Composite material internal damage judgment system and method based on interlayer sensing data
By implanting fiber grating sensors inside the composite material to form an interlayer sensing network, the strain and damage degree of the composite material can be monitored in real time, solving the problem that traditional detection methods cannot monitor the internal damage of the composite material in real time, and realizing real-time health assessment of the composite material structure.
Patent Information
- Application Number
- CN202411490179.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-24
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2044-10-24
AI Technical Summary
Existing technologies make it difficult to monitor internal damage in composite materials in real time. Traditional detection methods cannot achieve real-time monitoring and analysis of large-scale composite materials structures. Traditional sensors are unstable in complex environments and cannot be implanted inside materials, resulting in less intuitive monitoring.
A method based on interlayer sensing data is adopted. By implanting fiber grating sensors inside the composite material, the strain and damage degree at each layer are calculated. The damage is detected in real time using the change in the central wavelength of the fiber grating, forming a three-dimensional sensing network for damage judgment.
It realizes real-time detection of internal damage of composite materials, can provide timely feedback on health status, and provide composite material structure damage analysis and safety assessment with high real-time and accuracy.
Smart Images
Figure CN119534454B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of composite material structure health monitoring, and in particular to a composite material internal damage judgment system and method based on interlayer sensing data. Background Art
[0002] Carbon fiber-reinforced resin-based composite laminates, due to their lightweight, high strength, and high specific stiffness, have attracted significant attention in both scientific research and engineering applications. The use of composite materials has been increasing year by year, particularly in aerospace, rail transit, wind power, and other fields, and their use as load-bearing structures is also steadily increasing. However, during the preparation and use of composite materials, factors such as fatigue, equipment drops, impacts, shocks, lightning strikes, and corrosion can cause nearly invisible damage to the composite material. This damage primarily originates and propagates within the composite material. For load-bearing composite structures, this damage can continue to grow during the load-bearing process, ultimately leading to material failure and posing a significant safety hazard to the entire structure. Therefore, timely assessment of the internal health of composite materials is crucial in their practical application. Traditional inspection methods such as visual inspection, ultrasonic testing, and radiographic testing are unable to achieve real-time monitoring and analysis of the interior of large-scale composite structures. Because composite structures often operate in complex environments, traditional sensors such as surface-mounted strain gauges and piezoelectric sensors are susceptible to environmental influences, are unstable, and cannot be implanted within the material, making them less intuitive for monitoring structural health. Summary of the Invention
[0003] The purpose of the present invention is to address the defects of the existing technology and provide a composite material internal damage judgment system and method based on interlayer sensing data.
[0004] The present invention provides a composite material internal damage judgment system based on interlayer sensing data, comprising:
[0005] The composite material internal interlayer strain calculation module is used to calculate the strain at the composite material layer position corresponding to each fiber grating of all fiber optic sensors implanted in each layer of the composite material based on the changes in the central wavelength of each fiber optic Bragg grating detected by all fiber optic sensors;
[0006] The internal damage degree calculation module of the composite material is used to divide the strain corresponding to the same fiber Bragg grating position in each layer of the composite material by the strain at the corresponding position on the surface of the composite material to obtain the relative strain value at the corresponding position of each layer. Then, by calculating the rate of change of the relative strain value at the corresponding position of each layer with the number of impacts, the damage degree at the corresponding position of each layer of the composite material is obtained.
[0007] Furthermore, it also includes: a composite material health scoring module, which is used to assign weights to the corresponding positions of each fiber grating of all fiber optic sensors. Each weight is multiplied by the damage degree of the corresponding fiber grating corresponding to the composite material position to characterize the health of the composite material.
[0008] Furthermore, when preparing the composite material, each layer of the composite material includes a base material and a prepreg, the prepreg is laid on the base material, and the optical fiber sensor is flatly fixed on the prepreg, and then the next layer of base material for preparing the composite material is laid on the prepreg. The optical fiber sensor is composed of a plurality of grating array sensing optical fibers, and the grating array sensing optical fibers are engraved with a fiber grating array. The fiber grating array is composed of a plurality of fiber grating strings, and the fiber grating string is composed of a plurality of fiber gratings with different initial center wavelengths.
[0009] Furthermore, the initial center wavelength of the fiber Bragg grating is in the range of 1510 nm to 1590 nm, and the initial wavelength interval between two adjacent fiber Bragg gratings in the fiber Bragg grating string is in the range of 4 nm to 20 nm.
[0010] Furthermore, in the composite material internal interlayer strain calculation module, the specific method for calculating the strain at the composite material layer position corresponding to each fiber Bragg grating of all fiber sensors implanted in each layer of the composite material based on the change in the central wavelength of each fiber Bragg grating detected by all fiber sensors implanted in each layer of the composite material is:
[0011] The strain at the corresponding composite material layer position is calculated based on the change in the central wavelength of each fiber Bragg grating:
[0012]
[0013] in, is the strain of the fiber Bragg grating u of the i-th layer fiber sensor in the composite material corresponding to the composite material layer position, k is the strain sensitivity coefficient of the fiber Bragg grating, is the central wavelength of the fiber Bragg grating u of the i-th layer fiber sensor in the composite material during detection, is the initial value of the central wavelength of the fiber Bragg grating u of the i-th layer optical fiber sensor in the composite material.
[0014] Furthermore, in the composite material internal damage degree calculation module, the specific method of dividing the strain corresponding to the same fiber Bragg grating position in each layer of the composite material by the strain at the corresponding position on the surface of the composite material to obtain the relative strain value at the corresponding position of each layer is:
[0015] The strain information collected by the optical fiber sensor on the i-th layer The two-dimensional coordinates of the positions of each fiber Bragg grating corresponding to the composite material layer are rearranged into a two-dimensional matrix:
[0016]
[0017] in, is the strain set of all fiber Bragg gratings of the i-th layer fiber sensor in the composite material corresponding to the composite material layer position, is the strain of the fiber Bragg grating in the mth row and nth column of the i-th layer of the composite material corresponding to the composite material surface;
[0018] The relative strain values between the fiber grating positions with the same two-dimensional coordinates on each layer where the fiber optic sensor is implanted:
[0019]
[0020] in, It represents the relative strain value of the fiber Bragg grating in the mth row and nth column of the i-th layer fiber sensor corresponding to the composite material layer position, is the strain of the fiber Bragg grating in the mth row and nth column of the i-th layer fiber sensor corresponding to the composite material layer position, is the strain of the fiber Bragg grating in the mth row and nth column of the first layer of optical fiber sensor corresponding to the composite material layer position.
[0021] Furthermore, in the composite material internal damage degree calculation module, the specific method for obtaining the damage degree at the corresponding position of each layer of the composite material by calculating the rate of change of the relative strain value at the corresponding position of each layer with the number of impacts is as follows:
[0022] Based on the number of impacts, the damage degree is calculated as follows:
[0023]
[0024] in, is the damage degree of the fiber Bragg grating position in the mth row and nth column of the i-th layer fiber sensor after the composite material is subjected to the tth impact, is the relative strain value of the fiber Bragg grating in the mth row and nth column of the i-th fiber sensor corresponding to the composite material surface after the composite material is subjected to the t-th impact, is the initial value of the relative strain of the fiber Bragg grating in the mth row and nth column of the optical fiber sensor of the i-th layer of the composite material corresponding to the composite material surface position.
[0025] A composite material internal damage judgment method based on interlayer sensing data, comprising:
[0026] Calculate the strain at the composite layer corresponding to each fiber Bragg grating of each fiber sensor based on the change in the central wavelength of each fiber Bragg grating detected by all fiber sensors embedded in each layer of the composite material;
[0027] The strain corresponding to the same fiber Bragg grating position in each layer of the composite material is divided by the strain at the corresponding position on the surface of the composite material to obtain the relative strain value at the corresponding position of each layer. Then, by calculating the rate of change of the relative strain value at the corresponding position of each layer with the number of impacts, the degree of damage at the corresponding position of each layer of the composite material is obtained.
[0028] A computer-readable medium stores a computer program / instruction, which, when run, executes the above-mentioned method for determining internal damage of a composite material based on interlayer sensing data.
[0029] A computer program product includes a computer program / instruction, which, when executed by a processor, implements the above-mentioned method for determining internal damage of a composite material based on interlayer sensing data.
[0030] The beneficial effects of the present invention are:
[0031] 1. The present invention implants fiber Bragg grating (FBG) sensors within the material and combines them with a three-dimensional fiber Bragg grating (FBG) sensing network to monitor the physical field between composite material layers. In particular, the present invention uses the relative strain values between fiber Bragg grating (FBG) positions with the same two-dimensional coordinates on each layer where the fiber Bragg grating (FBG) sensors are implanted to determine damage to the composite material during service, thereby enabling analysis of composite material structural damage and assessment of composite material structural safety.
[0032] 2. By detecting whether the central wavelength of the fiber Bragg grating of the optical fiber sensor changes, it is possible to detect in real time whether the composite material has been impacted. This sensor has a high degree of real-time performance and can provide timely feedback on the health of the composite material. The strain at that location can be calculated by the change in the central wavelength of the fiber Bragg grating before and after the composite material is subjected to force, intuitively reflecting the damage to the composite material.
[0033] 3. Since the fiber optic sensors are implanted into the composite material layer by layer, and each fiber grating corresponds to each other in the thickness direction (the two-dimensional coordinates of the fiber gratings in each layer are the same), they together form a three-dimensional sensing network. At the same time, the relative strain value is calculated by ratio to indicate the relative strain size of each layer. This can reflect whether the local strain exceeds the normal range. The degree of damage is then calculated by the relative strain value to truly reflect the health status of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 This is a system block diagram of the present invention;
[0035] Figure 2 This is a schematic diagram of the layout of a three-dimensional interlayer sensing network of multi-layer optical fiber sensors;
[0036] Figure 3 Schematic diagram of grating array sensing fiber;
[0037] Figure 4 Schematic diagram of the layout of single-layer grating array sensing optical fiber inside the composite material;
[0038] Figure 5 Schematic diagram of internal damage monitoring system for composite materials structure with full-time sensing data between layers;
[0039] Figure 6 Schematic diagram of a three-dimensional interlayer sensing network.
[0040] Description of the accompanying drawings: 1—carbon fiber composite material, 2—fiber optic sensor, 3—fiber optic connector, 4—grating array sensing fiber, 5—fiber grating, 6—prepreg, 7—grating array sensing fiber, 8—connecting fiber, 9—fiber optic demodulator. DETAILED DESCRIPTION
[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.
[0042] Example 1
[0043] A composite material internal damage judgment system based on interlayer sensing data, comprising:
[0044] The composite material internal interlayer strain calculation module is used to calculate the strain at the composite material layer position corresponding to each fiber grating of all fiber optic sensors implanted in each layer of the composite material based on the changes in the central wavelength of each fiber optic Bragg grating detected by all fiber optic sensors;
[0045] The internal damage degree calculation module of the composite material is used to divide the strain corresponding to the same fiber Bragg grating position in each layer of the composite material by the strain at the corresponding position on the surface of the composite material to obtain the relative strain value at the corresponding position of each layer, and then calculate the rate of change of the relative strain value at the corresponding position of each layer with the number of impacts to obtain the damage degree at the corresponding position of each layer of the composite material;
[0046] The composite material health scoring module is used to assign weights to the corresponding positions of each fiber grating of all fiber optic sensors. Each weight is multiplied by the damage degree of the corresponding fiber grating corresponding to the composite material position to represent the health of the composite material.
[0047] (1) When preparing a composite material, each layer of the composite material includes a base material (such as resin-based carbon fiber) and a prepreg. The prepreg is laid on the base material, and the optical fiber sensor is flatly fixed on the prepreg. Then, the next layer of the base material for preparing the composite material is laid on the prepreg. The optical fiber sensor is composed of a plurality of grating array sensing optical fibers. The grating array sensing optical fibers are engraved with a fiber grating array. The fiber grating array is composed of a plurality of fiber grating strings. The fiber grating string is composed of a plurality of fiber gratings with different initial center wavelengths.
[0048] See also Figure 2-Figure 6 The fiber sensor 2 is composed of several grating array optical fibers 4. The grating array sensing fiber is inscribed with a fiber grating array. The fiber grating array consists of multiple fiber gratings 5 of different wavelengths, with a central wavelength range of 1510nm-1590nm. Each fiber grating string has a length of L1, and the fiber grating string spacing is L2. Each fiber grating string contains five fiber gratings 5 of different wavelengths. The initial wavelength spacing between two adjacent fiber gratings in the fiber grating string is between 4nm and 20nm. The included fiber gratings are evenly distributed at intervals of L3, which ensures that the fiber gratings do not interfere with each other while maintaining a large detection range.
[0049] For the installation method of single-layer optical fiber sensor 2, refer to Figure 5 After prepreg 6 is laid, the grating array sensing fiber is laid flat and fixed on top. The fiber gratings in the grating array sensing fiber 7 are laid parallel to the fibers of prepreg 6. To form a grating sensing network, the fiber gratings are looped around the edges using the grating strings. The parallel spacing is set to L3, and the fiber gratings 5 before and after the loop are symmetrical to ensure a uniform rectangular grating sensing array. The lead end of the grating array sensing fiber 7 is connected to the optical fiber connector 3.
[0050] After the single-layer fiber optic sensor is laid out, continue to lay the composite material prepreg, and implant the fiber optic sensor 4 into the composite material 1 at the designed fiber optic sensor 2 position according to the above steps, and ensure that the fiber optic layout between the layers of each fiber optic sensor 2 is consistent, the fiber optic Bragg grating 5 corresponds one to one along the longitudinal position, and the lead-out end of each layer of grating array sensing fiber 7 is connected to the fiber optic connector 3 respectively.
[0051] (2) In the composite material internal interlayer strain calculation module, the specific method for calculating the strain at the composite material layer position corresponding to each fiber Bragg grating of all fiber sensors embedded in each layer of the composite material based on the change in the central wavelength of each fiber Bragg grating detected by all fiber sensors embedded in each layer of the composite material is as follows:
[0052] The strain at the corresponding composite material layer position is calculated based on the change in the central wavelength of each fiber Bragg grating:
[0053]
[0054] in, is the strain of the fiber Bragg grating u of the i-th layer fiber sensor in the composite material corresponding to the composite material layer position, k is the strain sensitivity coefficient of the fiber Bragg grating, is the central wavelength of the fiber Bragg grating u of the i-th layer fiber sensor in the composite material during detection, is the initial value of the central wavelength of the fiber Bragg grating u of the i-th layer optical fiber sensor in the composite material.
[0055] By detecting changes in the central wavelength of the fiber Bragg grating of the optical fiber sensor, it is possible to detect in real time whether the composite material has been impacted. This method has a high degree of real-time performance and can provide timely feedback on the health of the composite material. The strain at that location can be calculated by the change in the central wavelength of the fiber Bragg grating before and after the composite material is subjected to force, intuitively reflecting the damage to the composite material.
[0056] (3) In the composite material internal damage degree calculation module, the specific method of dividing the strain corresponding to the same fiber Bragg grating position in each layer of the composite material by the strain at the corresponding position on the surface of the composite material to obtain the relative strain value at the corresponding position of each layer is:
[0057] The strain information collected by the optical fiber sensor on the i-th layer The two-dimensional coordinates of the positions of each fiber Bragg grating corresponding to the composite material layer are rearranged into a two-dimensional matrix:
[0058]
[0059] in, is the strain set of all fiber Bragg gratings of the i-th layer fiber sensor in the composite material corresponding to the composite material layer position, is the strain of the fiber Bragg grating in the mth row and nth column of the i-th layer of the composite material corresponding to the composite material surface;
[0060] The relative strain values between the fiber grating positions with the same two-dimensional coordinates on each layer where the fiber optic sensor is implanted:
[0061]
[0062] in, It represents the relative strain value of the fiber Bragg grating in the mth row and nth column of the i-th layer fiber sensor corresponding to the composite material layer position, is the strain of the fiber Bragg grating in the mth row and nth column of the i-th layer fiber sensor corresponding to the composite material layer position, is the strain of the fiber Bragg grating in the mth row and nth column of the first layer of optical fiber sensor corresponding to the composite material layer position.
[0063] In the composite material internal damage degree calculation module, the specific method for obtaining the damage degree at the corresponding position of each layer of the composite material by calculating the rate of change of the relative strain value at the corresponding position of each layer with the number of impacts is as follows:
[0064] Based on the number of impacts, the damage degree is calculated as follows:
[0065]
[0066] in, is the damage degree of the fiber Bragg grating position in the mth row and nth column of the i-th layer fiber sensor after the composite material is subjected to the tth impact, is the relative strain value of the fiber Bragg grating in the mth row and nth column of the i-th fiber sensor corresponding to the composite material surface after the composite material is subjected to the t-th impact, is the initial value of the relative strain of the fiber Bragg grating in the mth row and nth column of the optical fiber sensor of the i-th layer of the composite material corresponding to the composite material surface position.
[0067] like Figure 6 As shown, because the fiber optic sensors are stacked layer by layer and embedded in the composite material, and each fiber Bragg grating corresponds to the composite material in the thickness direction (the fiber Bragg gratings in each layer have the same two-dimensional coordinates), they together form a three-dimensional sensing network. At the same time, the relative strain values are calculated by ratio to indicate the relative strain magnitude of each layer. This can indicate whether the local strain exceeds the normal range. The degree of damage is then calculated using the relative strain values to truly reflect the health of the composite material. The specific value involved in determining whether the local strain exceeds the normal range depends on the application scenario of the composite material and the properties of the material itself, and cannot be generalized.
[0068] Example 2
[0069] A composite material internal damage judgment method based on interlayer sensing data, comprising:
[0070] Calculate the strain at the composite layer corresponding to each fiber Bragg grating of each fiber sensor based on the change in the central wavelength of each fiber Bragg grating detected by all fiber sensors embedded in each layer of the composite material;
[0071] The strain corresponding to the same fiber Bragg grating position in each layer of the composite material is divided by the strain at the corresponding position on the surface of the composite material to obtain the relative strain value at the corresponding position of each layer. Then, by calculating the rate of change of the relative strain value at the corresponding position of each layer with the number of impacts, the damage degree at the corresponding position of each layer of the composite material is obtained.
[0072] Weights are assigned to the corresponding positions of the fiber gratings of all fiber sensors. Each weight is multiplied by the damage degree of the corresponding fiber grating at the composite material position to represent the health of the composite material.
[0073] (1) When preparing a composite material, each layer of the composite material includes a base material (such as resin-based carbon fiber) and a prepreg. The prepreg is laid on the base material, and the optical fiber sensor is flatly fixed on the prepreg. Then, the next layer of the base material for preparing the composite material is laid on the prepreg. The optical fiber sensor is composed of a plurality of grating array sensing optical fibers. The grating array sensing optical fibers are engraved with a fiber grating array. The fiber grating array is composed of a plurality of fiber grating strings. The fiber grating string is composed of a plurality of fiber gratings with different initial center wavelengths.
[0074] During the preparation of the carbon fiber composite material 1 , the optical fiber sensor 2 is implanted between the composite material layers according to the material design requirements and connected to the optical fiber connector 3 for signal transmission.
[0075] See also Figure 2-Figure 6 The fiber sensor 2 is composed of several grating array optical fibers 4. The grating array sensing fiber is inscribed with a fiber grating array. The fiber grating array consists of multiple fiber gratings 5 of different wavelengths, with a central wavelength range of 1510nm-1590nm. Each fiber grating string has a length of L1, and the fiber grating string spacing is L2. Each fiber grating string contains five fiber gratings 5 of different wavelengths. The initial wavelength spacing between two adjacent fiber gratings in the fiber grating string is between 4nm and 20nm. The included fiber gratings are evenly distributed at intervals of L3, which ensures that the fiber gratings do not interfere with each other while maintaining a large detection range.
[0076] For the installation method of single-layer optical fiber sensor 2, refer to Figure 5 After prepreg 6 is laid, the grating array sensing fiber is laid flat and fixed on top. The fiber gratings in the grating array sensing fiber 7 are laid parallel to the fibers of prepreg 6. To form a grating sensing network, the fiber gratings are looped around the edges using the grating strings. The parallel spacing is set to L3, and the fiber gratings 5 before and after the loop are symmetrical to ensure a uniform rectangular grating sensing array. The lead end of the grating array sensing fiber 7 is connected to the optical fiber connector 3.
[0077] After the single-layer fiber optic sensor is laid out, continue to lay the composite material prepreg, and implant the fiber optic sensor 4 into the composite material 1 at the designed fiber optic sensor 2 position according to the above steps, and ensure that the fiber optic layout between the layers of each fiber optic sensor 2 is consistent, the fiber optic Bragg grating 5 corresponds one to one along the longitudinal position, and the lead-out end of each layer of grating array sensing fiber 7 is connected to the fiber optic connector 3 respectively.
[0078] (2) Based on the changes in the central wavelengths of the fiber gratings detected by all the fiber optic sensors at each layer inside the composite material, the specific method for calculating the strain at the composite material layer position corresponding to each fiber grating of all the fiber optic sensors is as follows:
[0079] The strain at the corresponding composite material layer position is calculated based on the change in the central wavelength of each fiber Bragg grating:
[0080]
[0081] in, is the strain of the fiber Bragg grating u of the i-th layer fiber sensor in the composite material corresponding to the composite material layer position, k is the strain sensitivity coefficient of the fiber Bragg grating, is the central wavelength of the fiber Bragg grating u of the i-th layer fiber sensor in the composite material during detection, is the initial value of the central wavelength of the fiber Bragg grating u of the i-th layer optical fiber sensor in the composite material.
[0082] By detecting changes in the central wavelength of the fiber Bragg grating of the optical fiber sensor, it is possible to detect in real time whether the composite material has been impacted. This method has a high degree of real-time performance and can provide timely feedback on the health of the composite material. The strain at that location can be calculated by the change in the central wavelength of the fiber Bragg grating before and after the composite material is subjected to force, intuitively reflecting the damage to the composite material.
[0083] (3) The specific method of dividing the strain corresponding to the same fiber Bragg grating position in each layer of the composite material by the strain at the corresponding position on the surface of the composite material to obtain the relative strain value at the corresponding position of each layer is:
[0084] The strain information collected by the optical fiber sensor on the i-th layer The two-dimensional coordinates of the positions of each fiber Bragg grating corresponding to the composite material layer are rearranged into a two-dimensional matrix:
[0085]
[0086] in, is the strain set of all fiber Bragg gratings of the i-th layer fiber sensor in the composite material corresponding to the composite material layer position, is the strain of the fiber Bragg grating in the mth row and nth column of the i-th layer of the composite material corresponding to the composite material surface;
[0087] The relative strain values between the fiber grating positions with the same two-dimensional coordinates on each layer where the fiber optic sensor is implanted:
[0088]
[0089] in, It represents the relative strain value of the fiber Bragg grating in the mth row and nth column of the i-th layer fiber sensor corresponding to the composite material layer position, is the strain of the fiber Bragg grating in the mth row and nth column of the i-th layer fiber sensor corresponding to the composite material layer position, is the strain of the fiber Bragg grating in the mth row and nth column of the first layer of optical fiber sensor corresponding to the composite material layer position.
[0090] In the composite material internal damage degree calculation module, the specific method for obtaining the damage degree at the corresponding position of each layer of the composite material by calculating the rate of change of the relative strain value at the corresponding position of each layer with the number of impacts is as follows:
[0091] Based on the number of impacts, the damage degree is calculated as follows:
[0092]
[0093] in, is the damage degree of the fiber Bragg grating position in the mth row and nth column of the i-th layer fiber sensor after the composite material is subjected to the tth impact, is the relative strain value of the fiber Bragg grating in the mth row and nth column of the i-th fiber sensor corresponding to the composite material surface after the composite material is subjected to the t-th impact, is the initial value of the relative strain of the fiber Bragg grating in the mth row and nth column of the optical fiber sensor of the i-th layer of the composite material corresponding to the composite material surface position.
[0094] like Figure 6 As shown, because the fiber optic sensors are stacked layer by layer and embedded in the composite material, and each fiber Bragg grating corresponds to the composite material in the thickness direction (the fiber Bragg gratings in each layer have the same two-dimensional coordinates), they together form a three-dimensional sensing network. At the same time, the relative strain values are calculated by ratio to indicate the relative strain magnitude of each layer. This can indicate whether the local strain exceeds the normal range. The degree of damage is then calculated using the relative strain values to truly reflect the health of the composite material. The specific value involved in determining whether the local strain exceeds the normal range depends on the application scenario of the composite material and the properties of the material itself, and cannot be generalized.
[0095] Example 3
[0096] A computer-readable medium having a computer program / instruction stored thereon, wherein the computer program / instruction executes the composite material internal damage judgment method based on interlayer sensing data in Example 2 when the computer program / instruction is executed
[0097] Example 4
[0098] A computer program product includes a computer program / instruction, which, when executed by a processor, implements the composite material internal damage judgment method based on interlayer sensing data in Example 2.
[0099] The contents not described in detail in this specification belong to the prior art known to those skilled in the art. It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.
[0100] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.
[0101] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.
[0102] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.
[0103] Finally, 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 its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art may still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.
Claims
1. A composite material internal damage judgment system based on interlayer sensing data, characterized in that: include: The composite material internal interlayer strain calculation module is used to calculate the strain at the composite material layer position corresponding to each fiber grating of all fiber optic sensors implanted in each layer of the composite material based on the changes in the central wavelength of each fiber optic Bragg grating detected by all fiber optic sensors; The internal damage degree calculation module of the composite material is used to divide the strain corresponding to the same fiber Bragg grating position in each layer of the composite material by the strain at the corresponding position on the surface of the composite material to obtain the relative strain value at the corresponding position of each layer, and then calculate the rate of change of the relative strain value at the corresponding position of each layer with the number of impacts to obtain the damage degree at the corresponding position of each layer of the composite material; Based on the number of impacts, the damage degree is calculated as follows: in, For composite materials t After the first impact The first layer of fiber optic sensor OK The damage degree of the fiber Bragg grating position of the column, For composite materials t After the first impact The first layer of fiber optic sensor OK The relative strain value of the fiber Bragg grating corresponding to the composite material layer position, For composite materials The first layer of fiber optic sensor OK The relative initial values of strain at the fiber Bragg grating positions corresponding to the composite material layers are shown in the table.
2. The composite material internal damage judgment system based on interlayer sensing data according to claim 1 is characterized in that: Also includes: The composite material health scoring module is used to assign weights to the corresponding positions of each fiber grating of all fiber optic sensors. Each weight is multiplied by the damage degree of the corresponding fiber grating corresponding to the composite material position to represent the health of the composite material.
3. The composite material internal damage judgment system based on interlayer sensing data according to claim 1 is characterized in that: When preparing a composite material, each layer of the composite material includes a base material and a prepreg. The prepreg is laid on the base material, and the optical fiber sensor is flatly fixed on the prepreg. Then, the next layer of base material for preparing the composite material is laid on the prepreg. The optical fiber sensor is composed of a plurality of grating array sensing optical fibers. The grating array sensing optical fibers are engraved with a fiber grating array. The fiber grating array is composed of a plurality of fiber grating strings. The fiber grating string is composed of a plurality of fiber gratings with different initial center wavelengths.
4. The composite material internal damage judgment system based on interlayer sensing data according to claim 3 is characterized by: The initial center wavelength range of the fiber Bragg grating is between 1510nm and 1590nm, and the initial wavelength interval between two adjacent fiber Bragg gratings in the fiber Bragg grating string is between 4nm and 20nm.
5. The composite material internal damage judgment system based on interlayer sensing data according to claim 1 is characterized in that: In the composite material internal interlayer strain calculation module, the specific method for calculating the strain at the composite material layer position corresponding to each fiber Bragg grating of all fiber sensors embedded in each layer of the composite material based on the changes in the central wavelengths of the fiber Bragg gratings detected by all fiber sensors embedded in each layer of the composite material is as follows: The strain at the corresponding composite material layer position is calculated based on the change in the central wavelength of each fiber Bragg grating: in, For composite materials Fiber Bragg Grating Sensor Corresponding to the strain at the composite layer position, is the strain sensitivity coefficient of the fiber Bragg grating, For composite materials Fiber Bragg Grating Sensor The central wavelength at the time of detection, For composite materials Fiber Bragg Grating Sensor The initial value of the center wavelength.
6. The composite material internal damage judgment system based on interlayer sensing data according to claim 1 is characterized by: In the composite material internal damage degree calculation module, the specific method of dividing the strain corresponding to the same fiber Bragg grating position in each layer of the composite material by the strain at the corresponding position on the surface of the composite material to obtain the relative strain value at the corresponding position of each layer is: The first Strain information collected by optical fiber sensors The two-dimensional coordinates of the positions of each fiber Bragg grating corresponding to the composite material layer are rearranged into a two-dimensional matrix: in, For composite materials The strain set of all fiber Bragg gratings of the layer fiber sensor corresponding to the position of the composite material layer, For composite materials The first layer of fiber optic sensor OK The fiber Bragg grating array corresponds to the strain at the composite material layer position; The relative strain values between the fiber grating positions with the same two-dimensional coordinates on each layer where the fiber optic sensor is implanted: in, Indicates the The first layer of fiber optic sensor OK The relative strain value of the fiber Bragg grating corresponding to the composite material layer position, For the The first layer of fiber optic sensor OK The fiber Bragg grating array corresponds to the strain at the composite material layer position, The first layer of optical fiber sensor OK The fiber Bragg grating array corresponds to the strain at the composite material layer position.
7. A composite material internal damage judgment method based on interlayer sensing data, characterized in that: include: Calculate the strain at the composite layer corresponding to each fiber Bragg grating of each fiber sensor based on the change in the central wavelength of each fiber Bragg grating detected by all fiber sensors embedded in each layer of the composite material; The strain corresponding to the same fiber Bragg grating position in each layer of the composite material is divided by the strain at the corresponding position on the surface of the composite material to obtain the relative strain value at the corresponding position of each layer. Then, by calculating the rate of change of the relative strain value at the corresponding position of each layer with the number of impacts, the damage degree at the corresponding position of each layer of the composite material is obtained. Based on the number of impacts, the damage degree is calculated as follows: in, For composite materials t After the first impact The first layer of fiber optic sensor OK The damage degree of the fiber Bragg grating position of the column, For composite materials t After the first impact The first layer of fiber optic sensor OK The relative strain value of the fiber Bragg grating corresponding to the composite material layer position, For composite materials The first layer of fiber optic sensor OK The relative initial values of strain at the fiber Bragg grating positions corresponding to the composite material layers are shown in the table.
8. A computer-readable medium having a computer program / instruction stored thereon, wherein the computer program / instruction, when run, executes the composite material internal damage judgment method based on interlayer sensing data according to claim 7.
9. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the method for determining internal damage of a composite material based on interlayer sensing data as described in claim 7 is implemented.