A natural accelerated aging test method for carbon fiber composite materials

Abstract

The present invention discloses a natural accelerated aging test method for carbon fiber composite materials, comprising: S1, selecting a typical climate environment test station and collecting local climate environment data; S2, building a natural accelerated aging test facility; S3, determining the test parameters of natural accelerated aging based on the local climate environment data, and conducting a natural accelerated aging test; S4, calculating the acceleration ratio of the natural accelerated aging test for the carbon fiber composite material; S5, conducting a mechanical property test on the test sample that has completed the natural accelerated aging test, obtaining the mechanical property change data of the test sample, and estimating the performance change of the test sample under a natural storage environment non-accelerated state in combination with the acceleration ratio. The present invention simulates the actual storage environment of the composite material, utilizes the natural accelerated aging test facility to strengthen the temperature and humidity, high and low temperature cycles and mechanical load conditions to accelerate the aging of the material, and combines the acceleration ratio to make an accurate evaluation of the weather resistance of the carbon fiber composite material under the storage environment.

Description

Technical Field

[0001] The invention relates to a natural accelerated aging test method for carbon fiber composite materials. Background Art

[0002] Carbon fiber reinforced composites (CFRPs) are widely used in aerospace, construction, energy, infrastructure, marine, pipelines, and storage tanks due to their advantages of light weight, high strength, high modulus, and corrosion resistance. However, due to the diversity of CFRP raw materials, structural designs, and processing techniques, the mechanical properties of CFRPs vary after long-term storage.

[0003] Currently, the main methods used in the industry to evaluate the weather resistance and lifespan of composite materials include natural aging and artificial accelerated aging. Natural aging is the most reliable aging test method, but it has the disadvantages of slow aging rate and long experimental time. Artificial accelerated aging test has a short time and controllable conditions, but it is difficult to simulate the coupling of multiple environmental factors in actual service environment. The natural accelerated aging test strengthens the key environmental factors that affect the aging of carbon fiber composite materials, such as temperature, humidity, and high and low temperature cycles. At the same time, it combines the characteristics of the material's actual service environment and applies mechanical loads to achieve accelerated aging of the material under the coupling of multiple environmental factors such as temperature, humidity, and mechanical stress. This method has the advantage of high correlation with natural storage aging.

[0004] At present, there are two main research directions on the aging laws and mechanisms of indoor carbon fiber composite materials. One is the influence of traditional environmental temperature and humidity on composite materials, and the other is the influence of temperature cycle / humidity / load coupling on composite materials. Among them, there are many results that can be used as reference for traditional temperature and humidity accelerated aging methods and models, but there are very few natural accelerated aging methods with temperature cycle / humidity / load coupling. Summary of the Invention

[0005] The object of the present invention is to provide a natural accelerated aging test method for carbon fiber composite materials, which can accurately evaluate the weather resistance of carbon fiber composite materials in a storage environment.

[0006] The purpose of the present invention is achieved by the following technical measures: A natural accelerated aging test method for carbon fiber composite materials, characterized by comprising the following steps:

[0007] S1. Select a typical climate and environmental test station and collect local climate and environmental data;

[0008] S2. Construct a natural accelerated aging test facility at the selected typical climate environment test station;

[0009] S3. Determine the test parameters for natural accelerated aging based on local climate and environmental data, record the mechanical properties data of the initial test samples, and conduct natural accelerated aging tests;

[0010] S4. Calculate the acceleration rate of the natural accelerated aging test of carbon fiber composite materials;

[0011] S5. Conduct mechanical property tests on the test samples that have completed the natural accelerated aging test to obtain data on changes in the mechanical properties of the test samples, and estimate the performance changes of the test samples under non-accelerated conditions in a natural storage environment in combination with the acceleration rate.

[0012] The present invention simulates the actual storage environment of composite materials and utilizes natural accelerated aging test facilities to accelerate material aging by strengthening temperature and humidity, high and low temperature cycles, and mechanical load conditions. Combined with the acceleration rate, the weather resistance of carbon fiber composite materials in storage environments can be accurately evaluated.

[0013] In the step S4 of the present invention, the calculation process of the acceleration rate is:

[0014] The chemical acceleration factor AF is calculated by taking the standard tensile part of dumbbell twill weave T700 carbon fiber epoxy resin matrix composite material as the object. i and physical acceleration rate AF j :

[0015]

[0016]

[0017] Chemical aging acceleration factor AF i and physical aging acceleration factor AF j The larger value is the acceleration rate:

[0018] AF=Max(AF i ,AF j ) Formula (3)

[0019] Where: AF i : Temperature / humidity / load comprehensive acceleration rate, that is, chemical aging acceleration rate; AF j : Temperature cycle / load coupling acceleration rate, i.e., physical aging acceleration rate; 1: Natural accelerated aging; 2: Storage warehouse; T: Average temperature, K; RH: Average humidity, %; ΔT: Average temperature difference, °C; v: Temperature change rate, °C / h; T max : average maximum temperature, K; Ea: aging activation energy, 41 kJ / mol; R: molar gas constant, 8.31 J·mol -1 ·K -1 ; S: load, N.

[0020] The test parameters of the present invention are annual temperature change, annual humidity change, daily average temperature difference and mechanical stress loading value.

[0021] The range of annual temperature variation in the present invention is as follows: 5-50°C in humid hot areas, with a high temperature threshold of 40°C; -20-60°C in dry hot areas, with a high temperature threshold of 50°C; -30-50°C in cold areas, with a high temperature threshold of 40°C; -5-40°C in sub-humid hot areas, with a high temperature threshold of 30°C; -20-40°C in warm areas, with a high temperature threshold of 30°C;

[0022] The range of the daily average temperature difference is: 3-5°C in humid hot areas; 10-13°C in dry hot areas; 10-15°C in cold areas; 5-7°C in sub-humid hot areas; 8-10°C in warm areas;

[0023] The range of annual humidity changes is: 40-90% in humid and hot areas; 10-50% in dry and hot areas; 0-80% in cold areas; 40-90% in sub-humid and hot areas; and 30-80% in warm and temperate areas.

[0024] The mechanical stress loading value is 5%, 10% or 15% of the tensile breaking stress of the test object.

[0025] The natural accelerated aging test facility described in the present invention includes a ground simulation warehouse, a temperature and humidity control system that can remotely read the temperature and humidity data of the ground simulation warehouse and perform regulation, a working load loading system for remotely monitoring the static load state of a dumbbell-shaped standard specimen, and a software control system. The software control system includes a monitoring screen module for displaying a monitoring screen, a program setting module for setting program parameters, a history curve module for displaying a parameter history curve, a reservation setting module for reservation setting parameters, an archive management module for storing historical data, and an alarm history module for displaying alarm history information.

[0026] The test parameters of the present invention, namely the temperature cycle / humidity / load parameter control process, are as follows:

[0027] When the temperature in the natural accelerated aging test facility is lower than the minimum set temperature, the heating system is started; when the temperature reaches the high temperature threshold, the heating system is started and stops immediately after heating to the maximum set temperature;

[0028] When the humidity is lower than the minimum set relative humidity, the humidification system is started, and when the humidity is higher than the maximum set relative humidity, the dehumidification system is started;

[0029] The load is a static load, and no additional control is performed after the load value is set.

[0030] In the step S5 of the present invention, the mechanical property of the test sample is the tensile stress σ f , elongation at break η f and elastic modulus E f , tensile stress σ of the test sample under non-accelerated stateo , elongation at break η o and elastic modulus E o The change in is expressed as an aging rate and is calculated using the following formula:

[0031] σ o =σ f / AF formula (4)

[0032] η o =η f / AF formula (5)

[0033] E o =E f / AF formula (6)

[0034] Compared with the prior art, the present invention has the following significant effects:

[0035] The present invention conducts natural accelerated aging tests with the help of a typical climatic environment, simultaneously involving two aging mechanisms, namely, accelerating the chemical aging of the composite matrix by strengthening the effects of temperature and humidity, and accelerating the physical aging of the composite interface and interlayer by strengthening the coupling of high and low temperature cycles, high and low humidity cycles, and mechanical loads. Therefore, the present invention is a natural accelerated testing method that strengthens the temperature cycle / humidity / load coupling and simulates the storage environment of carbon fiber composite materials. The present invention has the advantages of high correlation and fast aging speed, and can make accurate evaluations of the weather resistance of non-metallic materials such as carbon fiber composite materials in storage environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Figure 1 This is a schematic structural diagram of a ground simulation warehouse constructed at the Qionghai test site according to Example 1 of the present invention;

[0038] Figure 2 This is a temperature distribution diagram of the Qionghai natural accelerated aging facility throughout the year according to Example 1 of the present invention;

[0039] Figure 3 This is a year-round humidity distribution diagram in the Qionghai natural accelerated aging facility according to Example 1 of the present invention;

[0040] Figure 4 This is a schematic structural diagram of a load-loading shampoo head according to working condition 1 of the present invention;

[0041] Figure 5 This is a temperature distribution diagram of the entire year in the Hailar natural accelerated aging facility according to Example 2 of the present invention;

[0042] Figure 6This is a year-round humidity distribution diagram in the Hailar natural accelerated aging facility according to Example 2 of the present invention. DETAILED DESCRIPTION

[0043] The present invention is described in detail below in conjunction with the embodiments and the accompanying drawings to help those skilled in the art better understand the inventive concept of the present invention. However, the scope of protection of the claims of the present invention is not limited to the following embodiments. For those skilled in the art, all other embodiments obtained without creative work without departing from the inventive concept of the present invention shall fall within the scope of protection of the present invention.

[0044] Example 1

[0045] A natural accelerated aging test method for carbon fiber composite materials according to the present invention comprises the following steps:

[0046] S1. Select a typical climate and environmental test station and collect local climate and environmental data;

[0047] This example focuses on the long-term storage of carbon fiber composite materials in a southern tropical climate environment. The Qionghai Climate Environment Test Station, which represents a humid and hot marine atmosphere, was selected to conduct a natural accelerated aging test. The extreme temperature and humidity information of this typical humid and hot climate environment station are shown in the following table:

[0048]

[0049] (Table 1)

[0050] S2. Construct a natural accelerated aging test facility at the selected typical climate environment test station;

[0051] In this embodiment, the natural accelerated aging test facility mainly consists of a ground simulation warehouse, a temperature and humidity control system that can remotely read the temperature and humidity data of the ground simulation warehouse and adjust it, a working load loading system for remotely monitoring the static load state of the dumbbell-shaped standard specimen, and a software control system. The software control system includes a monitoring screen module for displaying a monitoring screen, a program setting module for setting program parameters, a history curve module for displaying parameter history curves, a reservation setting module for reservation setting parameters, a file management module for storing historical data, and an alarm history module for displaying alarm history information. The area of ​​the ground simulation warehouse is 16m 2 The structure of the ground simulation warehouse is as follows Figure 1 As shown, it consists of a roof 1, walls, a floor 4, a door 5, windows 2 and vents 3.

[0052] In this embodiment, the temperature and humidity in the Qionghai natural accelerated aging test facility are controlled by a temperature and humidity control system. Data can be read remotely in real time, and data storage is required to be recorded once every 5 minutes. Figure 2 、 Figure 3 As shown, the temperature deviation throughout the year is ±2°C, and the relative humidity deviation throughout the year is ±4%.

[0053] The working load loading system inside the natural accelerated aging test facility consists of a base 6, a bracket 7, a fixture 8, a stress sensor 9, a connecting rod 11, a screw 12 and a locking nut 13. The test sample 10 is clamped on the fixture 8. Figure 4 As shown, the main structural material of the working load loading system is 316 stainless steel. The system can realize remote monitoring of the static load status of the dumbbell-shaped standard specimen. The static load range of the device is 0 to 5000N, and the load deviation is required to be controlled within 5% of the applied static load.

[0054] S3. Determine the test parameters for natural accelerated aging based on local climate and environmental data, record the mechanical properties data of the initial test samples, and conduct natural accelerated aging tests;

[0055] In this embodiment, the test condition parameters of the temperature cycle / humidity / load coupling of the natural accelerated aging test method are set based on the climate data collected from the typical humid and hot environment test station in Qionghai, including parameter information such as the annual temperature variation range, the daily average temperature difference range, the annual humidity variation range and the mechanical stress loading value.

[0056] The annual temperature variation range of the natural accelerated aging test in Qionghai is 5-50°C in Qionghai (hot and humid area), and the high temperature threshold is 40°C. The daily average temperature difference range of the natural accelerated aging test is 3-5°C in Qionghai (hot and humid area). The annual humidity variation range is 50-90% in Qionghai (hot and humid area). The mechanical load is 10% of the tensile fracture stress of the dumbbell-shaped standard part of the test object, twill woven T700 carbon fiber epoxy resin-based composite material, which is 3000N here.

[0057] The control strategy for the environmental conditions within the Qionghai Accelerated Aging Test Facility, specifically the temperature cycling, humidity, and load parameters, is as follows: When the temperature within the Qionghai Accelerated Aging Test Facility falls 5°C below the minimum set point, the heating system is activated. When the temperature reaches the high temperature threshold of 40°C, the heating system is activated and immediately stops after heating to the maximum set point of 50°C. This simulates the actual storage environment while increasing the average temperature and expanding the temperature cycling range.

[0058] Through the above temperature and temperature cycle change range control, the average daily temperature difference during the test period was 3 to 4°C, which met the requirements of the corresponding set range of 3-5°C.

[0059] When the humidity is lower than the minimum set relative humidity of 40%, the humidification system is activated, and when the humidity is higher than the maximum set relative humidity of 90%, the dehumidification system is activated. In this way, the humidity variation range is controlled to simulate the actual storage environment.

[0060] The load is a static load of 3000N. No additional control is performed after the load value is set.

[0061] The test condition parameters of the temperature cycle / humidity / load coupling of the Qionghai natural accelerated aging test method are shown in the following table:

[0062]

[0063]

[0064] (Table 2)

[0065] According to the test condition parameters set above, the temperature cycle / humidity / load coupled accelerated aging test was carried out using the natural storage accelerated aging test facilities built by the Qionghai Test Station. During the test, samples were taken every six months, with 6 samples taken each time.

[0066] S4. Calculate the acceleration rate of the natural accelerated aging test of carbon fiber composite materials;

[0067] In this embodiment, a dumbbell-shaped standard tensile member of twill woven T700 carbon fiber epoxy resin-based composite material is used as the object, and the temperature / humidity / mechanical load acceleration model [Formula (1)] and the improved temperature cycle / mechanical load model [Formula (2)] are combined. The environmental conditions of the Qionghai natural accelerated aging test facility and the cave storage environmental conditions parameters (Table 3) are substituted, and the chemical aging acceleration ratio is calculated to be 6.3 and the physical aging acceleration ratio is 0.4. The maximum value of the two is the acceleration ratio of the method [Formula (3)]. That is, the acceleration ratio of the natural accelerated aging test method under the set conditions in Qionghai is 6.3 times.

[0068]

[0069]

[0070]

[0071] Where: AF i : Temperature / humidity / load comprehensive acceleration rate; AF j : Temperature cycle / load coupling acceleration ratio; 1: Natural accelerated aging; 2: Storage warehouse; T: Average temperature, K; RH: Average humidity, %; ΔT: Average temperature difference, °C; υ: Temperature change rate, °C / h; T max: average maximum temperature, K; Ea: aging activation energy, 41 kJ / mol; R: molar gas constant, 8.31 J·mol -1 ·K -1 ; S: load, N.

[0072]

[0073]

[0074] (Table 3)

[0075] S5. Conduct mechanical property tests on the test samples that have completed the natural accelerated aging test to obtain data on changes in the mechanical properties of the test samples, and estimate the performance changes of the test samples under non-accelerated conditions in a natural storage environment in combination with the acceleration rate.

[0076] In this embodiment, a dumbbell-shaped standard tensile member of a twill woven T700 carbon fiber epoxy resin-based composite material was used as the object, and mechanical properties tests were conducted on the initial test sample and the test sample after one year of natural accelerated aging test. The results showed that the elastic modulus E f Attenuation is about 2%. Assuming that the aging law of carbon fiber composite materials conforms to the linear change law, based on the acceleration ratio of 6.3, it is inferred that the annual performance attenuation rate of the test sample when stored in the natural environment of Qionghai is about 0.32%, that is:

[0077]

[0078] Example 2

[0079] A natural accelerated aging test method for carbon fiber composite materials according to the present invention comprises the following steps:

[0080] S1. Select a typical climate and environmental test station and collect local climate and environmental data;

[0081] In this embodiment, Hailar (cold) is selected as a typical climate environment test station for the natural accelerated aging test. The extreme temperature, humidity and other information of this typical hot and humid climate environment station are shown in the following table:

[0082]

[0083] (Table 4)

[0084] S2. Construct a natural accelerated aging test facility at the selected typical climate environment test station;

[0085] In this embodiment, the natural accelerated aging test facility is mainly composed of a ground simulation warehouse, a temperature and humidity control system, a working load loading system and a software control system. The area of ​​the simulated warehouse of the Qionghai natural accelerated aging test facility is 12m2 .

[0086] In this embodiment, the temperature and humidity in the Qionghai natural accelerated aging test facility are controlled by a temperature and humidity control system. Data can be read remotely in real time, and data storage is required to be recorded once every 5 minutes. Figure 5 、 Figure 6 As shown, the temperature deviation throughout the year is ±3°C, and the relative humidity deviation throughout the year is ±5%.

[0087] In this embodiment, the working load loading system inside the natural accelerated aging test facility is the same as that in embodiment 1. The load accuracy is controlled within ±75N, and the load deviation requirement is controlled within 5% of the applied load.

[0088] S3. Determine the test parameters for natural accelerated aging based on local climate and environmental data, record the mechanical properties data of the initial test samples, and conduct natural accelerated aging tests;

[0089] In this embodiment, the test condition parameters of the temperature cycle / humidity / load coupling of the natural accelerated aging test method are set based on the climate data collected from the typical humid and hot environment test station in Hailar, including parameter information such as the annual temperature variation range, the daily average temperature difference range, the humidity variation range and the mechanical stress loading value.

[0090] The annual temperature range for the natural accelerated aging test is -30-50°C in Hailar (cold region), with a high temperature threshold of 40°C. The daily average temperature range is 11-15°C in Hailar (cold region). The annual humidity range is 0-80% in Hailar (cold region). The mechanical load is 5% of the tensile breaking stress of the test object, a standard dumbbell-shaped twill-woven T700 carbon fiber epoxy resin composite material, i.e., 1500N.

[0091] The control strategy for the environmental conditions in the Hailar natural accelerated aging test facility, namely the temperature cycle / humidity / load condition parameters, is as follows:

[0092] When the temperature inside the Hailar accelerated aging test facility falls below the minimum set point of -30°C, the heating system activates. When the temperature reaches the high temperature threshold of 40°C, the heating system is activated and continues heating to the maximum set point of 50°C, where it stops immediately. This simulates the actual storage environment while increasing the average temperature and expanding the range of temperature cycles.

[0093] Through the above temperature and temperature cycle change range control, the average daily temperature difference during the test period was 10 to 12°C, which met the requirements of the corresponding set range of 11-15°C.

[0094] When the humidity is higher than the maximum set relative humidity of 80%, the dehumidification system is activated to control the humidity range and simulate the actual storage environment.

[0095] The load is a static load of 1500N. No additional control is performed after the load value is set.

[0096] The test condition parameters of the Hailar natural accelerated aging test method temperature cycle / humidity / load coupling are shown in the following table:

[0097]

[0098] (Table 5)

[0099] According to the test condition parameters set above, two accelerated aging tests, temperature cycling / humidity / load coupling and temperature cycling / humidity / no load, were carried out using the natural storage accelerated aging test facilities built at the Qionghai test station. During the test, samples were taken every six months, with 6 samples taken each time.

[0100] S4. Calculate the acceleration rate of the natural accelerated aging test of carbon fiber composite materials;

[0101] In this embodiment, a dumbbell-shaped standard tensile member of twill woven T700 carbon fiber epoxy resin-based composite material is used as the object, and the temperature / humidity / mechanical load acceleration model [Formula (1)] and the improved temperature cycle / mechanical load model [Formula (2)] are combined. The environmental conditions of the Qionghai natural accelerated aging test facility and the cave storage environmental conditions parameters (Table 6) are substituted, and the chemical aging acceleration rate is calculated to be 0.3 and the physical aging acceleration rate is 13.7. The larger value of the two is the acceleration rate of this method [Formula (3)]. That is, the acceleration rate of the natural accelerated aging test method under the set conditions in Qionghai is 13.7 times.

[0102]

[0103]

[0104]

[0105] Environmental conditions Inside the Hailar warehouse Cavern storage Average temperature ℃ 11 20 Average humidity% 40 55 Average temperature difference ℃ 11.2 5 Average maximum temperature ℃ 18.9 25 Temperature change rate ℃ / h 0.93 0.42 Mechanical Machinery N 1500 1000

[0106] (Table 6)

[0107] S5. Conduct mechanical property tests on the test samples that have completed the natural accelerated aging test to obtain data on changes in the mechanical properties of the test samples, and estimate the performance changes of the test samples under non-accelerated conditions in a natural storage environment in combination with the acceleration rate.

[0108] In this embodiment, a dumbbell-shaped standard tensile member of a twill woven T700 carbon fiber epoxy resin-based composite material was used as the object, and mechanical properties tests were conducted on the initial test sample and the sample after one year of natural accelerated aging test. The results showed that the elastic modulus E f The attenuation is around 20%. Assuming that the aging law of carbon fiber composite materials follows a linear law of change, based on an acceleration factor of 13.7, it is estimated that the elastic modulus of the test sample will decay at a rate of about 1.5% per year when stored in the natural environment of Hailar.

[0109]

Claims

1. A natural accelerated aging test method for carbon fiber composite materials, characterized in that The following steps are involved: S1. Select a typical climate and environmental test station and collect local climate and environmental data; S2. Construct a natural accelerated aging test facility at the selected typical climate environment test station; S3. Determine the test parameters for natural accelerated aging based on local climate and environmental data, record the mechanical properties data of the initial test samples, and conduct natural accelerated aging tests; The test parameters are annual temperature change, annual humidity change, daily average temperature difference and mechanical stress loading value; The test parameters, namely the temperature cycle / humidity / load parameter control process, are as follows: When the temperature in the natural accelerated aging test facility is lower than the minimum set temperature, the heating system is started; when the temperature reaches the high temperature threshold, the heating system is started and stops immediately after heating to the maximum set temperature; When the humidity is lower than the minimum set relative humidity, the humidification system is started, and when the humidity is higher than the maximum set relative humidity, the dehumidification system is started; The load is a static load, and no additional control is performed after the load value is set; S4. Calculate the acceleration rate of the natural accelerated aging test of carbon fiber composite materials; The chemical aging acceleration factor AF is calculated by taking the standard tensile parts of dumbbell twill weave T700 carbon fiber epoxy resin matrix composite materials as the objects. i and physical aging acceleration factor AF j : Chemical aging acceleration factor AF i and physical aging acceleration factor AF j The larger value is the acceleration rate: AF = Max(AF i , AF j ) Formula (3) Where: AF i : Temperature / humidity / load comprehensive acceleration rate, that is, chemical aging acceleration rate; AF j : Temperature cycle / load coupling acceleration rate, that is, physical aging acceleration rate; 1: Natural accelerated aging; 2: Storage warehouse; T: average temperature, K; RH: average humidity, %; ΔT: average temperature difference, °C; υ: temperature change rate, ℃ / h; T max : average maximum temperature, K; Ea: aging activation energy, 41 kJ / mol; R: molar gas constant, 8.31 J·mol -1 ·K -1 ; S : load, N; S5. Conduct mechanical property tests on the test samples that have completed the natural accelerated aging test to obtain data on changes in the mechanical properties of the test samples, and estimate the performance changes of the test samples under non-accelerated conditions in a natural storage environment in combination with the acceleration rate.

2. The carbon fiber composite material natural accelerated aging test method according to claim 1, characterized in that: The annual temperature range is as follows: 5-50℃ in humid hot areas, with a high temperature threshold of 40℃; -20-60℃ in dry hot areas, with a high temperature threshold of 50℃; -30-50℃ in cold areas, with a high temperature threshold of 40℃; -5-40℃ in sub-humid hot areas, with a high temperature threshold of 30℃; -20-40℃ in warm areas, with a high temperature threshold of 30℃; The range of the daily average temperature difference is: 3-5°C in humid hot areas; 10-13°C in dry hot areas; 10-15°C in cold areas; 5-7°C in sub-humid hot areas; 8-10°C in warm areas; The range of annual humidity changes is: 40-90% in humid and hot areas; 10-50% in dry and hot areas; 0-80% in cold areas; 40-90% in sub-humid and hot areas; and 30-80% in warm and temperate areas. The mechanical stress loading value is 5%, 10% or 15% of the tensile breaking stress of the test object.

3. The carbon fiber composite material natural accelerated aging test method according to claim 2, characterized in that: The naturally accelerated aging test facility includes a ground simulation warehouse, a temperature and humidity control system that can remotely read the temperature and humidity data of the ground simulation warehouse and adjust it, a working load loading system for remotely monitoring the static load state of dumbbell-shaped standard specimens, and a software control system. The software control system includes a monitoring screen module for displaying a monitoring screen, a program setting module for setting program parameters, a history curve module for displaying a parameter history curve, a reservation setting module for reservation setting parameters, an archive management module for storing historical data, and an alarm history module for displaying alarm history information.

4. The carbon fiber composite material natural accelerated aging test method according to claim 3, characterized in that: In step S5, the mechanical property of the test sample is the tensile stress σ f , elongation at break η f and elastic modulus E f , tensile stress σ of the test sample under non-accelerated state o , elongation at break η o and elastic modulus E o The change in is expressed as an aging rate and is calculated using the following formula: σ o =σ f / AF Official(4) η o =η f / AF Official(5) E o =E f / AF formula (6).

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