Thermogravimetric Testing Methods for Resin-Based Composite Materials Used in Aero-Engine Components
By extracting the operating state points of aero-engine components, simplifying and merging state points with temperature differences less than a predetermined value, and conducting temperature gradient grouping tests, the problems of low reference value and long cycle of test results in existing technologies are solved, thereby achieving accuracy of test results and shortening the cycle, and mastering the laws of material thermal aging performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- AECC SHENYANG ENGINE RES INST
- Filing Date
- 2026-03-20
- Publication Date
- 2026-05-26
AI Technical Summary
Existing thermal aging test methods for resin-based composite materials cannot accurately reflect the actual working condition of aero-engine components, resulting in low reference value of test results, long test cycles, and high costs.
By extracting the operating state points of aero-engine components, simplifying and merging state points with temperature differences less than a predetermined value, conducting thermal aging weight loss tests based on statistical results, using temperature gradient grouping and step-by-step testing, judging the thermal weight loss trend and performance degradation of materials, determining the temperature threshold, and cumulatively calculating the thermal weight loss rate.
This approach ensures the accuracy and operability of test results, shortens the test cycle, rapidly obtains the thermal weight loss rate of materials during the engine's lifespan, helps to understand the thermal aging performance of materials, and saves time and costs.
Smart Images
Figure CN122084448A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of composite material testing, and specifically relates to a method for thermogravimetric testing of resin-based composite materials for aero-engine components. Background Technology
[0002] Due to their excellent mechanical properties and weight advantages, composite materials are being used more and more in aero engines. However, aero engine components have strict temperature resistance requirements, which is a limiting factor for the widespread application of resin-based composite materials in engines. In other words, temperature resistance is an extremely important factor when selecting composite materials.
[0003] Unlike metallic materials, resin-based composite materials undergo physical or chemical changes in their components under long-term high-temperature operation, leading to performance degradation. Furthermore, the performance degradation varies significantly among different resins operating in different environments. Aero-engine components are characterized by long structural lifespans, high operating temperatures, and variable conditions, while also requiring extremely high safety and reliability. Performance degradation of composite material components during use poses safety hazards after long-term operation. Therefore, research on performance degradation of composite material components for aero-engines is necessary.
[0004] Currently, in the performance degradation test of resin-based composite materials, the main method is to place the composite material specimens under a certain high temperature condition and conduct a thermal aging test over time to obtain the weight loss rate of the composite material specimens.
[0005] Because the performance degradation of different resin-based composite materials varies significantly with changes in thermal aging time and temperature, test conditions directly affect the performance degradation results. Therefore, targeted thermal aging tests are needed for different materials and actual usage environments. Currently, the thermal aging test conditions for composite material specimens are relatively crude, i.e., a given empirical high-temperature environment is provided, and the weight loss rate of the material is monitored over time. The test temperature and time are unrelated to the operating state of the engine components. Therefore, existing thermal aging weight loss test methods and results have extremely low reference value for engine component use.
[0006] Aero-engines operate under numerous conditions, with components experiencing fluctuating operating environments and their operating time determined by flight mission requirements. Currently, there is a lack of research on selecting appropriate thermal aging conditions for engine components; that is, there are no directly applicable test conditions or methods for extracting these conditions. Aero-engine components have long design lives, and the thermal aging performance degradation of composite materials accumulates over time. Using conventional testing methods to conduct tests under actual engine operating conditions results in very long testing cycles—at least 120 days if considering the specific usage requirements of engine components. This makes implementation difficult and time-consuming. Summary of the Invention
[0007] The purpose of this application is to provide a method for thermogravimetric testing of resin-based composite materials for aero-engine components, in order to solve or mitigate at least one of the problems in the prior art.
[0008] The technical solution of this application is: a method for testing the thermogravimetric loss of resin-based composite materials for aero-engine components, including:
[0009] Step S1: Extract the operating status points of the aero-engine components;
[0010] Step S2: Simplify the operating state points of the aero-engine components;
[0011] Step S3: Based on the simplified operating state points of the aero-engine components, determine the statistical results of the component operating temperature and operating time for the thermal aging weightlessness test;
[0012] Step S4: Conduct a preliminary thermal aging weight loss test based on the statistical results of the component's operating temperature and operating time;
[0013] Step S5: Based on the results of the thermal aging weight loss test in Step S4, determine the trend of thermal weight loss of the test piece under the test conditions in Step S4, and determine the direction of carrying out the thermal weight loss test with temperature gradient.
[0014] Step S6: Determine the temperature threshold for thermal aging weight loss based on the temperature gradient thermogravimetric test results in step S5.
[0015] Step S7: The cumulative thermal weight loss rate at each operating temperature above the cumulative temperature threshold is obtained, thereby obtaining the cumulative thermal weight loss rate of the composite material used in the aero-engine components throughout the engine's entire lifespan.
[0016] Step S8: The new test piece is subjected to thermal aging accelerated to the state of cumulative thermal weight loss obtained in step S7. The mechanical properties of the test piece after thermal weight loss are tested based on the performance judgment index, which is the final performance loss result of the composite material component in the complete working state.
[0017] In at least one embodiment of this application, step S1, the process of extracting the operating state points of the aero-engine components, includes:
[0018] The operating time of the aero-engine at the corresponding Mach number is determined based on the aircraft mission profile and mission spectrum of the aero-engine.
[0019] The operating temperature of aero-engine components under various operating conditions is determined based on the overall performance of the aero-engine.
[0020] By combining the operating altitude and Mach number of the aero-engine with the operating time of the aero-engine components under each operating condition, and the operating temperature of the aero-engine components under each operating condition, the operating temperature and corresponding operating time of the aero-engine components are obtained, thus forming the operating state point of the aero-engine.
[0021] In at least one embodiment of this application, step S2, the process of simplifying the operating state points of the aero-engine components, includes:
[0022] Multiple consecutive operating points of the aero-engine with a temperature difference less than a predetermined temperature difference are merged, and the operating time is calculated based on the operating point with the highest temperature.
[0023] In at least one embodiment of this application, step S3, the process of determining the statistical results of the component operating temperature and operating time for the thermal aging weightlessness test based on the simplified operating state point of the aero-engine component, includes:
[0024] The working time of multiple simplified working state points is accumulated and merged using a temperature step with a predetermined temperature difference. The highest temperature and the accumulated working time within the accumulated and merged temperature step are the statistical results of the component's working temperature and working time used for thermal aging weight loss test.
[0025] In at least one embodiment of this application, step S4, the process of conducting a preliminary thermal aging weight loss test based on the statistical results of the component's operating temperature and operating time, is as follows:
[0026] Based on the statistical results of the component's operating temperature and operating time, the longest operating time of the component and its corresponding operating temperature, and the highest operating temperature and its corresponding operating time are determined.
[0027] Two sets of test pieces were placed in a thermogravimetric oven, and two initial thermogravimetric tests were carried out at the working temperature corresponding to the longest working time and the highest working temperature, respectively. The weight was recorded at regular intervals until the working time required by the corresponding test conditions was reached.
[0028] In at least one embodiment of this application, step S5, which involves determining the thermal weight loss trend of the test specimen under the test conditions of step S4 based on the results of the thermogravimetric test in step S4, and determining the direction for conducting the thermogravimetric test using a temperature gradient, is as follows:
[0029] a) If, under low-temperature test conditions, the thermal weight loss and mechanical property degradation of the material do not exceed the predetermined values and the performance does not deteriorate over time, then the thermal weight loss test will not be carried out below the operating temperature, but will be transitioned to high-temperature conditions and the thermal weight loss test will continue.
[0030] b) If both groups of test pieces show significant thermal weight loss and mechanical property degradation, then take the low temperature condition as the benchmark, select several test conditions in the low temperature direction, and continue to carry out thermal aging weight loss tests in groups.
[0031] In at least one embodiment of this application, the process of determining the thermal aging weight loss temperature threshold based on the results of the temperature gradient thermal aging weight loss test in step S5 is as follows:
[0032] a) Compile thermal aging weight loss result curves for each temperature gradient. Based on the curves, if the weight loss rate of the test piece is lower than the threshold and the weight of the test piece does not change with the cumulative increase over time at a certain temperature, then that temperature is the temperature threshold for thermal aging weight loss.
[0033] b) If the above temperature threshold is not reached, continue to select a lower temperature condition to carry out the thermal aging weight loss test until the temperature threshold of the thermal aging weight loss test is obtained.
[0034] In at least one embodiment of this application, the actual ply of an aero-engine component is used as the ply structure of the test specimen, and four performance parameters—transverse tension, longitudinal compression, longitudinal bending, and interlaminar shear—are used as performance evaluation indicators for the thermogravimetric test.
[0035] The thermogravimetric testing method for high-temperature resistant resin-based composite materials for aero-engine components proposed in this application has the following advantages:
[0036] 1) The method of this application can serve as an operable or feasible test condition for the thermal aging weight loss test of the composite material of the engine component, ensuring the accuracy of the test results;
[0037] 2) Based on the given working temperature-time test conditions, this application can conduct thermal aging weight loss test method according to temperature gradient grouping, step-by-step test-step analysis, to obtain the temperature threshold of the material's temperature resistance performance, and can screen out a part of the temperature range that does not need to be carried out thermal weight loss test, while mastering the law of thermal aging weight loss performance of materials in the working state of engine components.
[0038] 3) The test method of this application effectively shortens the time cycle of thermal aging weight loss test of composite materials for long-life components of aero-engines by accumulating the results of grouped tests, and quickly obtains the thermal weight loss rate of materials within the design life of the engine, thus effectively shortening the test cycle. Attached Figure Description
[0039] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.
[0040] Figure 1 This is a schematic diagram of the thermogravimetric testing method of this application.
[0041] Figure 2 This is a partial cross-sectional view of an aircraft for use with an engine, according to an embodiment of this application.
[0042] Figure 3 This is a schematic diagram of the component's operating temperature and operating time according to an embodiment of this application.
[0043] Figure 4 This is a schematic diagram of the thermal aging weight loss curve of a test specimen according to an embodiment of this application. Detailed Implementation
[0044] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.
[0045] Based on the working tasks of the engine, this application designs a thermal aging weight loss test method for composite material specimens suitable for the working environment of aero-engines. This method simplifies the test requirements, saves costs and time, and can accurately reflect the degradation of the thermal aging performance of engine components.
[0046] like Figure 1 As shown, the thermogravimetric testing method for resin-based composite materials used in aero-engine components provided in this application includes the following steps:
[0047] Step S1: Extract the operating status points of the aero-engine components.
[0048] This application uses the mission spectrum of aircraft equipped with aero engines, in order to Figure 2 Taking the partial mission profile shown as an example, the operating time corresponding to the operating altitude H and Mach number M of the aero-engine is determined. Based on the overall performance of the aero-engine, the cross-sectional temperature parameters of the components under each operating state are determined, as shown in Table 1. By comparing the engine's mission profile with the aforementioned cross-sectional temperature parameters, the operating temperatures (T0, T1, T2…Tn) and corresponding operating times of the components in the complete mission spectrum are determined. Figure 3 As shown, the operating temperature and its corresponding operating time are the operating state points of the aero-engine.
[0049] Table 1 Calculation parameters of cross-sectional performance of engine research components
[0050]
[0051] Step S2: Simplify the working status of aircraft engine components.
[0052] Since there are many working mission profiles and mission segments of the engine, it is necessary to simplify the working state points of the aero-engine. In this application, multiple consecutive state points with a temperature difference less than a predetermined temperature difference in the working state points of the aero-engine are merged, and the working time is counted according to the working state point with the highest temperature, thus simplifying the data statistics.
[0053] In this application, the predetermined temperature difference is set to 10°C.
[0054] like Figure 3 In the dashed box portion of the illustrated embodiment, the temperature difference between multiple consecutive state points within the dashed box is less than 10°C. Therefore, in this application, the temperature of the highest temperature state point among the merged consecutive state points is used as the temperature of the merged state point, and the time period occupied by the dashed box is used as the working time represented by the merged working state point.
[0055] Step S3: Determine the operating temperature and operating time of the simplified operating state point of the aero-engine components.
[0056] The engine's operating state points involve numerous repetitive processes. Based on the statistical results of temperature versus operating time, the operating times of multiple simplified operating state points are accumulated and merged using a temperature step with a predetermined temperature difference (e.g., 10°C). The highest temperature within the temperature range and the accumulated operating time are used as the statistical results of the component's operating temperature and operating time during the test, as shown in Table 2.
[0057] Table 2 Statistical Results of Component Operating Temperature-Time
[0058]
[0059] Step S4: Conduct a preliminary thermal aging weight loss test based on the statistical results of the component's operating temperature and operating time.
[0060] Based on the statistical results of working temperature-working time in Table 2, the longest working time and its corresponding working temperature (e.g., condition n2 in Table 2) and the highest working temperature and its corresponding working time (e.g., condition nn in Table 2) of the component are determined as the test conditions for the two initial sets of thermal aging weight loss tests.
[0061] The two sets of test pieces were placed in a thermogravimetric oven and set to the working temperature (temperature of condition n2) corresponding to the longest working time and the highest working temperature (temperature of condition nn) respectively. The weight was recorded at regular intervals (e.g., 24 hours) until the time required by the corresponding test conditions was reached.
[0062] Step S5: Based on the thermogravimetric test results of step S4, determine the thermogravimetric trend of the test piece under the test conditions of step S4, and determine the direction of carrying out thermogravimetric tests with temperature gradient.
[0063] a) If the thermal weight loss and mechanical property degradation of the material are extremely low (e.g., not exceeding 5%) under low temperature test conditions, and the performance does not deteriorate over time, then the thermal weight loss test will not be carried out below the operating temperature, but will be carried out under high temperature conditions.
[0064] b) If both test results show significant thermal weight loss and mechanical property degradation, then take the low temperature condition as the benchmark, select several test conditions in the low temperature direction (e.g., conditions n1…m6, m3, etc.), and continue to carry out thermal aging weight loss tests in groups.
[0065] Step S6: Determine the thermal aging weight loss temperature threshold based on the temperature gradient thermal aging weight loss test results from step S5. The process includes:
[0066] a) Compile the thermal aging weight loss result curve of step S5 test, such as Figure 4 As shown, the curve reveals that at a certain temperature, the weight loss rate of the test piece is extremely low, and the weight of the test piece remains essentially unchanged over time. This indicates that at this temperature and below, the material's performance loss remains essentially constant, and the performance loss is extremely low. This temperature (i.e., ...) Figure 3 The temperature corresponding to the curve with the higher temperature among the multiple basic level curves, such as the temperature tm6 corresponding to condition m6, is the temperature threshold of the test. The test will not continue under the low temperature conditions below it, i.e., conditions m5 to m1 in Table 1.
[0067] b) If the above temperature threshold is not met, continue to select a lower temperature condition to carry out the thermal aging weight loss test until the temperature threshold of the thermal aging weight loss test is obtained. Eliminate the temperature conditions that do not need to be carried out thermal aging weight loss test. The temperature below this temperature threshold is the safe operating temperature of the component.
[0068] Step S7: The cumulative thermal weight loss rate at each operating temperature above the cumulative temperature threshold is obtained, thereby obtaining the cumulative thermal weight loss rate of the composite material used in the aero-engine components throughout the engine's entire lifespan.
[0069] Above the temperature threshold, the thermal weight loss and mechanical properties of the material increase over time. The test results at each operating temperature are accumulated to obtain the cumulative thermal weight loss rate p of the composite material used in this component over the entire lifespan of the engine, as shown in Table 3.
[0070] Table 3. Weight loss rate results during the material life of the component
[0071]
[0072] Step S8, Material mechanical property degradation test.
[0073] Using the component's highest operating temperature, a set of new test specimens are directly subjected to accelerated thermal aging to the state of cumulative thermal weight loss obtained in step S7. The mechanical properties of the test specimens after thermal weight loss are tested according to the performance evaluation index of the thermal weight loss test, which is the final performance loss result of the composite material under the complete operating state of the engine component. The cumulative loss rate of thermal aging performance is used as the reduction rate of the design margin to determine whether the material performance loss meets the usage requirements of the engine component.
[0074] High-temperature resistant resin-based composite materials are high-performance materials with a temperature resistance range of approximately 200~450℃. Certain components in aero-engine structures—such as fan casings, air intakes, or fairings—are manufactured using high-temperature resistant resin-based composite materials. Therefore, this application uses the actual plywood of an aero-engine component as the plywood structure of the test specimen, and employs four performance parameters—transverse tensile, longitudinal compression, longitudinal bending, and interlaminar shear—which are closely related to the load-bearing form of the aero-engine component, as performance evaluation indicators for the thermogravimetric test.
[0075] The thermogravimetric testing method for high-temperature resistant resin-based composite materials for aero-engine components proposed in this application has the following advantages:
[0076] 1) The method of this application can serve as an operable or feasible test condition for the thermal aging weight loss test of the composite material of the engine component, ensuring the accuracy of the test results;
[0077] 2) Based on the given working temperature-time test conditions, this application can conduct thermal aging weight loss test method according to temperature gradient grouping, step-by-step test-step analysis, to obtain the temperature threshold of the material's temperature resistance performance, and can screen out a part of the temperature range that does not need to be carried out thermal weight loss test, while mastering the law of thermal aging weight loss performance of materials in the working state of engine components.
[0078] 3) The test method of this application effectively shortens the time cycle of thermal aging weight loss test of composite materials for long-life components of aero-engines by accumulating the results of grouped tests, and quickly obtains the thermal weight loss rate of materials within the design life of the engine, thus effectively shortening the test cycle.
[0079] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A method for thermogravimetric testing of resin-based composite materials for aero-engine components, characterized in that, include: Step S1: Extract the operating status points of the aero-engine components; Step S2: Simplify the operating state points of the aero-engine components; Step S3: Based on the simplified operating state points of the aero-engine components, determine the statistical results of the component operating temperature and operating time for the thermal aging weightlessness test; Step S4: Conduct a preliminary thermal aging weight loss test based on the statistical results of the component's operating temperature and operating time; Step S5: Based on the results of the thermal aging weight loss test in Step S4, determine the trend of thermal weight loss of the test piece under the test conditions in Step S4, and determine the direction of carrying out the thermal weight loss test with temperature gradient. Step S6: Determine the temperature threshold for thermal aging weight loss based on the temperature gradient thermogravimetric test results in step S5. Step S7: The cumulative thermal weight loss rate at each operating temperature above the cumulative temperature threshold is obtained, thereby obtaining the cumulative thermal weight loss rate of the composite material used in the aero-engine components throughout the engine's entire lifespan. Step S8: The new test piece is subjected to thermal aging accelerated to the state of cumulative thermal weight loss obtained in step S7. The mechanical properties of the test piece after thermal weight loss are tested based on the performance judgment index, which is the final performance loss result of the composite material component in the complete working state.
2. The method for thermogravimetric testing of resin-based composite materials for aero-engine components as described in claim 1, characterized in that, Step S1, the process of extracting the operating state points of aero-engine components, includes: The operating time of the aero-engine at the corresponding Mach number is determined based on the aircraft mission profile and mission spectrum of the aero-engine. The operating temperature of aero-engine components under various operating conditions is determined based on the overall performance of the aero-engine. By combining the operating altitude and Mach number of the aero-engine with the operating time of the aero-engine components under each operating condition, and the operating temperature of the aero-engine components under each operating condition, the operating temperature and corresponding operating time of the aero-engine components are obtained, thus forming the operating state point of the aero-engine.
3. The method for thermogravimetric testing of resin-based composite materials for aero-engine components as described in claim 2, characterized in that, Step S2, the process of simplifying the operating state points of aero-engine components, includes: Multiple consecutive operating points of the aero-engine with a temperature difference less than a predetermined temperature difference are merged, and the operating time is calculated based on the operating point with the highest temperature.
4. The thermogravimetric testing method for resin-based composite materials used in aero-engine components as described in claim 3, characterized in that, Step S3, the process of determining the statistical results of the component operating temperature and operating time for the thermal aging weightlessness test based on the simplified operating state point of the aero-engine component, includes: The working time of multiple simplified working state points is accumulated and merged using a temperature step with a predetermined temperature difference. The highest temperature and the accumulated working time within the accumulated and merged temperature step are the statistical results of the component's working temperature and working time used for thermal aging weight loss test.
5. The method for thermogravimetric testing of resin-based composite materials for aero-engine components as described in claim 4, characterized in that, Step S4, the process of conducting a preliminary thermal aging weight loss test based on the statistical results of the component's operating temperature and operating time, is as follows: Based on the statistical results of the component's operating temperature and operating time, the longest operating time of the component and its corresponding operating temperature, and the highest operating temperature and its corresponding operating time are determined. Two sets of test pieces were placed in a thermogravimetric oven, and two initial thermogravimetric tests were carried out at the working temperature corresponding to the longest working time and the highest working temperature, respectively. The weight was recorded at regular intervals until the working time required by the corresponding test conditions was reached.
6. The method for thermogravimetric testing of resin-based composite materials for aero-engine components as described in claim 5, characterized in that, Step S5, based on the thermogravimetric test results of step S4, determines the thermogravimetric trend of the test specimen under the test conditions of step S4, and determines the direction of conducting thermogravimetric tests based on temperature gradients. a) If, under low-temperature test conditions, the thermal weight loss and mechanical property degradation of the material do not exceed the predetermined values and the performance does not deteriorate over time, then the thermal weight loss test will not be carried out below the operating temperature, but will be transitioned to high-temperature conditions and the thermal weight loss test will continue. b) If both groups of test pieces show significant thermal weight loss and mechanical property degradation, then take the low temperature condition as the benchmark, select several test conditions in the low temperature direction, and continue to carry out thermal aging weight loss tests in groups.
7. The method for thermogravimetric testing of resin-based composite materials for aero-engine components as described in claim 6, characterized in that, The process of determining the thermal aging weight loss temperature threshold based on the results of the temperature gradient thermal aging weight loss test in step S5 is as follows: a) Compile thermal aging weight loss result curves for each temperature gradient. Based on the curves, if the weight loss rate of the test piece is lower than the threshold and the weight of the test piece does not change with the cumulative increase over time at a certain temperature, then that temperature is the temperature threshold for thermal aging weight loss. b) If the above temperature threshold is not reached, continue to select a lower temperature condition to carry out the thermal aging weight loss test until the temperature threshold of the thermal aging weight loss test is obtained.
8. The method for thermogravimetric testing of resin-based composite materials for aero-engine components as described in claim 7, characterized in that, Using the actual plywood of an aero-engine component as the plywood structure of the test specimen, four performance parameters—transverse tension, longitudinal compression, longitudinal bending, and interlaminar shear—were used as performance evaluation indicators for the thermogravimetric test.