A method for detecting structural damage in carbon fiber reinforced resin matrix composites

Abstract

This invention discloses a method for structural damage detection of carbon fiber reinforced resin matrix composites, belonging to the field of non-destructive testing technology. The method includes: real-time acquisition of resonant frequency data using a microcantilever beam array; simultaneous irradiation of a composite sensitive coating on the surface of the microcantilever beam array with a plasmonic laser beam to excite plasmonic resonance; identifying locations on the microcantilever beam array where the resonant frequency data exceeds a reference offset threshold and the frequency shift of the plasmonic resonance exceeds a preset background noise fluctuation range as suspected damage locations; and triggering electrochemical deposition using the coordinates of the suspected damage locations, applying a constant negative voltage to the surface of the suspected damage locations to generate metallic marker stripes. This invention identifies locations where the frequency shift exceeds a preset threshold by comparing the resonant frequency data with the reference resonant frequency data in the initial state, achieving precise capture of abnormal mechanical responses.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology, and in particular to a method for detecting structural damage in carbon fiber reinforced resin matrix composites. Background Technology

[0002] Carbon fiber reinforced resin matrix composites are widely used in aerospace, marine engineering, and high-end transportation equipment due to their high specific strength, high specific modulus, and excellent fatigue properties. However, these composites are prone to irreversible damage such as microcracks, interfacial delamination, or fiber breakage in stress concentration areas under complex service environments. Therefore, how to achieve highly sensitive and visual detection of damage to the internal or surface structure of composite materials has become an important research direction for composite material structural health monitoring. In recent years, mechanical response monitoring based on micro-nano sensors and characterization methods based on optical methods have gradually attracted attention. By deploying sensitive units on the material surface and combining them with optical or electrical excitation methods to obtain damage signals, it has become an important path to achieve micro-damage identification of composite materials.

[0003] Existing technologies for detecting damage in composite materials can typically identify macroscopic defects, but they fall short in the early capture and localization of minute damage, particularly in stress concentration areas where it is difficult to simultaneously obtain highly sensitive mechanical and optical signals for enhanced coupling. This issue often leads to damage signals being susceptible to noise interference, affecting the accurate localization of damage. Current structural damage detection methods typically compensate for this by increasing sensor density or using complex signal filtering algorithms, but these approaches suffer from weakened micro-damage signals and strong noise interference. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a structural damage detection method for carbon fiber reinforced resin matrix composites to solve the problem of difficulty in simultaneously obtaining high-sensitivity mechanical signals and optical signals in stress concentration areas.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] In a first aspect, the present invention provides a method for detecting structural damage in carbon fiber reinforced resin matrix composites, comprising,

[0008] A microcantilever beam array is deployed on the surface of a carbon fiber reinforced resin matrix composite material at stress concentration locations; the surface of the microcantilever beam array is covered with a composite sensitive coating.

[0009] Resonance frequency data is collected in real time by a microcantilever beam array. At the same time, a composite sensitive coating on the surface of the microcantilever beam array is irradiated with a plasmonic laser beam to excite plasmonic resonance. The location of the microcantilever beam array where the resonance frequency data exceeds the reference offset threshold and the frequency shift of the plasmonic resonance exceeds the preset background noise fluctuation range is identified as the suspected damage location.

[0010] Electrochemical deposition is triggered by the coordinates of the suspected damage location. The exposed carbon fibers of the carbon fiber reinforced resin matrix composite material are used as a reference electrode. A constant negative voltage is applied to the surface of the suspected damage location to generate metallic marker stripes.

[0011] The spatial distribution image of the metal marker stripes is scanned using a portable optical microscope, and the crystal structure diffraction peak intensity data of the metal marker stripes is scanned using a portable X-ray diffractometer. Based on the distribution morphology and crystal structure diffraction peak intensity data, a structural damage verification report is generated.

[0012] As a preferred embodiment of the structural damage detection method for carbon fiber reinforced resin matrix composites described in this invention, the deployment of a micro-cantilever beam array on the surface at stress concentration locations of the carbon fiber reinforced resin matrix composite is specifically as follows.

[0013] Oxygen plasma treatment is applied to the bolt hole edge and curved surface transition area of ​​the carbon fiber reinforced resin matrix composite material to form a pretreatment zone for the carbon fiber reinforced resin matrix composite material.

[0014] In the pretreatment zone of carbon fiber reinforced resin matrix composite, nano-silver conductive adhesive is used to bond silicon-based microcantilever beams to form a rectangular array of microcantilever beams.

[0015] As a preferred embodiment of the structural damage detection method for carbon fiber reinforced resin matrix composites of the present invention, the resonant frequency data is acquired in real time using a microcantilever beam array, as detailed below.

[0016] Establish an electrical connection between the microcantilever beam array and the resonant frequency acquisition instrument;

[0017] An alternating electrostatic excitation is applied to the microcantilever beam array using a resonant frequency acquisition instrument. The response frequency of the microcantilever beam array is scanned, and the resonant frequency value displayed by the resonant frequency acquisition instrument is read as the resonant frequency data of the microcantilever beam array.

[0018] As a preferred embodiment of the structural damage detection method for carbon fiber reinforced resin matrix composites described in this invention, the step of irradiating the composite sensitive coating on the surface of the microcantilever beam array with a plasmonic laser beam to excite plasmonic polariton resonance is as follows.

[0019] One end of the optical fiber is connected to the output port of the plasmonic laser emitting device, and the other end is led to the microcantilever beam array.

[0020] Adjust the position and angle of the optical fiber outlet to align with the composite sensitive coating on the surface of the microcantilever beam array, and keep the emission direction perpendicular to the surface of the composite sensitive coating.

[0021] The plasma laser emitting device is started. After preheating and stabilization, the plasma laser emitting device outputs a plasma laser beam.

[0022] A plasmonic laser beam is transmitted to the composite sensitive coating on the surface of the microcantilever beam array through an optical fiber that has been connected and aligned with the composite sensitive coating, thereby exciting plasmonic resonance.

[0023] In a preferred embodiment of the structural damage detection method for carbon fiber reinforced resin matrix composites described in this invention, the determination of whether the resonant frequency data exceeds a reference offset threshold is as follows.

[0024] The initial resonance frequency values ​​of the microcantilever beam array under stress-free loading are obtained as reference resonance frequency data.

[0025] The resonant frequency data of each position of the microcantilever beam array collected in real time are compared with the reference resonant frequency data of the corresponding position to determine the resonant frequency offset of each position of the microcantilever beam array.

[0026] When the resonant frequency offset at a certain position of the microcantilever beam array is greater than the preset reference offset threshold, the check of the plasmon resonant frequency shift at the microcantilever beam array position where the resonant frequency offset exceeds the reference offset threshold is initiated.

[0027] As a preferred embodiment of the structural damage detection method for carbon fiber reinforced resin matrix composites of the present invention, the reference offset threshold is determined based on the initial resonant frequency distribution of the microcantilever beam array under stress-free conditions.

[0028] As a preferred embodiment of the structural damage detection method for carbon fiber reinforced resin matrix composites described in this invention, the location of the microcantilever beam array where the frequency shift of the plasmon resonance exceeds the preset background noise fluctuation range is as follows.

[0029] Under the conditions of plasmon resonance excitation, the optical near-field enhancement response spectrum of the composite sensitive coating is monitored to obtain the real-time resonance frequency of plasmon resonance.

[0030] The frequency shift of the plasmon resonance is determined by comparing the real-time resonance frequency of the plasmon resonance with the initial resonance frequency under stress-free loading.

[0031] When the frequency shift of the plasmon resonance is greater than the maximum value of the preset background noise fluctuation range, it is determined that the frequency shift of the plasmon resonance exceeds the background noise fluctuation range.

[0032] As a preferred embodiment of the structural damage detection method for carbon fiber reinforced resin matrix composites of the present invention, the background noise fluctuation range is determined based on the plasmon resonance frequency fluctuation characteristics of the optical near-field enhancement response spectrum of the composite sensitive coating under stress-free loading conditions.

[0033] In a preferred embodiment of the structural damage detection method for carbon fiber reinforced resin matrix composites described in this invention, the electrochemical deposition is triggered by the coordinates of the suspected damage location. Using the exposed carbon fibers of the carbon fiber reinforced resin matrix composite as a reference electrode, a constant negative voltage is applied to the surface of the suspected damage location to generate metallic marker stripes, as detailed below.

[0034] Based on the coordinates of the suspected damage location, drive the electrochemical deposition probe to move directly above the suspected damage location;

[0035] The exposed carbon fibers of the carbon fiber reinforced resin matrix composite are connected to the reference electrode interface of the electrochemical controller as a reference electrode for electrochemical deposition.

[0036] The electrolyte release component of the electrochemical deposition probe is activated to release an electrolyte containing metal ions onto the surface of the suspected damage site, forming a local electrochemical reaction area;

[0037] In the localized electrochemical reaction region, a constant negative voltage is applied between the electrochemical deposition probe and the exposed carbon fibers of the carbon fiber reinforced resin matrix composite material by an electrochemical controller;

[0038] Under a constant negative voltage, metal ions are reduced and deposited on the surface of suspected damage sites, forming metal deposition spots;

[0039] A constant negative voltage is continuously applied until the metal deposition spots grow to a size that can be recognized by optical means, and metal marker stripes are output.

[0040] As a preferred embodiment of the structural damage detection method for carbon fiber reinforced resin matrix composites described in this invention, the method involves scanning the spatial distribution image of the metal marker stripes using a portable optical microscope, scanning the crystal structure diffraction peak intensity data of the metal marker stripes using a portable X-ray diffractometer, and generating a structural damage verification report based on the distribution morphology and crystal structure diffraction peak intensity data, as detailed below.

[0041] Aim the portable optical microscope at the location of the metal marking stripes on the surface of the carbon fiber reinforced resin matrix composite material, adjust the focal length and light source of the portable optical microscope, drive the portable optical microscope to scan the area covered by the metal marking stripes along the grid scanning path, and record the spatial distribution image of the metal marking stripes.

[0042] The portable X-ray diffractometer was activated to scan the metal marker stripes and obtain the crystal structure diffraction pattern.

[0043] Extract the crystal structure diffraction peak intensity data of the metallic marker stripes from the diffraction pattern.

[0044] The beneficial effects of this invention are as follows: By comparing the resonant frequency data with the reference resonant frequency data in the initial state, the location where the frequency shift exceeds a preset threshold is identified, achieving precise capture of abnormal mechanical response. Simultaneously, a plasmonic laser beam is applied to the frequency shift location to excite plasmonic resonance on the surface of the composite sensitive coating, monitoring the frequency shift of its optical near-field enhanced response spectrum to determine whether it exceeds the range of background noise fluctuations. This dual-judgment mechanism utilizes cross-verification of mechanical vibration and optical near-field enhancement signals to avoid misjudgment caused by environmental interference with a single signal, significantly improving the reliability and sensitivity of damage identification. The synergistic effect of the microcantilever beam array and the composite sensitive coating enables the effective detection of minute deformations caused by microcracks and changes in the surface chemical environment, achieving high-precision positioning and confirmation of early damage to carbon fiber reinforced resin matrix composites. Attached Figure Description

[0045] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a flowchart of a method for detecting structural damage in carbon fiber reinforced resin matrix composites.

[0047] Figure 2 A flowchart for deploying a microcantilever beam array.

[0048] Figure 3 This is a flowchart for determining the suspected location of damage.

[0049] Figure 4 A flowchart for generating a structural damage verification report. Detailed Implementation

[0050] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0051] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0052] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0053] Reference Figures 1-4 As one embodiment of the present invention, this embodiment provides a method for detecting structural damage in carbon fiber reinforced resin matrix composites, comprising the following steps:

[0054] S1. Deploy a microcantilever beam array on the surface of the stress concentration location of the carbon fiber reinforced resin matrix composite material; cover the surface of the microcantilever beam array with a composite sensitive coating.

[0055] Oxygen plasma treatment is applied to the bolt hole edge and curved surface transition area of ​​the carbon fiber reinforced resin matrix composite material to form a pretreatment zone for the carbon fiber reinforced resin matrix composite material.

[0056] Specifically, the process involves placing the bolt hole edge and curved transition area of ​​the carbon fiber reinforced resin matrix composite material within the working chamber of an oxygen plasma treatment device; adjusting the operating parameters of the oxygen plasma treatment device to ensure stable oxygen flow and maintain a vacuum environment within the working chamber; starting the oxygen plasma treatment device to generate oxygen plasma, which then contacts the bolt hole edge and curved transition area surface of the carbon fiber reinforced resin matrix composite material; and maintaining the oxygen plasma treatment device running for a specified time, such as 10 minutes, to allow the oxygen plasma to remove surface contaminants and activate the surface of the bolt hole edge and curved transition area of ​​the carbon fiber reinforced resin matrix composite material, forming a pre-treatment zone of the carbon fiber reinforced resin matrix composite material with increased surface roughness and enhanced chemical activity.

[0057] In the pretreatment zone of carbon fiber reinforced resin matrix composite, nano-silver conductive adhesive is used to bond silicon-based microcantilever beams to form a rectangular array of microcantilever beams.

[0058] A composite sensitive coating solution consisting of polydimethylsiloxane precursor and platinum nanoparticles mixed in a certain mass ratio was prepared and coated onto the surface of a microcantilever beam array by spin coating.

[0059] The surface of the coated microcantilever beam array is annealed to form a composite sensitive coating.

[0060] Specifically, the process involves placing the microcantilever beam array of the composite sensitive coating solution inside an annealing furnace; adjusting the furnace temperature to a specified value, such as 150 degrees Celsius, and ensuring that the furnace atmosphere is an inert gas environment, such as nitrogen, to prevent oxidation; starting the annealing furnace and continuously heating the composite sensitive coating solution on the surface of the microcantilever beam array at a specified temperature, such as 30 minutes, to promote the curing of the polydimethylsiloxane precursor and enhance the bonding between platinum nanoparticles and the polydimethylsiloxane precursor; after heating is complete, turning off the annealing furnace and allowing the microcantilever beam array to cool naturally to room temperature, forming a uniform and stable composite sensitive coating.

[0061] S2. Real-time acquisition of resonant frequency data through the microcantilever beam array, and simultaneous irradiation of the composite sensitive coating on the surface of the microcantilever beam array with a plasmonic laser beam to excite plasmonic resonance; the location of the microcantilever beam array where the resonant frequency data exceeds the reference offset threshold and the frequency shift of the plasmonic resonance exceeds the preset background noise fluctuation range is determined as the suspected damage location.

[0062] Establish an electrical connection between the microcantilever beam array and the resonant frequency acquisition instrument;

[0063] An alternating electrostatic excitation is applied to the microcantilever beam array using a resonant frequency acquisition instrument. The response frequency of the microcantilever beam array is scanned, and the resonant frequency value displayed by the resonant frequency acquisition instrument is read as the resonant frequency data of the microcantilever beam array.

[0064] Specifically, the process involves: connecting the resonant frequency acquisition instrument to the electrode interface of the microcantilever beam array via wires to ensure stable electrical signal transmission; starting the resonant frequency acquisition instrument and setting the frequency range of the alternating electrostatic excitation, for example, from 1 kHz to 100 kHz; applying the alternating electrostatic excitation to the microcantilever beam array to cause each silicon-based microcantilever beam unit to vibrate; using the resonant frequency acquisition instrument to scan the vibration response of the microcantilever beam array and recording the frequency value corresponding to the maximum amplitude of each silicon-based microcantilever beam unit under excitation; and reading the frequency value displayed by the resonant frequency acquisition instrument as the resonant frequency data of the microcantilever beam array.

[0065] One end of the optical fiber is connected to the output port of the plasmonic laser emitting device, and the other end is led to the microcantilever beam array.

[0066] Adjust the position and angle of the optical fiber outlet to align with the composite sensitive coating on the surface of the microcantilever beam array, and keep the emission direction perpendicular to the surface of the composite sensitive coating.

[0067] The plasma laser emitting device is started. After preheating and stabilization, the plasma laser emitting device outputs a plasma laser beam.

[0068] A plasmonic laser beam is transmitted to the composite sensitive coating on the surface of the microcantilever beam array through an optical fiber that has been connected and adjusted to align the composite sensitive coating, thereby exciting plasmonic resonance.

[0069] Specifically, a plasmonic laser beam is transmitted via optical fiber to a composite sensitive coating on the surface of a microcantilever beam array, causing the plasmonic laser beam to irradiate the composite sensitive coating composed of polydimethylsiloxane and platinum nanoparticles. The interaction between the platinum nanoparticles in the composite sensitive coating induces an enhancement of the local electromagnetic field, which excites plasmonic resonance on the surface of the composite sensitive coating, providing an optical near-field enhanced response spectrum for subsequent monitoring of the frequency shift of the plasmonic resonance.

[0070] The initial resonance frequency values ​​of the microcantilever beam array under stress-free loading are obtained as reference resonance frequency data.

[0071] Specifically, the process involves: fixing the carbon fiber reinforced resin matrix composite material in a stress-free loading environment to ensure the microcantilever beam array is not affected by external mechanical forces; connecting the resonant frequency acquisition instrument to the electrode interface of the microcantilever beam array to confirm the integrity of the electrical signal path; activating the resonant frequency acquisition instrument and configuring the frequency range of alternating electrostatic excitation, such as 1 kHz to 100 kHz, to drive the center of each silicon-based microcantilever beam to vibrate; using the resonant frequency acquisition instrument to detect the vibration behavior of the microcantilever beam array and recording the frequency value corresponding to the maximum amplitude at the center of each silicon-based microcantilever beam; and extracting the frequency value displayed by the resonant frequency acquisition instrument as the reference resonant frequency data of the microcantilever beam array.

[0072] The resonant frequency data of each position of the microcantilever beam array collected in real time are compared with the reference resonant frequency data of the corresponding position to determine the resonant frequency offset of each position of the microcantilever beam array.

[0073] Specifically, the real-time resonant frequency data of the microcantilever beam array and the reference resonant frequency data are input into the frequency comparison component of the resonant frequency acquisition instrument. The frequency comparison component compares the real-time frequency value of the center of each silicon-based microcantilever beam with the corresponding reference frequency value and records the difference between the two. All comparison results are arranged in order of position to form a list of resonant frequency offset values ​​containing information on the difference at each position. The resonant frequency offset value of each position is extracted from the list of resonant frequency offset values ​​as the resonant frequency offset of the center of each silicon-based microcantilever beam in the microcantilever beam array.

[0074] When the resonant frequency offset at a certain position of the microcantilever beam array is greater than the preset reference offset threshold, the check of the plasmonic resonant frequency shift at the microcantilever beam array position where the resonant frequency offset exceeds the reference offset threshold is initiated.

[0075] Specifically, the process involves: comparing the resonant frequency offset of the center of each silicon-based microcantilever beam in the microcantilever array with a preset reference offset threshold; activating the plasmonic laser emission device when the resonant frequency offset of a certain silicon-based microcantilever beam center exceeds the preset reference offset threshold; transmitting the plasmonic laser beam through an optical fiber to the composite sensitive coating surface at the corresponding silicon-based microcantilever beam center in the microcantilever array; adjusting the optical fiber exit position and angle to ensure that the plasmonic laser beam perpendicularly irradiates the composite sensitive coating surface, exciting plasmonic polariton resonance; and activating the optical near-field enhanced response spectrometer to collect data on the silicon-based microcantilever beam center of the microcantilever array. The optical near-field enhanced response spectrum of the microcantilever beam center under plasmonic resonance excitation is analyzed. The real-time frequency value of the plasmonic resonance is extracted from the optical near-field enhanced response spectrum. The real-time frequency value of the plasmonic resonance is compared with the initial plasmonic resonance frequency value under stress-free loading, and the frequency difference between the two is recorded. The frequency difference is stored as the basis for checking the frequency shift of the plasmonic resonance. The preset reference offset threshold is determined according to the initial resonance frequency distribution of the microcantilever beam array under stress-free loading, for example, it is set to 5Hz, which is used to detect the frequency shift caused by microcracks.

[0076] Under the conditions of plasmon resonance excitation, the optical near-field enhancement response spectrum of the composite sensitive coating is monitored to obtain the real-time resonance frequency of plasmon resonance.

[0077] Specifically, under plasmon resonance excitation conditions, an optical near-field enhanced response spectrometer is activated; the probe of the optical near-field enhanced response spectrometer is aligned with the surface of the composite sensitive coating at the center of the silicon-based microcantilever beam corresponding to the microcantilever beam array; the probe position and angle are adjusted to ensure that the probe maintains a distance from and is perpendicularly aligned with the surface of the composite sensitive coating; the optical near-field enhanced response spectrum data of the composite sensitive coating at the center of the silicon-based microcantilever beam corresponding to the microcantilever beam array is acquired using the optical near-field enhanced response spectrum meter; the real-time resonance frequency value of the plasmon resonance is extracted from the optical near-field enhanced response spectrum data; and the real-time resonance frequency value of the plasmon resonance is recorded as the real-time resonance frequency monitoring result of the plasmon resonance.

[0078] The frequency shift of the plasmon resonance is determined by comparing the real-time resonance frequency of the plasmon resonance with the initial resonance frequency under stress-free loading.

[0079] Specifically, the process involves: transmitting the real-time plasmon resonance frequency values ​​of the composite sensitive coating at the center of each silicon-based microcantilever beam in the microcantilever beam array, acquired by an optical near-field enhanced response spectrum analyzer under plasmon resonance excitation conditions, to a frequency comparison component; extracting the initial plasmon resonance frequency values ​​at the corresponding positions from the stored initial plasmon resonance frequency values ​​at the center of each silicon-based microcantilever beam in the microcantilever beam array under stress-free loading conditions; and comparing the plasmon resonance frequency values ​​at the center of each silicon-based microcantilever beam in the microcantilever beam array one by one using the frequency comparison component. The real-time resonance frequency value of the polariton resonance and the initial plasmon resonance frequency value at the corresponding position are recorded; the frequency difference between the real-time resonance frequency value and the initial plasmon resonance frequency value at the center of each silicon-based microcantilever beam in the microcantilever beam array are recorded; the frequency difference is recorded as the frequency shift of the plasmon resonance; for example, if the real-time resonance frequency value of the plasmon resonance is 1000THz and the initial plasmon resonance frequency value is 995THz, then the frequency shift of the plasmon resonance is 5THz.

[0080] When the frequency shift of the plasmon resonance is greater than the maximum value of the preset background noise fluctuation range, it is confirmed that the frequency shift of the plasmon resonance exceeds the background noise fluctuation range. The preset background noise fluctuation range is determined based on the plasmon resonance frequency fluctuation characteristics of the optical near-field enhancement response spectrum of the composite sensitive coating under stress-free loading conditions. For example, the value range is 0.1-1THz, in order to distinguish the frequency shift caused by microcracks from environmental noise.

[0081] The locations of microcantilever beam arrays where the resonant frequency offset exceeds the reference offset threshold and the frequency shift of the plasmon resonance exceeds the preset background noise fluctuation range are identified as suspected damage locations.

[0082] It should be noted that this step enables high-precision online monitoring of structural damage in carbon fiber reinforced resin matrix composites, improving detection sensitivity, real-time performance, and accuracy, and reducing the false judgment rate. Compared with traditional ultrasonic or thermal imaging detection, the innovation of this step lies in the integration of mechanical vibration response and optical near-field enhancement, overcoming the limitations of low resolution and non-real-time monitoring of microcracks, improving efficiency and simplifying operation, and fully demonstrating the application value of mechanical sensors, namely the microcantilever beam array in this step.

[0083] S3. Electrochemical deposition is triggered by the coordinates of the suspected damage location. The exposed carbon fibers of the carbon fiber reinforced resin matrix composite material are used as the reference electrode. A constant negative voltage is applied to the surface of the suspected damage location to generate metallic marker stripes.

[0084] The coordinate system of the electrochemical deposition positioning component is spatially aligned with that of the microcantilever beam array positioning component to ensure that the coordinate information of the suspected damage location can be directly accessed by the electrochemical deposition process. The electrochemical deposition positioning component is a device used to precisely align coordinates and move the probe to a specific surface position for electrochemical deposition, based on microcantilever beam array coordinate positioning technology and precision mechanical control technology.

[0085] Specifically, the process involves: transmitting the coordinate system data of the microcantilever beam array positioning component to the electrochemical deposition positioning component; reading the coordinate system data of the microcantilever beam array positioning component using the coordinate calibration instrument built into the electrochemical deposition positioning component; adjusting the coordinate calibration instrument of the electrochemical deposition positioning component to achieve precise alignment between the coordinate system of the electrochemical deposition positioning component and the coordinate system of the microcantilever beam array positioning component in three-dimensional space; verifying that the coordinate points of the center of each silicon-based microcantilever beam in the microcantilever beam array are consistent with the coordinate points of the electrochemical deposition positioning component; and storing the aligned coordinate system data to ensure that the coordinate information of the suspected damage location is directly transmitted to the electrochemical deposition positioning component for subsequent electrochemical deposition probe positioning.

[0086] Based on the coordinates of the suspected damage location, the electrochemical deposition probe is driven to move directly above the suspected damage location; wherein, the electrochemical deposition probe is a precision device used to release electrolyte and apply voltage to the surface of the suspected damage location to induce metal ion deposition;

[0087] The exposed carbon fibers of the carbon fiber reinforced resin matrix composite are connected to the reference electrode interface of the electrochemical controller as a reference electrode for electrochemical deposition; wherein, the electrochemical controller is a device used to regulate and maintain voltage or current stability during the electrochemical deposition process, and is an existing device.

[0088] The electrolyte release component of the electrochemical deposition probe is activated to release an electrolyte containing metal ions onto the surface of the suspected damage site, forming a local electrochemical reaction area;

[0089] Specifically, the process involves: transferring a metal ion-containing electrolyte to the electrolyte release nozzle via the electrolyte storage chamber of the electrochemical deposition probe; adjusting the position of the electrolyte release nozzle to ensure it is aligned with the suspected damage location on the surface of the carbon fiber reinforced resin matrix composite; opening the electrolyte release nozzle to release the metal ion-containing electrolyte to the suspected damage location on the surface of the carbon fiber reinforced resin matrix composite; continuously releasing the metal ion-containing electrolyte until a localized electrochemical reaction zone covering the suspected damage location on the surface of the carbon fiber reinforced resin matrix composite is formed; and closing the electrolyte release nozzle to stop electrolyte release and ensure the stable formation of the localized electrochemical reaction zone.

[0090] In the local electrochemical reaction region, a constant negative voltage is applied between the electrochemical deposition probe and the exposed carbon fibers of the carbon fiber reinforced resin matrix composite material by an electrochemical controller to maintain the voltage constant;

[0091] Specifically, the process involves: activating the electrochemical controller to initialize the electrical signal pathway between the electrochemical deposition probe and the exposed carbon fibers near the suspected damage location on the surface of the carbon fiber reinforced resin matrix composite; setting a constant negative voltage value, for example, -0.2V, through the electrochemical controller; placing the electrode of the electrochemical deposition probe within the local electrochemical reaction region at the suspected damage location on the surface of the carbon fiber reinforced resin matrix composite; applying a constant negative voltage to the electrode of the electrochemical deposition probe through the electrochemical controller, while using the exposed carbon fibers near the suspected damage location on the surface of the carbon fiber reinforced resin matrix composite as a reference electrode; continuously monitoring the voltage output status of the electrochemical controller to ensure that the constant negative voltage remains stable within the local electrochemical reaction region; and maintaining the constant negative voltage applied by the electrochemical controller until the subsequent metal deposition process is completed.

[0092] Under a constant negative voltage, metal ions are reduced and deposited on the surface of suspected damage sites, forming metal deposition spots;

[0093] Specifically, the process involves: inducing the reduction of metal ions in an electrolyte containing metal ions within a localized electrochemical reaction region using the electrode of an electrochemical deposition probe; depositing the reduced metal ions at microcracks or pores on the surface of the carbon fiber reinforced resin composite material where damage is suspected; continuously maintaining a constant negative voltage applied by the electrochemical controller to promote the formation of metal deposition spots at the suspected damage sites on the surface of the carbon fiber reinforced resin composite material; and observing the formation of the metal deposition spots to ensure their stable formation within the localized electrochemical reaction region.

[0094] A constant negative voltage is continuously applied until the metal deposition spot grows to a size that can be recognized by optical means, and metal marker stripes are output; wherein, the size that can be recognized by optical means refers to the size of the metal deposition spot with a width of, for example, 20 micrometers, which can be clearly imaged by a portable optical microscope.

[0095] S4. Scan the spatial distribution image of the metal marker stripes using a portable optical microscope, and scan the crystal structure diffraction peak intensity data of the metal marker stripes using a portable X-ray diffractometer. Generate a structural damage verification report based on the distribution morphology and crystal structure diffraction peak intensity data.

[0096] A portable optical microscope is aimed at the location of the metal marking stripes on the surface of the carbon fiber reinforced resin matrix composite material. The focal length and light source of the portable optical microscope are adjusted to make the metal marking stripes clear images. Among them, it is a lightweight imaging device for magnifying and observing the surface morphology of small objects, and it is an existing device.

[0097] Drive the portable optical microscope to scan the area covered by the metal marker stripes along the grid scanning path and record the spatial distribution image of the metal marker stripes;

[0098] Specifically, the process involves: activating the mobile platform of the portable optical microscope and loading a preset grid scanning path; driving the lens of the portable optical microscope to scan line by line the area covered by the metal marker stripes on the surface of the carbon fiber reinforced resin matrix composite material via the mobile platform; adjusting the lens movement speed of the portable optical microscope to ensure that the lens covers each grid area of ​​the metal marker stripe coverage area; acquiring images of the metal marker stripe coverage area within each grid area through the imaging component of the portable optical microscope; integrating the acquired images within each grid area according to the grid scanning path sequence to generate a spatial distribution image of the metal marker stripes; and storing the spatial distribution image of the metal marker stripes to the storage device of the portable optical microscope. The preset grid scanning path is determined based on the coordinate range of the suspected damage location on the surface of the carbon fiber reinforced resin matrix composite material and the field of view of the portable optical microscope, for example, covering the metal marker stripe area with a 1mm × 1mm grid area.

[0099] Align the portable X-ray diffractometer with the same area of ​​metallic marker stripes, adjust the incident angle and focusing position to ensure that the X-ray beam is incident directly on the surface of the metallic marker stripes; the portable X-ray diffractometer is a lightweight X-ray device for on-site analysis of the crystal structure of materials and is an existing device.

[0100] The portable X-ray diffractometer was activated to scan the metal marker stripes and obtain the crystal structure diffraction pattern.

[0101] Specifically, the process involves: activating the portable X-ray diffractometer and initializing the X-ray emission source and detector; aligning the X-ray emission source of the portable X-ray diffractometer with the area covered by the metallic marking stripes on the surface of the carbon fiber reinforced resin matrix composite material; adjusting the angle of the X-ray emission source of the portable X-ray diffractometer to ensure that the X-ray beam is incident perpendicularly onto the surface of the metallic marking stripes; driving the X-ray emission source and detector to scan point by point along the area covered by the metallic marking stripes using the moving platform of the portable X-ray diffractometer; acquiring the X-ray diffraction signals generated by the metallic marking stripes at each scanning point using the detector of the portable X-ray diffractometer; integrating the X-ray diffraction signals from all scanning points to generate the crystal structure diffraction pattern of the metallic marking stripes; and storing the crystal structure diffraction pattern of the metallic marking stripes in the storage device of the portable X-ray diffractometer.

[0102] Extracting crystal structure diffraction peak intensity data of metal-marked fringes from crystal structure diffraction patterns;

[0103] The spatial distribution image of the metal marker stripes is correlated and integrated with the diffraction peak intensity data of the crystal structure to generate a metal marker stripe dataset;

[0104] Extract the distribution density, morphological features, and crystal structure diffraction peak intensity variation trends from the metal marker stripe dataset;

[0105] The distribution density, morphological features, and crystal structure diffraction peak intensity variation trends are compared with the preset damage feature template. Based on the comparison results, a structural damage verification report is generated.

[0106] Data including standard distribution density, standard morphological features, and standard crystal structure diffraction peak intensities are extracted from a preset damage feature template. The preset damage feature template is determined based on experimental data of carbon fiber reinforced resin matrix composites under known damage types (such as microcracks and delamination). The distribution density of the metal marker stripes is compared with the standard distribution density of the preset damage feature template one by one through the data analysis component. The morphological features of the metal marker stripes are compared with the standard morphological features of the preset damage feature template. The crystal structure diffraction peak intensity data of the metal marker stripes are compared with the standard crystal structure diffraction peak intensity of the preset damage feature template. The matching degree of the distribution density, morphological features, and crystal structure diffraction peak intensity data of the metal marker stripes with the preset damage feature template is recorded. Based on the matching degree, a structural damage verification report containing the distribution density, morphological features, crystal structure diffraction peak intensity data of the metal marker stripes and the damage type determination is generated.

[0107] This embodiment also provides a computer device applicable to the structural damage detection method of carbon fiber reinforced resin matrix composites, including: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to realize the structural damage detection method of carbon fiber reinforced resin matrix composites as proposed in the above embodiment.

[0108] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0109] This embodiment also provides a storage medium storing a computer program, which, when executed by a processor, implements the structural damage detection method for carbon fiber reinforced resin matrix composites as proposed in the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0110] In summary, this invention achieves precise capture of abnormal mechanical responses by comparing resonant frequency data with reference resonant frequency data in the initial state to identify positions where frequency shifts exceed a preset threshold. Simultaneously, a plasmonic laser beam is applied to the frequency shift position to excite plasmonic resonance on the surface of the composite sensitive coating, and the frequency shift of its optical near-field enhancement response spectrum is monitored to determine whether it exceeds the range of background noise fluctuations. This dual-judgment mechanism utilizes cross-verification of mechanical vibration and optical near-field enhancement signals to avoid misjudgments caused by environmental interference with a single signal, significantly improving the reliability and sensitivity of damage identification. The synergistic effect of the microcantilever beam array and the composite sensitive coating enables the effective detection of minute deformations caused by microcracks and changes in the surface chemical environment, achieving high-precision localization and confirmation of early damage to carbon fiber reinforced resin matrix composites.

[0111] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. 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 be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for detecting structural damage in carbon fiber reinforced resin matrix composites, characterized in that: include, Microcantilever beam arrays are deployed on the surface at stress concentration points of carbon fiber reinforced resin matrix composites; The surface of the microcantilever beam array is covered with a composite sensitive coating; Resonance frequency data are collected in real time by a microcantilever beam array, and the composite sensitive coating on the surface of the microcantilever beam array is irradiated with a plasmonic laser beam to excite plasmonic resonance. The location of a microcantilever beam array where the resonant frequency data exceeds the reference offset threshold and the frequency shift of the plasmon resonance exceeds the preset background noise fluctuation range is identified as a suspected damage location. Electrochemical deposition is triggered by the coordinates of the suspected damage location. The exposed carbon fibers of the carbon fiber reinforced resin matrix composite material are used as a reference electrode. A constant negative voltage is applied to the surface of the suspected damage location to generate metallic marker stripes. The spatial distribution image of the metal marker stripes is scanned by a portable optical microscope, and the crystal structure diffraction peak intensity data of the metal marker stripes is scanned by a portable X-ray diffractometer. Based on the distribution morphology and crystal structure diffraction peak intensity data, a structural damage verification report is generated. The spatial distribution image of the metal marker stripes is correlated and integrated with the diffraction peak intensity data of the crystal structure to generate a metal marker stripe dataset; Extract the distribution density, morphological features, and crystal structure diffraction peak intensity variation trends from the metal marker stripe dataset; The distribution density, morphological features, and crystal structure diffraction peak intensity variation trends are compared with the preset damage feature template. Based on the comparison results, a structural damage verification report is generated. The preset damage feature template is determined based on experimental data of carbon fiber reinforced resin matrix composites under known damage types.

2. The structural damage detection method for carbon fiber reinforced resin matrix composites as described in claim 1, characterized in that: The deployment of microcantilever beam arrays at stress concentration locations on the surface of carbon fiber reinforced resin matrix composites is described in detail below. Oxygen plasma treatment is applied to the bolt hole edge and curved surface transition area of ​​the carbon fiber reinforced resin matrix composite material to form a pretreatment zone for the carbon fiber reinforced resin matrix composite material. In the pretreatment zone of carbon fiber reinforced resin matrix composite, nano-silver conductive adhesive is used to bond silicon-based microcantilever beams to form a rectangular array of microcantilever beams.

3. The structural damage detection method for carbon fiber reinforced resin matrix composites as described in claim 1, characterized in that: The resonant frequency data is acquired in real time using a microcantilever beam array, as detailed below. Establish an electrical connection between the microcantilever beam array and the resonant frequency acquisition instrument; An alternating electrostatic excitation is applied to the microcantilever beam array using a resonant frequency acquisition instrument. The response frequency of the microcantilever beam array is scanned, and the resonant frequency value displayed by the resonant frequency acquisition instrument is read as the resonant frequency data of the microcantilever beam array.

4. The structural damage detection method for carbon fiber reinforced resin matrix composites as described in claim 1, characterized in that: The process of irradiating the composite sensitive coating on the surface of the microcantilever beam array with a plasmonic laser beam to excite plasmonic resonance is as follows: One end of the optical fiber is connected to the output port of the plasmonic laser emitting device, and the other end is led to the microcantilever beam array. Adjust the position and angle of the optical fiber outlet to align with the composite sensitive coating on the surface of the microcantilever beam array, and keep the emission direction perpendicular to the surface of the composite sensitive coating. The plasma laser emitting device is started. After preheating and stabilization, the plasma laser emitting device outputs a plasma laser beam. A plasmonic laser beam is transmitted to the composite sensitive coating on the surface of the microcantilever beam array through an optical fiber that has been connected and aligned with the composite sensitive coating, thereby exciting plasmonic resonance.

5. The structural damage detection method for carbon fiber reinforced resin matrix composites as described in claim 1, characterized in that: The determination that the resonant frequency data exceeds the reference offset threshold is as follows: The initial resonance frequency values ​​of the microcantilever beam array under stress-free loading are obtained as reference resonance frequency data. The resonant frequency data of each position of the microcantilever beam array collected in real time are compared with the reference resonant frequency data of the corresponding position to determine the resonant frequency offset of each position of the microcantilever beam array. When the resonant frequency offset at a certain position of the microcantilever beam array is greater than the preset reference offset threshold, the check of the plasmon resonant frequency shift at the microcantilever beam array position where the resonant frequency offset exceeds the reference offset threshold is initiated.

6. The structural damage detection method for carbon fiber reinforced resin matrix composites as described in claim 1, characterized in that: The location of the microcantilever beam array where the frequency shift of the plasmonic resonance exceeds the preset background noise fluctuation range is as follows. Under the conditions of plasmon resonance excitation, the optical near-field enhancement response spectrum of the composite sensitive coating is monitored to obtain the real-time resonance frequency of plasmon resonance. The frequency shift of the plasmon resonance is determined by comparing the real-time resonance frequency of the plasmon resonance with the initial resonance frequency under stress-free loading. When the frequency shift of the plasmon resonance is greater than the maximum value of the preset background noise fluctuation range, it is determined that the frequency shift of the plasmon resonance exceeds the background noise fluctuation range.

7. The structural damage detection method for carbon fiber reinforced resin matrix composites as described in claim 1, characterized in that: The electrochemical deposition, triggered by the coordinates of the suspected damage location, uses the exposed carbon fibers of the carbon fiber reinforced resin matrix composite as a reference electrode. A constant negative voltage is applied to the surface of the suspected damage location to generate metallic marker stripes, as detailed below. Based on the coordinates of the suspected damage location, drive the electrochemical deposition probe to move directly above the suspected damage location; The exposed carbon fibers of the carbon fiber reinforced resin matrix composite are connected to the reference electrode interface of the electrochemical controller as a reference electrode for electrochemical deposition. The electrolyte release component of the electrochemical deposition probe is activated to release an electrolyte containing metal ions onto the surface of the suspected damage site, forming a local electrochemical reaction area; In the localized electrochemical reaction region, a constant negative voltage is applied between the electrochemical deposition probe and the exposed carbon fibers of the carbon fiber reinforced resin matrix composite material by an electrochemical controller; Under a constant negative voltage, metal ions are reduced and deposited on the surface of suspected damage sites, forming metal deposition spots; A constant negative voltage is continuously applied until the metal deposition spots grow to a size that can be recognized by optical means, and metal marker stripes are output.

8. The structural damage detection method for carbon fiber reinforced resin matrix composites as described in claim 1, characterized in that: The process involves scanning the spatial distribution image of the metal marker stripes using a portable optical microscope, scanning the crystal structure diffraction peak intensity data of the metal marker stripes using a portable X-ray diffractometer, and generating a structural damage verification report based on the distribution morphology and crystal structure diffraction peak intensity data, as detailed below. Aim the portable optical microscope at the location of the metal marking stripes on the surface of the carbon fiber reinforced resin matrix composite material, adjust the focal length and light source of the portable optical microscope, drive the portable optical microscope to scan the area covered by the metal marking stripes along the grid scanning path, and record the spatial distribution image of the metal marking stripes. The portable X-ray diffractometer was activated to scan the metal marker stripes and obtain the crystal structure diffraction pattern. Extract the crystal structure diffraction peak intensity data of the metallic marker stripes from the diffraction pattern.

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