A rapid test method for wear life of aviation brake disc

Abstract

This invention discloses a rapid testing method for the wear life of aircraft brake discs. A pair of test rings are taken from a single aircraft brake disc and paired to obtain test sample A. Test sample A undergoes a first set of friction and wear tests according to a test sequence. After the first set of friction and wear tests, test sample A is processed to a 50% wear state to obtain test sample B. Test sample B undergoes a second set of friction and wear tests according to the test sequence. After the second set of friction and wear tests, test sample B is processed to a 75% wear state to obtain test sample C. Test sample C undergoes a third set of friction and wear tests according to the test sequence. The full-state wear life is then calculated based on the data from the three sets of friction and wear tests, and multiplied by an external field coefficient to obtain the wear life of the aircraft brake disc. This invention can greatly improve the R&D efficiency of aircraft brake disc products, shorten the R&D cycle, and reduce R&D costs.

Description

Technical Field

[0001] This invention relates to a rapid testing method for the wear life of aircraft brake discs, belonging to the field of aircraft brake disc technology. Background Technology

[0002] Brake discs are the core component of aircraft braking systems. Regardless of the material, brake discs will inevitably wear and oxidize during frequent braking. As the most important aircraft system, the reliability of braking components is directly related to flight safety. Therefore, brake discs need to be replaced in a timely manner when their wear reaches a certain standard. Thus, increasing the lifespan of brake discs has always been a key focus in brake disc research and manufacturing. During the research and manufacturing process, it is necessary to test the wear life of brake discs. In the current technology, the test that can truly reflect the wear life of brake discs requires long-term testing of complete sets of products according to industry-standard practices. The cost of a single test exceeds 100,000 yuan, and the test cycle exceeds one month. The long cycle and high test costs severely restrict the technical research and product development of aviation brake discs. Summary of the Invention

[0003] To address the issues of high cost and long testing time in existing aviation brake disc wear testing technologies, the present invention aims to provide a rapid testing method for aviation brake disc wear life. This method eliminates the need for testing complete sets of aviation brake discs; instead, it requires only a portion of a test sample taken from a single test disc for rapid performance testing. The cost is only 20% of that of commonly used methods in the industry, and the testing time is only 10% of existing testing methods. This can significantly improve the R&D efficiency of aviation brake disc products, shorten the R&D cycle, and reduce R&D costs.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] This invention discloses a rapid testing method for the wear life of aircraft brake discs. A pair of test rings are taken from a single aircraft brake disc and paired to obtain test sample A. Test sample A undergoes a first set of friction and wear tests according to a test sequence. After the first set of friction and wear tests, test sample A is processed to a 50% wear state to obtain test sample B. Test sample B undergoes a second set of friction and wear tests according to the test sequence. After the second set of friction and wear tests, test sample B is processed to a 75% wear state to obtain test sample C. Test sample C undergoes a third set of friction and wear tests according to the test sequence. The full-state wear life is then calculated based on the data from the three sets of friction and wear tests. The full-state wear life is multiplied by an external field coefficient to obtain the wear life of the aircraft brake disc. The test sequence is as follows: first taxiing deceleration, second taxiing deceleration, third taxiing deceleration, first taxiing stop, designed landing, fourth taxiing deceleration, fifth taxiing deceleration, sixth taxiing deceleration, and second taxiing stop.

[0006] In this invention, a single aircraft brake disc refers to an unworn aircraft brake disc, i.e., test sample A is a brand new test sample, while test sample B with 50% wear means that the thickness of test sample B is 50% of the thickness of test sample A, and test sample B with 75% wear means that the thickness of test sample C is 50% of the thickness of test sample A.

[0007] The rapid testing method of this invention uses small test rings cut from a single test disc as paired new test samples (test sample A). The test samples are then subjected to cyclical testing based on a test sequence determined according to the working distance experienced by an aircraft during a single takeoff and landing, under three different conditions. The wear amount is calculated based on the test results, and finally, the wear amount of the aircraft brake disc is obtained by multiplying this wear amount by the external field coefficient. The entire aircraft brake assembly is then subjected to life testing on a ground-based inertial test bench. The results show that the testing method designed in this invention has extremely high reliability, a short testing cycle, and a single test cost that can be reduced by 80% compared to current testing methods.

[0008] In a preferred embodiment, the aircraft brake disc is selected from one of the following: carbon-carbon aircraft brake disc, carbon-ceramic aircraft brake disc, and metal-based brake disc.

[0009] In a preferred embodiment, the initial speed of the first coasting deceleration test is 25.5–29.5 km / h, the test ends at 7.5–10.5 km / h, and the energy is 0.1–0.3 MJ.

[0010] In a preferred embodiment, the starting speed of the second coasting deceleration test is 62.5–66.5 km / h, the ending speed is 35.5–39.5 km / h, and the energy is 0.35–0.65 MJ.

[0011] In a preferred embodiment, the starting speed of the third coasting deceleration test is 43.5–49.5 km / h, the ending speed is 7.5–10.5 km / h, and the energy is 0.25–0.45 MJ.

[0012] In a preferred embodiment, the test start speed for coasting braking is 25.5–29.5 km / h, the test end speed is 0 km / h, and the energy is 0.1–0.3 MJ.

[0013] In a preferred embodiment, the test start speed for the designed landing is 230–260 km / h, the test stop speed is 0 km / h, and the energy is 2.2–3.5 MJ.

[0014] In a preferred embodiment, the starting speed of the fourth coasting deceleration test is 51.5–58.5 km / h, the ending speed is 32.5–39.5 km / h, and the energy is 0.15–0.28 MJ.

[0015] In a preferred embodiment, the starting speed of the fifth coasting deceleration test is 51.5–58.5 km / h, the ending speed is 25.5–29.5 km / h, and the energy is 0.35–0.45 MJ.

[0016] In a preferred embodiment, the starting speed of the sixth coasting deceleration test is 25.5–29.5 km / h, the ending speed is 16.5–19.5 km / h, and the energy is 0.03–0.09 MJ.

[0017] In a preferred embodiment, the starting speed for the second coasting braking test is 16.5–19.5 km / h, the ending speed is 0 km / h, and the energy is 0.03–0.09 MJ.

[0018] The inventors discovered that the parameters of various test conditions in the test sequence need to be controlled within the range of the present invention in order to achieve high reliability of the test method designed in this invention.

[0019] In the preferred embodiment, for any set of friction and wear tests, the number of cycles according to the test sequence is 50-90. The inventors found that controlling the number of cycles within this range results in the highest accuracy of data fitting.

[0020] In a preferred embodiment, the calculation process for the full-state wear life is as follows: Three sets of friction and wear test data are fitted using a second-order polynomial function to obtain the polynomial coefficients k, m, and n; then, Equation 1 is used for integration to obtain the full-state wear life of the material.

[0021]

[0022] In equation 1, Kl 2 +ml+n is the wear fitting function for different wear stages of the material, k, m, and n are polynomial coefficients, and L is the overall wear capacity of the material.

[0023] In a preferred embodiment, the external field coefficient is 2.1-4.2.

[0024] Further optimizations include: the external field coefficient of carbon-carbon or carbon-ceramic aviation brake discs used in UAVs is 2.1-2.5; the external field coefficient of metal-based brake discs used in UAVs is 2.3-2.6; the external field coefficient of carbon-carbon or carbon-ceramic aviation brake discs used in heavy-duty transport aircraft is 2.5-2.8; the external field coefficient of metal-based brake discs used in heavy-duty transport aircraft is 2.9-3.3; the external field coefficient of carbon-carbon or carbon-ceramic aviation brake discs used in civil passenger aircraft is 2.8-3.2; the external field coefficient of metal-based brake discs used in civil passenger aircraft is 3.2-3.5; the external field coefficient of carbon-carbon or carbon-ceramic aviation brake discs used in trainer aircraft is 3.2-3.5; and the external field coefficient of metal-based brake discs used in trainer aircraft is 3.7-4.2.

[0025] Beneficial effects

[0026] Current testing methods require the consumption of an entire brake disc assembly, costing hundreds of thousands of dollars. The testing method provided by this invention only requires sampling from a single piece of material, and the remaining material can be used for other performance tests, saving 90% of the testing material.

[0027] Current testing methods require the entire brake assembly to be installed within the aircraft brake wheel. The testing process releases a significant amount of heat, causing the entire brake assembly to reach a high temperature. Therefore, cooling is necessary before each test cycle. Furthermore, because the brake assembly is installed within the aircraft wheel, heat dissipation is insufficient, resulting in a long cooling time and a lifespan testing cycle of at least one month. The testing method provided by this invention generates less heat during sample testing, provides an excellent heat dissipation environment, and has a shorter waiting time for each test. The entire testing process can be completed in just three days, significantly shortening the testing cycle and improving the efficiency of technical research and product development.

[0028] Current methods for testing the lifespan of aircraft brake materials require a complete set of aircraft brake devices and testing systems, consuming the entire set of brake components for testing. Moreover, the testing cycle is very long, and the cost of a single test generally exceeds 100,000 yuan. The testing method provided by this invention only requires sampling from a single brake disc for testing, and the testing cycle is short. The cost of a single test can be reduced by 80% compared to the current testing methods.

[0029] The test sequence for aviation brake materials defined in this invention is designed based on the working state of the brakes during aircraft takeoff and landing. It can perfectly simulate the working state of aircraft brake discs during service. Numerous engineering applications demonstrate that the aviation brake disc life results obtained from the test sequence designed in this invention have high reliability and can reflect the life characteristics of aviation brake discs during service. Attached Figure Description

[0030] Figure 1The existing technology uses a complete braking assembly.

[0031] Figure 2 A schematic diagram of small-scale test ring sampling in this invention.

[0032] Figure 3 Diagram of test ring pairing. Detailed Implementation

[0033] Example 1

[0034] Test samples were taken from the single carbon-carbon composite brake disc (B767) and used as test rings. Figure 2 As shown, the selected test rings are then paired to obtain test samples in a completely new state, as follows. Figure 3 As shown in Table 1, the test samples in the virgin state, 50% wear state, and 75% wear state were tested 70 times each according to the test sequence shown in Table 1. The wear data in the three stages were statistically analyzed. Then, the three sets of friction and wear test data were fitted with a second-order polynomial function to obtain the polynomial coefficients k, m, and n. Finally, Equation 1 was used for integration to obtain the full-state wear life of the material.

[0035]

[0036] In equation 1, Kl 2 +ml+n is the wear fitting function for different wear stages of the material, k, m, and n are polynomial coefficients, and L is the overall wear capacity of the material.

[0037] Then, multiplying the all-condition wear life by the external field coefficient 2.9, we obtain the wear life of the aircraft brake disc.

[0038] Table 1: Single Test Cycle

[0039] Test Project Test start speed (km / h) Test termination speed (km / h) Energy (MJ) coasting deceleration 27.78 9.26 0.11 coasting deceleration 64.82 37.04 0.45 coasting deceleration 46.3 9.26 0.33 coasting and braking 27.78 0 0.12 Design landing 250 0 2.88 coasting deceleration 55.56 37.04 0.27 coasting deceleration 55.56 27.78 0.37 coasting deceleration 27.78 18.52 0.07 coasting and braking 18.52 0 0.05

[0040] The entire aircraft braking assembly was subjected to life testing on a ground-based inertial test bench. A comparison of the life data obtained from the two methods revealed that the testing method designed in this invention has extremely high reliability. (See Table 3 for details.)

[0041] Example 2

[0042] Test samples were taken from a single piece of carbon-carbon composite brake disc (Airbus A320), such as... Figure 2 As shown, the selected test rings are then paired to obtain test samples in a completely new state, as follows. Figure 3As shown in Table 1, the test samples in the virgin state, 50% wear state, and 75% wear state were tested 70 times each according to the test sequence shown in Table 1. The wear data in the three stages were statistically analyzed. Then, the three sets of friction and wear test data were fitted with a second-order polynomial function to obtain the polynomial coefficients k, m, and n. Finally, Equation 1 was used for integration to obtain the full-state wear life of the material.

[0043]

[0044] In equation 1, Kl 2 +ml+n is the wear fitting function for different wear stages of the material, k, m, and n are polynomial coefficients, and L is the overall wear capacity of the material.

[0045] Then, by multiplying the wear life under the full-condition condition by the external field coefficient and then by the external field coefficient 2.9, the wear amount of the aircraft brake disc can be obtained.

[0046] Table 2: Single Test Cycle

[0047] Test Project Test start speed (km / h) Test termination speed (km / h) Energy (MJ) coasting deceleration 28.58 8.25 0.18 coasting deceleration 65.82 36.52 0.55 coasting deceleration 48.5 8.5 0.38 coasting and braking 26.8 0 0.22 Design landing 252 0 3.2 coasting deceleration 53.5 35.8 0.23

[0048]

[0049] Table 3: Comparison of Implementation Results

[0050]

[0051] In Implementation Case 1 for B767, tests were conducted using both the current testing method and the testing method provided by this invention. The wear lifespans obtained were 2250 cycles and 2380 cycles, respectively, with a deviation of 5.78%.

[0052] In Implementation Case 2 for A320, tests were conducted using both the current testing method and the testing method provided by this invention. The wear lifespans obtained were 2580 cycles and 2760 cycles, respectively, with a deviation of 6.98%.

[0053] Both implementation cases meet the requirements of engineering applications.

[0054] Comparative Example 1

[0055] To verify the necessity of the test sequence provided by this invention, the test sequence was adjusted according to the lifetime test requirements in GJB 1184A-2010. As shown in Table 4,

[0056] Table 4 Comparative test sequences

[0057]

[0058] Then, according to the test sequence shown in Table 4, the B767 and A320 samples in Implementation Cases 1 and 2 were subjected to 70 cycles of testing in the new condition, 50% wear condition and 75% wear condition, respectively. The wear data at each stage were collected and the wear amount was calculated using the same method.

[0059] The results are shown in Table 5.

[0060] Table 5 Implementation Status of the Comparison

[0061]

[0062]

[0063] Comparative Example 1 shows that, after adjusting the test sequence, even with the same number of tests and data calculation methods, the experimental results obtained are significantly different from the current test method and cannot be applied to practical engineering.

Claims

1. A method for rapid testing of wear life of an aircraft brake disc, characterized in that: A pair of test rings are taken from a single piece of an aviation brake disc, the test rings are matched to obtain a test sample A, the test sample A is subjected to a first set of friction and wear tests according to a test sequence cycle, after the first set of friction and wear tests is completed, the test sample A is processed to a 50% wear state to obtain a test sample B, the test sample B is subjected to a second set of friction and wear tests according to the test sequence cycle, after the second set of friction and wear tests is completed, the test sample B is processed to a 75% wear state to obtain a test sample C, the test sample C is subjected to a third set of friction and wear tests according to the test sequence cycle, then the full-state wear life is obtained by calculating according to the data of the three sets of friction and wear tests, and the wear life of the aviation brake disc is obtained by multiplying the full-state wear life by an external field coefficient; the test sequence is in turn: first sliding deceleration, second sliding deceleration, third sliding deceleration, first sliding stop, designed landing, fourth sliding deceleration, fifth sliding deceleration, sixth sliding deceleration, and second sliding stop; The calculation process of the full-state wear life is that: the three sets of friction and wear test data are fitted by using a second-degree polynomial function to obtain polynomial coefficients k, m and n, and then the full-state wear life of the material is obtained by integrating formula 1, Formula 1 wherein in formula 1, is a loss fitting function of the material at different wear stages, k, m and n are polynomial coefficients, and L is the total abradable amount of the material; The external field coefficient is 2.1-4.

2.

2. The method of claim 1, wherein: The aviation brake disc is selected from one of a carbon-carbon aviation brake disc, a carbon-tile aviation brake disc, and a metal-based brake disc.

3. The rapid test method for the wear life of an aviation brake disc according to claim 1, characterized in that: the test start speed of the first sliding deceleration is 25.5-29.5 KM / H, the test stop speed is 7.5-10.5 KM / H, and the energy is 0.1-0.3 MJ; the test start speed of the second sliding deceleration is 62.5-66.5 KM / H, the test stop speed is 35.5-39.5 KM / H, and the energy is 0.35-0.65 MJ; the test start speed of the third sliding deceleration is 43.5-49.5 KM / H, the test stop speed is 7.5-10.5 KM / H, and the energy is 0.25-0.45 MJ; the test start speed of the first sliding stop is 25.5-29.5 KM / H, the test stop speed is 0 KM / H, and the energy is 0.1-0.3 MJ; the test start speed of the designed landing is 230-260 KM / H, the test stop speed is 0 KM / H, and the energy is 2.2-3.5 MJ; the test start speed of the fourth sliding deceleration is 51.5-58.5 KM / H, the test stop speed is 32.5-39.5 KM / H, and the energy is 0.15-0.28 MJ; the test start speed of the fifth sliding deceleration is 51.5-58.5 KM / H, the test stop speed is 25.5-29.5 KM / H, and the energy is 0.35-0.45 MJ; The test start speed of the sixth glide deceleration is 25.5-29.5 KM / H, the test stop speed is 16.5-19.5 KM / H, and the energy is 0.03-0.09 MJ; The test start speed of the second glide stop is 16.5-19.5 KM / H, the test stop speed is 0 KM / H, and the energy is 0.03-0.09 MJ.

4. The method of claim 1, wherein: In any one group of friction and wear tests, the number of cycles of the test sequence is 50-90 times.

5. The method of claim 1, wherein: The outer field coefficient of the carbon-carbon aviation brake disc or carbon-tao aviation brake disc used in the unmanned aerial vehicle is 2.1-2.5, the outer field coefficient of the metal-based brake disc used in the unmanned aerial vehicle is 2.3-2.6, the outer field coefficient of the carbon-carbon aviation brake disc or carbon-tao aviation brake disc used in the heavy transport aircraft is 2.5-2.8, the outer field coefficient of the metal-based brake disc used in the heavy transport aircraft is 2.9-3.3, the outer field coefficient of the carbon-carbon aviation brake disc or carbon-tao aviation brake disc used in the civil aircraft is 2.8-3.2, the outer field coefficient of the metal-based brake disc used in the civil aircraft is 3.2-3.5, the outer field coefficient of the carbon-carbon aviation brake disc or carbon-tao aviation brake disc used in the trainer is 3.2-3.5, and the outer field coefficient of the metal-based brake disc used in the trainer is 3.7-4.2.

Images