vibration signal acquisition is achieved using structurally color-changing materials. Furthermore, by arranging cantilever beams with different natural frequencies using an array of cantilever beams, vibration signals of different frequencies can be acquired. The vibration frequency can then be determined based on the color-changing area. Simultaneously, a nitrogen chamber envelops the cantilever beams to achieve undamped vibration, thereby improving the accuracy of vibration acquisition. Additionally, the flexible main body and flexible sticker are applicable to objects with different shapes and surfaces, thus expanding the applicability of vibration measurement. Attached Figure Description

[0018] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0019] Figure 1 This is a schematic diagram of the main structure of a passive resonant color-changing flexible vibration sensor provided in an exemplary embodiment of this application.

[0020] Figure 2 This is a top view of the passive resonant color-changing flexible vibration sensor provided in an exemplary embodiment of this application.

[0021] Figure 3 This is a schematic flowchart of a method for fabricating a passive resonant color-changing flexible vibration sensor provided in an exemplary embodiment of this application.

[0022] Figure 4 This is a flowchart illustrating the measurement method of a passive resonant color-changing flexible vibration sensor provided in an exemplary embodiment of this application.

[0023] Explanation of reference numerals in the attached figures: 1. Flexible main body; 2. Cantilever beam array; 3. Nitrogen gas chamber; 4. Metal under test; 11. Flexible substrate; 12. Flexible encapsulation layer; 21. Cantilever beam. Detailed Implementation

[0024] Hereinafter, exemplary embodiments according to this application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein.

[0025] Figure 1 This is a schematic diagram of the main structure of a passive resonant color-changing flexible vibration sensor provided in an exemplary embodiment of this application. Figure 2 This is a top view schematic diagram of a passive resonant color-changing flexible vibration sensor provided in an exemplary embodiment of this application. Figure 1 and Figure 2 As shown, the passive resonant color-changing flexible vibration sensor includes: a flexible body 1, a cantilever beam array 2, a nitrogen chamber 3, and a flexible sticker (not shown in the figure). The flexible body 1 includes a flexible substrate 11 and a flexible encapsulation layer 12, which together form a closed cavity. The cantilever beam array 2 is arranged within the closed cavity and includes multiple cantilever beams 21 arranged in different areas with different thicknesses and lengths. Each cantilever beam 21 has a unique natural frequency. When the cantilever beam 21 receives vibration at its corresponding natural frequency, it undergoes structural color change. The nitrogen chamber 3 fills the closed cavity and encloses all the cantilever beams 21, providing undamped vibration space for the cantilever beams 21. The flexible body 1 is embedded in the flexible sticker, and the bottom surface of the flexible sticker has an adhesive layer for attaching to the surface of the metal being measured 4.

[0026] This application provides a passive resonant color-changing flexible vibration sensor, comprising a flexible body, a cantilever beam array, a nitrogen chamber, and a flexible sticker. The flexible body includes a flexible substrate and a flexible encapsulation layer, forming a closed cavity. The cantilever beam array is arranged within the closed cavity, comprising multiple cantilever beams of varying thickness and length located in different areas. Each cantilever beam has a unique natural frequency. When a cantilever beam receives vibration at its corresponding natural frequency, it undergoes structural color change. The nitrogen chamber fills the closed cavity, enveloping all the cantilever beams and providing them with undamped vibration. The system utilizes a flexible substrate embedded in a flexible sticker. The bottom surface of the sticker has an adhesive layer for attaching to the metal surface being measured. Passive vibration signal acquisition is achieved using structurally color-changing materials. Furthermore, by arranging cantilever beams with different natural frequencies in an array, vibration signals of varying frequencies can be acquired. The vibration frequency can then be determined based on the color-changing area. Simultaneously, a nitrogen chamber encases the cantilever beams to achieve undamped vibration, thereby improving the accuracy of vibration acquisition. Additionally, the flexible substrate and sticker are suitable for measuring objects of different shapes and surfaces, thus expanding the applicability of vibration measurement.

[0027] In one embodiment, the thickness of the cantilever beam 21 ranges from 0.1 to 0.5 mm, and / or the length of the cantilever beam 21 ranges from 1 to 5 mm, and / or the natural frequency range of the cantilever beam 21 ranges from 10 to 1000 Hz.

[0028] Specifically, this application divides the cantilever beam array 2 into 9 regions, each region having a size of 10mm × 10mm. The natural frequencies of the cantilever beams 21 in each region are 10Hz, 100Hz, 200Hz, 300Hz, 400Hz, 500Hz, 600Hz, 800Hz, and 1000Hz, respectively. Preferably, the thickness of the cantilever beam 21 with a natural frequency of 10Hz is 0.1mm and the length is 5mm, the thickness of the cantilever beam 21 with a natural frequency of 1000Hz is 0.5mm and the length is 1mm, and the thickness and length of the other cantilever beams 21 are set in order of their natural frequencies. All cantilever beams 21 are made of deformation-sensitive thin films. When such materials are deformed under stress, their microstructure changes, and when the deformation is greater than 5%, the color changes from red to green.

[0029] In one embodiment, the nitrogen concentration in the nitrogen chamber 3 is greater than 99.5%, and the difference between the pressure inside the nitrogen chamber 3 and the standard atmospheric pressure is less than a preset value.

[0030] Specifically, each cantilever beam 21 corresponds to an independent nitrogen chamber 3. The volume of the nitrogen chamber 3 is 10mm×10mm×1.5mm. The nitrogen purity of the nitrogen chamber 3 is 99.9%, and the difference between the pressure inside the nitrogen chamber 3 and the standard atmospheric pressure is less than the preset value (i.e., equivalent to the standard atmospheric pressure). After sealing, there is no leakage, ensuring that there is no air resistance interference when the cantilever beam 21 vibrates.

[0031] In one embodiment, the flexible body 1 is a thin cuboid structure with a square base.

[0032] Specifically, the flexible body 1 has a volume of 90mm×90mm×5mm. Both the flexible substrate 11 and the flexible encapsulation layer 12 are made of flexible materials, which have good flexibility and sealing properties and can be bent to a curvature radius greater than 50mm without damage.

[0033] Preferably, the flexible sticker can be made of waterproof material, with a special silicone adhesive layer, and can be repeatedly peeled off and reused without leaving any adhesive residue.

[0034] The passive resonant color-changing flexible vibration sensor provided in this application is suitable for vibration monitoring of metal structures such as mechanical equipment, building steel structures, and pipelines. It requires no power supply and complex installation, can work stably in normal temperature environments, and has a service life of more than one year after a single installation.

[0035] Figure 3This is a schematic flowchart illustrating a method for fabricating a passive resonant color-changing flexible vibration sensor according to an exemplary embodiment of this application. Figure 3 As shown, the fabrication method of this passive resonant color-changing flexible vibration sensor includes the following steps: Step 310: Cast the flexible substrate into the mold.

[0036] This application uses a laser-engraved mold with a dimensional error of less than ±0.01mm to ensure the precise installation position of the cantilever beam 21 and avoid interference between areas.

[0037] Step 320: Cast partitions on a flexible substrate to form multiple regional grooves, thus obtaining a sandwich structure.

[0038] The partition is cast on the flexible substrate, and the area groove is pressed on the flexible substrate 11 using a special mold. The size of the area groove is precisely matched with the corresponding area cantilever beam 21.

[0039] Step 330: Embed one end of each of the multiple cantilever beams into the grooves of the multiple regions to obtain a cantilever beam array.

[0040] In this application, one end of each cantilever beam 21 is embedded in the corresponding area groove, and the other end is suspended, to obtain a cantilever beam array 2.

[0041] Step 340: Cast a flexible encapsulation layer on top of the sandwich structure to form a closed cavity with the flexible substrate, and reserve a gas injection channel on the flexible encapsulation layer.

[0042] A flexible material of the same material as the flexible substrate 11 is cast on top of the sandwich structure, with the same thickness as the flexible substrate 11, to form a flexible encapsulation layer 12. The flexible encapsulation layer 12 is tightly attached to the edge of the flexible substrate 11, with only one gas injection channel with a diameter of less than 0.5 mm reserved.

[0043] Step 350: After extracting the air from the closed cavity and injecting nitrogen, seal the gas injection channel to form a nitrogen chamber.

[0044] This application uses a gas injection channel to extract air from a closed cavity, inject nitrogen, and then seal the gas injection channel to form a closed nitrogen chamber.

[0045] Step 360: Arrange flexible stickers on the outer surface of the flexible substrate.

[0046] Finally, a flexible sticker is placed on the outer surface of the flexible substrate 11 to attach the entire sensor to the surface of the metal 4 being measured.

[0047] This application provides a method for fabricating a passive resonant color-changing flexible vibration sensor, which involves setting up a flexible body, a cantilever beam array, a nitrogen chamber, and a flexible sticker. The flexible body includes a flexible substrate and a flexible encapsulation layer, forming a closed cavity. The cantilever beam array is arranged within the closed cavity and includes multiple cantilever beams with different thicknesses and lengths located in different areas. Each cantilever beam has a unique natural frequency. When a cantilever beam receives vibration at its corresponding natural frequency, it undergoes structural color change. The nitrogen chamber fills the closed cavity, enveloping all the cantilever beams and providing undamped protection. The vibration space consists of a flexible main body embedded in a flexible sticker. The bottom surface of the flexible sticker has an adhesive layer for attaching to the metal surface being measured. Passive vibration signal acquisition is achieved using structurally color-changing materials. By setting up a cantilever beam array to arrange cantilever beams with different natural frequencies, vibration signals of different frequencies can be acquired. The vibration frequency can then be determined based on the color-changing area. Simultaneously, a nitrogen gas chamber is used to enclose the cantilever beams to achieve undamped vibration, thereby improving the accuracy of vibration acquisition. In addition, the flexible main body and flexible sticker can be applied to objects with different shapes and surfaces, thus expanding the applicability of vibration measurement.

[0048] In one embodiment, step 310 can be implemented by casting a flexible material into a mold and controlling the casting temperature to be 25°C-30°C. After curing, a square sheet-like substrate is formed, thus obtaining a flexible substrate.

[0049] Flexible materials are selected and cast in a high-precision mold. The casting temperature is controlled at 25℃-30℃. After curing for 24 hours, a square sheet-like lower flexible substrate 11 is formed, ensuring that the flexible substrate 11 has uniform hardness and no internal stress. Furthermore, a groove structure for installing the cantilever beam interlayer is reserved on the flexible substrate 11.

[0050] In one embodiment, step 330 can be implemented by cutting the structural color-changing flexible film into cantilever beams according to different preset sizes, and fixing one end of the cantilever beam to the side wall of the area groove using a flexible adhesive.

[0051] In this application, the structural color-changing flexible film is cut into cantilever beams 21 according to a preset size, and one end of the cantilever beam 21 is fixed to the side wall of the groove using a flexible adhesive to ensure that the cantilever beam 21 can vibrate freely.

[0052] In one embodiment, the specific implementation of step 350 above may be as follows: the closed cavity is evacuated to a pressure of less than 10 Pa through the gas injection channel, nitrogen is injected to the standard atmospheric pressure after maintaining the pressure for 5 minutes, and the evacuation and nitrogen injection operations are repeated multiple times. Then, the gas injection channel is sealed with a local high temperature of 200℃-250℃ to form a nitrogen chamber.

[0053] Specifically, the closed cavity is evacuated to a pressure less than 10 Pa through the gas injection channel and held for 5 minutes before nitrogen is injected to the standard atmospheric pressure. The evacuation and nitrogen injection operations are repeated multiple times (e.g., 3-5 times) to ensure that there is no residual air in the cavity. Finally, infrared heating (heating temperature 200℃-250℃, heating time 10 seconds) is used to locally heat and seal the gas injection channel at a high temperature, causing the silicone rubber to melt and seal, forming a nitrogen chamber.

[0054] In one embodiment, step 360 can be implemented by coating an adhesive layer on the outer surface of a flexible substrate and attaching a flexible protective sticker to the outer surface of the adhesive layer.

[0055] A medical-grade adhesive layer is coated on the outer surface of the flexible substrate 11, a waterproof flexible protective sticker is attached, and a scale and frequency comparison table are marked to complete the sensor manufacturing.

[0056] Figure 4 This is a schematic flowchart illustrating the measurement method of a passive resonant color-changing flexible vibration sensor provided in an exemplary embodiment of this application. Figure 4 As shown, the measurement method of this passive resonant color-changing flexible vibration sensor includes the following steps: Step 410: Apply the vibration sensor to the metal surface to be tested using the adhesive layer of the flexible sticker.

[0057] The vibration sensor is any of the passive resonant color-changing flexible vibration sensors mentioned above. The vibration sensor is attached to the metal surface 4 to be measured via the adhesive layer of a flexible sticker (the bonding area is free of oil and impurities), ensuring that there is no gap between the sensor and the surface of the metal 4 to be measured.

[0058] Step 420: When the metal surface under test vibrates, the cantilever beam array collects the vibration signal.

[0059] When the surface of the metal being tested 4 vibrates, the vibration energy is transmitted through the flexible body 1 to the internal cantilever beam array 2, and the cantilever beam 21 in the cantilever beam array 2 collects the vibration signal.

[0060] Step 430: If the vibration frequency of the vibration signal is consistent with the natural frequency of the cantilever beam in the cantilever beam array, then the cantilever beam in the corresponding area will undergo structural discoloration.

[0061] Since the natural frequencies of the cantilever beam 21 in different regions are different, the cantilever beam 21 in a certain region will resonate only when the difference between the external vibration frequency and the natural frequency of the cantilever beam 21 in a certain region is ≤5% (i.e. they are the same). The mechanical deformation caused by the resonance changes the microstructure of the structural color-changing film, thus exhibiting obvious color changes.

[0062] Step 440: Determine the vibration frequency value of the tested metal surface based on the natural frequency corresponding to the cantilever beam at the location of the structural discoloration area.

[0063] By observing the location of the color change area on the sensor surface and referring to the area-natural frequency reference table marked on the sensor, the vibration frequency value of the measured metal 4 surface can be directly determined. For example, when the vibration frequency of the measured metal 4 surface is 200Hz, the cantilever beam 21 corresponding to the 200Hz region resonates, and its color changes from red to green. By observing the location of the red area and referring to the frequency reference table marked on the sensor surface, the operator can quickly determine that the vibration frequency is 200Hz.

[0064] This application provides a measurement method for a passive resonant color-changing flexible vibration sensor, which comprises a flexible main body, a cantilever beam array, a nitrogen chamber, and a flexible sticker. The flexible main body includes a flexible substrate and a flexible encapsulation layer, forming a closed cavity. The cantilever beam array is arranged within the closed cavity and includes multiple cantilever beams of varying thickness and length located in different areas. Each cantilever beam has a unique natural frequency. When a cantilever beam receives vibration at its corresponding natural frequency, it undergoes structural color change. The nitrogen chamber fills the closed cavity, enveloping all the cantilever beams and providing undamped protection. The vibration space consists of a flexible main body embedded in a flexible sticker. The bottom surface of the flexible sticker has an adhesive layer for attaching to the metal surface being measured. Passive vibration signal acquisition is achieved using structurally color-changing materials. By setting up a cantilever beam array to arrange cantilever beams with different natural frequencies, vibration signals of different frequencies can be acquired. The vibration frequency can then be determined based on the color-changing area. Simultaneously, a nitrogen gas chamber is used to enclose the cantilever beams to achieve undamped vibration, thereby improving the accuracy of vibration acquisition. In addition, the flexible main body and flexible sticker can be applied to objects with different shapes and surfaces, thus expanding the applicability of vibration measurement.

[0065] In addition to the methods and apparatus described above, embodiments of this application may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the methods according to various embodiments of this application described in the "Exemplary Methods" section above.

[0066] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this application. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0067] Furthermore, embodiments of this application may also be computer-readable storage media storing computer program instructions thereon, which, when executed by a processor, cause the processor to perform the steps in the methods according to various embodiments of this application described in the "Exemplary Methods" section above.

[0068] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof.

[0069] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0070] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0071] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0072] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0073] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A passive resonant color-changing flexible vibration sensor, characterized in that, include: A flexible body, comprising a flexible substrate and a flexible encapsulation layer, wherein the flexible substrate and the flexible encapsulation layer constitute a closed cavity; A cantilever beam array is arranged within the closed cavity. The cantilever beam array includes multiple cantilever beams with different thicknesses and lengths, located in different areas. Each cantilever beam has a unique natural frequency. When the cantilever beam receives vibration at its corresponding natural frequency, it undergoes structural discoloration. A nitrogen chamber, which fills the closed cavity and encloses all the cantilever beams, is used to provide undamped vibration space for the cantilever beams; A flexible sticker, wherein a flexible body is embedded in the flexible sticker, and an adhesive layer is provided on the bottom surface of the flexible sticker for applying to the metal surface to be tested.

2. The passive resonant color-changing flexible vibration sensor according to claim 1, characterized in that, The thickness of the cantilever beam is in the range of 0.1-0.5 mm, and / or the length of the cantilever beam is in the range of 1-5 mm, and / or the natural frequency range of the cantilever beam is 10-1000 Hz.

3. The passive resonant color-changing flexible vibration sensor according to claim 1, characterized in that, The nitrogen concentration in the nitrogen chamber is greater than 99.5%, and the difference between the pressure inside the nitrogen chamber and the standard atmospheric pressure is less than a preset value.

4. The passive resonant color-changing flexible vibration sensor according to claim 1, characterized in that, The flexible body is a thin cuboid structure with a square base.

5. A method for fabricating a passive resonant color-changing flexible vibration sensor, characterized in that, include: Cast a flexible substrate into a mold; A partition is cast on the flexible substrate to form multiple regional grooves, resulting in a sandwich structure. One end of each of the multiple cantilever beams is embedded into the grooves of the multiple regions to obtain a cantilever beam array; A flexible encapsulation layer is cast above the sandwich structure to form a closed cavity with the flexible substrate, and a gas injection channel is reserved on the flexible encapsulation layer; After the air in the closed cavity is extracted and nitrogen is injected, the gas injection channel is sealed to form a nitrogen chamber. Flexible stickers are disposed on the outer surface of the flexible substrate.

6. The method for fabricating a passive resonant color-changing flexible vibration sensor according to claim 5, characterized in that, The process of casting the flexible substrate in the mold includes: Flexible material is poured into a mold and the pouring temperature is controlled at 25℃-30℃. After curing, a square sheet-like substrate is formed, thus obtaining the flexible substrate.

7. The method for fabricating a passive resonant color-changing flexible vibration sensor according to claim 5, characterized in that, The step of embedding one end of each of the multiple cantilever beams into the multiple grooves in the region includes: The structural color-changing flexible film is cut into cantilever beams according to different preset sizes, and one end of the cantilever beam is fixed to the side wall of the groove in the region using a flexible adhesive.

8. The method for fabricating a passive resonant color-changing flexible vibration sensor according to claim 5, characterized in that, The step of extracting air from the closed cavity, injecting nitrogen, and then sealing the gas injection channel to form a nitrogen chamber includes: The closed cavity is evacuated to a pressure less than 10 Pa through the gas injection channel. After maintaining this pressure for 5 minutes, nitrogen is injected to the standard atmospheric pressure. After repeating the evacuation and nitrogen injection operations multiple times, the gas injection channel is sealed with a local high temperature of 200℃-250℃ to form the nitrogen chamber.

9. The method for fabricating a passive resonant color-changing flexible vibration sensor according to claim 5, characterized in that, The process of arranging flexible stickers on the outer surface of the flexible substrate includes: An adhesive layer is coated on the outer surface of the flexible substrate, and a flexible protective sticker is attached to the outer surface of the adhesive layer.

10. A measurement method for a passive resonant color-changing flexible vibration sensor, characterized in that, include: The vibration sensor is attached to the metal surface being tested via the adhesive layer of a flexible sticker; wherein the vibration sensor is a passive resonant color-changing flexible vibration sensor as described in any one of claims 1-4; When the tested metal surface vibrates, the cantilever beam array collects the vibration signal; If the vibration frequency of the vibration signal is consistent with the natural frequency of the cantilever beam in the cantilever beam array, the cantilever beam in the corresponding region will undergo structural discoloration. The vibration frequency value of the tested metal surface is determined based on the natural frequency of the cantilever beam corresponding to the location of the structural discoloration area.

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