A non-destructive measurement system and method for multiple thermophysical parameters based on harmonic signals

Abstract

The present application provides a kind of based on harmonic signal's multiple thermal physical parameter nondestructive measurement system and method, it is related to material's thermal physical parameter measurement technical field.The present application includes fractal flexible sensor, signal processing module and data analysis module, using fractal flexible sensor direct contact the test scheme of material to be measured, based on the side length correction radius of fractal flexible sensor, and based on multiple thermal diffusion model obtains multiple thermal physical parameters of material to be measured, constructs multiple model integrated framework, realizes the simultaneous nondestructive measurement of thermal conductivity, bulk heat capacity and the contact thermal resistance between each layer of material, reaches the delicacy demand of measurement technology for the product of multilayer material stack, simultaneously through the Peano curve design of sensor unit, the anti-interference ability of fractal flexible sensor for uneven surface measurement is enhanced, and through the structure design of fractal detection unit and fractal heating unit, the interference caused by bending deformation is inhibited, and the anti-interference ability of system is improved.

Description

TECHNICAL FIELD

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

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

[0003] The prior art has few types of thermal physical property parameters and a single model, and cannot solve the problem of simultaneous non-destructive testing of the thermal conductivity, volumetric heat capacity and contact thermal resistance between layers of multi-layer materials, and cannot meet the fine measurement requirements of products stacked with multi-layer materials. In addition, the prior art cannot eliminate the mutual interference of temperature during low-frequency measurement of the nonlinear one-piece sensor and the interference of the external environment on the sensor, and has poor anti-interference ability. SUMMARY

[0004] To solve the above problems in the prior art, the present application provides a non-destructive measurement system and method for multiple thermal physical parameters based on harmonic signals. The present application uses a test scheme in which a 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 physical parameters of the material to be measured based on a multi-layer thermal diffusion model, thereby constructing a multi-model integrated framework, solving the problem of a single model, realizing simultaneous non-destructive measurement of the thermal conductivity, volumetric heat capacity and contact thermal resistance between layers of material, and meeting the fine measurement requirements of products stacked with multi-layer materials. In addition, 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. To achieve the above purpose, the technical solution is as follows:

[0005] In one aspect, the present application provides a non-destructive measurement system for multiple thermal physical parameters based on harmonic signals, which comprises:

[0006] a fractal flexible sensor for adhering to the surface of a material to be measured, providing heat source excitation and collecting signals generated by the material to be measured during the response process;

[0007] a signal processing module for providing heating current and bias signals for the fractal flexible sensor, receiving and processing signals collected by the fractal flexible sensor and sending them to a data analysis module;

[0008] a data analysis module for obtaining thermal physical parameters of the material to be measured by using a nonlinear fitting method to iteratively fit the signal data from the signal processing module and the fractal flexible sensor, the thermal physical parameters of the material to be measured including thermal conductivity of the material, volumetric heat capacity of the material, and contact thermal resistance between materials.

[0009] Optionally, the fractal flexible sensor comprises:

[0010] a sensor unit for providing heat source excitation and collecting signals generated by the material to be measured during the response process;

[0011] an insulation protection unit for electrically insulating and physically protecting the sensor unit.

[0012] Optionally, the sensor unit comprises:

[0013] a current heating unit for connecting an alternating current source of the signal processing module to provide heat source excitation for the material to be measured;

[0014] a fractal detection unit for collecting signals generated by the material to be measured during the response process;

[0015] a connection heating unit for providing a current loop for the current heating unit and providing 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 comprises a flexible insulation protection shell and a flexible insulation protection film.

[0018] Optionally, the sensor unit is designed 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 are applied to both sides of the sensor unit from a direction perpendicular to the sensor unit.

[0020] Optionally, the sensor unit has a length of 70-140 mm and a width of 10-100 μm.

[0021] Optionally, the signal processing module comprises:

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

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

[0024] an amplification 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 amplification circuit unit and sending to the data analysis module;

[0026] an adjustable program-controlled resistance unit for adjusting the differential pressure of the amplification circuit unit;

[0027] a power supply circuit unit for supplying power to the amplification circuit unit;

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

[0029] Optionally, the amplification circuit unit comprises:

[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 program-controlled 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 comprises:

[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 program-controlled resistance unit and the second differential amplifier and comparing with the second harmonic voltage of the material to be measured to obtain the amplification voltage of the adjustable program-controlled resistance unit;

[0037] According to the second harmonic voltage of the material to be measured and the amplification voltage of the adjustable program-controlled resistance unit, signal data of a signal processing module is obtained through the signal acquisition unit.

[0038] Optionally, according to the signal data of the signal processing module and the fractal flexible sensor, a nonlinear fitting method is used for iterative fitting, and thermal physical parameters of the material to be measured are obtained, including:

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

[0040]

[0041] In the formula, ΔT peak is the harmonic disturbance temperature peak value of the material to be measured, U 2ω is the second harmonic voltage of the material to be measured, U DC is the amplification voltage of the adjustable program-controlled resistance unit, and 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 thermal source radius corrected by the side length of the fractal flexible sensor are obtained.

[0043] According to the harmonic disturbance temperature peak value of the material to be measured, the heating power of the fractal flexible sensor and the thermal source radius corrected by the side length of the fractal flexible sensor, a plurality of positions of the material to be measured are measured within the input angular frequency set set by the signal processing module, and a nonlinear fitting method is used for iterative fitting, and thermal physical parameters of the material to be measured are obtained.

[0044] In another aspect, the present application provides a non-destructive measurement method of multiple thermal physical parameters based on harmonic signals, which is realized by a non-destructive measurement system of multiple thermal physical parameters based on harmonic signals, and the method comprises:

[0045] S1, the fractal flexible sensor is fixed on the top of the material to be measured, and the fractal flexible sensor is connected with the signal processing module to obtain a thermal physical parameter device.

[0046] S2, according to the signal processing module and the fractal flexible sensor, the heating power of the fractal flexible sensor and the thermal 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 material parameter set is obtained.

[0048] S4, according to the thermal physical parameter device, turning on the power supply of the signal processing module and adjusting the adjustable program-controlled resistance unit, the first resistance switch and the second resistance switch, so that the voltage of the first differential amplifier and the voltage of the second differential amplifier are consistent, obtaining the second harmonic voltage of the material to be measured and the amplification voltage of the adjustable program-controlled resistance unit;

[0049] S5, changing the input angular frequency of the signal processing module or the measurement position of the material to be measured, repeating the above step S4, obtaining the second harmonic voltage set of the material to be measured and the amplification voltage set of the adjustable program-controlled resistance unit;

[0050] S6, according to the heating power of the fractal flexible sensor, the side length corrected heat source radius 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 amplification voltage set of the adjustable program-controlled resistance unit, using a nonlinear fitting method for iterative fitting, obtaining the thermal physical parameters of the material to be measured.

[0051] Compared with the prior art, the technical scheme of the present application has at least the following beneficial effects:

[0052] The above-mentioned scheme on the one hand adopts a test scheme in which the fractal flexible sensor directly contacts the material to be measured, obtains multiple thermal physical parameters of the material to be measured based on the side length corrected radius of the fractal flexible sensor and based on a multi-layer heat diffusion model, constructs a multi-model integrated framework, solves the problem of single model, realizes the simultaneous nondestructive measurement of the thermal conductivity, the volume heat capacity and the contact thermal resistance between layers of the material, meets the requirement of the precision of the measurement technology for the product of the multi-layer material stack, on the other hand, through the Peano curve design of the sensor unit, the anti-interference ability of the fractal flexible sensor for the uneven surface measurement is enhanced, and through the structural design of the fractal detection unit and the fractal heating unit, the interference caused by the bending deformation is suppressed, and the anti-interference ability of the system is improved. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0054] Figure 1 is a system block diagram of a nondestructive measurement system for multiple thermal physical parameters based on harmonic signals according to an embodiment of the present application;

[0055] Figure 2 is a flowchart of the process of processing the signals collected by the fractal flexible sensor in the nondestructive measurement system for multiple thermal physical parameters based on harmonic signals according to an embodiment of the present application;

[0056] Figure 3 is a flowchart of obtaining the thermal physical parameters of the material to be measured in the harmonic signal-based non-destructive measurement system of multiple thermal physical parameters of the present application;

[0057] Figure 4 is a top view of installing the fractal flexible sensor in the harmonic signal-based non-destructive measurement system of multiple thermal physical parameters of the present application;

[0058] Figure 5 is a front view of installing the fractal flexible sensor in the harmonic signal-based non-destructive measurement system of multiple thermal physical parameters of the present application;

[0059] Figure 6 is a partial schematic view of the P1 area in the top view of installing the fractal flexible sensor in the harmonic signal-based non-destructive measurement system of multiple thermal physical parameters of the present application;

[0060] Figure 7 is a partial schematic view of the P2 area in the top view of installing the fractal flexible sensor in the harmonic signal-based non-destructive measurement system of multiple thermal physical parameters of the present application;

[0061] Figure 8 is a schematic view of the signal processing module in the harmonic signal-based non-destructive measurement system of multiple thermal physical parameters of the present application;

[0062] Figure 9 is a flowchart of the harmonic signal-based non-destructive measurement method of multiple thermal physical parameters of the present application.

[0063] The figure label explanation: fractal flexible sensor 1, signal processing module 2, data analysis module 3, material to be measured 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, alternating current source 21, direct current source 22, amplification circuit unit 23, signal acquisition unit 24, power supply circuit unit 25, adjustable program-controlled resistance unit R7, first differential amplifier 231, second differential amplifier 232, first resistance switch S2, second resistance switch S1, first low-temperature drift resistance R1, second low-temperature drift resistance R2, third low-temperature drift resistance R3, fourth low-temperature drift resistance R4, fifth low-temperature drift resistance R5, sixth low-temperature drift resistance R6, first filter capacitor C1, second filter capacitor C2, third filter capacitor C3, fourth filter capacitor C4, fifth filter capacitor C5, sixth filter capacitor C6, seventh filter capacitor C7, eighth filter capacitor C8, ninth filter capacitor C9, tenth filter capacitor C10, eleventh filter capacitor C11, twelfth filter capacitor C12, first current heating unit connection end 2a, second current heating unit connection end 2d, first fractal detection unit connection end 2b, second fractal detection unit connection end 2e, first connection heating unit connection end 2c, second connection heating unit connection end 2f. DETAILED DESCRIPTION

[0064] The technical solutions in the embodiments of the present application will be described below with reference to the drawings.

[0065] In the embodiments of the present application, the words "example", "for example", and the like are used to represent an example, an illustration, or a description. Any embodiment or design scheme described as "example" in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the word "example" is intended to present the concept in a specific manner. In addition, in the embodiments of the present application, the meaning expressed by "and / or" can be both, or can be either one of the two.

[0066] To make the technical problems, technical solutions, and advantages of the present application clearer, the following will be described in detail with reference to the drawings and specific embodiments.

[0067] As Figure 1 shown in the system block diagram of the embodiment of the non-destructive measurement system of multiple thermal physical parameters based on harmonic signals of the present application and as Figure 4 shown in the top view of the installation of the fractal flexible sensor in the embodiment of the non-destructive measurement system of multiple thermal physical parameters based on harmonic signals of the present application, the present application provides a non-destructive measurement system of multiple thermal physical parameters based on harmonic signals, which can realize a non-destructive measurement method of multiple thermal physical parameters based on harmonic signals, and the system comprises 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 test material 4, provide heat source excitation and collect the signal generated by the test material 4 during the response process;

[0069] Specifically, such as Figure 4 The diagram shown is a top view of an embodiment of the nondestructive measurement system for multiple thermophysical parameters based on harmonic signals of the present invention, in which a fractal flexible sensor 1 is installed. The fractal flexible sensor 1 includes:

[0070] Sensor unit 11 is used to provide thermal excitation and acquire the signal generated by the test material 4 during the response process;

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

[0072] Specifically, such as Figure 6 The diagram shown is a partial schematic of region P1 in the top view of the embodiment of the non-destructive measurement system for multiple thermophysical parameters based on harmonic signals of the present invention, where a fractal flexible sensor is installed. Figure 7 The diagram shown is a partial schematic diagram of region P2 in a top view of an embodiment of the nondestructive measurement system for multiple thermophysical parameters based on harmonic signals of the present invention, in which a fractal flexible sensor is installed. 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 under test 4;

[0074] Fractal detection unit 112 is used to collect the signal generated by the material under test 4 during the response process;

[0075] The heating unit 113 is connected to provide a current loop for the current heating unit 111 and to provide a heat source excitation for the material under test 4.

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

[0077] Furthermore, the sensor unit 11 adopts a Peano curve design, and the fractal detection unit 112 is located between the current heating unit 111 and the connecting 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 70-140mm, the width is 10-100μm, and the material of the sensor unit 11 is a chromium / platinum, chromium / gold, chromium / nickel or chromium / copper composite layer, with a composite layer thickness of 10nm / 200nm-18μm.

[0078] like Figure 5The front view of the fractal flexible sensor installed in the harmonic signal based multi-thermal physical parameter nondestructive measurement system embodiment of the present application is shown. The insulation protection unit 12 comprises 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 are located on both sides of the sensor unit 11 from the direction perpendicular to the sensor unit 11, which plays a role in reducing friction loss and electrical insulation when contacting the material to be tested, so as to prolong the service life of the sensor unit 11.

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

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

[0082] Specifically, as Figure 8 The schematic diagram of the signal processing module in the harmonic signal based multi-thermal physical parameter nondestructive measurement system embodiment of the present application is shown. The signal processing module comprises:

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

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

[0085] The amplification circuit unit 23 is used to amplify and process the signal generated by the fractal flexible sensor 1.

[0086] Further, the amplification circuit unit 23 comprises:

[0087] The first differential amplifier 231 is used to amplify the signal generated by the fractal flexible sensor 1.

[0088] The second differential amplifier 232 is used to amplify the signal generated by the adjustable program-controlled resistance unit R7.

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

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

[0091] A signal collection unit 24 is configured to collect the signal processed by the amplification circuit unit 23 and send the signal to the data analysis module 3.

[0092] An adjustable program-controlled resistance unit R7 is configured to adjust the voltage difference of the amplification circuit unit 23.

[0093] A power supply circuit unit 25 is configured to supply power to the amplification circuit unit 23.

[0094] A circuit connection unit is configured 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 two 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 two 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 two ends of the connection heating unit 113.

[0096] The adjustable programmable resistor unit R7 is connected to the second differential amplifier 232 via the first low-temperature drift resistor R1 and the second low-temperature drift resistor R2, respectively. The first fractal detection unit connection terminal 2b and the second fractal detection unit connection terminal 2e are connected to the first differential amplifier 231 via the fourth low-temperature drift resistor R4 and the fifth low-temperature drift resistor R5, respectively. The positive terminal of the power supply circuit unit 25 is connected to the positive terminal of the first differential amplifier 231 via the sixth low-temperature drift resistor R6, and the negative terminal of the power supply circuit unit 25 is directly connected to the negative terminal of the first differential amplifier 231. The positive terminal of the power supply circuit unit 25 is connected to the positive terminal of the second differential amplifier 232 via the third low-temperature drift resistor R3, and the negative terminal of the power supply circuit unit 25 is directly connected to the negative terminal of the second differential amplifier 232. The positive terminal of the power supply circuit unit 25 is connected to the output terminal of the first differential amplifier 231 via the first filter capacitor C1, the second filter capacitor C2, and the third filter capacitor C3, and the negative terminal of the power supply circuit unit 25 is connected to the output terminal of the first differential amplifier 231 via the fourth filter capacitor C4 and the fifth filter capacitor C5. Capacitor C5 and the sixth filter capacitor C6 are connected to the output terminal of the first differential amplifier 231. The positive terminal of the power supply circuit unit 25 is connected to the output terminal 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 terminal of the power supply circuit unit 25 is connected to the output terminal 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 terminals 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 terminal 2a and the second current heating unit connection terminal 2f. The DC current source 22 is connected to the first fractal detection unit connection terminal 2b and the second fractal detection unit connection terminal 2e. The first resistor switch S2 can adjust the amplification factor to 2x, 5x, 10x, and 20x. The second resistor switch S1 can adjust the amplification factor to 2x, 5x, 10x, and 20x.

[0097] Specifically, such as Figure 2 The flowchart shown is a process for processing the signal acquired by the fractal flexible sensor in an embodiment of the non-destructive measurement system for multiple thermophysical parameters based on harmonic signals of the present invention. This process includes:

[0098] Based on the signal collected by the fractal flexible sensor and the first differential amplifier 231, the position of the first resistance switch S2 is adjusted to obtain the second harmonic voltage of the material under test.

[0099] Based on the adjustable programmable resistor unit R7 and the second differential amplifier 232, the position of the second resistor switch S1 is adjusted and compared with the second harmonic voltage of the material under test to obtain the amplified voltage of the adjustable programmable resistor unit.

[0100] Based on the second harmonic voltage of the material under test and the amplified voltage of the adjustable programmable resistor unit, the signal acquisition unit acquires 24, and the signal data of the signal processing module is obtained.

[0101] The data analysis module 3 is used to perform iterative fitting using a nonlinear fitting method based on the signal data from the signal processing module 2 and the fractal flexible sensor 1, and to obtain the thermal properties of the material under test. The thermal properties of the material under test include: the thermal conductivity of the material, the volumetric heat capacity of the material, and the contact thermal resistance between the materials.

[0102] Specifically, such as Figure 3 The flowchart shown in this embodiment of the nondestructive measurement system for multiple thermophysical parameters based on harmonic signals of the present invention illustrates the process of obtaining the thermophysical parameters of the material under test. Based on the signal data from the signal processing module 2 and the fractal flexible sensor 1, an iterative fitting method using nonlinear fitting is employed to simultaneously obtain the thermophysical parameters of the material under test, including:

[0103] Based on the signal data from the signal processing module 2, the peak value of the harmonic disturbance temperature of the material under test 4 is obtained using formula (1).

[0104]

[0105] Where: ΔT peak U represents the peak value of the harmonic disturbance temperature of the material under test. 2ω U is the second harmonic voltage of the material under test. DC α is the amplified voltage of the adjustable programmable resistor unit. CR The temperature coefficient of resistance of the fractal detection unit;

[0106] Based on the signal data from 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] Based on the peak value of the harmonic disturbance temperature of the material under test 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, the signal processing module 2 measures multiple positions of the material under test 4 within the input angular frequency set and performs iterative fitting using a nonlinear fitting method, thereby obtaining the thermal property parameters of the material under test.

[0108] Furthermore, iterative fitting is performed using formulas (2) to (6) using a nonlinear fitting method, thereby obtaining the thermophysical parameters of the material under test.

[0109]

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

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

[0112] like Figure 9 The flowchart shown is an embodiment of the nondestructive measurement method for multiple thermophysical parameters based on harmonic signals according to the present invention. The present invention provides a nondestructive measurement method for multiple thermophysical parameters based on harmonic signals, which is implemented by a nondestructive measurement system for multiple thermophysical parameters based on harmonic signals. The method includes:

[0113] S1. Fix the fractal flexible sensor on the top of the material to be tested, and connect the fractal flexible sensor to the signal processing module to obtain the thermophysical parameter device;

[0114] S2. Based on 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.

[0115] S3. Obtain the parameter set of the material to be tested based on its characteristics;

[0116] S4. Based on the thermophysical parameter device, turn on the power of the signal processing module and adjust the adjustable programmable resistor unit, the first resistor switch and the second resistor switch so that the voltage of the first differential amplifier and the voltage of the second differential amplifier are the same, and obtain the second harmonic voltage of the material under test and the amplified voltage of the adjustable programmable resistor unit.

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

[0118] 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, a nonlinear fitting method is used for iterative fitting to obtain the thermal physical parameters of the material to be measured.

[0119] The application provides a non-destructive measurement system and method for multiple thermal physical parameters based on harmonic signals, which comprises a fractal flexible sensor, a signal processing module and a data analysis module, adopts a test scheme of directly contacting the material to be measured by the fractal flexible sensor, corrects the radius based on the side length of the fractal flexible sensor, and obtains multiple thermal physical parameters of the material to be measured based on a multiple-layer thermal diffusion model, constructs a multiple-model integrated framework, solves the problem of single model, realizes the simultaneous non-destructive measurement of thermal conductivity, bulk heat capacity and contact thermal resistance between layers of the material, meets the fine requirement of the measurement technology of the product stacked by multiple layers of materials, enhances the anti-interference ability of the fractal flexible sensor for measuring uneven surfaces through the Peano curve design of the sensor unit, and suppresses the interference caused by bending deformation through the structural design of the fractal detection unit and the fractal heating unit, thereby improving the anti-interference ability of the system.

[0120] It can be understood that the application is described by the above embodiments, which should not be interpreted as limiting the embodiments and the scope of the application. Those skilled in the art can make various changes or equivalent replacements to the features and embodiments without departing from the spirit and scope of the application. In addition, the features and embodiments can be modified to adapt to specific conditions and materials without departing from the spirit and scope of the application. Therefore, the application is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the application are within the scope of the application.

Claims

1. A non-destructive measurement system of multiple thermophysical parameters based on harmonic signals, characterized in that, The system comprises: a fractal flexible sensor for adhering to the surface of a material to be measured, providing heat source excitation and collecting signals generated by the material to be measured during the response process; a signal processing module for providing heating current and bias signals for the fractal flexible sensor, receiving and processing signals collected by the fractal flexible sensor and sending them to a data analysis module; a data analysis module for obtaining thermal physical parameters of the material to be measured by iterative fitting using a nonlinear fitting method according to signal data of the signal processing module and the fractal flexible sensor, wherein the thermal physical parameters of the material to be measured include thermal conductivity of the material, volumetric heat capacity of the material and contact thermal resistance between materials; the fractal flexible sensor comprises: a sensor unit for providing heat source excitation and collecting signals generated by the material to be measured during the response process; an insulation protection unit for electrically insulating and physically protecting the sensor unit; the sensor unit comprises a current heating unit, a fractal detection unit and a connecting heating unit; the sensor unit adopts a Peano curve design, and the fractal detection unit is located between the current heating unit and the connecting heating unit; the thermal physical parameters of the material to be measured are obtained by: obtaining harmonic disturbance temperature peaks of the material to be measured by formula (1) according to signal data of the signal processing module, wherein: ΔT peak is the harmonic perturbation temperature peak of the material under test, U 2ω is the second harmonic voltage of the material under test, U DC is the amplification voltage of the programmable resistance unit, α CR is the resistance temperature coefficient of the fractal detection unit; obtaining heating power of the fractal flexible sensor and heat source radius corrected by side length of the fractal flexible sensor according to signal data of the signal processing module and the fractal flexible sensor; measuring multiple positions of the material to be measured within a set input angular frequency set of the signal processing module and obtaining thermal physical parameters of the material to be measured by iterative fitting using a nonlinear fitting method through formulas (2)-(6) according to the harmonic disturbance temperature peaks 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; K xz,j = K x,j / K z,j (1≤j≤n) (6) wherein n is the number of layers of material and protective film, wherein the 1st layer is a flexible insulating protective film, the 2nd layer to the nth layer is the material to be measured, P is the heating power of the fractal flexible sensor, κ j is the thermal conductivity of the jth layer, θ j is the iteration coefficient of the jth layer, c V,j is the volumetric heat capacity of the jth layer, b is the heat source radius of the fractal flexible sensor side length correction, ω is the angular frequency value of the input signal, κ z,j is the thermal conductivity of the jth layer z vertical position point, κ x,j is the thermal conductivity of the jth layer x horizontal position point, κ xz,j is the ratio of the thermal conductivity of the jth layer horizontal point x position and the thermal conductivity of the vertical point z position, R is the correction term of the inverse of the thermal penetration depth of the jth layer, R Cj,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 of the jth layer and the thermal penetration depth, d j is the thickness of the jth layer.

2. The non-invasive multi-thermal-property parameter measurement system based on harmonic signals according to claim 1, characterized in that, the current heating unit is used for connecting an alternating current source of the signal processing module to provide heat source excitation for the material to be measured; the fractal detection unit is used for collecting signals generated by the material to be measured during the response process; the connecting heating unit is used for providing a current loop for the current heating unit and providing heat source excitation for the material to be measured; the current heating unit and the connecting heating unit constitute a fractal heating unit; the insulation protection unit comprises a flexible insulation protection shell and a flexible insulation protection film.

3. The harmonic signal-based non-destructive measurement system of multiple thermal physical parameters according to claim 2, wherein: 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 are overlaid on both sides of the sensor unit from a direction perpendicular to the sensor unit.

4. The non-invasive multi-thermal-property parameter measurement system based on harmonic signals of claim 1, wherein, The length of the sensor unit is 70-140 mm, and the width is 10-100 μm.

5. The non-invasive multi-thermal-property parameter measurement system based on harmonic signals of claim 1, wherein, the signal processing module comprises: An alternating current source for providing an alternating current to the fractal flexible sensor to cause the fractal flexible sensor to generate a heat source; A direct current source for loading a bias current to a signal generated by the fractal flexible sensor; An amplification circuit unit for amplifying and processing the signal generated by the fractal flexible sensor; A signal acquisition unit for acquiring the signal processed by the amplification circuit unit and sending the signal to the data analysis module; An adjustable program-controlled resistance unit for adjusting a differential pressure of the amplification circuit unit; A power supply circuit unit for supplying power to the amplification circuit unit; A circuit connection unit for connecting the fractal flexible sensor.

6. The non-invasive multi-thermal-property parameter measurement system based on harmonic signals according to claim 5, characterized in that, The amplification circuit unit comprises: A first differential amplifier for amplifying the signal generated by the fractal flexible sensor; A second differential amplifier for amplifying a signal generated by the adjustable program-controlled resistance unit; A first resistance switch for adjusting an amplification factor of the first differential amplifier; A second resistance switch for adjusting an amplification factor of the second differential amplifier.

7. The non-invasive multi-thermal-property parameter system based on harmonic signals according to claim 6, characterized in that, The process of processing the signal acquired by the fractal flexible sensor comprises: Adjusting a gear position of the first resistance switch according to the signal acquired by the fractal flexible sensor and the first differential amplifier to obtain a second harmonic voltage of the material to be measured; Adjusting a gear position of the second resistance switch according to the adjustable program-controlled resistance unit and the second differential amplifier and comparing the gear position with the second harmonic voltage of the material to be measured to obtain an amplification voltage of the adjustable program-controlled resistance unit; Acquiring, by the signal acquisition unit, signal data of a signal processing module according to the second harmonic voltage of the material to be measured and the amplification voltage of the adjustable program-controlled resistance unit.

8. A method for non-destructive measurement of multiple thermophysical parameters based on harmonic signals, the method being implemented by the system for non-destructive measurement of multiple thermophysical parameters based on harmonic signals according to any one of claims 1 to 7, characterized in that, The method comprises: S1, fixing the fractal flexible sensor on a top of the material to be measured, and connecting the fractal flexible sensor with the signal processing module to obtain a thermal physical parameter device; S2, obtaining a heating power of the fractal flexible sensor and a heat source radius corrected by a side length of the fractal flexible sensor according to the signal processing module and the fractal flexible sensor; S3, obtaining a parameter set of the material to be measured according to a characteristic of the material to be measured; S4, turning on a power supply of the signal processing module and adjusting the adjustable program-controlled resistance unit, the first resistance switch and the second resistance switch according to the thermal physical parameter device, so that a voltage of the first differential amplifier is consistent with a voltage of the second differential amplifier, to obtain a second harmonic voltage of the material to be measured and an amplification voltage of the adjustable program-controlled resistance unit; S5, changing an input angular frequency of the signal processing module or a measurement position of the material to be measured, and repeating the previous step S4 to obtain a second harmonic voltage set of the material to be measured and an amplification voltage set of the adjustable program-controlled resistance unit; S6, using a nonlinear fitting method to iteratively fit 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 amplification voltage set of the adjustable program-controlled resistance unit to obtain thermal physical parameters of the material to be measured.

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