A method and system for detecting the degree of cure of a polymer-based composite

Abstract

The present application belongs to the technical field of composite material performance detection, and particularly relates to a polymer matrix composite curing degree detection method and system. The present application takes the curing degree data and the temperature rise data point set of the polymer matrix composite sample after heating as training data, and establishes a curing degree detection model based on the machine learning method, taking the temperature rise data point set of the sample to be detected as input and the curing degree of the sample to be detected as output. The temperature change data of the sample to be detected with the same sample morphology and the same heating condition is input into the curing degree detection model, so that the curing degree of the sample to be detected can be obtained, and the rapid analysis and judgment of the curing degree of the polymer matrix composite material are realized. The method is low in cost, high in efficiency, and suitable for industrial batch detection application.

Description

Technical Field

[0001] This invention belongs to the field of composite material performance testing technology, and particularly relates to a method and system for testing the degree of curing of polymer-based composite materials. Background Technology

[0002] Curing of polymer-based composite materials is a crucial process step in composite material molding, determining the quality of the final product. During curing, reactive groups on the polymer resin molecular chains interconnect under the influence of heat and / or catalysts / curing agents, undergoing a cross-linking reaction to form a three-dimensional network structure. During the reaction, the thermosetting resin matrix gradually transforms from a liquid phase to a gel state, ultimately becoming a solid substance with a certain strength. Currently, methods for detecting the degree of curing of thermosetting polymer-based composite materials include differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), dynamic thermomechanical analysis (TMA), dielectric analysis, ultrasonic testing, and fiber optic sensor methods. Among these, DSC, Fourier transform infrared spectroscopy, and TMA have strict limitations on sample size and shape. Ultrasonic testing and fiber optic sensor methods involve complex signal decoupling and high equipment costs, making them unsuitable for industrial production. Dielectric analysis is currently the most widely used method in industrial production inspection, but it requires integrating the sensor into the component or mold, potentially introducing weak points. Currently, there is no efficient, low-cost, and suitable non-destructive testing method for detecting the degree of curing of composite material products, suitable for industrial production inspection.

[0003] Patent CN107796787A discloses a method for real-time monitoring of the curing degree of composite materials. This method uses a fiber optic sensor to monitor the refractive index of the composite material during the curing process, and simultaneously analyzes the effects of curing and temperature changes on the refractive index in real time, achieving real-time monitoring of the microwave curing process of the composite material. Patent CN113030191A discloses a method for in-situ monitoring of resin curing degree based on an embedded fiber sensor. This method connects a sensor embedded in the resin to an impedance testing circuit. By testing the impedance of the sensor during the curing process, the maximum impedance of the fiber sensor is extracted to obtain an impedance-curing time curve, and subsequently, an impedance-curing degree curve. Both of these methods require embedding impedance sensors in the composite structure, allowing only localized detection and potentially creating weak points in the structure.

[0004] Patent CN113624596A discloses a device and method for detecting the pre-curing degree of a solid rocket motor propellant liner. The method uses a robotic arm to drive a probe at its end for detection. The probe is first inserted into the solid rocket motor, and after touching the inner diameter surface liner, it is immediately lifted. The pre-curing degree of the solid rocket motor can be detected when the filament breaks. This method involves invasive testing of composite material structures and is not suitable for repeated testing. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a method and system for detecting the degree of curing of polymer-based composite materials, which can quickly and efficiently achieve non-destructive testing of the degree of curing of polymer-based composite materials.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for detecting the degree of curing of polymer-based composite materials, comprising:

[0008] Acquire data on the temperature change of the heated sample over time;

[0009] The temperature rise data point set of the sample is obtained based on the temperature change data of the sample over time;

[0010] The temperature rise data points of the sample to be tested are input into the pre-trained curing degree detection model to obtain the curing degree of the sample to be tested.

[0011] The set of temperature rise data points is a collection of temperature change ratios at different times when heating begins;

[0012] The temperature change ratio is based on the heating time of the sample, the temperature on the back of the center point of the heated area of ​​the sample measured during that time, the initial temperature of the sample, and the maximum temperature on the back of the heated point when the sample with 100% curing degree is heated.

[0013] Optionally, the curing degree detection model is trained using the following method:

[0014] Obtain the degree of curing of each sample in the sample set;

[0015] Acquire the temperature change data of each sample after heating over time, and obtain its temperature rise data point set based on the temperature change data of each sample over time;

[0016] The curing degree detection model is trained based on the curing degree and temperature rise data points of each sample.

[0017] Optionally, the temperature change ratio is calculated using the following formula:

[0018] ;

[0019] Among them, V s Let T be the percentage of temperature rise at time t. s T is the temperature value on the back side of the center point of the heated area of ​​the sample at time t, T0 is the initial temperature of the sample, and T max The maximum temperature on the back side of the heating point when a sample with 100% curing degree is heated.

[0020] Optionally, the temperature change data of each sample over time and the temperature change data of the sample under test over time are obtained based on the same sample morphology and the same heating conditions.

[0021] Optionally, obtaining the degree of curing of each sample in the sample set includes obtaining the degree of curing of each sample by one of differential scanning calorimetry, dynamic mechanical analysis, chemical titration and infrared spectroscopy.

[0022] Optionally, a set of temperature rise data points of the sample to be tested after heating can be obtained, wherein the total heating time is not less than 10 minutes.

[0023] Optionally, the heating method includes one of laser heat source, planar heat source, infrared radiation, electric heating plate, and flexible heating film, and the heating temperature is not higher than the operating temperature of the sample to be tested.

[0024] Optionally, it also includes: comparing the degree of curing of the sample to be tested with the required degree of curing range to determine whether the degree of curing of the polymer-based composite material meets the requirements.

[0025] Secondly, the present invention also provides a polymer-based composite material curing degree detection system, comprising:

[0026] The data acquisition module is configured to acquire data on the temperature change of the heated sample over time.

[0027] The data processing module is configured to: obtain a set of temperature rise data points of the sample based on the temperature change data of the sample over time;

[0028] The data analysis module is configured to input the temperature rise data point set of the sample to be tested into a pre-trained curing degree detection model to obtain the curing degree of the sample to be tested.

[0029] The set of temperature rise data points is a collection of temperature change ratios at different times when heating begins;

[0030] The temperature change ratio is based on the heating time of the sample, the temperature on the back of the center point of the heated area of ​​the sample measured during that time, the initial temperature of the sample, and the maximum temperature on the back of the heated point when the sample with 100% curing degree is heated.

[0031] Thirdly, the present invention also provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of the polymer-based composite material curing degree detection method described in the first aspect.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] This invention uses the curing degree data of polymer-based composite material samples and their temperature rise data points after heating as training data. Based on machine learning, a curing degree detection model is established, which takes the temperature rise data points of the sample as input and the curing degree of the sample as output. The temperature change data of the sample over time, obtained under the same sample morphology and heating conditions as the sample, is input into the curing degree detection model to obtain the curing degree of the sample. This enables rapid analysis and judgment of the curing degree of polymer-based composite materials. This method is low in cost, high in efficiency, and suitable for industrial batch testing applications. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic flowchart of the method for detecting the degree of curing of polymer-based composite materials in an embodiment of the present invention;

[0036] Figure 2 This is a partial data example of the curing degree detection model in an embodiment of the present invention; Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0039] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0040] Example 1:

[0041] like Figure 1 As shown, this embodiment provides a method for detecting the degree of curing of polymer-based composite materials, including:

[0042] Acquire data on the temperature change of the heated sample over time;

[0043] The temperature rise data point set of the sample is obtained based on the temperature change data of the sample over time;

[0044] The temperature rise data points of the sample to be tested are input into the pre-trained curing degree detection model to obtain the curing degree of the sample to be tested.

[0045] The set of temperature rise data points is a collection of temperature change ratios at different times when heating begins;

[0046] The temperature change ratio is based on the heating time of the sample, the temperature on the back of the center point of the heated area of ​​the sample measured during that time, the initial temperature of the sample, and the maximum temperature on the back of the heated point when the sample with 100% curing degree is heated.

[0047] In some possible embodiments, the curing degree detection model is trained using the following method:

[0048] Obtain the degree of curing of each sample in the sample set;

[0049] Acquire the temperature change data of each sample after heating over time, and obtain its temperature rise data point set based on the temperature change data of each sample over time;

[0050] A curing degree detection model is obtained based on the curing degree and temperature rise data points of each sample.

[0051] Specifically, the temperature change ratio is calculated using the following formula:

[0052] ;

[0053] Among them, V s Let T be the percentage of temperature rise at time t. s T is the temperature value on the back side of the center point of the heated area of ​​the sample at time t, T0 is the initial temperature of the sample, and T max The maximum temperature on the back side of the heating point when a standard sample with 100% curing degree is heated.

[0054] Specifically, the temperature change data of each sample over time and the temperature change data of the test sample over time are obtained based on the same sample morphology and the same heating conditions.

[0055] In some possible embodiments, obtaining the degree of curing of each sample in the sample set includes obtaining the degree of curing of each sample by one of differential scanning calorimetry, dynamic mechanical analysis, chemical titration and infrared spectroscopy.

[0056] In some possible embodiments, a set of temperature rise data points of the heated sample is obtained, wherein the total heating time is not less than 10 minutes.

[0057] In some possible embodiments, the heating method includes one of the following: laser heat source, planar heat source, infrared radiation, electric heating plate, and flexible heating film.

[0058] In some possible embodiments, the heating temperature is not higher than the operating temperature of the sample being tested.

[0059] In some possible embodiments, the method further includes: comparing the degree of curing of the sample to be tested with the required degree of curing range to determine whether the degree of curing of the polymer-based composite material meets the requirements.

[0060] This embodiment takes the testing of a 1000mm×1000mm×10mm (length×width×thickness) carbon fiber reinforced epoxy resin composite material plate sample as an example (in this embodiment of the invention, the types of raw materials used to prepare the test sample and the samples used to prepare the sample set are the same):

[0061] The sample preparation procedure for the plate is as follows:

[0062] A 1000mm × 1000mm (length × width) carbon fiber cloth (Toray T700SC-12K from Japan) was laid, followed by the application of epoxy resin (a mixture of SW 2513-A and SW 2513-BL resins in a specific ratio, as detailed in Table 1). The carbon fiber cloth was laid and epoxy resin was applied alternately until the desired thickness was achieved, followed by curing to obtain the board sample. The mass ratio of carbon fiber cloth to epoxy resin used was 3:1. The curing conditions were as follows: after curing at room temperature for a certain time, the temperature was increased at 5℃ / min to the holding temperature and held for a certain time, and finally cooled to room temperature at 10℃ / min. The degree of curing was measured by differential scanning calorimetry.

[0063] By adjusting the content of resin components A and B and / or the curing mode, 500 samples with a degree of cure ranging from 40% to 100% were prepared. Some preparation methods and corresponding degree of cure values ​​are shown in Table 1.

[0064] Table 1 Sample Preparation Scheme

[0065]

[0066] First, a sample set containing 500 samples was selected, and the degree of curing of each sample was obtained by differential scanning calorimetry.

[0067] Ceramic heating plates were laid on the surface of each sample to heat the sample. A thermally conductive silicone pad was placed between the heating plate and the heating area to enhance contact. The heating area was circular with a diameter of 50 mm. The heating energy was automatically adjusted to maintain the temperature of the heating plate at 150℃±3℃. An infrared thermal imager was used to measure the temperature of the back of the heating center point of the composite material arm and the temperature data of the back of the heating center point of the sample at different times within 10 minutes were recorded.

[0068] By calculating the temperature change ratio at different times based on the temperature data of the sample at different times, the set of temperature change ratios at different times at the start of heating can be obtained, which is the temperature rise data point set of the sample set. Some data can be found in [link to data]. Figure 2 ;

[0069] The temperature change ratio is calculated using the following formula:

[0070] ;

[0071] Among them, V s Let T be the percentage of temperature rise at time t. s T is the temperature value on the back side of the center point of the heated area of ​​the sample at time t, T0 is the initial temperature of the sample, and T max The maximum temperature on the back side of the heating point when a standard sample with 100% curing degree is heated.

[0072] The curing degree of each sample and the corresponding temperature rise data points are used as training data. Based on the machine learning algorithm, the temperature rise data points are used as input and the curing degree (the specific value of curing degree or the range of curing degree value, such as between 80-90%) is used as output to obtain the curing degree detection model.

[0073] A ceramic heating plate was placed on the surface of the sample to be tested to heat the sample. The heating conditions were the same as those of the sample (a thermally conductive silicone pad was placed between the heating plate and the heating area to enhance contact. The heating area was circular with a diameter of 50 mm. The heating energy was automatically adjusted to maintain the temperature of the heating plate at 150℃±3℃. An infrared thermal imager was used to measure the temperature of the back of the heating center point of the composite material arm. The temperature data of the back of the heating center point of the sample was recorded at different times within 10 minutes).

[0074] The temperature change ratio at different times is calculated based on the temperature of the sample at different times, and the temperature change ratio at different times after the start of heating can be obtained, which is the set of temperature rise data points for the sample; the calculation method of the temperature change ratio is the same as above.

[0075] Finally, the temperature rise data set of the sample to be tested is input into the pre-built curing degree detection model to obtain the curing degree of the sample (the specific value of the curing degree or the range of the curing degree value, such as between 80-90%).

[0076] By comparing the measured curing degree results with the curing degree health threshold, it can be determined whether the curing degree of the sample is qualified.

[0077] Example 2:

[0078] Based on the method for detecting the degree of curing of polymer-based composite materials described in Example 1, this embodiment also provides a system for detecting the degree of curing of polymer-based composite materials, including:

[0079] The data acquisition module is configured to acquire data on the temperature change of the heated sample over time.

[0080] The data processing module is configured to: obtain a set of temperature rise data points of the sample based on the temperature change data of the sample over time;

[0081] The data analysis module is configured to input the temperature rise data point set of the sample to be tested into a pre-trained curing degree detection model to obtain the curing degree of the sample to be tested.

[0082] The set of temperature rise data points is a collection of temperature change ratios at different times when heating begins;

[0083] The temperature change ratio is based on the heating time of the sample, the temperature on the back of the center point of the heated area of ​​the sample measured during that time, the initial temperature of the sample, and the maximum temperature on the back of the heated point when the sample with 100% curing degree is heated.

[0084] Example 3:

[0085] This embodiment also provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the polymer-based composite material curing degree detection method described in Embodiment 1.

[0086] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0087] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations 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, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0088] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0089] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0090] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for detecting the degree of cure of polymer-based composite materials, characterized in that, include: Acquire data on the temperature change of the heated sample over time; The temperature rise data point set of the sample is obtained based on the temperature change data of the sample over time; The temperature rise data points of the sample to be tested are input into the pre-trained curing degree detection model to obtain the curing degree of the sample to be tested. The set of temperature rise data points is a collection of temperature change ratios at different times when heating begins; The temperature change ratio is based on the heating time of the sample, the back temperature of the center point of the heating area of ​​the sample measured at that time, the initial temperature of the sample, and the maximum back temperature of the heating point when the sample with 100% curing degree is heated. The temperature change ratio is calculated using the following formula: ； Among them, V s Let T be the percentage of temperature rise at time t. s T is the temperature value on the back side of the center point of the heated area of ​​the sample at time t, T0 is the initial temperature of the sample, and T max The maximum temperature on the back side of the heating point when a sample with 100% curing degree is heated.

2. The method for detecting the degree of curing of polymer-based composite materials according to claim 1, characterized in that, The curing degree detection model was trained using the following method: Obtain the degree of curing of each sample in the sample set; Acquire the temperature change data of each sample after heating over time, and obtain its temperature rise data point set based on the temperature change data of each sample over time; The curing degree detection model is trained based on the curing degree and temperature rise data points of each sample.

3. The method for detecting the degree of curing of polymer-based composite materials according to claim 2, characterized in that, The temperature variation data of each sample over time and the temperature variation data of the test sample over time are obtained based on the same sample morphology and the same heating conditions.

4. The method for detecting the degree of curing of polymer-based composite materials according to claim 2, characterized in that, The degree of curing of each sample in the sample set is obtained by using one of the following methods: differential scanning calorimetry, dynamic mechanical analysis, chemical titration, and infrared spectroscopy.

5. The method for detecting the degree of curing of polymer-based composite materials according to claim 1, characterized in that, Obtain a set of temperature rise data points for the sample after heating, where the total heating time is not less than 10 minutes.

6. The method for detecting the degree of curing of polymer-based composite materials according to claim 1, characterized in that, The heating method includes one of laser heat source, planar heat source, infrared radiation, electric heating plate, and flexible heating film, and the heating temperature is not higher than the operating temperature of the sample to be tested.

7. The method for detecting the degree of curing of polymer-based composite materials according to claim 1, characterized in that, Also includes: The degree of curing of the sample to be tested is compared with the required degree of curing range to determine whether the degree of curing of the polymer-based composite material meets the requirements.

8. A system for detecting the degree of curing of polymer-based composite materials, characterized in that, include: The data acquisition module is configured to acquire data on the temperature change of the heated sample over time. The data processing module is configured to: obtain a set of temperature rise data points of the sample based on the temperature change data of the sample over time; The data analysis module is configured to input the temperature rise data point set of the sample to be tested into a pre-trained curing degree detection model to obtain the curing degree of the sample to be tested. The set of temperature rise data points is a collection of temperature change ratios at different times when heating begins; The temperature change ratio is based on the heating time of the sample, the back temperature of the center point of the heating area of ​​the sample measured at that time, the initial temperature of the sample, and the maximum back temperature of the heating point when the sample with 100% curing degree is heated. The temperature change ratio is calculated using the following formula: ； Among them, V s Let T be the percentage of temperature rise at time t. s T is the temperature value on the back side of the center point of the heated area of ​​the sample at time t, T0 is the initial temperature of the sample, and T max The maximum temperature on the back side of the heating point when a sample with 100% curing degree is heated.

9. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method for detecting the curing degree of polymer-based composite materials according to any one of claims 1 to 7.

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