Wind field fault blade glass transition temperature detection method

Abstract

The invention discloses a wind field fault blade glass transition temperature detection method comprising the following steps: surveying a blade, and finding out a sampling position; sampling in the sampling position; pretreating the sample; adjusting the sample in a conventional environment; detecting the glass transition temperature of the wind field fault blade; the process of surveying the blade comprises the following steps; finding out all damaged areas of the blade through preliminary investigation; key investigation is carried out by combining all the damage areas of the blade found by the preliminary investigation, and key damage areas are found; preliminarily judging a damage reason in combination with the key damage area, and finding out a key position from the key damage area according to the preliminary judgment; and taking the found key position as a sampling position. According to the method, the whole blade can be surveyed, the sampling position with high precision can be obtained under the condition that the surveying efficiency is guaranteed, and the situation that the damage analysis result of the fault blade of the wind field is finally influenced due to the detection difference influence caused by the wrong sampling position is effectively avoided.

Description

Technical Field

[0002] The invention relates to the technical field of temperature detection, and in particular to a method for detecting the glass transition temperature of a faulty blade in a wind farm. Background Art

[0003] The glass transition temperature refers to the temperature at which amorphous or partially amorphous non-crystalline materials change from a glassy state to a highly elastic state. It has an important influence on the performance and process performance of the material, and directly affects the performance of the material during use. Therefore, it is very important to detect the glass transition temperature of faulty wind farm blades for analyzing the causes of faulty wind farm blades.

[0004] There are two main methods for detecting glass transition temperature in the wind power industry, one is DSC (differential scanning calorimeter) and the other is DMA (dynamic thermomechanical method). The principles of the two detection methods are different. The main working principle of DSC is to place the sample under a certain temperature program (or heating, cooling, or constant temperature) and observe the change of the heat flow power difference between the sample end and the reference end with temperature or time, so as to obtain the relevant thermal effect information such as heat absorption, heat release, and specific heat change of the sample during the temperature program, and calculate the heat absorption and release (enthalpy) and characteristic temperature (starting point, peak value, end point...) of the thermal effect; the working principle of DMA is to determine its glass transition temperature by measuring the change of viscoelasticity of the polymer during the glass transition process. During the glass transition process, the viscoelasticity of the polymer will change significantly, especially the storage modulus and loss modulus will decrease significantly. In contrast, the DMA method has high sensitivity and is close to the real application scenario of the material when detecting the glass transition temperature of the faulty wind farm blade.

[0005] Since wind farm blades are special-shaped and have been eroded by wind, sun and other environmental factors for many years, the samples taken from the faulty wind farm blades are unique, and the DMA method is completely inapplicable. The reason is that the DMA method has high requirements for the shape and size of the samples, and the samples taken from the blades cannot meet the testing requirements. In contrast, the DSC method has its own advantages. The current DSC method for testing the glass transition temperature is GB / T19466.2-2004, but this method is not applicable to samples taken from the faulty wind farm blades for the following reasons: 1) It only stipulates that grinding is not allowed, but does not specify the sampling method, sampling location, and sampling quantity in detail, which affects the accuracy of the test results.

[0006] 2) There are no regulations on sample pretreatment before testing. Studies have shown that this has a significant impact on the test results. 3) It is recommended to take the results of two scans as the glass transition temperature value of the wind farm faulty blade. This is not applicable to samples taken from the wind farm faulty blades, because the first scan may cause the resin to further solidify, resulting in a higher test result, which is not conducive to analyzing the cause of the fault.

[0007] 4) It is recommended to take the midpoint value As the glass transition temperature value of the faulty blade in the wind farm, since the material has begun to undergo phase transition at the starting point, the load that the blade can withstand will also change, so taking the midpoint is not applicable. Summary of the invention

[0008] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for detecting the glass transition temperature of a faulty blade in a wind farm.

[0009] To achieve the above purpose, the technical solution provided by the present invention is: A method for detecting the glass transition temperature of a faulty blade in a wind farm, comprising: Survey the leaves to find the sampling location; Sampling is performed in a sampling location; Pre-treating the obtained samples; Conditioning the pretreated samples in a conventional environment; Combine the conditioned samples to test the glass transition temperature of the faulty blades in the wind farm; Among them, the process of inspecting the blades includes: Find all damaged areas of the blade through preliminary inspection; Combined with all the damaged areas of the blades found in the preliminary survey, conduct a focused survey to find the key damaged areas; Combine the key damage areas to preliminarily determine the cause of the damage, and find the key locations from the key damage areas based on the preliminary determination; The key positions found are used as sampling positions.

[0010] Furthermore, if the cause of the damage cannot be preliminarily determined by combining the key damaged areas, all damaged areas of the blade found by the preliminary investigation will be used as sampling locations.

[0011] Furthermore, preliminary inspections were performed to identify all damaged areas of the blade, including: Detailed inspection of the damaged blade spar cap, web and trailing edge UD from the blade root to the blade tip. Mark the location of all the damages with a marker, take photos to record the damage shape and measure the damage size. Conduct a detailed inspection of the visible parts of the inner and outer cavities of the damaged blade shell from the blade root to the blade tip, mark the location of the damage with a marker, take photos to record the damage shape and measure the damage size; Carry out a detailed inspection of the visible parts of the damaged blade bonding area from the root to the tip of the blade, mark the location of the damage with a marker and record it with photos, and measure the width of the adhesive in the contactable area.

[0012] Furthermore, when conducting a focused investigation on all damaged areas of the blade found in the preliminary investigation, the position and size of the fracture in the key damaged area are marked with a marker pen, and detailed photos are taken and recorded, and the photos are required to clearly reflect the damage situation; the position and size of other damaged areas are marked with a marker pen, and special attention is paid to taking photos and recording abnormal points.

[0013] Further, sampling requirements include: Take samples from the chord-wise beam cap, web, shell, shell bonding area, and web bonding area at the fracture location, with three samples taken from each area; Take samples from the chord-wise beam cap, web, shell, shell bonding area, and web bonding area at a distance of one meter from the fracture position toward the blade root and blade tip, and take three samples from each area; At other locations, samples of relevant fiberglass and structural adhesives are taken every four meters, and the number of samples taken is one.

[0014] Furthermore, the obtained samples are pre-processed, including: Remove the sample flash by sandpaper polishing; Sample after removing flash by solvent cleaning; The cleaned samples were then placed in a dryer and dried for more than twelve hours.

[0015] Furthermore, the glass transition temperature of the faulty blades in the wind farm is tested in combination with the adjusted samples, including: A1. Take out three identical sample dishes, namely the first sample dish, the second sample dish, and the third sample dish, and weigh the three sample dishes; A2. After placing the sample in the first sample dish, weigh the first sample dish again; A3. Place the empty second sample dish and the third sample dish into the sample holder of the differential scanning calorimeter, with the second sample dish serving as the sample dish and the third sample dish serving as the reference dish, and cover the sample holder with a cover; A4. Raise the temperature at a rate of 20 °C / min and scan and record the temperature from 50 °C below the expected glass transition temperature to 30 °C above the expected glass transition temperature. Set the DSC curve obtained at this time as the baseline. A5. Turn on the cooling device of the differential scanning calorimeter to rapidly cool the interior of the sample holder to room temperature. A6. After the temperature inside the sample holder returns to room temperature, take out the second sample dish from the sample holder, and put the first sample dish containing the sample into the sample holder; A7. The temperature inside the sample holder is raised to 50°C at a rate of 3°C / min, i.e., the upper limit of the temperature for the first scan after the sample is placed is set to 50°C to eliminate the influence of small molecules on the test results. A8. Maintain the internal temperature of the sample holder for 5 minutes; A9. Rapidly cool the internal temperature of the sample holder to 50°C below the expected glass transition temperature; A10. Maintain the internal temperature of the sample holder for 5 minutes; A11. Raise the temperature inside the sample holder for the second time at a rate of 20 °C / min and record the temperature until it reaches a temperature higher than the expected extrapolated starting temperature. The complete DSC curve was obtained by 30°C high, and the half-height method was used to obtain the value of the complete DSC curve to obtain the determined extrapolated onset temperature. , and the determined extrapolated onset temperature as the glass transition temperature of the leaf.

[0016] Furthermore, it also includes: A12, cool the interior of the sample holder to room temperature, take out the first sample dish, and observe whether the first sample dish is deformed or has sample overflow. If so, lower the upper limit temperature and retest. Otherwise, proceed to step A13; A13. Weigh the first sample dish containing the sample again. If the mass decreases and exceeds the set range, it is considered that the sample has undergone chemical changes. Lower the upper temperature limit and retest.

[0017] Furthermore, before using the differential scanning calorimeter for detection, nitrogen gas is introduced into the sample holder of the differential scanning calorimeter to exhaust the air inside the sample holder.

[0018] Furthermore, the first sample dish, the second sample dish and the third sample dish are cleaned before use.

[0019] Compared with the prior art, the principles and advantages of this technical solution are as follows: 1. The blade inspection process includes preliminary inspection and key inspection. It can not only inspect the entire blade, but also obtain a high-precision sampling position while ensuring the inspection efficiency, effectively avoiding the impact of detection differences caused by incorrect sampling positions, which ultimately affects the damage analysis results of faulty blades in the wind farm.

[0020] 2. The wind farm environment is complex. This technical solution pre-treats the samples obtained to prevent surface defects such as stains, moisture, burrs, etc. from affecting the test results.

[0021] 3. Considering that the resin and structural adhesive used in wind farm blades are both thermosetting materials, this technical solution sets the upper temperature limit of the first scan to 50°C, which can effectively avoid the influence of small molecule volatiles on the test results and prevent the sample from being cured for the second time during the scanning process, resulting in high results and affecting fault analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the services required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a flow chart of a method for detecting the glass transition temperature of a faulty blade in a wind farm according to the present invention; Figure 2 It is a flow chart of inspecting blades in a method for detecting the glass transition temperature of a faulty blade in a wind farm according to the present invention; Figure 3 is a cross-sectional view of the blade (A is the spar cap, B is the web, C is the trailing edge UD, and D is the shell); Figure 4 It is a typical DSC curve diagram; Figure 5 Schematic diagram of glass transition temperature. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with specific embodiments: like Figure 1 As shown, a method for detecting the glass transition temperature of a faulty blade in a wind farm according to this embodiment includes: S1. Investigate the leaves and find the sampling location; In this step, if Figure 2 As shown, the process of inspecting the blade includes: S1-1. Find all damaged areas of the blade through preliminary inspection, including: 1) Detailed inspection of the damaged blade spar cap, web and trailing edge UD (the area between the trailing edge and the upstream and downstream edges) from the blade root to the blade tip. Mark the location of all the damages with a marker, take photos to record the damage shape and measure the damage size; 2) Conduct a detailed inspection of the visible parts of the damaged blade shell from the root to the tip of the blade, mark the location of the damage with a marker, take photos to record the shape of the damage, and measure the size of the damage; 3) Carry out a detailed inspection of the damaged blade bonding area from the root to the tip of the blade. Mark the location of the damage with a marker and take photos to record it. Measure the width of the adhesive in the contactable area.

[0025] S1-2. Combine all damaged areas of the blade found in the preliminary survey and conduct a focused survey to find the key damaged areas. In the key damaged areas, mark the position and size of the fracture with a marker pen, take detailed photos and record them, and require the photos to clearly reflect the damage. Mark the position and size of other damaged areas with a marker pen, and focus on taking photos of abnormal points.

[0026] S1-3. Preliminary judgment of the cause of damage is made in combination with the key damaged areas, and key positions are found from the key damaged areas based on the preliminary judgment, and the found key positions are used as sampling positions; if the cause of damage cannot be preliminarily judged in combination with the key damaged areas, all damaged areas of the blade found in the preliminary investigation are used as sampling positions.

[0027] S2. sampling at the sampling position; Sampling requirements include: (1) Take samples from the spar cap, web, shell, shell bonding area, and web bonding area in the chord direction of the fracture location, with three samples taken from each location; (2) Take samples from the chord-wise spar cap, web, shell, shell bonding area, and web bonding area at a distance of one meter from the fracture position toward the blade root and blade tip, and take three samples from each area; (3) At other locations, samples of relevant fiberglass and structural adhesives are taken at intervals of four meters, with the number of samples being one.

[0028] S3. Pre-process the obtained samples, including: S3-1, remove the sample flash by sandpaper polishing; S3-2, sample after removing flash by solvent cleaning; S3-3. Then, the cleaned sample is placed in a dryer and dried for more than twelve hours.

[0029] S4. Condition the pretreated sample in a conventional environment, specifically by placing it statically for more than 24 hours; S5. Perform glass transition temperature detection on the faulty blades in the wind farm based on the adjusted samples; This step specifically includes: S5-1, taking out the first sample dish, the second sample dish, and the third sample dish, which are identical, and cleaning them, and weighing the three to ensure that the weights of the three are consistent; S5-2, after placing the sample in the first sample dish, weigh the first sample dish containing the sample again; S5-3, introducing nitrogen into the sample holder of the differential scanning calorimeter to exhaust the air inside the sample holder; S5-4, placing the empty second sample dish and the third sample dish into the sample holder of the differential scanning calorimeter, with the second sample dish serving as the sample dish and the third sample dish serving as the reference dish, and covering the sample holder with a cover; S5-5, heating at a rate of 20 °C / min and scanning and recording, the temperature range is from 50 °C lower than the expected glass transition temperature to 30 °C higher than the expected glass transition temperature, and the DSC curve obtained at this time is set as the baseline; S5-6, turning on the cooling device of the differential scanning calorimeter to rapidly cool the interior of the sample holder to room temperature; S5-7, after the temperature inside the sample holder returns to room temperature, take out the second sample dish from the sample holder, and put the first sample dish containing the sample into the sample holder; S5-8, the temperature inside the sample holder is raised to 50°C at a rate of 3°C / min, that is, the upper limit of the temperature of the first scan after the sample is placed is set to 50°C, so as to eliminate the influence of small molecules on the test results; S5-9, maintaining the internal temperature of the sample holder for 5 minutes; S5-10, rapidly cooling the internal temperature of the sample holder to 50°C lower than the expected glass transition temperature; S5-11, maintaining the internal temperature of the sample holder for 5 minutes; S5-12, raise the temperature inside the sample holder for the second time at a rate of 20 °C / min and record it until it reaches a temperature higher than the expected extrapolated starting temperature. The complete DSC curve was obtained by 30°C high, and the half-height method was used to obtain the value of the complete DSC curve to obtain the determined extrapolated onset temperature. , midpoint temperature and the extrapolated end temperature ,like Figure 5 As shown, the extrapolated starting temperature determined as the glass transition temperature of the leaf; S5-13, cooling the interior of the sample holder to room temperature, taking out the first sample dish, and observing whether the first sample dish is deformed or has sample overflow. If so, lowering the upper limit temperature and retesting, otherwise proceeding to step S5-14; S5-14. Weigh the first sample dish containing the sample again. If the mass decreases and the decrease exceeds the set range, it is considered that the sample has undergone chemical changes, and the upper limit temperature is lowered and retested.

[0030] In this embodiment, the blade inspection process includes preliminary inspection and key inspection, which can not only inspect the entire blade, but also obtain a high-precision sampling position while ensuring the inspection efficiency, effectively avoiding the impact of detection differences caused by incorrect sampling positions, which ultimately affects the damage analysis results of faulty blades in the wind farm.

[0031] The environment of a wind farm is complex. By pre-treating the samples obtained, we can avoid the surface defects of the samples, such as stains, moisture, burrs, etc., affecting the test results.

[0032] As the resin and structural adhesive used in wind farm blades are both thermosetting materials, the upper temperature limit of the first scan is set to 50°C. This can not only effectively avoid the influence of small molecule volatiles on the test results, but also prevent the sample from undergoing a second curing during the scanning process, which would result in higher results and affect fault analysis.

[0033] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, all changes made according to the shape and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for detecting the glass transition temperature of a faulty blade in a wind farm, characterized in that: include: Survey the leaves to find the sampling location; Sampling is performed in a sampling location; Pre-treating the obtained samples; Conditioning the pretreated samples in a conventional environment; Combine the conditioned samples to test the glass transition temperature of the faulty blades in the wind farm; Among them, the process of inspecting the blade includes: Find all damaged areas of the blade through preliminary inspection; Combined with all the damaged areas of the blades found in the preliminary survey, conduct a focused survey to find the key damaged areas; Combine the key damage areas to preliminarily determine the cause of the damage, and find the key locations from the key damage areas based on the preliminary determination; The key positions found are used as sampling positions.

2. A method for detecting glass transition temperature of faulty blades in a wind farm according to claim 1, characterized in that: If the cause of damage cannot be preliminarily determined by combining the key damaged areas, all damaged areas of the blade found by the preliminary investigation will be used as sampling locations.

3. A method for detecting glass transition temperature of faulty blades in a wind farm according to claim 1 or 2, characterized in that: The initial inspection identified all damaged areas of the blade, including: Detailed inspection of the damaged blade spar cap, web and trailing edge UD from the blade root to the blade tip. Mark the location of all the damages with a marker, take photos to record the damage shape and measure the damage size. Conduct a detailed inspection of the visible parts of the inner and outer cavities of the damaged blade shell from the blade root to the blade tip, mark the location of the damage with a marker, take photos to record the damage shape and measure the damage size; Carry out a detailed inspection of the visible parts of the damaged blade bonding area from the root to the tip of the blade, mark the location of the damage with a marker and record it with photos, and measure the width of the adhesive in the contactable area.

4. A method for detecting glass transition temperature of faulty blades in a wind farm according to claim 1, characterized in that: When conducting a focused investigation on all damaged areas of the blade found during the preliminary investigation, the position and size of the fracture in the key damaged area should be marked with a marker pen, and detailed photos should be taken and recorded, requiring the photos to clearly reflect the damage situation; the position and size of other damaged areas should be marked with a marker pen, and special attention should be paid to taking photos and recording abnormal points.

5. The method for detecting the glass transition temperature of a faulty wind farm blade according to claim 1, characterized in that: Sampling requirements include: Take samples from the chord-wise beam cap, web, shell, shell bonding area, and web bonding area at the fracture location, with three samples taken from each area; Take samples from the chord-wise beam cap, web, shell, shell bonding area, and web bonding area at a distance of one meter from the fracture position toward the blade root and blade tip, and take three samples from each area; At other locations, samples of relevant fiberglass and structural adhesives are taken every four meters, and the number of samples taken is one.

6. A method for detecting glass transition temperature of faulty blades in a wind farm according to claim 1, characterized in that: The obtained samples are pre-processed, including: Remove the sample flash by sandpaper polishing; Sample after removing flash by solvent cleaning; The cleaned samples were then placed in a dryer and dried for more than twelve hours.

7. The method for detecting glass transition temperature of faulty blades in a wind farm according to claim 1, characterized in that: Combine the conditioned samples to test the glass transition temperature of wind farm fault blades, including: A1. Take out three identical sample dishes, namely the first sample dish, the second sample dish, and the third sample dish, and weigh the three sample dishes; A2. After placing the sample in the first sample dish, weigh the first sample dish again; A3. Place the empty second sample dish and the third sample dish into the sample holder of the differential scanning calorimeter, with the second sample dish serving as the sample dish and the third sample dish serving as the reference dish, and cover the sample holder with a cover; A4. Raise the temperature at a rate of 20 °C / min and scan and record the temperature from 50 °C below the expected glass transition temperature to 30 °C above the expected glass transition temperature. Set the DSC curve obtained at this time as the baseline. A5. Turn on the cooling device of the differential scanning calorimeter to rapidly cool the interior of the sample holder to room temperature. A6. After the temperature inside the sample holder returns to room temperature, take out the second sample dish from the sample holder, and put the first sample dish containing the sample into the sample holder; A7. The temperature inside the sample holder is raised to 50°C at a rate of 3°C / min, i.e., the upper limit of the temperature for the first scan after the sample is placed is set to 50°C to eliminate the influence of small molecules on the test results. A8. Maintain the internal temperature of the sample holder for 5 minutes; A9. Rapidly cool the internal temperature of the sample holder to 50°C below the expected glass transition temperature; A10. Maintain the internal temperature of the sample holder for 5 minutes; A11. Raise the temperature inside the sample holder for the second time at a rate of 20 °C / min and record the temperature until it reaches a temperature higher than the expected extrapolated starting temperature. The complete DSC curve was obtained by 30°C high, and the half-height method was used to obtain the value of the complete DSC curve to obtain the determined extrapolated onset temperature. , and the determined extrapolated onset temperature as the glass transition temperature of the leaf.

8. A method for detecting glass transition temperature of faulty blades in a wind farm according to claim 7, characterized in that: Also included are: A12, cool the interior of the sample holder to room temperature, take out the first sample dish, and observe whether the first sample dish is deformed or has sample overflow. If so, lower the upper limit temperature and retest. Otherwise, proceed to step A13; A13. Weigh the first sample dish containing the sample again. If the mass decreases and exceeds the set range, it is considered that the sample has undergone chemical changes. Lower the upper temperature limit and retest.

9. A method for detecting glass transition temperature of faulty blades in a wind farm according to claim 7 or 8, characterized in that: Before using the differential scanning calorimeter for testing, nitrogen gas was introduced into the sample holder of the differential scanning calorimeter to exhaust the air inside the sample holder.

10. A method for detecting glass transition temperature of faulty blades in a wind farm according to claim 7 or 8, characterized in that: The first sample dish, the second sample dish and the third sample dish are cleaned before use.

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