Alternating current impedance spectroscopy ceramic matrix composite material damage and temperature synchronous monitoring method

Abstract

The invention discloses an alternating current impedance spectroscopy ceramic matrix composite material damage and temperature synchronous monitoring method, which comprises the following steps of: firstly, verifying that real part resistance of a CMC (Carboxymethyl Cellulose) material responds to temperature and damage through a ceramic matrix composite material damage-electrical impedance response measurement and variable temperature electrical impedance response test method; and imaginary part reactance is only sensitive to structural damage, so that a data basis is provided for further providing a ceramic-based composite material damage and temperature state decoupling method based on the alternating-current impedance spectroscopy, synchronous identification of the structural temperature state and the damage state is realized only through single CMC electrical impedance response data, and the accuracy of the temperature state and the damage state is improved. The problem that an additional sensor needs to be installed when the health state of the structure is monitored through an electric signal is avoided, and the reliability of health monitoring of the CMC structure in a severe environment through alternating-current impedance response is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material health monitoring, and in particular relates to a method for synchronously monitoring damage and temperature of ceramic-based composite materials using an alternating current impedance spectrum. Background Art

[0002] Ceramic matrix composites (CMC) have excellent mechanical properties at high temperatures, corrosion resistance, and oxidation resistance, so they are increasingly widely used in hot-end components of aviation engines and ablation-resistant components of spacecraft. In order to ensure the reliable operation of such key components, regular inspection and maintenance are widely used and reliable means. For example, ultrasonic and X-ray computer scanning methods are used to detect the damage of CMC components when they are shut down or disassembled, and experts evaluate the maintenance plan or replace the components based on the test results. However, for CMC components that work at high temperatures, strong vibrations, and face the risk of foreign body impact for a long time, the existing regular inspection technology cannot provide real-time structural health monitoring during the operation of the equipment, resulting in potential structural failure risks. Current research has found that CMC has certain electrical conductivity, and there is a corresponding relationship between its damage degree and the overall electrical characteristics, making the use of the electrical characteristics of the CMC structure itself to achieve damage self-sensing a new structural health monitoring technology. Some scholars have used this characteristic and combined it with electrical impedance imaging technology to monitor CMC structural damage and temperature field (temperature measurement method of high-temperature components of ceramic-based composite materials based on electrical impedance imaging, CN110186583B; composite material strength prediction method based on electrical impedance imaging damage monitoring, CN109101742B).

[0003] However, the material components in CMC materials often have significant temperature resistance effect characteristics, and the resistivity of the material itself will change significantly with temperature changes. This leads to the fact that the electrical characteristics of the CMC structure are not only related to the damage condition, but also closely related to the ambient temperature. Existing methods can only independently measure the CMC damage condition and temperature under the condition of a single influencing factor, and cannot distinguish when the damage and temperature field exist at the same time, which is far from the actual needs. Temperature compensation through simulation will introduce large errors, and the arrangement of additional temperature sensors will significantly increase the complexity of the method on the one hand, and it is difficult to find sensing equipment that can work in such harsh environments on the other hand. In summary, the temperature resistance effect of CMC components significantly affects the realization and ultimate application of damage self-sensing technology using its own electrical characteristics.

[0004] Therefore, it is urgent to develop a method that can completely rely on the electrical response signal of the CMC structure to achieve real-time decoupling and monitoring of the CMC damage state and operating temperature, and solve the impact of the temperature resistance effect. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for synchronously monitoring damage and temperature of ceramic matrix composite materials by AC impedance spectroscopy in view of the above-mentioned existing deficiencies. The present invention can distinguish the temperature and damage state of ceramic matrix composite parts only by AC impedance response data.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0007] The method for synchronously monitoring damage and temperature of ceramic matrix composite materials by AC impedance spectroscopy comprises the following steps:

[0008] Step 1: According to the actual real-time temperature to be measured and the microstructure of the damaged CMC component, the electrical impedance response test specimen of its basic component unit structure is manufactured by the same process;

[0009] Step 2: Perform a constant temperature loading test on the electrical impedance response test sample under different temperature environments, measure the electrical impedance spectrum of the electrical impedance response test sample in real time during the loading process and record it, and obtain the electrical impedance spectrum data that changes with the increase of load under different constant temperature environments;

[0010] Step 3: Use a high temperature environment box to control the temperature of the electrical impedance response test sample, and obtain data on the change of the electrical impedance spectrum response curve of the electrical impedance response test sample under no load as the ambient temperature changes;

[0011] Step 4: decompose the obtained electrical impedance spectrum data that changes with the increase of load under different constant temperature environments into real resistance components and imaginary reactance components at different frequency points, normalize them based on the initial state, and superimpose the variation law of the real resistance component caused by temperature obtained by measurement without external load on the electrical impedance spectrum data that changes with the increase of load under different constant temperature environments, so as to form an electrical impedance spectrum data set with load and temperature conditions as variables;

[0012] Step 5: Prepare electrodes for AC impedance spectroscopy testing according to the actual real-time temperature to be measured and the structure of the damaged CMC component;

[0013] Step 6: Measure the impedance spectrum data of a brand new CMC component that has not been used at room temperature and under no-load conditions as a benchmark data set. The equipment parameters used in the impedance test are consistent with those in the benchmark data set test process.

[0014] Step 7, multiplying the electrical impedance spectrum data set obtained in step 4 with the load and temperature conditions as variables with the reference data set obtained in step 6 to obtain an impedance database matching the actual real-time temperature to be measured and the damaged CMC component;

[0015] Step 8. After the actual real-time temperature to be measured and the damaged CMC component are assembled to the working position, the electrical impedance spectrum data of the actual real-time temperature to be measured and the damaged CMC component are measured again, and compared with the data in step 6 to verify the reliability and structural integrity of the assembled electrode. There should be no obvious difference between the two.

[0016] Step 9: During the operation of the CMC component with the actual real-time temperature to be measured and the damage, the impedance analyzer is continuously used to measure the electrical impedance spectrum response using the same test parameters, or a representative frequency in the benchmark data set is selected to measure the electrical impedance response of the CMC component with the actual real-time temperature to be measured and the damage;

[0017] Step 10: Decompose the measured electrical impedance response data in the same way as in S4 to obtain resistance and reactance component values;

[0018] Step 11: according to the numerical value of the reactance component measured in step 10, the corresponding load / damage state is searched in the impedance database in step 7. A single reactance value may correspond to different load / damage states under multiple temperature conditions;

[0019] Step 12: Based on the different load / damage state points under multiple temperature conditions obtained in step 11, further find out the real resistance component sizes that may correspond to these load-temperature state points, make a judgment based on the resistance component values ​​obtained in step 10, and obtain the only state point that meets the requirements, and finally know the current temperature, load state and corresponding damage condition of the actual real-time temperature to be measured and the damaged CMC component.

[0020] To optimize the above technical solutions, the specific measures taken also include:

[0021] The method for synchronously monitoring damage and temperature of ceramic matrix composite materials by AC impedance spectroscopy is as follows: a high-temperature environmental chamber is used to heat the electrical impedance response test sample, and a tensile testing machine is used to apply a load to the electrical impedance response test sample. In step one, the method for preparing the electrical impedance response test sample is as follows: first, a CMC sample matching the length of the temperature-averaging section and the clamping length of the high-temperature environmental chamber is processed, a metal wire is bonded to the end of the CMC sample with conductive glue as an electrode, and a ceramic tube is bonded with a temperature-resistant epoxy resin glue in the clamping area at both ends of the CMC sample to provide protection and electrical insulation.

[0022] In step 1, the CMC sample is a CMC plate having the same weaving pattern as the actual CMC component to be tested for real-time temperature and damage, or a ceramic component having the same process and composition.

[0023] In step 2, the tensile testing machine clamps the two ends of the electrical impedance response test sample through two tensile testing machine chucks, and then applies a load. When the impedance analyzer tests the electrical impedance spectrum of the electrical impedance response test sample, the testing machine does not move to avoid the loading process affecting the measurement results.

[0024] In step three, the electrical impedance response test specimen is ensured not to suffer structural damage in the no-load variable temperature impedance test, so that the obtained electrical impedance parameters are only related to the temperature change.

[0025] In step 4, the electrical impedance spectrum data is decomposed into real resistance component and imaginary reactance component according to the following formula:

[0026]

[0027] Where Z' is the real resistance, Z" is the imaginary reactance, θ is the phase angle obtained by the impedance analyzer test, and |Z| is the impedance amplitude tested by the impedance analyzer.

[0028] In step 4, the specific method of superimposing the variation law of the real resistance component caused by temperature obtained under no external load on the impedance spectrum data that changes with the increase of load under different constant temperature environments is to use the temperature-impedance response data under no external load measured in step 3, and the ratio of the real component change with temperature obtained after decomposition of formula (1) as a reference, and perform proportional correction on the real response of the load / loss-impedance data in step 2 at the same temperature.

[0029] In step nine, the representative frequency is the frequency at which the CMC component changes most significantly with damage during the test.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The method for synchronously monitoring damage and temperature of ceramic-based composite materials using AC impedance spectroscopy provided by the present invention can decouple the damage and temperature states of ceramic-based composite materials, and realize the synchronous identification of the temperature state and damage state of the structure only through a single CMC electrical impedance response data, thereby avoiding the need to install additional sensors when using electrical signals to monitor the health state of the structure, and significantly improving the reliability of using AC impedance response to perform health monitoring on CMC structures in harsh environments.

[0032] 2. Steps 1 to 4 of the present invention provide a novel method for measuring damage-impedance response and testing temperature-dependent impedance response of ceramic-based composite materials, which realizes impedance response testing and data processing of ceramic-based composite materials samples during stretching under high-temperature environments, and provides a reference for other experimental tests on the impedance response of composite materials. The unit structure of ceramic-based composite materials is used as the test object, which reduces the number of tests, and the test method is clear, simple, and low-cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is an overall flow chart of the method for synchronously monitoring damage and temperature of ceramic-based composite materials using AC impedance spectroscopy of the present invention;

[0034] Figure 2 It is a schematic diagram of the damage-electrical impedance response measurement and temperature-dependent electrical impedance response test method of ceramic matrix composite materials;

[0035] Figure 3 This is the load / damage-electrical impedance response result diagram obtained from the test at typical frequencies at room temperature;

[0036] Figure 4 This is the load / damage-electrical impedance response result diagram obtained at a typical frequency of 600℃;

[0037] Figure 5 This is the test result diagram of temperature-electrical impedance response at typical frequencies from room temperature to 600°C;

[0038] Figure 6 It is a process diagram of using the AC impedance spectrum ceramic matrix composite material damage and temperature synchronous monitoring method of the present invention to perform damage and temperature identification on a ceramic matrix fiber bundle composite material.

[0039] The reference numerals in the figure are: ceramic tube 201, heat-resistant epoxy resin glue 202, conductive glue 203, metal wire 204, CMC sample 205, tensile testing machine chuck 206, high temperature environment box 207. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0041] Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0042] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0043] Unless otherwise defined, the technical terms or scientific terms involved in this application should be understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation, and may represent the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or units (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" / "several" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0044] See also Figure 1 The present invention discloses a method for synchronously monitoring damage and temperature of ceramic matrix composite materials using AC impedance spectroscopy, the method comprising the following steps:

[0045] Step 1: According to the microstructure of the CMC component to be tested, a representative unit structure with the same preparation process and component composition is selected to prepare a sample suitable for carrying out impedance response testing.

[0046] Step 2: According to the working environment temperature of the CMC component to be tested, firstly carry out a variable temperature no-load impedance response test in a high temperature vacuum environment box to verify whether the sample has a regular impedance response characteristic and make a record.

[0047] Step 3, further selecting the same temperature range as in step 2 on a tensile testing machine equipped with a high-temperature vacuum environment chamber, and conducting impedance response characteristics during tensile loading at different temperatures.

[0048] Step 4, decomposing the impedance response characteristic spectra obtained in step 2 and step 3 to obtain resistance and reactance data at different frequencies, and normalizing them based on the initial state to form an impedance database.

[0049] Step 5, prepare electrodes on the actual CMC component to be tested, and use the impedance spectrum data of the component under no-load condition as a reference, and superimpose it with the normalized impedance data in step 4 to form an impedance database matching the actual component.

[0050] In step 6, during actual operation, the impedance response of the CMC component is measured in real time and decomposed using the same method as in step 4.

[0051] Step 7: Search the impedance database obtained in step 5 according to the imaginary reactance data obtained by decomposition to obtain all possible temperatures and load states of the current component.

[0052] Step 8, further based on the real resistance data obtained by decomposition, from all the real resistances corresponding to the component temperature and load state obtained in step 7, the only matching ambient temperature and corresponding load state are screened out to complete the decoupling of load and temperature.

[0053] The key to the present invention is that, firstly, a ceramic matrix composite material damage-electrical impedance response measurement and temperature-dependent electrical impedance response test method is used to verify that the real resistance of the CMC material responds to both temperature and damage, while the imaginary reactance is only sensitive to structural damage, thereby providing a data basis for a further proposed method of decoupling damage and temperature states of ceramic matrix composite materials based on AC impedance spectroscopy.

[0054] Ceramic-based fiber bundle composites were used as test objects, combined with Figure 2-6 , the method of the present invention is further introduced.

[0055] A method for measuring damage-impedance response of ceramic matrix composite materials and testing temperature-dependent impedance response is provided, which is used to obtain a benchmark damage-impedance response and temperature-impedance response data set, corresponding to steps 1-4.

[0056] S1. According to the final need, the CMC damage and temperature decoupling method based on AC impedance spectroscopy is used to perform real-time temperature and damage monitoring in the structural microscopic form, and the electrical impedance response test specimen of its basic component unit structure is made. The ceramic-based fiber bundle composite material is the most basic CMC component structure, so the ceramic-based fiber bundle composite material is directly selected for sample preparation. The sample structure and size are as follows: Figure 2 , the length numbers in the figure are in mm;

[0057] S2, such as Figure 2 As shown, a tensile testing machine equipped with a high-temperature environment box is used to carry out loading tests on the specimens under different temperature environments. During the loading process, an impedance analyzer is used to measure and record the electrical impedance response spectrum in real time, and the electrical impedance spectrum data that changes with the load under different temperature conditions is obtained;

[0058] S3, such as Figure 2 As shown, a high temperature environment box is used to control the sample temperature, and an impedance analyzer is used to test the data of the electrical impedance spectrum response curve of the sample under unconstrained conditions as the ambient temperature changes;

[0059] S4. Decompose the acquired impedance spectrum data into real resistance component and imaginary inductive reactance component at different frequency points, perform normalization processing with the initial state, and superimpose the change of real resistance component caused by temperature on the impedance spectrum data that changes with load under different temperature environments to form an impedance spectrum data set with load and temperature conditions as variables.

[0060] like Figure 2 As shown, the sample preparation method in S1 is to first process a suitable CMC sample according to the temperature equalization section length and clamping length of the high-temperature environmental box 207. The temperature equalization section length of the high-temperature environmental box used is 20mm, the furnace body height is 40mm, and the clamping length is reserved at both ends for 20mm each. The fixture is separated from the high-temperature furnace body by a 20mm spacing for heat insulation, so the length of the processed sample is 120mm. After processing, the metal wire 204 is bonded to the two ends using conductive glue 203 to prepare electrodes, and the ceramic tube 201 is further bonded to the clamping area at both ends using heat-resistant epoxy resin glue 202 for reinforcement and insulation.

[0061] Furthermore, before making the electrode, samples of the same geometric dimensions should be selected, and conductive glue should be coated on the electrode preparation area. After curing, an impedance analyzer should be used to directly connect the conductive glue area for testing, and the test data should be compared after bonding the metal wires to see if there are any differences, so as to avoid interference of the wires on the test results.

[0062] Furthermore, in S2, the loading of the test machine should be suspended according to the test speed of the impedance analyzer to ensure that the test machine is not moving during the test.

[0063] Furthermore, the ambient temperature range used in this example is from room temperature to 600° C., and the impedance measurement is performed at intervals of 100° C.

[0064] Furthermore, the impedance test frequency range used in this example is 10 Hz-5 MHz.

[0065] Furthermore, in the no-load temperature-varying impedance test in S3, the sample should not have any structural damage, so the electrical impedance parameters obtained at this time are only related to the temperature change.

[0066] Furthermore, the impedance spectrum data decomposition in S4 is performed according to the following formula:

[0067]

[0068] Where Z' is the real resistance, Z" is the imaginary reactance, θ is the phase angle obtained by the impedance analyzer test, and |Z| is the impedance amplitude tested by the impedance analyzer.

[0069] Furthermore, the normalized test data results in S4 at a typical frequency (2.5 MHz) are as follows: Figure 3 , Figure 4 and Figure 5 As shown in the figure, it can be seen that during the variable temperature no-load impedance test, the imaginary reactance does not change with the ambient temperature, and the real resistance decreases with the increase of temperature. During the constant temperature loading test, the real resistance increases with the increase of load, and the imaginary resistance decreases with the increase of load.

[0070] Further, according to Figure 5 As a result, the real resistance effect caused by temperature change is added to the normalized Figure 3 and Figure 4 The impedance spectrum data shown in Figure 1 shows the impedance spectrum data of the load. For example, based on room temperature, Figure 3 The room temperature load-impedance response is shown without correction. Figure 5 The real impedance of the sample shown will decrease by 5.5% at 600℃ compared to room temperature. Figure 4 The load-impedance response shown at 600°C should drop by 5.5% overall to compensate for the effect of temperature change.

[0071] Combination Figure 6 , a method for decoupling damage and temperature state of ceramic matrix composites based on AC impedance spectroscopy is introduced:

[0072] S5. According to the structural form of the component that needs to use the CMC damage and temperature decoupling method based on AC impedance spectroscopy for real-time temperature and damage monitoring, electrodes are prepared at appropriate positions for impedance spectroscopy testing. The electrode preparation method in this example is the same as S1.

[0073] S6. Measure the impedance spectrum data of new components that have not been used at room temperature (25 degrees Celsius) and under no-load conditions as the benchmark data. The equipment parameters used in the impedance test should be consistent with those in the benchmark data set test process;

[0074] S7, after the specimen is assembled to the normal working position, the electrical impedance spectrum data is measured again and compared with the S6 data to verify the reliability and structural integrity of the electrode after assembly. There should be no significant difference between the two. In this example, it is when clamped to the tensile testing machine;

[0075] S8. During the stretching process of the component, the impedance analyzer is continuously used to measure the electrical impedance spectrum response using the same test parameters, or a representative frequency in the benchmark data set is selected to measure the electrical impedance response of the component. In this example, a frequency of 2.5 MHz is selected;

[0076] S9, decomposing the measured electrical impedance response data in the same manner as in S4 to obtain real-time resistance and reactance component values;

[0077] S10, according to the numerical value of the reactance component measured by S9, searching for the corresponding load state in the load-impedance spectrum data set under different temperature environments in the reference impedance spectrum data set. Figure 6 As shown, in this example, the search is performed at two temperature points, room temperature and 600°C, and the corresponding impedance state may correspond to a 96% fracture stress ratio state at room temperature, or a 90% fracture stress ratio state at 600°C.

[0078] According to the different load state points under different temperature conditions obtained by S10, the real resistance component values ​​corresponding to these state points are further found in the database. Figure 6 As shown, in this example, the real resistance change rate corresponding to the 96% fracture stress state at room temperature should be 5.5%, while the real resistance change rate corresponding to the 90% stress state at 600°C should be 0.13%. By judging based on the resistance component change rate obtained by S9, the current temperature, load state and corresponding damage condition can be finally known.

[0079] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A method for synchronously monitoring damage and temperature of ceramic matrix composite materials using AC impedance spectroscopy, characterized in that: The following steps are involved: Step 1: According to the actual real-time temperature to be measured and the microstructure of the damaged CMC component, the electrical impedance response test specimen of its basic component unit structure is manufactured by the same process; Step 2: Perform a constant temperature loading test on the electrical impedance response test sample under different temperature environments, measure the electrical impedance spectrum of the electrical impedance response test sample in real time during the loading process and record it, and obtain the electrical impedance spectrum data that changes with the increase of load under different constant temperature environments; Step 3: Use a high temperature environment box to control the temperature of the electrical impedance response test sample, and obtain data on the change of the electrical impedance spectrum response curve of the electrical impedance response test sample under no load as the ambient temperature changes; Step 4: decompose the obtained electrical impedance spectrum data that changes with the increase of load under different constant temperature environments into real resistance components and imaginary reactance components at different frequency points, normalize them based on the initial state, and superimpose the variation law of the real resistance component caused by temperature obtained by measurement without external load on the electrical impedance spectrum data that changes with the increase of load under different constant temperature environments, so as to form an electrical impedance spectrum data set with load and temperature conditions as variables; Step 5: Prepare electrodes for AC impedance spectroscopy testing according to the actual real-time temperature to be measured and the structure of the damaged CMC component; Step 6: Measure the impedance spectrum data of a brand new CMC component that has not been used at room temperature and under no-load conditions as a benchmark data set. The equipment parameters used in the impedance test are consistent with those in the benchmark data set test process. Step 7, multiplying the electrical impedance spectrum data set obtained in step 4 with the load and temperature conditions as variables with the reference data set obtained in step 6 to obtain an impedance database matching the actual real-time temperature to be measured and the damaged CMC component; Step 8. After the actual real-time temperature to be measured and the damaged CMC component are assembled to the working position, the electrical impedance spectrum data of the actual real-time temperature to be measured and the damaged CMC component are measured again, and compared with the data in step 6 to verify the reliability and structural integrity of the assembled electrode. There should be no obvious difference between the two. Step 9: During the operation of the CMC component with the actual real-time temperature to be measured and the damage, the impedance analyzer is continuously used to measure the electrical impedance spectrum response using the same test parameters, or a representative frequency in the benchmark data set is selected to measure the electrical impedance response of the CMC component with the actual real-time temperature to be measured and the damage; Step 10: Decompose the measured electrical impedance response data in the same way as in S4 to obtain resistance and reactance component values; Step 11: according to the numerical value of the reactance component measured in step 10, the corresponding load / damage state is searched in the impedance database in step 7. A single reactance value may correspond to different load / damage states under multiple temperature conditions; Step 12: Based on the different load / damage state points under multiple temperature conditions obtained in step 11, further find out the real resistance component sizes that may correspond to these load-temperature state points, make a judgment based on the resistance component values ​​obtained in step 10, and obtain the only state point that meets the requirements, and finally know the current temperature, load state and corresponding damage condition of the actual real-time temperature to be measured and the damaged CMC component.

2. The method for synchronously monitoring damage and temperature of ceramic matrix composite materials by AC impedance spectroscopy according to claim 1, characterized in that: A high temperature environment box (207) is used to heat the electrical impedance response test sample, and a tensile testing machine is used to apply a load to the electrical impedance response test sample. In step 1, the method for preparing the electrical impedance response test sample is as follows: first, a CMC sample (205) matching the length of the temperature equalization section and the clamping length of the high temperature environment box (207) is processed, a metal wire (204) is bonded to the end of the CMC sample (205) using a conductive glue (203) as an electrode, and a ceramic tube (201) is bonded to the clamping area at both ends of the CMC sample (205) using a heat-resistant epoxy resin glue (202) to provide protection and electrical insulation.

3. The method for synchronously monitoring damage and temperature of ceramic matrix composite materials by AC impedance spectroscopy according to claim 2, characterized in that: In step 1, the CMC sample (205) is a CMC plate having the same weaving pattern as the CMC component whose real-time temperature and damage are to be measured, or a ceramic component having the same process and composition.

4. The method for synchronously monitoring damage and temperature of ceramic matrix composite materials by AC impedance spectroscopy according to claim 2, characterized in that: In step 2, the tensile testing machine clamps the two ends of the electrical impedance response test sample respectively through two tensile testing machine chucks (206), and then applies a load. When the impedance analyzer tests the electrical impedance spectrum of the electrical impedance response test sample, the testing machine does not move to avoid the loading process affecting the measurement result.

5. The method for synchronously monitoring damage and temperature of ceramic matrix composite materials by AC impedance spectroscopy according to claim 1, characterized in that: In step three, the electrical impedance response test specimen is ensured not to suffer structural damage in the no-load variable temperature impedance test, so that the obtained electrical impedance parameters are only related to the temperature change.

6. The method for synchronously monitoring damage and temperature of ceramic matrix composite materials by AC impedance spectroscopy according to claim 1, characterized in that: In step 4, the electrical impedance spectrum data is decomposed into real resistance component and imaginary reactance component according to the following formula: Where Z' is the real resistance, Z" is the imaginary reactance, θ is the phase angle obtained by the impedance analyzer test, and |Z| is the impedance amplitude tested by the impedance analyzer.

7. The method for synchronously monitoring damage and temperature of ceramic matrix composite materials by AC impedance spectroscopy according to claim 6, characterized in that: In step 4, the specific method of superimposing the variation law of the real resistance component caused by temperature obtained under no external load on the impedance spectrum data that changes with the increase of load under different constant temperature environments is to use the temperature-impedance response data under no external load measured in step 3, and the ratio of the real component change with temperature obtained after decomposition of formula (1) as a reference, and perform proportional correction on the real response of the load / loss-impedance data in step 2 at the same temperature.

8. The method for synchronously monitoring damage and temperature of ceramic matrix composite materials by AC impedance spectroscopy according to claim 1, characterized in that: In step nine, the representative frequency is the frequency at which the CMC component changes most significantly with damage during the test.

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