Harmonic signal-based lossless measurement system and method for multiple thermophysical parameters

Abstract

The invention provides a nondestructive measurement system and method for multiple thermophysical parameters based on harmonic signals, and relates to the technical field of thermophysical parameter measurement of materials. The device comprises a fractal flexible sensor, a signal processing module and a data analysis module, a test scheme that the fractal flexible sensor is in direct contact with a to-be-tested material is adopted, a plurality of thermophysical parameters of the to-be-tested material are obtained based on the side length correction radius of the fractal flexible sensor and a multilayer thermal diffusion model, and a multi-model integrated framework is constructed; according to the fractal flexible sensor, simultaneous nondestructive measurement of thermal conductivity, volume thermal capacity and contact thermal resistance between layers of materials is realized, the requirement of a product with multiple layers of stacked materials on the fineness of a measurement technology is met, and meanwhile, through Peano curve design of the sensor unit, the anti-interference capability of the fractal flexible sensor on uneven surface measurement is enhanced, and the measurement accuracy is improved. And through the structural design of the fractal detection unit and the fractal heating unit, interference caused by bending deformation is inhibited, and the anti-interference capability of the system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring thermal physical parameters of materials, and in particular to a non-destructive measurement system and method for multiple thermal physical parameters based on harmonic signals. Background Art

[0002] With the development of the microelectronics field, multi-layer materials are gradually stacked in the normal direction to form macroscopic devices. The element ratio, uniformity, doping, etc. inside each layer of material result in changes in thermal physical properties such as thermal conductivity and volumetric heat capacity of the material, thereby affecting the heat transfer characteristics and service life of the device. Another representative multi-layer structure is the human skin tissue, and its water content, cell number, and other pathological changes will all affect the thermal physical properties of the tissue, thereby reflecting the health status of the human body. Therefore, accurate and non-destructive measurement of the thermal physical properties of multi-layer structures in macroscopic devices or human skin tissues has important application value for research in high-tech fields such as the microelectromechanical field and the life science field. At the same time, reducing the contact thermal resistance between different materials is an effective means to solve the conflict between the performance and heat dissipation of microelectromechanical products and maintain the stability and high performance of the products. When using contact measurement means, the influence of contact thermal resistance on the measurement results also needs to be considered. Therefore, it is very difficult to simultaneously obtain the thermal conductivity, volumetric heat capacity, and contact thermal resistance of each layer of material during the entire measurement process.

[0003] The existing technologies extract few types of thermal physical characteristic parameters and have a single model, and cannot solve the problem of simultaneous non-destructive testing of the thermal conductivity, volumetric heat capacity of multi-layer materials, and the contact thermal resistance between layers, and cannot meet the requirements of the existing multi-layer material stacked products for the fineness of measurement technology. At the same time, the existing technologies cannot eliminate the mutual interference of temperature during low-frequency measurement of non-linear integrated sensors and the interference of the external environment on the sensors, and have poor anti-interference ability. Summary of the Invention

[0004] To solve the above problems in the existing technologies, the present invention provides a non-destructive measurement system and method for multiple thermal physical parameters based on harmonic signals. The invention adopts a test scheme in which a fractal flexible sensor directly contacts the material to be tested, corrects the radius based on the side length of the fractal flexible sensor, and obtains multiple thermal physical parameters of the material to be tested based on a multi-layer thermal diffusion model, constructs a multi-model integration framework, solves the problem of a single model, realizes the simultaneous non-destructive measurement of the thermal conductivity, volumetric heat capacity of the material, and the contact thermal resistance between layers, meets the requirements of the existing multi-layer material stacked products for the fineness of measurement technology. At the same time, through the design of the Peano curve of the sensor unit, the anti-interference ability of the fractal flexible sensor for measuring uneven surfaces is enhanced, and through the structural design of the fractal detection unit and the fractal heating unit, the interference caused by bending deformation is suppressed, and the anti-interference ability of the system is improved. To achieve the above object, the technical solution is as follows:

[0005] On the one hand, the present invention provides a non-destructive measurement system for multiple thermal physical parameters based on harmonic signals, and the system includes:

[0006] A fractal flexible sensor, which is used to fit the surface of the material to be measured, provide a heat source excitation, and collect the signals generated by the material to be measured during the response process;

[0007] A signal processing module, which is used to provide a heating current and a bias signal for the fractal flexible sensor, receive and process the signals collected by the fractal flexible sensor, and send them to the data analysis module;

[0008] A data analysis module, which is used to perform iterative fitting on the signal data of the signal processing module and the fractal flexible sensor by using a non-linear fitting method, and simultaneously obtain the thermal physical parameters of the material to be measured. The thermal physical parameters of the material to be measured include: the thermal conductivity of the material, the volume heat capacity of the material, and the contact thermal resistance between the materials.

[0009] Optionally, the fractal flexible sensor includes:

[0010] A sensor unit, which is used to provide a heat source excitation and collect the signals generated by the material to be measured during the response process;

[0011] An insulation protection unit, which is used to perform electrical insulation and physical protection on the sensor unit.

[0012] Optionally, the sensor unit includes:

[0013] A current heating unit, which is used to connect to the alternating current source of the signal processing module and provide a heat source excitation for the material to be measured;

[0014] A fractal detection unit, which is used to collect the signals generated by the material to be measured during the response process;

[0015] A connection heating unit, which is used to provide a current loop for the current heating unit and provide a heat source excitation for the material to be measured;

[0016] The current heating unit and the connection heating unit form a fractal heating unit;

[0017] The insulation protection unit includes: a flexible insulation protection shell and a flexible insulation protection film.

[0018] Optionally, the sensor unit is designed by using a Peano curve, and the fractal detection unit is located between the current heating unit and the connection heating unit;

[0019] The flexible insulation protection shell is located above the sensor unit, the flexible insulation protection film is located below the sensor unit, or the flexible insulation protection shell and the flexible insulation protection film cover both sides of the sensor unit from a direction perpendicular to the sensor unit.

[0020] Optionally, the length of the sensor unit is 70 to 140 mm, and the width is 10 to 100 μm.

[0021] Optionally, the signal processing module includes:

[0022] An alternating current source for providing an alternating current to the fractal flexible sensor to generate a heat source for the fractal flexible sensor;

[0023] A direct current source for loading a bias current on the signal generated by the fractal flexible sensor;

[0024] An amplifier circuit unit for amplifying and processing the signal generated by the fractal flexible sensor;

[0025] A signal acquisition unit for acquiring the signal processed by the amplifier circuit unit and sending it to the data analysis module;

[0026] An adjustable programmable resistance unit for adjusting the pressure difference of the amplifier circuit unit;

[0027] A power supply circuit unit for supplying power to the amplifier circuit unit;

[0028] A circuit connection unit for connecting the fractal flexible sensor.

[0029] Optionally, the amplifier circuit unit includes:

[0030] A first differential amplifier for amplifying the signal generated by the fractal flexible sensor;

[0031] A second differential amplifier for amplifying the signal generated by the adjustable programmable resistance unit;

[0032] A first resistance switch for adjusting the amplification factor of the first differential amplifier;

[0033] A second resistance switch for adjusting the amplification factor of the second differential amplifier.

[0034] Optionally, the process of processing the signal collected by the fractal flexible sensor includes:

[0035] Adjusting the gear position of the first resistance switch according to the signal collected by the fractal flexible sensor and the first differential amplifier to obtain the second harmonic voltage of the material to be measured;

[0036] Adjusting the gear position of the second resistance switch according to the adjustable programmable resistance unit and the second differential amplifier and comparing it with the second harmonic voltage of the material to be measured to obtain the amplified voltage of the adjustable programmable resistance unit;

[0037] Based on the second-harmonic voltage of the material to be measured and the amplified voltage of the adjustable programmable resistor unit, the signal acquisition unit collects the signal data of the signal processing module.

[0038] Optionally, according to the signal data of the signal processing module and the fractal flexible sensor, a non-linear fitting method is used for iterative fitting, and at the same time, the thermal physical properties of the material to be measured are obtained, including:

[0039] According to the signal data of the signal processing module, the peak value of the harmonic disturbance temperature of the material to be measured is obtained through formula (1),

[0040]

[0041] In the formula: ΔT peak is the peak value of the harmonic disturbance temperature of the material to be measured, U 2ω is the second-harmonic voltage of the material to be measured, U DC is the amplified voltage of the adjustable programmable resistor unit, α CR is the resistance temperature coefficient of the fractal detection unit;

[0042] According to the signal data of the signal processing module and the fractal flexible sensor, the heating power of the fractal flexible sensor and the heat source radius corrected by the side length of the fractal flexible sensor are obtained;

[0043] According to the peak value of the harmonic disturbance temperature of the material to be measured, the heating power of the fractal flexible sensor and the heat source radius corrected by the side length of the fractal flexible sensor, multiple positions of the material to be measured are measured within the input angular frequency set set by the signal processing module and iterative fitting is performed using a non-linear fitting method, and at the same time, the thermal physical properties of the material to be measured are obtained.

[0044] On the other hand, the present invention provides a non-destructive measurement method for multiple thermal physical properties based on harmonic signals. This method is implemented by a non-destructive measurement system for multiple thermal physical properties based on harmonic signals. The method includes:

[0045] S1. Fix the fractal flexible sensor on the top of the material to be measured and connect the fractal flexible sensor to the signal processing module to obtain a thermal physical property device;

[0046] S2. According to the signal processing module and the fractal flexible sensor, the heating power of the fractal flexible sensor and the heat source radius corrected by the side length of the fractal flexible sensor are obtained;

[0047] S3. According to the characteristics of the material to be measured, a set of material parameters to be measured is obtained;

[0048] S4. According to the thermal property parameter device, turn on the power supply of the signal processing module and adjust the adjustable programmable resistance unit, the first resistance switch, and the second resistance switch so that the voltages of the first differential amplifier and the second differential amplifier are the same, obtaining the second harmonic voltage of the material to be measured and the amplified voltage of the adjustable programmable resistance unit.

[0049] S5. Change the input angular frequency of the signal processing module or the measurement position of the material to be measured, and repeat the previous step S4 to obtain the second harmonic voltage set of the material to be measured and the amplified voltage set of the adjustable programmable resistance unit.

[0050] S6. According to the heating power of the fractal flexible sensor, the heat source radius corrected by the side length of the fractal flexible sensor, the parameter set of the material to be measured, the second harmonic voltage set of the material to be measured, and the amplified voltage set of the adjustable programmable resistance unit, use the nonlinear fitting method for iterative fitting to obtain the thermal property parameters of the material to be measured.

[0051] The technical solution of the present invention has at least the following beneficial effects compared with the prior art:

[0052] On the one hand, the above solution adopts a test solution in which the fractal flexible sensor directly contacts the material to be measured, corrects the radius based on the side length of the fractal flexible sensor, and obtains multiple thermal property parameters of the material to be measured based on the multi-layer thermal diffusion model, constructs a multi-model integration framework, solves the problem of single model, realizes the simultaneous non-destructive measurement of the thermal conductivity, volume heat capacity and contact thermal resistance between layers of the material, and meets the fine measurement technology requirements of products with multi-layer material stacking. On the other hand, through the Peano curve design of the sensor unit, the anti-interference ability of the fractal flexible sensor for measuring uneven surfaces is enhanced, and through the structural design of the fractal detection unit and the fractal heating unit, the interference caused by bending deformation is suppressed, and the anti-interference ability of the system is improved. Description of the Drawings

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0054] Figure 1 is the system block diagram of the embodiment of the non-destructive measurement system for multiple thermal property parameters based on harmonic signals of the present invention;

[0055] Figure 2 is the flowchart of the process of processing the signals collected by the fractal flexible sensor in the embodiment of the non-destructive measurement system for multiple thermal property parameters based on harmonic signals of the present invention;

[0056] Figure 3 It is a flowchart for obtaining the thermal property parameters of a material to be measured in an embodiment of the non-destructive measurement system for multiple thermal property parameters based on harmonic signals of the present invention;

[0057] Figure 4 It is a top view of installing a fractal flexible sensor in an embodiment of the non-destructive measurement system for multiple thermal property parameters based on harmonic signals of the present invention;

[0058] Figure 5 It is a front view of installing a fractal flexible sensor in an embodiment of the non-destructive measurement system for multiple thermal property parameters based on harmonic signals of the present invention;

[0059] Figure 6 It is a partial schematic view of the P1 area in the top view of installing a fractal flexible sensor in an embodiment of the non-destructive measurement system for multiple thermal property parameters based on harmonic signals of the present invention;

[0060] Figure 7 It is a partial schematic view of the P2 area in the top view of installing a fractal flexible sensor in an embodiment of the non-destructive measurement system for multiple thermal property parameters based on harmonic signals of the present invention;

[0061] Figure 8 It is a schematic view of the signal processing module in an embodiment of the non-destructive measurement system for multiple thermal property parameters based on harmonic signals of the present invention;

[0062] Figure 9 It is a flowchart of an embodiment of the non-destructive measurement method for multiple thermal property parameters based on harmonic signals of the present invention.

[0063] Explanation of the symbols in the figure: fractal flexible sensor 1, signal processing module 2, data analysis module 3, material to be tested 4, sensor unit 11, insulation protection unit 12, current heating unit 111, fractal detection unit 112, connection heating unit 113, flexible insulation protection shell 121, flexible insulation protection film 122, AC current source 21, DC current source 22, amplifier circuit unit 23, signal acquisition unit 24, power supply circuit unit 25, adjustable programmable resistance unit R7, first differential amplifier 231, second differential amplifier 232, first resistance switch S2, second resistance switch S1, first low temperature drift resistor R1, second low temperature drift resistor R2, third low temperature drift resistor R 3. the fourth low temperature drift resistor R4, the fifth low temperature drift resistor R5, the sixth low temperature drift resistor R6, the first filter capacitor C1, the second filter capacitor C2, the third filter capacitor C3, the fourth filter capacitor C4, the fifth filter capacitor C5, the sixth filter capacitor C6, the seventh filter capacitor C7, the eighth filter capacitor C8, the ninth filter capacitor C9, the tenth filter capacitor C10, the eleventh filter capacitor C11, the twelfth filter capacitor C12, the first current heating unit connection terminal 2a, the second current heating unit connection terminal 2d, the first fractal detection unit connection terminal 2b, the second fractal detection unit connection terminal 2e, the first connection heating unit connection terminal 2c, and the second connection heating unit connection terminal 2f. DETAILED DESCRIPTION

[0064] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0065] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0066] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0067] like Figure 1 The system block diagram of the embodiment of the non-destructive measurement system of multiple thermal physical property parameters based on harmonic signals of the present invention is shown in FIG. Figure 4 The top view of the fractal flexible sensor installed in the embodiment of the non-destructive measurement system of multiple thermal physical parameters based on harmonic signals of the present invention is shown. The present invention provides a non-destructive measurement system of multiple thermal physical parameters based on harmonic signals, which can implement a non-destructive measurement method of multiple thermal physical parameters based on harmonic signals. The system includes: a fractal flexible sensor 1, a signal processing module 2 and a data analysis module 3;

[0068] The fractal flexible sensor 1 is used to adhere to the surface of the material 4 to be measured, provide heat source excitation and collect the signals generated by the material 4 to be measured during the response process;

[0069] Specifically, as Figure 4 In the top view of the installation of the fractal flexible sensor in the embodiment of the non-destructive measurement system for multi-thermal property parameters based on harmonic signals of the present invention shown in the figure, the fractal flexible sensor 1 includes:

[0070] The sensor unit 11 is used to provide heat source excitation and collect the signals generated by the material 4 to be measured during the response process;

[0071] The insulation protection unit 12 is used for electrical insulation and physical protection of the sensor unit 11.

[0072] Specifically, as Figure 6 In the partial schematic diagram of the P1 area in the top view of the installation of the fractal flexible sensor in the embodiment of the non-destructive measurement system for multi-thermal property parameters based on harmonic signals of the present invention shown in the figure and as Figure 7 In the partial schematic diagram of the P2 area in the top view of the installation of the fractal flexible sensor in the embodiment of the non-destructive measurement system for multi-thermal property parameters based on harmonic signals of the present invention shown in the figure, the sensor unit 11 includes:

[0073] The current heating unit 111 is used to connect to the AC current source 21 of the signal processing module 2 to provide heat source excitation for the material 4 to be measured;

[0074] The fractal detection unit 112 is used to collect the signals generated by the material 4 to be measured during the response process;

[0075] The connection heating unit 113 is used to provide a current loop for the current heating unit 111 and provide heat source excitation for the material 4 to be measured;

[0076] The current heating unit 111 and the connection heating unit 113 form a fractal heating unit;

[0077] Furthermore, the sensor unit 11 is designed with Peano curves. The fractal detection unit 112 is located in the middle of the current heating unit 111 and the connection heating unit 113, and is distributed in parallel on a two-dimensional plane to form a square overall structure; the length of the sensor unit 11 is 70 - 140 mm, the width is 10 - 100 μm, and the material of the sensor unit 11 is a chromium / platinum, chromium / gold, chromium / nickel or chromium / copper composite layer, and the thickness of the composite layer is 10 nm / 200 nm - 18 μm.

[0078] As Figure 5Front view of the installation of the fractal flexible sensor in the embodiment of the non-destructive measurement system for multiple thermal property parameters based on harmonic signals of the present invention as shown. The insulation protection unit 12 includes: a flexible insulation protection shell 121 and a flexible insulation protection film 122.

[0079] The flexible insulation protection shell 121 is located above the sensor unit 11, and the flexible insulation protection film 122 is located below the sensor unit 11, or the flexible insulation protection shell 121 and the flexible insulation protection film 122 cover both sides of the sensor unit 11 from a direction perpendicular to the sensor unit 11, playing a role in reducing the frictional loss during contact testing with the material to be measured and electrical insulation, so as to achieve the purpose of extending the service life of the sensor unit 11.

[0080] Further, the flexible insulation protection shell 121 and the flexible insulation protection film 122 are made of polydimethylsiloxane or polyimide.

[0081] The signal processing module 2 is used to provide a heating current and a bias signal for the fractal flexible sensor 1, receive and process the signals collected by the fractal flexible sensor 1 and send them to the data analysis module 3;

[0082] Specifically, as Figure 8 Schematic diagram of the signal processing module in the embodiment of the non-destructive measurement system for multiple thermal property parameters based on harmonic signals of the present invention as shown. The signal processing module includes:

[0083] An alternating current source 21 is used to provide an alternating current for the fractal flexible sensor 1, so that the fractal flexible sensor 1 generates a heat source;

[0084] A direct current source 22 is used to load a bias current for the signal generated by the fractal flexible sensor 1;

[0085] An amplifier circuit unit 23 is used to amplify and process the signals generated by the fractal flexible sensor 1;

[0086] Further, the amplifier circuit unit 23 includes:

[0087] A first differential amplifier 231 is used to amplify the signals generated by the fractal flexible sensor 1;

[0088] A second differential amplifier 232 is used to amplify the signals generated by the adjustable programmable resistance unit R7;

[0089] A first resistance switch S2 is used to adjust the amplification factor of the first differential amplifier 231;

[0090] A second resistance switch S1 is used to adjust the amplification factor of the second differential amplifier 232.

[0091] The signal acquisition unit 24 is configured to acquire the signal processed by the amplifier circuit unit 23 and send it to the data analysis module 3;

[0092] The adjustable programmable resistor unit R7 is used to adjust the pressure difference of the amplifier circuit unit 23;

[0093] The power supply circuit unit 25 is used to supply power to the amplifier circuit unit 23;

[0094] The circuit connection unit is used to connect the fractal flexible sensor 1.

[0095] Further, the circuit connection unit includes: a first current heating unit connection end 2a, a second current heating unit connection end 2d, a first fractal detection unit connection end 2b, a second fractal detection unit connection end 2e, a first connection heating unit connection end 2c, and a second connection heating unit connection end 2f; the first current heating unit connection end 2a and the second current heating unit connection end 2d are connected to both ends of the current heating unit 111, the first fractal detection unit connection end 2b and the second fractal detection unit connection end 2e are connected to both ends of the fractal detection unit 112, and the first connection heating unit connection end 2c and the second connection heating unit connection end 2f are connected to both ends of the connection heating unit 113.

[0096] The adjustable programmable resistance unit R7 is connected to the second differential amplifier 232 through the first low-temperature drift resistor R1 and the second low-temperature drift resistor R2 respectively. The first fractal detection unit connection end 2b and the second fractal detection unit connection end 2e are connected to the first differential amplifier 231 through the fourth low-temperature drift resistor R4 and the fifth low-temperature drift resistor R5 respectively. The positive pole of the power supply circuit unit 25 is connected to the positive pole of the first differential amplifier 231 through the sixth low-temperature drift resistor R6. The negative pole of the power supply circuit unit 25 is directly connected to the negative pole of the first differential amplifier 231. The positive pole of the power supply circuit unit 25 is connected to the positive pole of the second differential amplifier 232 through the third low-temperature drift resistor R3. The negative pole of the power supply circuit unit 25 is directly connected to the negative pole of the second differential amplifier 232. The positive pole of the power supply circuit unit 25 is connected to the output end of the first differential amplifier 231 through the first filter capacitor C1, the second filter capacitor C2 and the third filter capacitor C3. The negative pole of the power supply circuit unit 25 is connected to the output end of the first differential amplifier 231 through the fourth filter capacitor C4, the fifth filter capacitor C5 and the sixth filter capacitor C6. The positive pole of the power supply circuit unit 25 is connected to the output end of the second differential amplifier 232 through the seventh filter capacitor C7, the eighth filter capacitor C8 and the ninth filter capacitor C9. The negative pole of the power supply circuit unit 25 is connected to the output end of the second differential amplifier 232 through the tenth filter capacitor C10, the eleventh filter capacitor C11 and the twelfth filter capacitor C12. The output ends of the first differential amplifier 231 and the second differential amplifier 232 are respectively connected to the signal acquisition unit 24. The AC current source 21 is connected to the first current heating unit connection end 2a and the second connection heating unit connection end 2f. The DC current source 22 is connected to the first fractal detection unit connection end 2b and the second fractal detection unit connection end 2e. The first resistance switch S2 can adjust the amplification factors of 2 times, 5 times, 10 times and 20 times. The second resistance switch S1 can adjust the amplification factors of 2 times, 5 times, 10 times and 20 times.

[0097] Specifically, as Figure 2 shown in the flowchart of the process of processing the signals collected by the fractal flexible sensor in the embodiment of the non-destructive measurement system for multiple thermophysical parameters based on harmonic signals of the present invention, the process of processing the signals collected by the fractal flexible sensor includes:

[0098] According to the signals collected by the fractal flexible sensor and the first differential amplifier 231, adjust the gear position of the first resistance switch S2 to obtain the second harmonic voltage of the material to be measured;

[0099] According to the adjustable programmable resistance unit R7 and the second differential amplifier 232, adjust the gear position of the second resistance switch S1 and compare it with the second harmonic voltage of the material to be measured to obtain the amplified voltage of the adjustable programmable resistance unit;

[0100] According to the second-harmonic voltage of the material to be measured and the amplified voltage of the adjustable programmable resistance unit, the signal acquisition unit acquires 24 to obtain the signal data of the signal processing module.

[0101] The data analysis module 3 is configured to perform iterative fitting using a non-linear fitting method based on the signal data of the signal processing module 2 and the fractal flexible sensor 1, and simultaneously obtain the thermal physical properties of the material to be measured. The thermal physical properties of the material to be measured include: the thermal conductivity of the material, the volumetric heat capacity of the material, and the contact thermal resistance between the materials.

[0102] Specifically, as Figure 3 shown in the flowchart of obtaining the thermal physical properties of the material to be measured in the embodiment of the non-destructive measurement system for multiple thermal physical properties based on harmonic signals of the present invention, iterative fitting is performed using a non-linear fitting method based on the signal data of the signal processing module 2 and the fractal flexible sensor 1, and simultaneously the thermal physical properties of the material to be measured are obtained, including:

[0103] According to the signal data of the signal processing module 2, the peak value of the harmonic disturbance temperature of the material to be measured 4 is obtained through formula (1).

[0104]

[0105] In the formula: ΔT peak is the peak value of the harmonic disturbance temperature of the material to be measured, U 2ω is the second-harmonic voltage of the material to be measured, U DC is the amplified voltage of the adjustable programmable resistance unit, α CR is the resistance temperature coefficient of the fractal detection unit;

[0106] According to the signal data of the signal processing module 2 and the fractal flexible sensor 1, the heating power of the fractal flexible sensor 1 and the heat source radius corrected by the side length of the fractal flexible sensor 1 are obtained.

[0107] According to the peak value of the harmonic disturbance temperature of the material to be measured 4, the heating power of the fractal flexible sensor 1, and the heat source radius corrected by the side length of the fractal flexible sensor 1, multiple positions of the material to be measured 4 are measured within the input angular frequency set set by the signal processing module 2, and iterative fitting is performed using a non-linear fitting method to simultaneously obtain the thermal physical properties of the material to be measured.

[0108] Further, through formula (2) to formula (6), iterative fitting is performed using a non-linear fitting method to simultaneously obtain the thermal physical properties of the material to be measured.

[0109]

[0110] κ xz,j = κ x,j / κz,j (1 ≤ j ≤ n)(6)

[0111] Where: n is the number of layers of the material and the protective film, where the first layer is a flexible insulating protective film, and the second layer to the nth layer are the materials to be measured, P is the heating power of the fractal flexible sensor, κ j is the thermal conductivity of the jth layer, is the iteration coefficient of the jth layer, c V,j is the volumetric heat capacity of the jth layer, b is the radius of the heat source corrected for the side length of the fractal flexible sensor, ω is the angular frequency value of the input signal, κ z,j is the thermal conductivity at the vertical position z of the jth layer, κ x,j is the thermal conductivity at the horizontal position x of the jth layer, κ xz,j is the ratio of the thermal conductivity at the horizontal position x to the thermal conductivity at the vertical position z of the jth layer, is the correction term for the reciprocal of the thermal penetration depth of the jth layer, R C j,j+1 is the contact thermal resistance between the jth layer and the j + 1th layer, η j is the ratio of the material thickness to the thermal penetration depth of the jth layer, d j is the thickness of the jth layer.

[0112] As Figure 9 shown in the flowchart of the embodiment of the non-destructive measurement method of multi-thermal physical property parameters based on harmonic signals of the present invention, the present invention provides a non-destructive measurement method of multi-thermal physical property parameters based on harmonic signals, which is implemented by a non-destructive measurement system of multi-thermal physical property parameters based on harmonic signals. The method includes:

[0113] S1. Fix the fractal flexible sensor on the top of the material to be measured, and connect the fractal flexible sensor to the signal processing module to obtain a thermal physical property parameter device;

[0114] S2. Obtain the heating power of the fractal flexible sensor and the radius of the heat source corrected for the side length of the fractal flexible sensor according to the signal processing module and the fractal flexible sensor;

[0115] S3. Obtain a set of material parameters to be measured according to the characteristics of the material to be measured;

[0116] S4. According to the thermal physical property parameter device, turn on the power supply of the signal processing module and adjust the adjustable program-controlled resistance unit, the first resistance switch and the second resistance switch so that the voltages of the first differential amplifier and the second differential amplifier are the same, and obtain the second harmonic voltage of the material to be measured and the amplified voltage of the adjustable program-controlled resistance unit;

[0117] S5. Change the input angular frequency of the signal processing module or the measurement position of the material to be measured, and repeat the previous step S4 to obtain the second harmonic voltage set of the material to be measured and the amplified voltage set of the adjustable programmable resistance unit;

[0118] S6. Based on the heating power of the fractal flexible sensor, the heat source radius corrected by the side length of the fractal flexible sensor, the parameter set of the material to be measured, the second harmonic voltage set of the material to be measured, and the amplified voltage set of the adjustable programmable resistance unit, use the non-linear fitting method for iterative fitting to obtain the thermal physical properties of the material to be measured.

[0119] The present invention provides a non-destructive measurement system and method for multiple thermal physical properties based on harmonic signals. The invention includes a fractal flexible sensor, a signal processing module, and a data analysis module. It adopts a test scheme of directly contacting the material to be measured with the fractal flexible sensor, corrects the radius based on the side length of the fractal flexible sensor, and obtains multiple thermal physical properties of the material to be measured based on a multi-layer heat diffusion model. A multi-model integration framework is constructed to solve the problem of a single model, realizing the simultaneous non-destructive measurement of the thermal conductivity, volume heat capacity, and contact thermal resistance between layers of the material, meeting the requirements of the fineness of the measurement technology for products with multi-layer material stacking. At the same time, through the Peano curve design of the sensor unit, the anti-interference ability of the fractal flexible sensor for measuring uneven surfaces is enhanced, and through the structural design of the fractal detection unit and the fractal heating unit, the interference caused by bending deformation is suppressed, improving the anti-interference ability of the system.

[0120] It can be understood that the present invention is described through the above embodiments, and should not be construed as a limitation on the embodiments and scope of the present invention. Those skilled in the art know that without departing from the spirit and scope of the present invention, these features and embodiments can be variously changed or equivalently replaced. In addition, under the teaching of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. A non-destructive measurement system for multiple thermal physical parameters based on harmonic signals, characterized in that: The system comprises: The fractal flexible sensor is used to fit the surface of the material to be tested, provide heat source excitation and collect the signal generated by the material to be tested during the response process; A signal processing module, used for providing a heating current and a bias signal for the fractal flexible sensor, receiving and processing the signal collected by the fractal flexible sensor and sending it to a data analysis module; The data analysis module is used to perform iterative fitting using a nonlinear fitting method according to the signal data of the signal processing module and the fractal flexible sensor, and simultaneously obtain the thermal physical property parameters of the material to be tested, wherein the thermal physical property parameters of the material to be tested include: thermal conductivity of the material, volume heat capacity of the material, and contact thermal resistance between materials.

2. The non-destructive measurement system of multiple thermal physical property parameters based on harmonic signals according to claim 1 is characterized in that: The fractal flexible sensor comprises: A sensor unit, used to provide heat source excitation and collect signals generated by the material to be tested during the response process; The insulating protection unit is used to electrically insulate and physically protect the sensor unit.

3. The non-destructive measurement system of multiple thermal physical property parameters based on harmonic signals according to claim 2 is characterized in that: The sensor unit comprises: A current heating unit, used to connect to the AC current source of the signal processing module to provide heat source excitation for the material to be tested; A fractal detection unit, used to collect the signal generated by the material to be tested during the response process; Connecting a heating unit to provide a current loop for the current heating unit and provide a heat source excitation for the material to be tested; The current heating unit and the connection heating unit constitute a fractal heating unit; The insulating protection unit comprises a flexible insulating protection shell and a flexible insulating protection film.

4. The non-destructive measurement system of multiple thermal physical property parameters based on harmonic signals according to claim 3 is characterized in that: The sensor unit adopts Peano curve design, and the fractal detection unit is located between the current heating unit and the connection heating unit; The flexible insulating protective shell is located above the sensor unit, the flexible insulating protective film is located below the sensor unit, or the flexible insulating protective shell and the flexible insulating protective film cover both sides of the sensor unit from a direction perpendicular to the sensor unit.

5. The non-destructive measurement system of multiple thermal physical property parameters based on harmonic signals according to claim 2, characterized in that: The sensor unit has a length of 70 to 140 mm and a width of 10 to 100 μm.

6. The non-destructive measurement system of multiple thermal physical property parameters based on harmonic signals according to claim 1, characterized in that: The signal processing module comprises: An alternating current source, used for providing an alternating current to the fractal flexible sensor, so that the fractal flexible sensor generates a heat source; A direct current source, used to load a bias current for the signal generated by the fractal flexible sensor; an amplifying circuit unit, used for amplifying and processing the signal generated by the fractal flexible sensor; A signal acquisition unit, used for acquiring the signal processed by the amplifying circuit unit and sending it to the data analysis module; An adjustable programmable resistance unit, used for adjusting the voltage difference of the amplifying circuit unit; A power supply circuit unit, used to supply power to the amplifying circuit unit; A circuit connection unit is used to connect the fractal flexible sensor.

7. The non-destructive measurement system of multiple thermal physical property parameters based on harmonic signals according to claim 6, characterized in that: The amplifying circuit unit comprises: a first differential amplifier, used to amplify the signal generated by the fractal flexible sensor; A second differential amplifier, used for amplifying the signal generated by the adjustable programmable resistance unit; A first resistance switch, used for adjusting the gain of the first differential amplifier; The second resistance switch is used to adjust the gain of the second differential amplifier.

8. The non-destructive measurement system of multiple thermal physical property parameters based on harmonic signals according to claim 7, characterized in that: The process of processing the signal collected by the fractal flexible sensor includes: According to the signal collected by the fractal flexible sensor and the first differential amplifier, adjusting the gear position of the first resistance switch to obtain the second harmonic voltage of the material to be tested; According to the adjustable programmable resistance unit and the second differential amplifier, the gear position of the second resistance switch is adjusted and compared with the second harmonic voltage of the material to be tested to obtain the amplified voltage of the adjustable programmable resistance unit; The signal data of the signal processing module is obtained by collecting data through the signal collection unit according to the second harmonic voltage of the material to be tested and the amplified voltage of the adjustable programmable resistance unit.

9. The non-destructive measurement system of multiple thermal physical property parameters based on harmonic signals according to claim 1, characterized in that: The method of iteratively fitting the signal data of the signal processing module and the fractal flexible sensor using a nonlinear fitting method to simultaneously obtain the thermal physical property parameters of the material to be tested includes: According to the signal data of the signal processing module, the peak value of the harmonic disturbance temperature of the material to be tested is obtained by formula (1): Where: ΔT peak is the peak value of the harmonic disturbance temperature of the material to be tested, U 2ω is the second harmonic voltage of the material to be tested, U DC is the amplified voltage of the adjustable programmable resistance unit, α CR is the resistance temperature coefficient of the fractal detection unit; According to the signal data of the signal processing module and the fractal flexible sensor, the heating power of the fractal flexible sensor and the heat source radius of the fractal flexible sensor side length correction are obtained; According to the harmonic disturbance temperature peak of the material to be tested, the heating power of the fractal flexible sensor and the heat source radius corrected by the side length of the fractal flexible sensor, multiple positions of the material to be tested are measured within the input angular frequency set set by the signal processing module and iterative fitting is performed using a nonlinear fitting method to obtain the thermal physical property parameters of the material to be tested.

10. A non-destructive measurement method for multiple thermal physical property parameters based on harmonic signals, wherein the non-destructive measurement method for multiple thermal physical property parameters based on harmonic signals is implemented by a non-destructive measurement system for multiple thermal physical property parameters based on harmonic signals according to any one of claims 1 to 9, characterized in that: The method comprises: S1, fixing the fractal flexible sensor on the top of the material to be tested, and connecting the fractal flexible sensor to a signal processing module to obtain a thermal physical property parameter device; S2. According to the signal processing module and the fractal flexible sensor, the heating power of the fractal flexible sensor and the heat source radius of the fractal flexible sensor side length correction are obtained; S3. Obtaining a parameter set of the material to be tested according to the characteristics of the material to be tested; S4, according to the thermophysical parameter device, turning on the power of the signal processing module and adjusting the adjustable programmable resistance unit, the first resistance switch and the second resistance switch, so that the voltage of the first differential amplifier is consistent with the voltage of the second differential amplifier, and obtaining the second harmonic voltage of the material to be tested and the amplified voltage of the adjustable programmable resistance unit; S5, changing the input angular frequency of the signal processing module or the measuring position of the material to be tested, repeating the previous step S4, and obtaining the second harmonic voltage set of the material to be tested and the amplified voltage set of the adjustable programmable resistance unit; S6. According to the heating power of the fractal flexible sensor, the heat source radius corrected by the side length of the fractal flexible sensor, the parameter set of the material to be tested, the second harmonic voltage set of the material to be tested and the amplified voltage set of the adjustable programmable resistance unit, a nonlinear fitting method is used to perform iterative fitting to obtain the thermal physical property parameters of the material to be tested.

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