A noise reduction function failure self-aware acoustic metamaterial component and a self-aware method thereof

Abstract

This invention relates to the field of acoustic metamaterials technology, and in particular to an acoustic metamaterial component and its self-sensing method for noise reduction function failure self-sensing. The acoustic metamaterial component includes a substrate frame, a sound insulation functional layer, a composite power generation layer, and an energy harvesting module. Electrode assemblies are deposited on both the upper and lower sides of the composite power generation layer. The composite power generation layer and the sound insulation functional layer are both fixedly connected within the substrate frame. The composite power generation layer is thermo-pressed onto the upper side of the sound insulation functional layer. The energy harvesting module is disposed within a wall panel on one side of the substrate frame and is electrically connected to the electrode assemblies via wires. This invention integrates the poly(fluoroethylene propylene) power generation layer with the metamaterial body into a single structure. It utilizes the vibration generated during noise reduction to convert it into an electrical signal, and uses this signal as a basis for functional status evaluation, achieving real-time monitoring of the noise reduction function status of the metamaterial. This, in turn, meets the stringent requirements for long-term reliability of noise reduction systems in special fields such as aerospace.

Description

Technical Field

[0001] This invention relates to the field of acoustic metamaterials technology, and in particular to an acoustic metamaterial component and its self-sensing method for noise reduction function failure self-sensing. Background Technology

[0002] Thin-film acoustic metamaterials, with their excellent low-frequency sound insulation performance and lightweight advantages, have become a key research material in the field of noise reduction. During long-term service, these metamaterials are affected by multiple factors such as continuous sound wave excitation, ambient temperature fluctuations, and vibration fatigue, which can lead to aging problems such as film wear, microstructure deformation, and pretension attenuation, resulting in deterioration and failure of noise reduction performance. Moreover, their functional degradation process is insidious and difficult to detect intuitively, posing potential safety hazards for engineering applications.

[0003] At present, the functional status assessment of this type of metamaterial is mostly carried out by offline periodic testing. The mechanical properties and sound insulation of the film are measured by disassembling the equipment to determine the working status of the material. However, it has the following defects: (1) The testing process requires interruption of equipment operation, which disrupts the continuity of equipment use; (2) It cannot capture the real-time aging status of the material during its service life, which can easily lead to safety accidents due to sudden material failure; (3) The testing relies on professional precision equipment, the operation process is cumbersome and the testing cost is high.

[0004] Furthermore, existing power-generating acoustic metamaterial technologies (such as patent CN117037757A) focus on energy recovery and have not established an intrinsic connection between electrical signal output and the functional state of the material; while structural health monitoring sensing technologies (such as patent CN106549100A) require external piezoelectric elements, which cannot achieve integrated integration with the metamaterial body and are difficult to meet the stringent requirements of engineering applications for structural simplicity and operational reliability. Summary of the Invention

[0005] The purpose of this invention is to provide an acoustic metamaterial component and its self-sensing method for noise reduction function failure self-sensing. By combining the polytetrafluoroethylene propylene power generation layer with the metamaterial body into an integrated structure, the vibration generated during the noise reduction process is converted into an electrical energy signal, and this signal is used as the basis for functional status evaluation, so as to realize real-time monitoring of the noise reduction function status of the metamaterial, thereby meeting the stringent requirements of long-term reliability of noise reduction systems in special fields such as aerospace.

[0006] To achieve the above objectives, this invention provides an acoustic metamaterial component with self-sensing noise reduction function failure. The acoustic metamaterial component includes a base frame, a sound insulation functional layer, a composite power generation layer, and an energy harvesting module. Electrode assemblies are deposited on both the upper and lower sides of the composite power generation layer. The composite power generation layer and the sound insulation functional layer are both fixedly connected within the base frame. The composite power generation layer is hot-pressed onto the upper side of the sound insulation functional layer. The energy harvesting module is disposed within a wall panel on one side of the base frame and is electrically connected to the electrode assemblies via wires. The energy harvesting module includes a signal amplification circuit, a filtering circuit, and an energy metering unit connected in sequence. The energy metering unit is electrically connected to a state assessment module.

[0007] Preferably, the base frame is made of one of the following materials: lightweight carbon fiber composite material, aluminum alloy material, titanium alloy material, and magnesium alloy material.

[0008] Preferably, the base frame includes a rectangular frame and frame plates located on the upper and lower sides of the rectangular frame. The composite power generation layer and the sound insulation functional layer are located between the upper frame plate and the lower frame plate. A vibrating mass block is provided on the upper frame plate.

[0009] Preferably, frame beams are provided on both the upper and lower frame plates. The frame beams are composed of horizontal beams and vertical beams. The intersection of the horizontal beams and vertical beams serves as the frame beam nodes. Vibrating mass blocks are alternately placed at the nodes of the upper frame beams, and a frame beam grid is formed between adjacent horizontal beams and vertical beams.

[0010] Preferably, the thickness of the sound insulation functional layer is 18-22mm, and the sound insulation functional layer uses one of the following sound insulation materials: polyurethane foam, polyimide foam, and glass fiber cotton.

[0011] Preferably, the composite power generation layer is a composite piezoelectric electret film with a thickness of 80-120 μm, including one of FEP-PTFE, FEP-PI, and FEP-PP.

[0012] Preferably, the electrode assembly includes one of a gold electrode, a silver electrode, and an aluminum electrode.

[0013] This invention also provides a self-sensing method for acoustic metamaterial components that are self-sensing noise reduction function failure, comprising the following steps: S1. Offline Calibration: An aging test experimental platform is built to simulate the actual service environment and accelerate the aging test of acoustic metamaterial components. During the aging cycle, the power acquisition module periodically collects the power parameters output by the composite power generation layer and sends them to the condition assessment module to establish a mapping database between power parameters and aging time. The power threshold ranges corresponding to five states—normal, mild aging, moderate aging, severe aging, and failure—are set to complete the calibration of the condition assessment model. S2, In-situ Real-time Acquisition: The acoustic metamaterial components from the same batch as the S1 sample are installed in the target noise reduction scene. External noise excitation causes the vibrating mass block and the composite power generation layer to vibrate synchronously with a small amplitude. The composite power generation layer generates electrical energy based on the piezoelectric electret effect. The electrode assembly captures the electrical energy and forms a weak electrical signal, which is then transmitted to the power acquisition module. S3, Signal Preprocessing: The power acquisition module amplifies the weak electrical signal through the signal amplification circuit, and then filters out electromagnetic interference and environmental noise through the filter circuit, filtering out invalid noise signals; the purified electrical signal is sent to the power metering unit, which converts it into a standardized digital signal in real time and sends it to the status assessment module after S1 calibration. S4. Functional Status Determination: The status assessment module retrieves the mapping database established by S1, compares the standardized digital signal of S3 with the power threshold range set by S1, and determines the current aging level of the acoustic metamaterial component; at the same time, it combines the continuously collected power attenuation rate, fits the attenuation change trend, and dynamically tracks the aging status of the acoustic metamaterial component and predicts its functional status. S5. Status Feedback and Early Warning: When the detection results determine that the acoustic metamaterial component is in a state of severe aging or failure, the status assessment module outputs an early warning signal to complete the self-detection, self-judgment and self-early warning of the noise reduction function of the acoustic metamaterial component.

[0014] Preferably, in S1, the aging test time is 600~1200h, and the sampling interval is 6~12h.

[0015] Preferably, in S1, the power threshold range is as follows: Normal: power output ≥ 90% of the initial value; Mild aging: power output is 80%-90% of the initial value; Moderate aging: power output is 60%-80% of the initial value; Severe aging: power output is 40%-60% of the initial value; Failure: power output ≤ 40% of the initial value.

[0016] The beneficial effects of this invention are: (1) The present invention combines the FEP composite power generation layer with the sound insulation functional layer by hot pressing to realize the integrated structure design of power generation and sound insulation. It utilizes the vibration power generation during the noise reduction process of the metamaterial itself to realize functional status perception. No external power supply or additional sensors are required. The structure is simple and the additional weight is extremely low, which meets the lightweight requirements of aviation, military and other fields.

[0017] (2) The piezoelectric charge coefficient d of the FEP composite piezoelectric electret thin film of the present invention 33With a power signal acquisition sensitivity of up to 750-800 pC / N, it can accurately identify performance degradation changes within 5%, directly acquire the power generation signal of the material itself, avoid the interference of environmental noise on the test results, and achieve an aging state identification accuracy of ≥95%. Combined with an amplifier circuit and a low-pass filter circuit, it effectively shields electromagnetic noise interference, resulting in high accuracy in aging identification.

[0018] (3) The present invention has a short response time for power acquisition and functional status assessment. The present invention can continuously collect power parameters in real time for a long time without stopping the machine for disassembly. It can not only determine the current aging level, but also predict the failure time based on the decay rate, and avoid the safety risks caused by noise reduction failure in advance.

[0019] (4) The FEP composite film of the present invention has excellent temperature resistance (-200℃~200℃) and chemical stability, and can be adapted to extreme service environments; it can be adapted to a variety of substrate materials and sound insulation materials, so that the acoustic metamaterial components can be widely used in noise reduction scenarios such as aircraft cabins, industrial computer rooms, and rail transit, with a wide range of applications and strong practicality.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is an overall schematic diagram of an acoustic metamaterial component with self-sensing noise reduction function failure according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the upper frame plate of an acoustic metamaterial component with self-sensing noise reduction function failure according to Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the lower frame plate of an acoustic metamaterial component with self-sensing noise reduction function failure according to Embodiment 1 of the present invention; Figure 4 This is the present invention. Figure 2 Cross-sectional view at point AA.

[0022] Figure label: 1. Base frame; 101. Rectangular border; 102. Frame plate; 103. Horizontal beam; 104. Longitudinal beam; 105. Frame beam joint; 106. Vibrating mass block; 107. Frame beam grid; 2. Sound insulation layer; 3. Composite power generation layer; 4. Power acquisition module. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0024] An acoustic metamaterial component with self-sensing noise reduction function failure is disclosed. The acoustic metamaterial component includes a base frame 1, a sound insulation functional layer 2, a composite power generation layer 3, and an energy harvesting module 4. Electrode assemblies are deposited on both the upper and lower sides of the composite power generation layer 3. The composite power generation layer 3 and the sound insulation functional layer 2 are both fixedly connected within the base frame 1. The composite power generation layer 3 is hot-pressed onto the upper side of the sound insulation functional layer 2. The energy harvesting module 4 is disposed within a wall panel on one side of the base frame 1 and is electrically connected to the electrode assemblies via wires. The energy harvesting module 4 includes a signal amplification circuit, a filter circuit, and an energy metering unit connected in sequence. The energy metering unit is electrically connected to a state assessment module.

[0025] The acoustic metamaterial component of this invention integrates the composite power generation layer 3 (FEP composite piezoelectric electret film) and the sound insulation functional layer 2 within a substrate frame 1. It directly generates electricity using vibrations generated by environmental noise excitation during noise reduction, achieving real-time self-sensing of its own noise reduction functional status. This component requires no external power supply or additional sensors; it can continuously monitor the electrical energy parameters output by the power generation layer through the power acquisition module 4, and the status assessment module automatically determines the aging stage based on a preset power decay threshold. Thus, without interrupting service, it solves the technical problems of poor real-time offline detection and inability to predict sudden failures in existing technologies, achieving lightweight integration, high-sensitivity response, and online self-diagnosis of the noise reduction functional status.

[0026] Preferably, the base frame 1 is made of one of the following materials: lightweight carbon fiber composite material, aluminum alloy, titanium alloy, and magnesium alloy. This ensures structural strength while meeting lightweight design requirements.

[0027] Preferably, the base frame 1 includes a rectangular frame 101 and frame plates 102 located on the upper and lower sides of the rectangular frame 101. The composite power generation layer 3 and the sound insulation functional layer 2 are located between the upper frame plate 102 and the lower frame plate 102. A vibrating mass block 106 is provided on the upper frame plate 102. The vibrating mass block 106 of the present invention works together with the thin film to generate a surface radiation phase cancellation mechanism, further enhancing the sound insulation effect.

[0028] Preferably, both the upper and lower frame plates 102 are provided with frame beams, which consist of horizontal beams 103 and vertical beams 104. The intersection of the horizontal beams 103 and vertical beams 104 serves as frame beam nodes 105. Vibrating mass blocks 106 are alternately arranged at the upper frame beam nodes 105, and adjacent horizontal beams 103 and vertical beams 104 form a frame beam grid 107. By arranging the vibrating mass blocks 106 alternately to form a two-dimensional periodic distribution, the present invention, together with the membrane, generates a surface radiation phase cancellation mechanism to further enhance the sound insulation effect. The frame beam grid 107 of the present invention facilitates the maintenance of the integrity of the overall structure.

[0029] Preferably, the number of horizontal beams 103 and vertical beams 104 in the lower frame plate 102 is greater than the number of horizontal beams 103 and vertical beams 104 in the upper frame plate 102, and the size of the frame beam grid 107 in the lower frame plate 102 is smaller than the size of the frame beam grid 107 in the upper frame plate 102.

[0030] Preferably, the thickness of the sound insulation functional layer 2 is 18-22 mm, and the sound insulation functional layer 2 is made of a sound insulation material including polyurethane foam, polyimide foam, and glass fiber cotton. The sound insulation material of the present invention has a rich pore structure and excellent impedance matching, which can effectively achieve low-frequency sound insulation effect.

[0031] Preferably, the composite power generation layer 3 is a composite piezoelectric electret film with a thickness of 80-120 μm, including one of FEP-PTFE (perfluoroethylene-polytetrafluoroethylene composite film), FEP-PI (perfluoroethylene-polyimide composite film), and FEP-PP (perfluoroethylene-polypropylene composite film).

[0032] More preferably, the hot-pressing composite parameters in this invention are: temperature 110-130℃, pressure 0.1-1.0MPa, and time 20-40min.

[0033] In some specific embodiments of the present invention, the composite power generation layer 3 and the sound insulation functional layer 2 are combined and then fixed to the base frame 1 by a tensioning device, and the pretension of the tensioning device is adjusted to 12-20N.

[0034] Preferably, the electrode assembly includes one of a gold electrode, a silver electrode, and an aluminum electrode.

[0035] Preferably, the electrode assembly has a 15μm thick epoxy resin insulating encapsulation layer at its edge, which effectively prevents electrode oxidation and environmental interference. The electrode assembly leads are connected to the power acquisition module 4 via 0.1mm diameter PTFE insulated wires, further improving signal transmission stability and anti-interference capability. A 10mm insulating gap is reserved between the electrode assembly and the edge of the composite power generation layer 3 to prevent electrode leakage, oxidation, and environmental corrosion interference.

[0036] Preferably, the filtering circuit is a second-order Butterworth low-pass filter circuit with a cutoff frequency of 1kHz. The overall response time of the power acquisition module 4 is ≤10ms, ensuring rapid capture and real-time updating of weak piezoelectric signals.

[0037] Preferably, the condition assessment module is embedded in the side wall of the base frame 1 and is arranged adjacent to the power acquisition module 4.

[0038] This invention also provides a self-sensing method for acoustic metamaterial components that are self-sensing noise reduction function failure, comprising the following steps: S1. Offline Calibration: An aging test experimental platform is built to simulate the actual service environment and accelerate the aging test of the acoustic metamaterial component samples. During the aging cycle, the power acquisition module 4 periodically collects the power parameters output by the composite power generation layer 3 and sends them to the condition assessment module to establish a mapping database between power parameters and aging time. The power threshold ranges corresponding to the five states of normal, mild aging, moderate aging, severe aging and failure are set to complete the calibration of the condition assessment model. S2, In-situ Real-time Acquisition: The acoustic metamaterial components of the same batch as the S1 sample are installed in the target noise reduction scene. External noise excitation causes the vibrating mass block 106 and the composite power generation layer 3 to vibrate synchronously with a small amplitude. The composite power generation layer 3 generates electrical energy based on the piezoelectric electret effect. The electrode assembly captures the electrical energy and forms a weak electrical signal. The weak electrical signal is transmitted to the power acquisition module 4. S3, Signal Preprocessing: The power acquisition module 4 amplifies the weak electrical signal through the signal amplification circuit, and then filters out electromagnetic interference and environmental noise through the filter circuit, filtering out invalid noise signals; the purified electrical signal is sent to the power metering unit, which converts it into a standardized digital signal in real time and sends it to the status assessment module after S1 calibration. S4. Functional Status Determination: The status assessment module retrieves the mapping database established by S1, compares the standardized digital signal of S3 with the power threshold range set by S1, and determines the current aging level of the acoustic metamaterial component; at the same time, it combines the continuously collected power attenuation rate, fits the attenuation change trend, and dynamically tracks the aging status of the acoustic metamaterial component and predicts its functional status. S5. Status Feedback and Early Warning: When the detection results determine that the acoustic metamaterial component is in a state of severe aging or failure, the status assessment module outputs an early warning signal to complete the self-detection, self-judgment and self-early warning of the noise reduction function of the acoustic metamaterial component.

[0039] Preferably, in S1, the aging test time is 600~1200h, and the sampling interval is 6~12h.

[0040] Preferably, in S1, the power threshold range is as follows: Normal: power output ≥ 90% of the initial value; Mild aging: power output is 80%-90% of the initial value; Moderate aging: power output is 60%-80% of the initial value; Severe aging: power output is 40%-60% of the initial value; Failure: power output ≤ 40% of the initial value.

[0041] Example 1 like Figures 1 to 4 As shown, this invention provides an acoustic metamaterial component with self-sensing noise reduction function failure, comprising a base frame 1, a sound insulation functional layer 2, a composite power generation layer 3, and an energy harvesting module 4. The base frame 1 is made of T800 carbon fiber composite material, with outer frame dimensions of 300mm × 300mm × 26mm; the sound insulation functional layer 2 is 20mm thick polyurethane foam; the composite power generation layer 3 is made of FEP-PTFE composite piezoelectric electret film (100μm thick), with a piezoelectric charge coefficient d. 33 =750pC / N.

[0042] Silver electrodes were deposited on the upper and lower surfaces of the composite power generation layer 3 using magnetron sputtering at a power of 100W for 30 minutes. The electrode dimensions were 280mm × 280mm, with a 10mm insulation gap maintained between the electrode and the edge of the composite power generation layer 3. 0.1mm diameter polytetrafluoroethylene (PTFE) insulated wires were welded to the electrode assembly leads, and the edges were coated with a 15μm thick epoxy resin insulation layer. The curing temperature was 80℃, and the curing time was 2 hours to ensure insulation performance.

[0043] The composite power generation layer 3 is laminated onto the sound insulation functional layer 2 using a hot pressing process (temperature 120℃, pressure 0.5MPa, heat preservation time 30min). After lamination, it is fixed in the base frame 1 by a tensioning device, and the pretension is adjusted to 15N to ensure that the film is in a stable working state.

[0044] The power acquisition module 4 is integrated into a single structure on a PCB board, measuring 30mm × 20mm × 3mm. It is housed within a wall panel on one side of the base frame 1. The power acquisition module 4 is electrically connected to the electrode assembly via PTFE insulated wires. The power acquisition module 4 includes, in sequence, an AD8221 preamplifier, a second-order Butterworth low-pass filter circuit (cutoff frequency 1kHz), and an ADE7758 power metering chip, all electrically connected. The ADE7758 power metering chip is electrically connected to the condition assessment module. The condition assessment module uses an STM32H7 microcontroller as its core control unit and incorporates a mapping database established through offline calibration.

[0045] The above-mentioned self-sensing method for acoustic metamaterial components that are self-sensing noise reduction function failure includes the following steps: S1. Offline calibration: The above-mentioned acoustic metamaterial components were placed in a high and low temperature humidity chamber to simulate the service environment inside a fighter jet cabin (temperature -40℃~60℃, humidity 10%-90%). Acoustic excitation of 50-8000Hz and 130dB sound pressure level was applied through an acoustic excitation device to conduct a 1000-hour accelerated aging test. During the aging cycle, the power acquisition module 4 collects the effective voltage value and output power data every 10 hours and sends them to the STM32H7 microcontroller to plot the power decay curve, establish a mapping database between power parameters and aging time, and set threshold ranges for each aging stage: Normal: Effective voltage value ≥ 200mV, output power ≥ 50μW; Mild aging: Effective voltage value 180-200mV, output power 45-50μW; Moderate aging: Effective voltage value 120-180mV, output power 30-45μW; Severe aging: Effective voltage value 80-120mV, output power 20-30μW; Failure: Effective voltage value ≤ 80mV, output power ≤ 20μW. The condition assessment model is then calibrated.

[0046] S2. In-situ Real-time Acquisition: Acoustic metamaterial components from the same batch as the S1 sample are installed into the noise reduction layer of the fighter jet cockpit. Bolt connections are used to ensure a secure installation. When the engine is running, the cabin noise excites the vibrating mass block 106 and the composite power generation layer 3, causing synchronous micro-vibrations. The composite power generation layer 3 generates electrical energy based on the piezoelectric electret effect. The electrode assembly captures this electrical energy and forms a weak electrical signal, which is transmitted to the power acquisition module 4.

[0047] S3. Signal preprocessing: The power acquisition module 4 amplifies the weak electrical signal through the AD8221 preamplifier, and then filters out electromagnetic interference and environmental noise through the second-order Butterworth low-pass filter circuit, filtering out invalid noise signals; the purified electrical signal is sent to the ADE7758 power metering chip, which converts it into a standardized digital signal in real time and sends it to the STM32H7 microcontroller calibrated by S1.

[0048] S4. Functional Status Determination: The status assessment module retrieves the mapping database established in S1 and compares the standardized digital signal from S3 with the power threshold range set in S1. Real-time monitoring shows an effective voltage value of 190mV and a power of 48μW, indicating the acoustic metamaterial component is currently in a state of mild aging. When the effective voltage value drops to 90mV and the power drops to 22μW, it is determined to be in a state of severe aging. Simultaneously, by combining continuously collected power attenuation rates and fitting the attenuation trend, the aging status of the acoustic metamaterial component is dynamically tracked and its functional status predicted.

[0049] S5. Status Feedback and Early Warning: When the test results determine that the acoustic metamaterial component is in a state of mild aging and can continue to be used, when the test results determine that the acoustic metamaterial component is in a state of severe aging or failure, the status assessment module outputs an early warning signal to complete the self-detection, self-judgment and self-early warning of the noise reduction function of the acoustic metamaterial component.

[0050] Example 2 This invention provides an acoustic metamaterial component with self-sensing noise reduction function failure, comprising a base frame 1, a sound insulation functional layer 2, a composite power generation layer 3, and an energy harvesting module 4. The base frame 1 is made of TC4 titanium alloy, with outer frame dimensions of 400mm × 400mm × 30mm; the sound insulation functional layer 2 is 20mm thick polyimide foam; the composite power generation layer 3 is selected from FEP-PI composite piezoelectric electret film (110μm thick), with a piezoelectric charge coefficient d. 33 =780pC / N.

[0051] Aluminum electrodes were deposited on the upper and lower surfaces of the composite power generation layer 3 using magnetron sputtering at a power of 120W for 25 minutes. The electrode dimensions were 380mm × 380mm, with a 10mm insulation gap maintained between the electrode and the edge of the composite power generation layer 3. 0.1mm diameter polytetrafluoroethylene (PTFE) insulated wires were welded to the electrode assembly leads, and the edges were coated with a 15μm thick epoxy resin insulation layer. The curing temperature was 80℃, and the curing time was 2 hours to ensure insulation performance.

[0052] The composite power generation layer 3 is laminated onto the sound insulation functional layer 2 using a hot pressing process (temperature 125℃, pressure 0.6MPa, heat preservation time 25min). After lamination, it is fixed in the base frame 1 by a tensioning device, and the pretension is adjusted to 18N to ensure that the film is in a stable working state.

[0053] The power acquisition module 4 is integrated into a single structure via a PCB board, measuring 35mm × 25mm × 4mm. It is housed within a wall panel on one side of the base frame 1. The power acquisition module 4 is electrically connected to the electrode assembly via PTFE insulated wires. The power acquisition module 4 includes, in sequence, an AD8227 preamplifier, a second-order Butterworth low-pass filter circuit (cutoff frequency 1kHz), and an ATT7053 power metering chip, all electrically connected. The ATT7053 power metering chip is electrically connected to the condition assessment module. The condition assessment module uses an STM32F4 microcontroller as its core control unit and incorporates a mapping database established through offline calibration.

[0054] The above-mentioned self-sensing method for acoustic metamaterial components that are self-sensing noise reduction function failure includes the following steps: S1. Offline calibration: The above-mentioned acoustic metamaterial components were placed in a high and low temperature humidity chamber to simulate the service environment of an industrial computer room (temperature -20℃~50℃, humidity 30%-80%). Continuous acoustic wave excitation of 50-5000Hz and sound pressure level of 110dB was applied to conduct an 800-hour accelerated aging test. During the aging cycle, the power acquisition module 4 collects the effective voltage value and output power data every 8 hours and sends them to the STM32F4 microcontroller to plot the power decay curve, establish a mapping database between power parameters and aging time, and set threshold ranges for each aging stage: Normal: Effective voltage value ≥ 220mV, output power ≥ 60μW; Mild aging: Effective voltage value 200-220mV, output power 55-60μW; Moderate aging: Effective voltage value 130-200mV, output power 35-55μW; Severe aging: Effective voltage value 90-130mV, output power 25-35μW; Failure: Effective voltage value ≤ 90mV, output power ≤ 25μW. The condition assessment model is then calibrated.

[0055] S2. In-situ Real-time Acquisition: Acoustic metamaterial components from the same batch as the S1 sample are installed on the noise reduction wall of the industrial air compressor room, using bolt connections to ensure secure installation. The noise from the equipment operation excites the vibrating mass block 106 and the composite power generation layer 3 to simultaneously undergo micro-amplitude vibration. The composite power generation layer 3 generates electrical energy based on the piezoelectric electret effect. The electrode assembly captures this electrical energy and forms a weak electrical signal, which is transmitted to the power acquisition module 4.

[0056] S3. Signal preprocessing: The power acquisition module 4 amplifies the weak electrical signal through the AD8227 preamplifier, and then filters out electromagnetic interference and environmental noise through the second-order Butterworth low-pass filter circuit, filtering out invalid noise signals; the purified electrical signal is sent to the ATT7053 power metering chip, which converts it into a standardized digital signal in real time and sends it to the STM32F4 microcontroller calibrated by S1.

[0057] S4. Functional Status Determination: The status assessment module retrieves the mapping database established in S1 and compares the standardized digital signal from S3 with the power threshold range set in S1. Real-time monitoring shows an effective voltage value of 210mV and a power of 58μW, indicating the acoustic metamaterial component is currently in a state of mild aging. When the effective voltage value drops to 100mV and the power drops to 28μW, it is determined to be in a state of severe aging. Simultaneously, by combining continuously collected power attenuation rates and fitting the attenuation trend, the aging status of the acoustic metamaterial component is dynamically tracked and its functional status predicted.

[0058] S5. Status Feedback and Early Warning: When the test results determine that the acoustic metamaterial component is in a state of mild aging and can continue to be used, when the test results determine that the acoustic metamaterial component is in a state of severe aging or failure, the status assessment module outputs an early warning signal to complete the self-detection, self-judgment and self-early warning of the noise reduction function of the acoustic metamaterial component.

[0059] Example 3 This invention provides an acoustic metamaterial component with self-sensing noise reduction failure, comprising a base frame 1, a sound insulation layer 2, a composite power generation layer 3, and an energy harvesting module 4. The base frame 1 is made of AZ31B magnesium alloy, with outer frame dimensions of 350mm × 350mm × 28mm; the sound insulation layer 2 is 20mm thick glass fiber cotton; the composite power generation layer 3 is made of FEP-PP composite piezoelectric electret film (90μm thick), with a piezoelectric charge coefficient d. 33 =720pC / N.

[0060] Gold electrodes were deposited on the upper and lower surfaces of the composite power generation layer 3 using magnetron sputtering at a power of 90W for 35 minutes. The electrode dimensions were 330mm × 330mm, with a 10mm insulation gap maintained between the electrode and the edge of the composite power generation layer 3. 0.1mm diameter polytetrafluoroethylene (PTFE) insulated wires were welded to the electrode assembly leads, and the edges were coated with a 15μm thick epoxy resin insulation layer. The curing temperature was 80℃, and the curing time was 2 hours to ensure insulation performance.

[0061] The composite power generation layer 3 is laminated onto the sound insulation functional layer 2 using a hot pressing process (temperature 115℃, pressure 0.4MPa, heat preservation time 35min). After lamination, it is fixed in the base frame 1 by a tensioning device, and the pretension is adjusted to 12N to ensure that the film is in a stable working state.

[0062] The power acquisition module 4 is integrated into a single structure on a PCB board, measuring 32mm × 22mm × 3.5mm. It is housed within a wall panel on one side of the base frame 1. The power acquisition module 4 is electrically connected to the electrode assembly via PTFE insulated wires. The power acquisition module 4 includes, in sequence, an AD620 preamplifier, a second-order Butterworth low-pass filter circuit (cutoff frequency 1kHz), and a BL6523 power metering chip. The BL6523 power metering chip is electrically connected to the condition assessment module. The condition assessment module uses an STM32G0 microcontroller as its core control unit and incorporates a mapping database established through offline calibration.

[0063] The above-mentioned self-sensing method for acoustic metamaterial components that are self-sensing noise reduction function failure includes the following steps: S1. Offline calibration: The above-mentioned acoustic metamaterial components were placed in a high and low temperature humidity chamber to simulate the service environment of a subway car (temperature -10℃~40℃, humidity 40%-70%). Vibration noise excitation of 50-6000Hz and sound pressure level 105dB was applied to conduct a 600-hour accelerated aging test. During the aging cycle, the power acquisition module 4 collects the effective voltage value and output power data every 6 hours and sends them to the STM32G0 microcontroller to plot the power decay curve, establish a mapping database between power parameters and aging time, and set threshold ranges for each aging stage: Normal: Effective voltage value ≥180mV, output power ≥45μW; Mild aging: Effective voltage value 160-180mV, output power 40-45μW; Moderate aging: Effective voltage value 100-160mV, output power 25-40μW; Severe aging: Effective voltage value 60-100mV, output power 15-25μW; Failure: Effective voltage value ≤60mV, output power ≤15μW. The condition assessment model is then calibrated.

[0064] S2. In-situ Real-time Acquisition: Acoustic metamaterial components from the same batch as the S1 sample are installed on the noise reduction layer at the top of the subway car, using bolt connections to ensure secure installation. Vehicle running noise excites the vibrating mass block 106 and the composite power generation layer 3, causing synchronous micro-vibrations. The composite power generation layer 3 generates electrical energy based on the piezoelectric electret effect. The electrode assembly captures this electrical energy and forms a weak electrical signal, which is transmitted to the power acquisition module 4.

[0065] S3. Signal preprocessing: The power acquisition module 4 amplifies the weak electrical signal through the AD620 preamplifier, and then filters out electromagnetic interference and environmental noise through the second-order Butterworth low-pass filter circuit, filtering out invalid noise signals; the purified electrical signal is sent to the BL6523 power metering chip, which converts it into a standardized digital signal in real time and sends it to the STM32G0 microcontroller calibrated by S1.

[0066] S4. Functional Status Determination: The status assessment module retrieves the mapping database established in S1 and compares the standardized digital signal from S3 with the power threshold range set in S1. Real-time monitoring shows an effective voltage value of 170mV and a power of 42μW, indicating the acoustic metamaterial component is currently in a state of mild aging. When the effective voltage value drops to 70mV and the power drops to 18μW, it is determined to be in a state of severe aging. Simultaneously, by combining continuously collected power attenuation rates and fitting the attenuation trend, the aging status of the acoustic metamaterial component is dynamically tracked and its functional status predicted.

[0067] S5. Status Feedback and Early Warning: When the test results determine that the acoustic metamaterial component is in a state of mild aging and can continue to be used, when the test results determine that the acoustic metamaterial component is in a state of severe aging or failure, the status assessment module outputs an early warning signal to complete the self-detection, self-judgment and self-early warning of the noise reduction function of the acoustic metamaterial component.

[0068] Example 4 This invention provides an acoustic metamaterial component with self-sensing noise reduction function failure, comprising a base frame 1, a sound insulation functional layer 2, a composite power generation layer 3, and an energy harvesting module 4. The base frame 1 is made of 5052 aluminum alloy, with outer frame dimensions of 250mm × 250mm × 24mm; the sound insulation functional layer 2 is 20mm thick glass fiber cotton; the composite power generation layer 3 is made of FEP-PTFE composite piezoelectric electret film (120μm thick), with a piezoelectric charge coefficient d. 33 =800pC / N.

[0069] Gold electrodes were deposited on the upper and lower surfaces of the composite power generation layer 3 using magnetron sputtering at a power of 110W for 30 minutes. The electrode dimensions were 230mm × 230mm, with a 10mm insulation gap maintained between the electrode and the edge of the composite power generation layer 3. 0.1mm diameter polytetrafluoroethylene (PTFE) insulated wires were welded to the electrode assembly leads, and the edges were coated with a 15μm thick epoxy resin insulation layer. The curing temperature was 80℃, and the curing time was 2 hours to ensure insulation performance.

[0070] The composite power generation layer 3 is laminated onto the sound insulation functional layer 2 using a hot pressing process (temperature 120℃, pressure 0.5MPa, heat preservation time 30min). After lamination, it is fixed in the base frame 1 by a tensioning device, and the pretension is adjusted to 20N to ensure that the film is in a stable working state.

[0071] The power acquisition module 4 is integrated into a single structure on a PCB board, measuring 28mm × 18mm × 3mm. It is housed within a wall panel on one side of the base frame 1. The power acquisition module 4 is electrically connected to the electrode assembly via PTFE insulated wires. The power acquisition module 4 includes, in sequence, an AD8221 preamplifier, a second-order Butterworth low-pass filter circuit (cutoff frequency 1kHz), and an ADE7758 power metering chip, all electrically connected. The ADE7758 power metering chip is electrically connected to the condition assessment module. The condition assessment module uses an STM32H7 microcontroller as its core control unit and incorporates a mapping database established through offline calibration.

[0072] The above-mentioned self-sensing method for acoustic metamaterial components that are self-sensing noise reduction function failure includes the following steps: S1. Offline calibration: The above-mentioned acoustic metamaterial components were placed in a high and low temperature humidity chamber to simulate the extreme environment outside the spacecraft cabin (temperature -180℃~150℃, high vacuum, humidity <5%), and an excitation of 50-10000Hz and 140dB sound pressure level was applied to conduct a 1200-hour accelerated aging test. During the aging cycle, the power acquisition module 4 collects the effective voltage value and output power data every 12 hours and sends them to the STM32H7 microcontroller to plot the power decay curve, establish a mapping database between power parameters and aging time, and set threshold ranges for each aging stage: Normal: Effective voltage value ≥ 240mV, output power ≥ 65μW; Mild aging: Effective voltage value 220-240mV, output power 60-65μW; Moderate aging: Effective voltage value 140-220mV, output power 40-60μW; Severe aging: Effective voltage value 100-140mV, output power 25-40μW; Failure: Effective voltage value ≤ 100mV, output power ≤ 25μW. The condition assessment model is then calibrated.

[0073] S2. In-situ Real-time Acquisition: Acoustic metamaterial components from the same batch as the S1 sample are installed on the spacecraft's external noise reduction assembly. Bolt connections are used for secure installation. Space noise and vibration excitation cause the vibrating mass block 106 and the composite power generation layer 3 to simultaneously undergo micro-amplitude vibrations. The composite power generation layer 3 generates electrical energy based on the piezoelectric electret effect. The electrode assembly captures this electrical energy and forms a weak electrical signal, which is transmitted to the power acquisition module 4.

[0074] S3. Signal preprocessing: The power acquisition module 4 amplifies the weak electrical signal through the AD8221 preamplifier, and then filters out electromagnetic interference and environmental noise through the second-order Butterworth low-pass filter circuit, filtering out invalid noise signals; the purified electrical signal is sent to the ADE7758 power metering chip, which converts it into a standardized digital signal in real time and sends it to the STM32H7 microcontroller calibrated by S1.

[0075] S4. Functional Status Determination: The status assessment module retrieves the mapping database established in S1 and compares the standardized digital signal from S3 with the power threshold range set in S1. Real-time monitoring shows an effective voltage value of 230mV and a power of 62μW, indicating the acoustic metamaterial component is currently in a state of mild aging. When the effective voltage value drops to 110mV and the power drops to 28μW, it is determined to be in a state of severe aging. Simultaneously, by combining continuously collected power attenuation rates and fitting the attenuation trend, the aging status of the acoustic metamaterial component is dynamically tracked and its functional status predicted.

[0076] S5. Status Feedback and Early Warning: When the test results determine that the acoustic metamaterial component is in a state of mild aging and can continue to be used, when the test results determine that the acoustic metamaterial component is in a state of severe aging or failure, the status assessment module outputs an early warning signal to complete the self-detection, self-judgment and self-early warning of the noise reduction function of the acoustic metamaterial component.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An acoustic metamaterial component with self-sensing noise reduction function failure, characterized in that: The acoustic metamaterial component includes a base frame, a sound insulation functional layer, a composite power generation layer, and an energy harvesting module. Electrode assemblies are deposited on both the upper and lower sides of the composite power generation layer. The composite power generation layer and the sound insulation functional layer are both fixedly connected within the base frame. The composite power generation layer is hot-pressed onto the upper side of the sound insulation functional layer. The energy harvesting module is located within a wall panel on one side of the base frame and is electrically connected to the electrode assemblies via wires. The energy harvesting module includes a signal amplification circuit, a filtering circuit, and an energy metering unit that are electrically connected in sequence. The energy metering unit is electrically connected to the condition assessment module.

2. The noise-reducing, function-failure self-aware acoustic metamaterial component of claim 1, wherein: The base frame is made of one of the following materials: lightweight carbon fiber composite material, aluminum alloy, titanium alloy, or magnesium alloy.

3. The noise-reducing, function-failure self-aware acoustic metamaterial component of claim 1, wherein: The base frame includes a rectangular frame and frame plates located on the upper and lower sides of the rectangular frame. The composite power generation layer and the sound insulation functional layer are located between the upper frame plate and the lower frame plate. Vibration mass blocks are provided on the upper frame plate.

4. The noise-reducing, function-failure self-aware acoustic metamaterial member of claim 1, wherein: Both the upper and lower frame slabs are equipped with frame beams, which consist of horizontal beams and vertical beams. The intersection of the horizontal and vertical beams serves as the frame beam node. Vibrating mass blocks are alternately placed at the upper frame beam node, and a frame beam grid is formed between adjacent horizontal and vertical beams.

5. The acoustic metamaterial component with self-sensing noise reduction function failure according to claim 1, characterized in that: The thickness of the sound insulation functional layer is 18-22mm, and the sound insulation material used in the sound insulation functional layer includes one of polyurethane foam, polyimide foam, and glass fiber cotton.

6. The noise-reducing, function-failure self-aware acoustic metamaterial member of claim 1, wherein: The composite power generation layer is a composite piezoelectric electret thin film with a thickness of 80-120μm, including one of FEP-PTFE, FEP-PI, and FEP-PP.

7. The noise-reducing, function-failure self-aware acoustic metamaterial member of claim 1, wherein: The electrode assembly includes one of a gold electrode, a silver electrode, and an aluminum electrode.

8. A self-awareness method of a noise-reducing function failure self-awareness acoustic metamaterial component according to any one of claims 1-7, characterized in that: Includes the following steps: S1. Offline Calibration: An aging test experimental platform is built to simulate the actual service environment and accelerate the aging test of acoustic metamaterial components. During the aging cycle, the power acquisition module periodically collects the power parameters output by the composite power generation layer and sends them to the condition assessment module to establish a mapping database between power parameters and aging time. The power threshold ranges corresponding to five states—normal, mild aging, moderate aging, severe aging, and failure—are set to complete the calibration of the condition assessment model. S2, In-situ Real-time Acquisition: The acoustic metamaterial components from the same batch as the S1 sample are installed in the target noise reduction scene. External noise excitation causes the vibrating mass block and the composite power generation layer to vibrate synchronously with a small amplitude. The composite power generation layer generates electrical energy based on the piezoelectric electret effect. The electrode assembly captures the electrical energy and forms a weak electrical signal, which is then transmitted to the power acquisition module. S3. Signal preprocessing: The power acquisition module amplifies the weak electrical signal through the signal amplification circuit, and then filters out electromagnetic interference and environmental noise through the filter circuit, filtering out invalid noise signals. The purified electrical signal is sent to the power metering unit, where it is converted into a standardized digital signal in real time and sent to the S1 calibrated status assessment module. S4. Functional Status Determination: The status assessment module retrieves the mapping database established by S1, compares the standardized digital signal of S3 with the power threshold range set by S1, and determines the current aging level of the acoustic metamaterial component. Simultaneously, by combining the continuously collected energy decay rate and fitting the decay trend, the aging state of acoustic metamaterial components is dynamically tracked and the functional state is predicted. S5. Status Feedback and Early Warning: When the detection results determine that the acoustic metamaterial component is in a state of severe aging or failure, the status assessment module outputs an early warning signal to complete the self-detection, self-judgment and self-early warning of the noise reduction function of the acoustic metamaterial component.

9. The self-aware method of an acoustic metamaterial component with a failure of a noise reduction function according to claim 8, characterized in that: In S1, the aging test time is 600~1200h, and the sampling interval is 6~12h.

10. The self-aware method of an acoustic metamaterial component with a failure of a noise reduction function according to claim 8, characterized in that: In S1, the power threshold range is as follows: Normal: Power output ≥ 90% of the initial value; Mild aging: Power output is 80%-90% of the initial value; Moderate aging: Power output is 60%-80% of the initial value; Severe aging: Power output is 40%-60% of the initial value; Failure: Power output ≤ 40% of the initial value.

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