Method and device for measuring expansion coefficient of epoxy material

Abstract

The invention discloses a method and device for measuring the expansion coefficient of an epoxy material, and the method comprises the steps: obtaining an epoxy material sample, gradually increasing the temperature value in an expansion cavity, and measuring the size of the epoxy material sample at the temperature value through a laser system, a signal receiving system and a data processing system, and generating a size-temperature change curve based on the size of the epoxy material sample at each temperature value, and calculating the expansion coefficient of the epoxy material sample at each temperature section according to the size-temperature change curve. Therefore, when the epoxy material is measured in the expansion cavity, the method can be suitable for a large-size sample, the epoxy material is heated in the expansion cavity and is not limited by high temperature, so that the measurement of the expansion coefficient of the epoxy material has a wider temperature range, and the expansion coefficient of the epoxy material can be measured by constructing a curve of the size of the epoxy material changing along with the temperature. The expansion coefficient of the epoxy material is represented more comprehensively and accurately, so that the applicability of the epoxy material in various temperature scenes is determined more accurately.

Description

Technical Field

[0001] This application relates to the field of materials science and engineering technology. More specifically, it relates to a method and device for measuring the coefficient of thermal expansion of epoxy materials. Background Art

[0002] Epoxy materials have a wide range of applications in many fields such as construction, electronics, machinery, aviation, and automobiles due to their excellent physical and chemical properties. Its coefficient of thermal expansion is a key physical quantity to measure the degree of expansion when the temperature changes, which is of great significance for the use, storage, and processing of materials. For example, for epoxy materials used in high-temperature environments, if the coefficient of thermal expansion is not appropriate, it is extremely easy to be damaged and deformed.

[0003] Currently, the methods for measuring the coefficient of thermal expansion of epoxy materials mainly include the dilatometer method, the cantilever beam method, and the immersion method. The dilatometer method usually measures the coefficient of thermal expansion of a material in a specific direction, which cannot comprehensively reflect the expansion behavior of anisotropic epoxy materials and is not suitable for large-size samples; the cantilever beam method calculates the coefficient of thermal expansion based on the bending amount of the cantilever beam, and the measurement accuracy is affected by factors such as the rigidity of the beam, the support conditions, and the loading method, making it difficult to accurately measure; the immersion method is generally only applicable to the measurement of the coefficient of thermal expansion at relatively low temperatures and cannot directly measure the linear coefficient of thermal expansion at high temperatures.

[0004] It can be seen that the above three measurement methods are difficult to accurately and efficiently obtain the coefficient of thermal expansion of epoxy materials. Therefore, how to accurately reflect the expansion behavior of epoxy materials, measure the coefficient of thermal expansion of epoxy materials in a wider temperature range, with high precision and accuracy, and provide strong support for the reasonable application of epoxy materials in various fields is an issue that needs attention. Summary of the Invention

[0005] In view of the above problems, this application provides a method and device for measuring the coefficient of thermal expansion of epoxy materials to accurately reflect the expansion behavior of epoxy materials, measure the coefficient of thermal expansion of epoxy materials in a wider temperature range, with high precision and accuracy, and provide strong support for the reasonable application of epoxy materials in various fields.

[0006] To achieve the above object, the following specific solutions are proposed:

[0007] A method for measuring the coefficient of thermal expansion of epoxy materials, which is applied to the control system of a coefficient of thermal expansion measurement system. The coefficient of thermal expansion measurement system further includes a laser system, an optical fiber, an expansion chamber, a signal receiving system, a data processing system, a display system, and a temperature detector;

[0008] Among them, the laser system is connected to the expansion cavity through the optical fiber, the expansion cavity is connected to the signal receiving system, the signal receiving system is connected to the data processing system, the data processing system, the laser system, and the display system are all connected to the control system, and the temperature detector is installed on the expansion cavity;

[0009] The method includes:

[0010] Obtain an epoxy material sample to be measured;

[0011] Drive the epoxy material sample to be measured to move into the expansion cavity;

[0012] For each temperature value in the expansion cavity, measure the size of the epoxy material sample to be measured at the temperature value through the laser system, the signal receiving system, and the data processing system;

[0013] Generate a size-temperature change curve based on the sizes of the epoxy material sample to be measured at various temperature values;

[0014] Calculate the expansion coefficient of the epoxy material sample to be measured in each temperature segment according to the size-temperature change curve.

[0015] Optionally, the step of measuring the size of the epoxy material sample to be measured at the temperature value through the laser system, the signal receiving system, and the data processing system for each temperature value in the expansion cavity includes:

[0016] For each temperature value in the expansion cavity, drive the laser system to emit a laser beam with preset laser parameters, so that the laser beam is transmitted through the optical fiber to the surface of the epoxy material sample to be measured in the expansion cavity, drive the signal receiving system to receive the laser signal reflected on the surface of the epoxy material sample to be measured, detect a distance signal from the laser signal, and drive the data processing system to calculate the size of the epoxy material sample to be measured at the temperature value according to the distance signal.

[0017] Optionally, the step of measuring the size of the epoxy material sample to be measured at the temperature value through the laser system, the signal receiving system, and the data processing system for each temperature value in the expansion cavity includes:

[0018] According to a preset temperature increasing mode, for each temperature value in the expansion cavity, measure the size of the epoxy material sample to be measured at the temperature value through the laser system, the signal receiving system, and the data processing system, where the temperature increasing mode is a mode in which, after completing the measurement of the size of the epoxy material sample to be measured at a first target temperature value, start measuring the size of the epoxy material sample to be measured at a second target temperature value, and the second target temperature value is greater than the first target temperature value.

[0019] Optionally, the method further includes:

[0020] Input the target temperature value into a pre-established epoxy material size-temperature prediction model to output a predicted size value;

[0021] Among them, the establishment process of the epoxy material size-temperature prediction model includes:

[0022] Obtain the historical measurement parameter data of the epoxy material sample to be measured, where the historical measurement parameter data includes historical temperature data, historical humidity data, historical air pressure data, and historical size data. The temperature data includes the temperature values of the epoxy material sample to be measured in each historical measurement, the humidity data includes the humidity values of the epoxy material sample to be measured in each historical measurement, the air pressure data includes the air pressure values of the epoxy material sample to be measured in each historical measurement, and the historical size data includes the size values of the epoxy material sample to be measured in each historical measurement;

[0023] Calculate the temperature average value and the temperature standard deviation according to the historical temperature data;

[0024] Calculate the humidity average value and the humidity standard deviation according to the historical humidity data;

[0025] Calculate the air pressure average value and the air pressure standard deviation according to the historical air pressure data;

[0026] Use the following formula to calculate the latest prediction weight based on the temperature average value, the temperature standard deviation, the humidity average value, the humidity standard deviation, the air pressure average value, and the air pressure standard deviation:

[0027]

[0028] Among them, is the latest prediction weight, is the first balance adjustment parameter, is the second balance adjustment parameter, is the latest temperature, is the temperature average value, is the latest humidity, is the humidity average value, is the latest air pressure, is the average value of the air pressure, is the temperature value measured at the i-th time in history, is the standard deviation of the temperature, is the humidity value measured at the i-th time in history, is the standard deviation of the humidity, is the air pressure value measured at the i-th time in history, is the standard deviation of the air pressure;

[0029] Measure the current size value of the epoxy material sample to be measured at the current temperature value, and fuse the current size value with the size values measured in each historical measurement according to the latest prediction weight to obtain fused size data;

[0030] Extract the temperature change amount sequence from the temperature values measured in each historical measurement and the current temperature value, and extract the size change amount sequence from the size values measured in each historical measurement and the fused size data;

[0031] Normalize the temperature change amount sequence and the size change amount sequence respectively to obtain a normalized temperature change amount sequence and a normalized size change amount sequence;

[0032] Use the normalized temperature change amount sequence and the normalized size change amount sequence as training data to train a long short-term memory network model to obtain an epoxy material size-temperature prediction model.

[0033] Optionally, using the normalized temperature change amount sequence and the normalized size change amount sequence as training data to train a long short-term memory network model to obtain an epoxy material size-temperature prediction model, including:

[0034] Under the mean square error loss function, use the normalized temperature change amount sequence and the normalized size change amount sequence as training data to train a long short-term memory network model to obtain an epoxy material size-temperature prediction model, and the mean square error loss function is:

[0035]

[0036] Wherein, is the target value of the mean square error loss function, is the number of samples of the training data constructed based on the training data, is the actual size change amount of the i-th data in the training data, is the predicted size change amount predicted by the long short-term memory network model based on the first i-1 data in the training data during the training process.

[0037] Optionally, under the mean square error loss function, using the normalized sequence of temperature change and the normalized sequence of dimension change as training data, training a long short-term memory network model to obtain an epoxy material dimension-temperature prediction model, including:

[0038] Under the mean square error loss function and the scale change amount accuracy threshold Using the normalized sequence of temperature change and the normalized sequence of dimension change as training data, training a long short-term memory network model to obtain an epoxy material dimension-temperature prediction model, where, during the training process of the long short-term memory network model, the scale change amount accuracy threshold Is used to compare with the dimension change amount Predicted by the long short-term memory network model. If , the long short-term memory network model skips training on the current data point.

[0039] Optionally, calculating the expansion coefficient of the epoxy material sample to be measured at each temperature segment according to the dimension-temperature change curve, including:

[0040] Using the following formula to calculate the expansion coefficient of the epoxy material sample to be measured at each temperature value:

[0041]

[0042] Where Is the first temperature value on the dimension-temperature change curve, Is the second temperature value on the dimension-temperature change curve, Is the first dimension measured for the epoxy material sample to be measured at , Is the second dimension measured for the epoxy material sample to be measured at , , Represents the dimension difference from Changing to , , Represents the temperature difference from Changing to , Is the expansion coefficient of the epoxy material sample to be measured in the temperature segment between And , Is the initial dimension of the epoxy material sample to be measured.

[0043] Optionally, the expansion cavity includes a photodetector, a beam splitter, an end mirror, an upper mirror, and a lower mirror;

[0044] The beam splitter is installed at the light incident end in the expansion cavity, and the optical fiber is connected to the beam splitter;

[0045] The end mirror is installed at the end in the expansion cavity, and the end mirror is parallel and opposite to the beam splitter;

[0046] The upper mirror is installed on the inner wall at the upper end in the expansion cavity, and the lower mirror is installed on the inner wall at the lower end in the expansion cavity; The photodetector is placed on the back of the end mirror, and the photodetector is connected to the signal receiving system.

[0047] Optionally, after calculating the expansion coefficient of the epoxy material sample to be measured in each temperature segment according to the size-temperature change curve, the method further includes:

[0048] Determine the applicability of the epoxy material sample to be measured in the temperature scenario corresponding to the target temperature segment according to the expansion coefficient of the epoxy material sample to be measured in the target temperature segment.

[0049] An expansion coefficient measuring device for epoxy materials is applied to the control system of an expansion coefficient measuring system. The expansion coefficient measuring system further includes a laser system, an optical fiber, an expansion cavity, a signal receiving system, a data processing system, a display system, and a temperature detector;

[0050] Wherein, the laser system is connected to the expansion cavity through the optical fiber, the expansion cavity is connected to the signal receiving system, the signal receiving system is connected to the data processing system, the data processing system, the laser system, and the display system are all connected to the control system, and the temperature detector is installed on the expansion cavity;

[0051] The device includes:

[0052] A unit for obtaining an epoxy material sample to be measured, which is used to obtain an epoxy material sample to be measured;

[0053] A movement control unit, which is used to drive the epoxy material sample to be measured to move into the expansion cavity;

[0054] A size measurement unit, which is used to measure the size of the epoxy material sample to be measured at each temperature value in the expansion cavity through the laser system, the signal receiving system, and the data processing system;

[0055] A curve generation unit, which is used to generate a size-temperature change curve based on the sizes of the epoxy material sample to be measured at each temperature value;

[0056] An expansion coefficient calculation unit, which is used to calculate the expansion coefficient of the epoxy material sample to be measured in each temperature segment according to the size-temperature change curve.

[0057] Optionally, the dimension measurement unit includes:

[0058] A dimension measurement subunit, configured to drive the laser system to emit a laser beam with preset laser parameters for each temperature value in the expansion cavity, so that the laser beam is transmitted through the optical fiber to the surface of the epoxy material sample to be measured in the expansion cavity, drive the signal receiving system to receive the laser signal reflected on the surface of the epoxy material sample to be measured, detect a distance signal from the laser signal, and drive the data processing system to calculate the dimension of the epoxy material sample to be measured at the temperature value according to the distance signal.

[0059] Optionally, the dimension measurement unit includes:

[0060] A temperature increasing measurement unit, configured to measure the dimension of the epoxy material sample to be measured at each temperature value in the expansion cavity according to a preset temperature increasing mode through the laser system, the signal receiving system, and the data processing system, where the temperature increasing mode is a mode in which after measuring the dimension of the epoxy material sample to be measured at a first target temperature value, the measurement of the dimension of the epoxy material sample to be measured at a second target temperature value is started, and the second target temperature value is greater than the first target temperature value.

[0061] Optionally, the device further includes:

[0062] A dimension prediction unit, configured to input a target temperature value into a pre-established epoxy material dimension-temperature prediction model and output a predicted dimension value;

[0063] A historical measurement parameter data acquisition unit, configured to acquire historical measurement parameter data of the epoxy material sample to be measured, where the historical measurement parameter data includes historical temperature data, historical humidity data, historical air pressure data, and historical dimension data, the temperature data includes the temperature values of the epoxy material sample to be measured at each historical measurement, the humidity data includes the humidity values of the epoxy material sample to be measured at each historical measurement, the air pressure data includes the air pressure values of the epoxy material sample to be measured at each historical measurement, and the historical dimension data includes the dimension values of the epoxy material sample to be measured at each historical measurement;

[0064] A temperature statistical data calculation unit, configured to calculate a temperature average value and a temperature standard deviation according to the historical temperature data;

[0065] A humidity statistical data calculation unit, configured to calculate a humidity average value and a humidity standard deviation according to the historical humidity data;

[0066] An air pressure statistical data calculation unit, configured to calculate an air pressure average value and an air pressure standard deviation according to the historical air pressure data;

[0067] A latest prediction weight calculation unit, configured to calculate a latest prediction weight based on the temperature average value, the temperature standard deviation, the humidity average value, the humidity standard deviation, the air pressure average value, and the air pressure standard deviation by using the following formula:

[0068]

[0069] wherein, is the latest prediction weight, is a first balance adjustment parameter, is a second balance adjustment parameter, is the latest temperature, is the temperature average value, is the latest humidity, is the humidity average value, is the latest air pressure, is the air pressure average value, is the temperature value measured at the i-th historical measurement, is the temperature standard deviation, is the humidity value measured at the i-th historical measurement, is the humidity standard deviation, is the air pressure value measured at the i-th historical measurement, is the air pressure standard deviation;

[0070] A dimension data fusion unit, configured to measure a current dimension value of the to-be-tested epoxy material sample at the current temperature value, and fuse the current dimension value with the dimension values measured at each historical measurement according to the latest prediction weight to obtain fused dimension data;

[0071] A change amount sequence extraction unit, configured to extract a temperature change amount sequence from the temperature values measured at each historical measurement and the current temperature value, and extract a dimension change amount sequence from the dimension values measured at each historical measurement and the fused dimension data;

[0072] A normalization processing unit, configured to perform normalization processing on the temperature change amount sequence and the dimension change amount sequence respectively to obtain a temperature change amount normalized sequence and a dimension change amount normalized sequence;

[0073] A model training unit, configured to use the temperature change amount normalized sequence and the dimension change amount normalized sequence as training data to train a long short-term memory network model to obtain an epoxy material dimension-temperature prediction model.

[0074] Optionally, the model training unit includes:

[0075] The mean square error loss function constrained training unit is used to train the long short-term memory network model with the temperature change amount normalized sequence and the size change amount normalized sequence as training data under the mean square error loss function, and obtain an epoxy material size-temperature prediction model. The mean square error loss function is:

[0076]

[0077] Wherein, is the target value of the mean square error loss function, is the number of samples of the training data constructed based on the training data, is the actual size change amount of the i-th data in the training data, is the predicted size change amount predicted by the long short-term memory network model based on the first i-1 data in the training data during the training process.

[0078] Optionally, the mean square error loss function constrained training unit includes:

[0079] The scale change amount accuracy constrained training unit is used to train the long short-term memory network model with the temperature change amount normalized sequence and the size change amount normalized sequence as training data under the mean square error loss function and the scale change amount accuracy threshold , and obtain an epoxy material size-temperature prediction model. Wherein, during the training process of the long short-term memory network model, the scale change amount accuracy threshold is used to compare with the size change amount predicted by the long short-term memory network model. If , the long short-term memory network model skips the training of the current data point.

[0080] Optionally, the coefficient of thermal expansion calculation unit includes:

[0081] The coefficient of thermal expansion calculation subunit is used to calculate the coefficient of thermal expansion of the epoxy material sample to be measured at each temperature value by using the following formula:

[0082]

[0083] Wherein, is the first temperature value on the size-temperature change curve, is the second temperature value on the size-temperature change curve, is the first size measured for the epoxy material sample to be measured at , is the second size measured for the epoxy material sample to be measured at . , represents the dimensional difference from to , the dimensional difference; , represents the temperature difference from to , the temperature difference; is the coefficient of thermal expansion of the epoxy material sample to be measured in the temperature range between and ; is the initial dimension of the epoxy material sample to be measured.

[0084] Optionally, the device further includes:

[0085] An epoxy material applicability determination unit, configured to determine the applicability of the epoxy material sample to be measured in the temperature scenario corresponding to the target temperature range according to the coefficient of thermal expansion of the epoxy material sample to be measured in the target temperature range after calculating the coefficient of thermal expansion of the epoxy material sample to be measured in each temperature range based on the dimension-temperature change curve.

[0086] With the above technical solution, the present application obtains an epoxy material sample to be measured, drives the epoxy material sample to move into the expansion chamber, and for each temperature value in the expansion chamber, measures the dimension of the epoxy material sample to be measured at the temperature value through a laser system, a signal receiving system, and a data processing system, generates a dimension-temperature change curve based on the dimensions of the epoxy material sample to be measured at each temperature value, and calculates the coefficient of thermal expansion of the epoxy material sample to be measured in each temperature range according to the dimension-temperature change curve. It can be seen that measuring the epoxy material in the expansion chamber can be applicable to large-size samples. Heating the epoxy material in the expansion chamber is not restricted by high temperatures, enabling the determination of the coefficient of thermal expansion of the epoxy material to have a wider temperature range. By constructing a curve of the epoxy material dimension changing with temperature, it can more comprehensively and accurately characterize the coefficient of thermal expansion of the epoxy material, thereby more accurately determining the applicability of the epoxy material in various temperature scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0088] Figure 1 is a system structure diagram of a coefficient of thermal expansion measurement system for realizing the determination of the coefficient of thermal expansion of an epoxy material provided by an embodiment of the present application;

[0089] Figure 2Schematic diagram of a structure of an expansion cavity of the expansion coefficient measurement system provided by an embodiment of the present application;

[0090] Figure 3 Schematic diagram of a process for realizing the determination of the expansion coefficient of epoxy materials provided by an embodiment of the present application;

[0091] Figure 4 Schematic diagram of a process for establishing a size - temperature prediction model of epoxy materials provided by an embodiment of the present application;

[0092] Figure 5 Schematic diagram of the curve of the size change of the first epoxy material with temperature during the heating process provided by an embodiment of the present application;

[0093] Figure 6 Schematic diagram of the curve of the size change of the second epoxy material with temperature during the heating process provided by an embodiment of the present application;

[0094] Figure 7 Schematic diagram of the curve of the size change of the third epoxy material with temperature during the heating process provided by an embodiment of the present application;

[0095] Figure 8 Schematic diagram of the structure of a device for realizing the determination of the expansion coefficient of epoxy materials provided by an embodiment of the present application.

[0096] In the drawings, 1 - laser system, 2 - optical fiber, 3 - expansion cavity, 4 - signal receiving system, 5 - data processing system, 6 - control system, 7 - display system, 8 - temperature detector, 9 - beam splitter, 10 - end beam splitter, 11 - upper reflector, 12 - lower reflector, 13 - photodetector. Detailed implementation manners

[0097] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0098] Figure 1 An optional structure of the expansion coefficient measurement system for realizing the determination of the expansion coefficient of epoxy materials provided by an embodiment of the present application is as Figure 1 shown. The system architecture may include:

[0099] Laser system 1, optical fiber 2, expansion cavity 3, signal receiving system 4, data processing system 5, control system 6, display system 7, and temperature detector 8.

[0100] Among them, the laser system 1 is connected to the expansion cavity 3 through the optical fiber 2.

[0101] The expansion cavity 3 is connected to the signal receiving system 4.

[0102] The signal receiving system 4 is connected to the data processing system 5.

[0103] The data processing system 5, the laser system 1, and the display system 7 are all connected to the control system 6.

[0104] The temperature detector 8 is installed on the expansion cavity 3.

[0105] Specifically, the laser system 1 can provide a laser light source for the expansion coefficient measurement system. The optical fiber 2 can achieve effective transmission of optical signals. The core and cladding in the optical fiber 2 can have different refractive indices, so that the optical signal can achieve total internal reflection transportation in the core, effectively avoiding the loss of optical signals during transmission. The expansion cavity 3 can enable the epoxy material to expand in the expansion cavity, and at the same time, the expansion coefficient is obtained in real time by the signal receiving system. The signal receiving system 4 can obtain the optical signal of the epoxy material after expansion in the expansion cavity in real time. The data processing system 5 can process and convert the optical signal into a digital signal reflecting the expansion of the epoxy material in the expansion cavity, and transmit the digital signal to the control system 6. The control system 6 can be the main executor for measuring the expansion coefficient of the epoxy material. The display system 7 can receive the measurement result of the expansion coefficient of the epoxy material based on the laser displacement sensor processed and analyzed by the control system and display it. The temperature detector 8 can control the temperature in the expansion cavity, improve the reliability of the measurement conditions, and thus obtain reliable measurement results.

[0106] Among them, the light source of the laser system 1 can be selected as an infrared laser. The infrared laser has the characteristics of high stability and long life, and can be easily integrated into the customer's system. The material of the expansion cavity 3 can be selected as tungsten alloy. Tungsten alloy has good high-temperature strength, so it also has good corrosion resistance to molten alkali metals and vapors, ensuring that it can still work normally in a high-temperature environment. The signal receiving system 4 can be selected as an infrared detector. The control system 6 can be an AT89C51 single-chip microcomputer to be compatible with the keilC51 UV2 debugging environment. The control system 6 can perform operations such as running, power-off, and full-speed through the UV2 environment, and can be debugged using C51 language or ASM assembly, with the advantages of small volume and convenient use. The display system 7 can be selected as a silicon-based OLED display system. The display system 7 can use a single-crystal silicon wafer as an active driving backplane, making it easier to achieve excellent characteristics such as high PPI (pixel density), high integration, small volume, easy to carry, good shock resistance, and ultra-low power consumption. The temperature detector 8 can be selected as an electronic temperature controller. The electronic temperature controller can adopt fuzzy control technology such as PID control to make the measurement result reliable and the working process stable.

[0107] Further, the structure of the expansion cavity 3 can be referred to Figure 2 as shown. The expansion cavity 3 includes a photodetector 13, a beam splitter 9, a terminal mirror 10, an upper mirror 11, and a lower mirror 12.

[0108] Specifically, the photodetector 13 can be installed on the back of the terminal mirror 10, and the photodetector 13 is connected to the signal receiving system 4. The photodetector 13 is used to receive the light energy signal reflected by the epoxy material for subsequent research on the expansion coefficient of the epoxy material.

[0109] The beam splitter 9 can be installed at the light input end inside the expansion cavity 3, and the optical fiber 2 can be connected to the beam splitter 9. The beam splitter splits the laser light emitted from the laser transmitted through the optical fiber 2, expands the beam diameter to the diameter of the expansion cavity 3, and receives the light energy signal reflected by the epoxy material, and transmits the received light energy signal to the photodetector 13.

[0110] The terminal mirror 10 is installed at the terminal inside the expansion cavity 3, and the terminal mirror 10 is parallel and opposite to the beam splitter 9. The terminal mirror 10 can totally reflect the laser signal transmitted to the terminal of the expansion cavity 3 after beam expansion by the beam splitter 9, receive the optical signal reflected from the epoxy material, and transmit the received light energy signal to the photodetector 13.

[0111] The upper mirror 11 is installed on the inner wall of the upper end inside the expansion cavity 3. The upper mirror 11 can totally reflect the laser signal transmitted to the inner wall of the upper end of the expansion cavity 3 after beam expansion by the beam splitter 9, receive the optical signal reflected from the epoxy material, and transmit the received light energy signal to the photodetector 13.

[0112] The lower mirror 12 is installed on the inner wall of the lower end inside the expansion cavity 3. The lower mirror 12 can totally reflect the laser signal transmitted to the inner wall of the lower end of the expansion cavity 3 after beam expansion by the beam splitter 9, receive the optical signal reflected from the epoxy material, and transmit the received light energy signal to the photodetector 13.

[0113] Based on Figure 1 the system architecture shown, Figure 3 a schematic flowchart of a method for implementing the expansion coefficient measurement of epoxy material by the control system provided in the embodiment of the present application is shown. Referring to Figure 3 , the process may include:

[0114] Step S101, obtain a sample of the epoxy material to be measured.

[0115] Specifically, the size of the epoxy material sample to be measured can be the size placed in the expansion cavity. The surface of the epoxy material sample to be expanded is free of other impurities except the epoxy material after being processed to avoid affecting the expansion coefficient detection result.

[0116] Step S102: Drive the epoxy material sample to be measured into the expansion cavity.

[0117] Specifically, the control system can be equipped with an object moving device to move the prepared epoxy material sample to be measured into the expansion cavity.

[0118] Step S103: For each temperature value in the expansion cavity, measure the size of the epoxy material sample to be measured at the temperature value through a laser system, a signal receiving system, and a data processing system.

[0119] Among them, 3 lower / upper limits of different temperatures can be set in the expansion cavity. Specifically, the 3 different upper limits of temperature can be: curing temperature of 40°C, curing temperature of 15°C, and curing temperature of 150°C.

[0120] Specifically, this step can specifically include:

[0121] For each temperature value in the expansion cavity, the laser system emits a laser beam with preset laser parameters, so that the laser beam is transmitted through an optical fiber to the surface of the epoxy material sample to be measured in the expansion cavity. Further, the signal receiving system receives the laser signal reflected on the surface of the epoxy material sample to detect a distance signal from the laser signal. Still further, the data processing system calculates the size of the epoxy material sample to be measured at the temperature value according to the distance signal.

[0122] It can be understood that the laser system emits a laser, which is transmitted through an optical fiber to the expansion cavity. The laser signal transmitted through the optical fiber is split by a beam splitter, and the light beam fills the expansion cavity. Since an end mirror, an upper mirror, a lower mirror, and a beam splitter that can reflect light are provided in the expansion cavity, the laser beam irradiates and reflects on the epoxy material surface from all angles. Each mirror receives the optical signal reflected from the epoxy material surface and transmits it to the photodetector. The photodetector collects the optical signal and transmits it to the signal receiving system. The signal receiving system cannot process the signal, so the signal receiving system transmits the optical signal to the data processing system for processing.

[0123] In addition, in terms of temperature control for this step, it can be carried out according to a preset temperature increasing mode. Based on this, this step can specifically include:

[0124] According to the preset temperature increasing mode, for each temperature value in the expansion cavity, measure the size of the epoxy material sample to be measured at the temperature value through a laser system, a signal receiving system, and a data processing system.

[0125] Among them, the temperature increasing mode can start the mode of measuring the size of the epoxy material sample to be measured at a second target temperature value after completing the measurement of the size of the epoxy material sample to be measured at a first target temperature value. Among them, the second target temperature value is greater than the first target temperature value.

[0126] It is understandable that by gradually increasing the temperature of the expansion cavity, the epoxy material undergoes thermal expansion during heating, so that the size of the epoxy material increases with the increase in temperature.

[0127] Step S104: Generate a curve of size varying with temperature based on the sizes of the epoxy material sample to be measured at various temperature values.

[0128] Specifically, after completing the measurement of the sizes of the epoxy material sample to be measured at various temperature values, multiple sets of (temperature, size) data can be obtained. Then, a curve of size varying with temperature can be plotted according to each set of data.

[0129] Step S105: Calculate the expansion coefficients of the epoxy material sample to be measured in each temperature segment according to the curve of size varying with temperature.

[0130] Specifically, the following formula can be used to calculate the expansion coefficient of the epoxy material sample to be measured at each temperature value:

[0131]

[0132] Wherein, is the first temperature value on the curve of size varying with temperature, is the second temperature value on the curve of size varying with temperature, is the first size measured for the epoxy material sample to be measured at , is the second size measured for the epoxy material sample to be measured at , , represents the change from to in size difference, , represents the change from to in temperature difference, is the expansion coefficient of the epoxy material sample to be measured in the temperature segment between and , is the initial size of the epoxy material sample to be measured.

[0133] It is understandable that through the curve of size varying with temperature, data corresponding to multiple temperature points can be combined to calculate the expansion coefficients in multiple temperature segments.

[0134] Further, considering that the expansion coefficient of the epoxy material needs to be determined when it is applied in a certain temperature scenario to determine the applicability of the epoxy material in this scenario. Therefore, it is necessary to first measure the target temperature range of the scenario, and then determine the applicability of the epoxy material sample to be measured in the temperature scenario corresponding to the target temperature range according to the expansion coefficient of the epoxy material sample to be measured in the target temperature range.

[0135] The method for measuring the expansion coefficient of the epoxy material provided in this embodiment drives the epoxy material sample to be measured to move into the expansion cavity by obtaining the epoxy material sample to be measured. For each temperature value in the expansion cavity, the size of the epoxy material sample to be measured at the temperature value is measured through a laser system, a signal receiving system, and a data processing system. Based on the sizes of the epoxy material sample to be measured at each temperature value, a size-temperature change curve is generated, and the expansion coefficient of the epoxy material sample to be measured in each temperature range is calculated according to the size-temperature change curve. It can be seen that measuring the epoxy material in the expansion cavity can be applicable to large-size samples. Heating the epoxy material in the expansion cavity can be unrestricted by high temperatures, enabling the measurement of the expansion coefficient of the epoxy material to have a wider temperature range. By constructing a curve of the epoxy material size changing with temperature, the expansion coefficient of the epoxy material can be characterized more comprehensively and accurately, so as to more accurately determine the applicability of the epoxy material in a variety of temperature scenarios.

[0136] Considering that the expansion characteristics of the epoxy material are different in different temperature ranges and the degree of interference by environmental factors also varies, the adaptive weighted fusion algorithm can be used to assign dynamic weights to the size data measured each time based on the real-time temperature, the historical expansion data of the material, and environmental parameters (such as humidity, air pressure), draw a more accurate behavior size-temperature curve of the epoxy material in a complex environment, and calculate the expansion coefficient. For this, the size of the epoxy material at a certain temperature can be predicted through a training model. Based on this, in some embodiments of the present application, the establishment process of the prediction model for the change of the epoxy material size with temperature is introduced, such as Figure 4 As shown, the establishment process may include:

[0137] Step S201, obtain the historical measurement parameter data of the epoxy material sample to be measured.

[0138] Among them, the historical measurement parameter data may include historical temperature data, historical humidity data, historical air pressure data, and historical size data.

[0139] Specifically, the temperature data may include the temperature values of the epoxy material sample to be measured in each historical measurement. The humidity data may include the humidity values of the epoxy material sample to be measured in each historical measurement. The air pressure data may include the air pressure values of the epoxy material sample to be measured in each historical measurement. The historical size data may include the size values of the epoxy material sample to be measured in each historical measurement.

[0140] For example, the measured temperature data of the epoxy material of the mobile phone , and the corresponding dimension data , humidity data , air pressure data .

[0141] Step S202: Calculate the temperature average value and the temperature standard deviation according to the historical temperature data.

[0142] Step S203: Calculate the humidity average value and the humidity standard deviation according to the historical humidity data.

[0143] Step S204: Calculate the air pressure average value and the air pressure standard deviation according to the historical air pressure data.

[0144] Step S205: Use the first formula to calculate the latest prediction weight based on the temperature average value, the temperature standard deviation, the humidity average value, the humidity standard deviation, the air pressure average value, and the air pressure standard deviation.

[0145] Among them, the first formula can be:

[0146]

[0147] Among them, is the latest prediction weight, is the first balance adjustment parameter, is the second balance adjustment parameter, is the latest temperature, is the temperature average value, is the latest humidity, is the humidity average value, is the latest air pressure, is the air pressure average value, is the temperature value measured in the historical i-th measurement, is the temperature standard deviation, is the humidity value measured in the historical i-th measurement, is the humidity standard deviation, is the air pressure value measured in the historical i-th measurement, is the air pressure standard deviation.

[0148] Step S206: Measure the current dimension value of the epoxy material sample to be measured at the current temperature value, and fuse the current dimension value with the dimension values measured in each historical measurement according to the latest prediction weight to obtain the fused dimension data.

[0149] Specifically, the following formula can be used to fuse the current dimension value with the dimension values measured in each historical measurement according to the latest prediction weight to obtain the fused dimension data:

[0150]

[0151] Specifically, to fuse the dimensional data, is the current dimensional value, is the dimensional value measured at the i-th historical measurement, is the prediction weight after the i-th historical dimensional value measurement.

[0152] Step S207: Extract the temperature change amount sequence from the temperature values measured at each historical time and the current temperature value, and extract the dimensional change amount sequence from the dimensional values measured at each historical time and the fused dimensional data.

[0153] Specifically, the temperature change amount sequence is:

[0154]

[0155] The dimensional change amount sequence is:

[0156]

[0157] Step S208: Normalize the temperature change amount sequence and the dimensional change amount sequence respectively to obtain the normalized temperature change amount sequence and the normalized dimensional change amount sequence.

[0158] Specifically, the temperature change amount sequence and the dimensional change amount sequence can be mapped to the interval [0, 1] to accelerate the model training speed and improve the model stability.

[0159] Step S209: Use the normalized temperature change amount sequence and the normalized dimensional change amount sequence as training data to train the long short-term memory network model to obtain the epoxy material dimension-temperature prediction model.

[0160] Among them, the number of input layer nodes of the long short-term memory network model can be set to 2 (corresponding to and ), the number of hidden layer units can be determined according to the data complexity and computing resources, such as being set to 64, and the number of output layer nodes is 1 (the predicted dimensional change amount )

[0161] Specifically, Step S209 may include:

[0162] Under the mean square error loss function, use the normalized temperature change amount sequence and the normalized dimensional change amount sequence as training data to train the long short-term memory network model to obtain the epoxy material dimension-temperature prediction model.

[0163] Among them, the model training can be optimized using an optimizer (such as the Adam optimizer), and the optimizer uses the mean square error as the loss function, specifically it can be:

[0164]

[0165] Among them, is the target value of the mean squared error loss function, is the number of samples of the training data constructed based on the training data, is the actual change in size of the i-th data in the training data, is the predicted change in size of the long short-term memory network model based on the previous i-1 data in the training data during the training process.

[0166] Furthermore, the model parameters can be continuously adjusted until the loss function converges to a satisfactory value.

[0167] Furthermore, during the measurement process, when the current temperature and size are measured, the current temperature change and the current size change can be calculated based on the previous temperature and size changes, and used as model inputs. The model outputs the predicted size change at the next temperature point, and then the predicted size is obtained.

[0168] Furthermore, on the basis of the above, under the mean squared error loss function, using the normalized sequence of temperature changes and the normalized sequence of size changes as training data to train the long short-term memory network model to obtain the epoxy material size-temperature prediction model, the training of the model can also be controlled by the scale change accuracy to make the model training process more efficient. Based on this, under the mean squared error loss function and the scale change accuracy threshold using the normalized sequence of temperature changes and the normalized sequence of size changes as training data to train the long short-term memory network model to obtain the epoxy material size-temperature prediction model.

[0169] Among them, during the training process of the long short-term memory network model, the scale change accuracy threshold is used to compare with the size change predicted by the long short-term memory network model. If , the long short-term memory network model skips the training of the current data point. If , normal measurement is performed, and the measurement result is used to update the model and subsequent calculations.

[0170] Furthermore, during the training process of the long short-term memory network model, every certain number of measurements (such as every 10 measurements), the newly obtained measurement data is added to the training dataset, and the long short-term memory network model is retrained to adapt to the possible changes in the expansion characteristics of the epoxy material and improve the prediction accuracy.

[0171] In the following several embodiments, the method for measuring the coefficient of thermal expansion of the epoxy material provided in this application will be introduced in combination with several examples.

[0172] Example 1: According to Figure 1 the system structure of, the coefficient of thermal expansion of the epoxy material is measured based on a laser displacement sensor according to the following steps.

[0173] Prepare an epoxy material sample, and record the curing condition parameters of the epoxy material sample, such as: the ratio of the epoxy material to the curing agent, the curing temperature condition of 30 °C, and the epoxy equivalent after curing, etc. Since the epoxy material exhibits different expansion sizes under different temperature conditions, in order to obtain the coefficient of thermal expansion of the epoxy material, a series of temperature parameters need to be set on the control system 6 according to the recorded curing condition parameters of the epoxy material. Starting from -10 °C as the initial temperature, the temperature of the expansion chamber is controlled to increase sequentially at intervals of 0.01 °C until 0 °C. Since the photothermal signal generated by the laser irradiating on the surface of the epoxy material will also have a certain impact on the temperature of the epoxy material, control parameters such as the expansion temperature parameter and the laser parameter of the laser system 1 are set on the control system 6; the epoxy material sample is placed in the expansion chamber 3, and a laser displacement sensor is used to measure its size. Every time the temperature for measuring the coefficient of thermal expansion of the epoxy material is reached, the size of the epoxy material is measured once, and the coefficient of thermal expansion of the epoxy material is obtained based on the sizes of the epoxy material at different temperatures. The laser system 1 emits laser light, which is transmitted to the expansion chamber 3 through the optical fiber 2. The laser signal transmitted by the optical fiber 2 is split by the beam splitter 9, and the light beam fills the inside of the expansion chamber 3. Since the end mirror 10, the upper mirror 11, the lower mirror 12, and the reflective beam splitter 9 are provided in the expansion chamber 3, the laser beam is irradiated and reflected from all angles on the surface of the epoxy material. Each mirror receives the optical signal reflected from the surface of the epoxy material and transmits it to the photodetector 13. The photodetector 13 collects the optical signal and transmits it to the signal receiving system 4. The signal receiving system 4 cannot perform signal processing, so the signal receiving system 4 transmits the optical signal to the data processing system 5 for processing. According to the temperature program set by the control system 6, the temperature of the expansion chamber 3 is gradually increased by the temperature control system 8, and the size of the material is measured using a laser displacement sensor at each temperature point. Since the epoxy material undergoes thermal expansion during the heating process, its size will increase with the increase in temperature. The control system 6 records the size of the material at each temperature point, and a size change curve varying with temperature can be obtained. As Figure 5 shown, it is displayed on the display system 7, and the coefficient of thermal expansion of the epoxy material is obtained based on the curve obtained according to the temperature.

[0174] Example 2: Follow the steps of Example 1, set the starting temperature at 0 °C, and use a PID temperature control system based on a BP neural network to control the temperature of the expansion chamber to increase sequentially at intervals of 0.1 °C up to 45 °C. The size change of the epoxy material at each temperature point is measured by a laser displacement sensor, and the control system 6 records the material size at each temperature point, thus obtaining a size change curve that varies with temperature. As Figure 6 shown, it is displayed on the display system 7, and the expansion coefficient of the epoxy material is obtained based on this curve.

[0175] Example 3: Follow the steps of Example 1, set the starting temperature at 0 °C, and use a PID temperature control system based on a BP neural network to control the temperature of the expansion chamber to increase sequentially at intervals of 1 °C up to 180 °C. The size change of the epoxy material at each temperature point is measured by a laser displacement sensor, and the control system 6 records the material size at each temperature point, thus obtaining a size change curve that varies with temperature. As Figure 7 shown, it is displayed on the display system 7, and the expansion coefficient of the epoxy material is obtained based on the curve obtained from the temperature.

[0176] Next, the device for measuring the expansion coefficient of the epoxy material provided in the embodiments of the present application will be described. The device for measuring the expansion coefficient of the epoxy material described below can be correspondingly referred to the method for measuring the expansion coefficient of the epoxy material described above.

[0177] See Figure 8 , Figure 8 which is a schematic structural diagram of a device for measuring the expansion coefficient of the epoxy material disclosed in the embodiments of the present application.

[0178] As Figure 8 shown, the device may include:

[0179] A unit 100 for obtaining a sample of the epoxy material to be measured, configured to obtain a sample of the epoxy material to be measured;

[0180] A moving control unit 200, configured to drive the sample of the epoxy material to be measured to move into the expansion chamber;

[0181] A size measurement unit 300, configured to measure the size of the sample of the epoxy material to be measured at each temperature value in the expansion chamber through the laser system, the signal receiving system, and the data processing system;

[0182] A curve generation unit 400, configured to generate a size-temperature change curve based on the sizes of the sample of the epoxy material to be measured at various temperature values;

[0183] An expansion coefficient calculation unit 500, configured to calculate the expansion coefficients of the sample of the epoxy material to be measured in each temperature segment according to the size-temperature change curve.

[0184] Optionally, the dimension measurement unit includes:

[0185] A dimension measurement subunit, configured to drive the laser system to emit a laser beam with preset laser parameters for each temperature value in the expansion cavity, so that the laser beam is transmitted through the optical fiber to the surface of the epoxy material sample to be measured in the expansion cavity, drive the signal receiving system to receive the laser signal reflected on the surface of the epoxy material sample to be measured, detect a distance signal from the laser signal, and drive the data processing system to calculate the dimension of the epoxy material sample to be measured at the temperature value according to the distance signal.

[0186] Optionally, the dimension measurement unit includes:

[0187] A temperature increasing measurement unit, configured to measure the dimension of the epoxy material sample to be measured at each temperature value in the expansion cavity according to a preset temperature increasing mode through the laser system, the signal receiving system, and the data processing system, where the temperature increasing mode is a mode in which, after completing the dimension measurement of the epoxy material sample to be measured at a first target temperature value, the dimension measurement of the epoxy material sample to be measured at a second target temperature value is started, and the second target temperature value is greater than the first target temperature value.

[0188] Optionally, the device further includes:

[0189] A dimension prediction unit, configured to input a target temperature value into a pre-established epoxy material dimension-temperature prediction model and output a predicted dimension value;

[0190] A historical measurement parameter data acquisition unit, configured to acquire historical measurement parameter data of the epoxy material sample to be measured, where the historical measurement parameter data includes historical temperature data, historical humidity data, historical air pressure data, and historical dimension data, the temperature data includes the temperature values of the epoxy material sample to be measured in each historical measurement, the humidity data includes the humidity values of the epoxy material sample to be measured in each historical measurement, the air pressure data includes the air pressure values of the epoxy material sample to be measured in each historical measurement, and the historical dimension data includes the dimension values of the epoxy material sample to be measured in each historical measurement;

[0191] A temperature statistical data calculation unit, configured to calculate a temperature average value and a temperature standard deviation according to the historical temperature data;

[0192] A humidity statistical data calculation unit, configured to calculate a humidity average value and a humidity standard deviation according to the historical humidity data;

[0193] An air pressure statistical data calculation unit, configured to calculate an air pressure average value and an air pressure standard deviation according to the historical air pressure data;

[0194] A latest prediction weight calculation unit, configured to calculate a latest prediction weight based on the temperature average value, the temperature standard deviation, the humidity average value, the humidity standard deviation, the air pressure average value, and the air pressure standard deviation by using the following formula:

[0195]

[0196] wherein, is the latest prediction weight, is a first balance adjustment parameter, is a second balance adjustment parameter, is the latest temperature, is the temperature average value, is the latest humidity, is the humidity average value, is the latest air pressure, is the air pressure average value, is the temperature value measured at the i-th historical measurement, is the temperature standard deviation, is the humidity value measured at the i-th historical measurement, is the humidity standard deviation, is the air pressure value measured at the i-th historical measurement, is the air pressure standard deviation;

[0197] A dimension data fusion unit, configured to measure a current dimension value of the epoxy material sample to be measured at the current temperature value, and fuse the current dimension value with the dimension values measured in each historical measurement according to the latest prediction weight to obtain fused dimension data;

[0198] A change amount sequence extraction unit, configured to extract a temperature change amount sequence from the temperature values measured in each historical measurement and the current temperature value, and extract a dimension change amount sequence from the dimension values measured in each historical measurement and the fused dimension data;

[0199] A normalization processing unit, configured to perform normalization processing on the temperature change amount sequence and the dimension change amount sequence respectively to obtain a temperature change amount normalized sequence and a dimension change amount normalized sequence;

[0200] A model training unit, configured to use the temperature change amount normalized sequence and the dimension change amount normalized sequence as training data to train a long short-term memory network model to obtain an epoxy material dimension-temperature prediction model.

[0201] Optionally, the model training unit includes:

[0202] The mean square error loss function constrained training unit is used to train the long short-term memory network model with the temperature change amount normalization sequence and the size change amount normalization sequence as training data under the mean square error loss function, and obtain an epoxy material size-temperature prediction model. The mean square error loss function is:

[0203]

[0204] where is the target value of the mean square error loss function, is the number of samples of the training data constructed based on the training data, is the actual size change amount of the i-th data in the training data, is the predicted size change amount predicted by the long short-term memory network model based on the previous i - 1 data in the training data.

[0205] Optionally, the mean square error loss function constrained training unit includes:

[0206] The scale change amount accuracy constrained training unit is used to train the long short-term memory network model with the temperature change amount normalization sequence and the size change amount normalization sequence as training data under the mean square error loss function and the scale change amount accuracy threshold . During the training process of the long short-term memory network model, the scale change amount accuracy threshold is used to compare with the size change amount predicted by the long short-term memory network model. If , the long short-term memory network model skips the training of the current data point.

[0207] Optionally, the coefficient of thermal expansion calculation unit includes:

[0208] The coefficient of thermal expansion calculation sub-unit is used to calculate the coefficient of thermal expansion of the epoxy material sample to be measured at each temperature value by using the following formula:

[0209]

[0210] where is the first temperature value on the size-temperature change curve, is the second temperature value on the size-temperature change curve, is the epoxy material sample to be measured at to measure the first size, is the epoxy material sample to be measured at to measure the second size, , Indicates from changing to the dimensional difference, , Indicates from changing to the temperature difference, is the coefficient of expansion of the epoxy material sample to be measured under the temperature range between and , and is the initial dimension of the epoxy material sample to be measured.

[0211] Optionally, the device further includes:

[0212] An epoxy material applicability determination unit, configured to determine the applicability of the epoxy material sample to be measured in the temperature scenario corresponding to the target temperature range according to the coefficient of expansion of the epoxy material sample to be measured in the target temperature range after calculating the coefficient of expansion of the epoxy material sample to be measured under each temperature range based on the dimension-temperature change curve.

[0213] Finally, it should also be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0214] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0215] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but rather is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for measuring the coefficient of thermal expansion of an epoxy material, characterized in that, A control system applied to a coefficient of thermal expansion measurement system, the coefficient of thermal expansion measurement system further comprising a laser system, an optical fiber, an expansion chamber, a signal receiving system, a data processing system, a display system, and a temperature detector; Wherein, the laser system is connected to the expansion chamber through the optical fiber, the expansion chamber is connected to the signal receiving system, the signal receiving system is connected to the data processing system, the data processing system, the laser system, and the display system are all connected to the control system, and the temperature detector is installed on the expansion chamber; The method includes: Obtain an epoxy material sample to be measured; Drive the epoxy material sample to be measured to move into the expansion chamber; For each temperature value in the expansion chamber, measure the size of the epoxy material sample to be measured at the temperature value through the laser system, the signal receiving system, and the data processing system; Generate a size-temperature change curve based on the sizes of the epoxy material sample to be measured at various temperature values; Calculate the coefficient of thermal expansion of the epoxy material sample to be measured in each temperature segment according to the size-temperature change curve.

2. The method according to claim 1, wherein For each temperature value in the expansion chamber, measuring the size of the epoxy material sample to be measured at the temperature value through the laser system, the signal receiving system, and the data processing system includes: For each temperature value in the expansion chamber, drive the laser system to emit a laser beam with preset laser parameters, so that the laser beam is transmitted through the optical fiber to the surface of the epoxy material sample to be measured in the expansion chamber, drive the signal receiving system to receive the laser signal reflected on the surface of the epoxy material sample to be measured, detect a distance signal from the laser signal, and drive the data processing system to calculate the size of the epoxy material sample to be measured at the temperature value according to the distance signal.

3. The method according to claim 1, wherein For each temperature value in the expansion chamber, measuring the size of the epoxy material sample to be measured at the temperature value through the laser system, the signal receiving system, and the data processing system includes: According to a preset temperature increasing mode, for each temperature value in the expansion chamber, measure the size of the epoxy material sample to be measured at the temperature value through the laser system, the signal receiving system, and the data processing system, wherein the temperature increasing mode is a mode in which after completing the measurement of the size of the epoxy material sample to be measured at a first target temperature value, start the measurement of the size of the epoxy material sample to be measured at a second target temperature value, and the second target temperature value is greater than the first target temperature value.

4. The method according to claim 1, wherein It further includes: Input a target temperature value into a pre-established epoxy material size-temperature prediction model and output a predicted size value; Wherein, the establishment process of the epoxy material size-temperature prediction model includes: Obtain the historical measurement parameter data of the epoxy material sample to be measured. The historical measurement parameter data includes historical temperature data, historical humidity data, historical air pressure data, and historical dimension data. The temperature data includes the temperature values of the epoxy material sample to be measured in each historical measurement. The humidity data includes the humidity values of the epoxy material sample to be measured in each historical measurement. The air pressure data includes the air pressure values of the epoxy material sample to be measured in each historical measurement. The historical dimension data includes the dimension values of the epoxy material sample to be measured in each historical measurement; Calculate the average temperature and temperature standard deviation according to the historical temperature data; Calculate the average humidity and humidity standard deviation according to the historical humidity data; Calculate the average air pressure and air pressure standard deviation according to the historical air pressure data; Use the following formula to calculate the latest prediction weight based on the average temperature, the temperature standard deviation, the average humidity, the humidity standard deviation, the average air pressure, and the air pressure standard deviation: Among them, is the latest prediction weight, is the first balance adjustment parameter, is the second balance adjustment parameter, is the latest temperature, is the average temperature, is the latest humidity, is the average humidity, is the latest air pressure, is the average air pressure, is the temperature value measured at the i-th historical measurement, is the standard deviation of the temperature, is the humidity value measured at the i-th historical measurement, is the standard deviation of the humidity, is the air pressure value measured at the i-th historical measurement, is the standard deviation of the air pressure; Measure the current dimension value of the epoxy material sample to be measured at the current temperature value, and fuse the current dimension value with the dimension values of each historical measurement according to the latest prediction weight to obtain fused dimension data; Extract the temperature change amount sequence from the temperature values of each historical measurement and the current temperature value, and extract the dimension change amount sequence from the dimension values of each historical measurement and the fused dimension data; Normalize the temperature change amount sequence and the dimension change amount sequence respectively to obtain a normalized temperature change amount sequence and a normalized dimension change amount sequence; Use the normalized temperature change amount sequence and the normalized dimension change amount sequence as training data to train a long short-term memory network model to obtain an epoxy material dimension-temperature prediction model.

5. The method according to claim 4, characterized in that, Use the normalized temperature change amount sequence and the normalized dimension change amount sequence as training data to train a long short-term memory network model to obtain an epoxy material dimension-temperature prediction model, including: Under the mean square error loss function, use the normalized temperature change amount sequence and the normalized dimension change amount sequence as training data to train a long short-term memory network model to obtain an epoxy material dimension-temperature prediction model. The mean square error loss function is: wherein, is the target value of the mean square error loss function, is the number of samples of the training data constructed based on the training data, is the actual change in size of the i-th data in the training data, is the predicted change in size predicted by the long short-term memory network model based on the first i-1 data in the training data during training.

6. The method according to claim 5, characterized in that, Under the mean square error loss function, use the normalized temperature change amount sequence and the normalized dimension change amount sequence as training data to train a long short-term memory network model to obtain an epoxy material dimension-temperature prediction model, including: Under the mean square error loss function and the scale change amount precision threshold Using the temperature change amount normalization sequence and the dimension change amount normalization sequence as training data, train the long short-term memory network model to obtain an epoxy material dimension-temperature prediction model. Among them, during the training process of the long short-term memory network model, the scale change amount precision threshold is used to compare with the dimension change amount predicted by the long short-term memory network model. If , the long short-term memory network model skips the training of the current data point.

7. The method according to claim 1, wherein Calculate the expansion coefficient of the epoxy material sample to be measured in each temperature segment according to the dimension-temperature change curve, including: Use the following formula to calculate the expansion coefficient of the epoxy material sample to be measured at each temperature value: Wherein, is the first temperature value on the dimension-temperature change curve, is the second temperature value on the dimension-temperature change curve, is the first dimension measured for the epoxy material sample to be tested at , is the second dimension measured for the epoxy material sample to be tested at , , represents the dimension difference from changing to , , represents the temperature difference from changing to , is the coefficient of thermal expansion of the epoxy material sample to be tested in the temperature range between and , is the initial dimension of the epoxy material sample to be tested.

8. The method according to claim 1, characterized in that, The expansion chamber includes a photodetector, a beam splitter, an end mirror, an upper mirror, and a lower mirror; The beam splitter is installed at the light incident end in the expansion chamber, and the optical fiber is connected to the beam splitter; The end mirror is installed at the end in the expansion chamber, and the end mirror is parallel and opposite to the beam splitter; The upper reflecting mirror is installed on the inner wall of the upper end in the expansion cavity, and the lower reflecting mirror is installed on the inner wall of the lower end in the expansion cavity; The photodetector is placed on the back of the end reflecting mirror, and the photodetector is connected to the signal receiving system.

9. The method according to any one of claims 1-8, characterized in that, After calculating the expansion coefficient of the epoxy material sample to be measured at each temperature segment according to the size-temperature change curve, it further includes: Determining the applicability of the epoxy material sample to be measured in the temperature scenario corresponding to the target temperature segment according to the expansion coefficient of the epoxy material sample to be measured in the target temperature segment.

10. An apparatus for measuring the coefficient of thermal expansion of an epoxy material, characterized in that, A control system applied to an expansion coefficient measurement system, and the expansion coefficient measurement system further includes a laser system, an optical fiber, an expansion cavity, a signal receiving system, a data processing system, a display system, and a temperature detector; Wherein, the laser system is connected to the expansion cavity through the optical fiber, the expansion cavity is connected to the signal receiving system, the signal receiving system is connected to the data processing system, the data processing system, the laser system, and the display system are all connected to the control system, and the temperature detector is installed on the expansion cavity; The device includes: A unit for obtaining an epoxy material sample to be measured, configured to obtain an epoxy material sample to be measured; A movement control unit, configured to drive the epoxy material sample to be measured to move into the expansion cavity; A size measurement unit, configured to measure the size of the epoxy material sample to be measured at each temperature value in the expansion cavity through the laser system, the signal receiving system, and the data processing system; A curve generation unit, configured to generate a size-temperature change curve based on the sizes of the epoxy material sample to be measured at each temperature value; An expansion coefficient calculation unit, configured to calculate the expansion coefficient of the epoxy material sample to be measured at each temperature segment according to the size-temperature change curve.

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