Wind power blade fatigue testing device
By combining acoustic emission technology and piezoelectric ceramic sensors, the problem of traditional detection methods being unable to detect internal defects in wind turbine blades in real time has been solved, achieving efficient and accurate fatigue performance assessment and ensuring the safe operation of wind turbine blades.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-17
- Publication Date
- 2026-03-31
AI Technical Summary
Traditional fatigue testing methods for wind turbine blades are difficult to detect internal defects in real time and with high sensitivity, especially micro-cracks and delamination. They also have low detection efficiency and cannot meet the fatigue performance evaluation requirements of wind turbine blades under actual operating conditions.
By employing acoustic emission technology combined with piezoelectric ceramic sensors, preamplifiers, and acoustic emitters, the piezoelectric ceramic sensors monitor minute changes inside the blade in real time. The preamplifier and acoustic emitter then perform signal processing and analysis to achieve real-time detection of internal defects in the blade.
It enables real-time and sensitive detection of internal defects in wind turbine blades, improves detection efficiency, and provides a guarantee for quality control and safe operation in the wind power industry.
Smart Images
Figure CN224066512U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of wind turbine blades, specifically a wind turbine blade fatigue testing device. Background Technology
[0002] Wind turbine blades are crucial components of the entire wind power generation system. During the operation of wind turbines, blades are subjected to strong external wind loads, impacts from sand and gravel particles, and ultraviolet radiation. During operation, blades must meet requirements for lightweight construction, optimal fatigue strength, and mechanical properties. As wind turbine power continues to increase, the demands on blade performance also rise. Therefore, material selection and optimization of the manufacturing process are extremely important for wind turbine blades. From the initial steel, aluminum, and wood, to the current fiber-reinforced polymer (FRP) composites, FRP offers advantages such as good fatigue resistance and high strength, largely resisting the interference of harsh environments on the stable operation of the blades. Currently, glass fiber reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP) are the most commonly used materials.
[0003] During the fatigue testing of wind turbine blades, traditional visual inspection methods mainly rely on manual visual inspection, which can only detect obvious defects on the surface of the blade. It is difficult to detect small internal defects and potential damage. Although non-destructive testing technologies such as ultrasonic testing and radiographic testing can detect internal defects of the blade, these methods usually need to be carried out under specific conditions, resulting in low detection efficiency and difficulty in detecting the fatigue performance of the blade under actual operating conditions. Utility Model Content
[0004] To address the shortcomings of existing technologies, this invention provides a wind turbine blade fatigue testing device. Utilizing acoustic emission technology, through the coordinated operation of a piezoelectric ceramic sensor, a preamplifier, and an acoustic emitter, it can detect the generation and propagation of internal defects in wind turbine blades under fatigue loads in real time and with high sensitivity, including micro-cracks and delamination.
[0005] To achieve the above objectives, this utility model is implemented through the following technical solution: a wind turbine blade fatigue testing device, comprising a protective shell, a fatigue loading device installed on the inner wall of the protective shell, a frame structure of the fatigue loading device installed on the inner bottom wall of the shell, a loading fixture of the fatigue loading device installed on the upper surface of the frame structure, a hydraulic cylinder of the fatigue loading device installed on the inner top wall of the protective shell, a pressure-applying element fixedly installed at the output end of the hydraulic cylinder, a pressure roller for rotation installed at the bottom end of the pressure-applying element, and a composite material specimen for receiving fatigue load placed on the upper part of the loading fixture.
[0006] The protective housing contains an acoustic emission device, which consists of two sensors, two preamplifiers, and an acoustic emitter. The two sensors are respectively installed at both ends of the composite material specimen. Each sensor is connected to the preamplifier via a signal line, and the preamplifier is connected to the acoustic emitter via a data line.
[0007] Preferably, the end of the loading fixture that contacts the composite material specimen is cylindrical.
[0008] Preferably, the gain selector of the preamplifier is set to 40dB, and the values of PDT, HDT and HLT are set to 50μs, 200μs and 300μs, respectively.
[0009] Preferably, the sensor is a piezoelectric ceramic sensor.
[0010] Preferably, the outer surface of the pressure roller is provided with anti-slip texture, and the pressure roller is driven to rotate by a motor.
[0011] Compared with existing technologies, this utility model has the following advantages: The piezoelectric ceramic sensor, through its acoustic emission equipment, possesses advantages such as high sensitivity, wide frequency response, non-destructive testing, convenient installation, and high reliability. It can achieve real-time monitoring of the blade without affecting its structure and performance. Utilizing acoustic emission technology, through the coordinated work of the piezoelectric ceramic sensor, preamplifier, and acoustic emitter, it can detect the generation and propagation of internal defects in wind turbine blades under fatigue loads in real time and with high sensitivity, including micro-cracks and delamination. The various parts of the entire testing device work together to quickly and accurately complete the fatigue test of wind turbine blades, providing strong support for quality control and safe operation in the wind power industry. Furthermore, the pressure roller allows for fatigue testing even when it is not rotating, and rapid adjustment of the composite material specimen's position while rotating, shortening preparation time and improving the overall efficiency of the fatigue testing process. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0013] Figure 2 This is a schematic diagram of the internal structure of the protective shell of this utility model;
[0014] Figure 3 The load-displacement curve of the composite material specimen of this utility model is shown.
[0015] The components include: 1. Protective shell; 2. Fatigue loading device; 201. Frame structure; 202. Loading fixture; 203. Hydraulic cylinder; 3. Lead screw; 4. Nut; 5. Pressure application element; 501. Pressure roller; 6. Composite material specimen; 7. Acoustic emission equipment; 701. Sensor; 702. Preamplifier; 703. Acoustic emission instrument; 8. T-shaped slide; 9. T-shaped slider; 10. Connecting parts. Detailed Implementation
[0016] like Figures 1-3 As shown, a wind turbine blade fatigue testing device includes a protective shell 1. A fatigue loading device 2 is installed on the inner wall of the protective shell 1. The frame structure 201 of the fatigue loading device 2 is installed on the inner bottom wall of the shell. The loading fixture 202 of the fatigue loading device 2 is installed on the upper surface of the frame structure 201. Two sets of symmetrical T-shaped grooves 8 are formed on the upper surface of the frame structure 201. A T-shaped slider 9 is slidably connected inside each T-shaped groove 8. Each T-shaped slider 9 is fixedly connected to its adjacent loading fixture 202. The number of loading fixtures 202 is set to two. Two connecting parts 10 are fixedly installed on both sides of the clamp 202. A lead screw 3 is slidably connected between the two sets of connecting parts 10. The threads at both ends of the lead screw 3 are arranged in opposite directions. The lead screw 3 passes through the two connecting parts 10. Two nuts 4 are threadedly connected to the outer surfaces of the two lead screws 3. Each nut 4 abuts against the connecting part 10 closest to it. The hydraulic cylinder 203 of the fatigue loading device 2 is installed on the inner top wall of the protective shell 1. A pressure element 5 is fixedly installed at the output end of the hydraulic cylinder 203. A pressure roller 501 for rotation is installed at the bottom end of the pressure element 5. The outer surface of the pressure roller 501 is... The surface is textured with anti-slip patterns. The pressure roller 501 is driven to rotate by a motor, which can be mounted on the pressure element 5 to fix the pressure element 5 relative to the motor. Sleeves are installed on both sides of the pressure element 5, and limit rods are inserted into the interior of each sleeve. Both limit rods are fixedly connected to the protective shell 1 to ensure stable lifting and lowering of the pressure element 5 and prevent deviation. A composite material specimen 6 to receive fatigue loads is placed on the upper part of the loading fixture 202. The end of the loading fixture 202 that contacts the composite material specimen 6 is cylindrical. Through this cylindrical design, the pressure element 5... When the pressure roller 501 and the loading fixture 202 come into contact with the composite material specimen 6, they can provide a relatively uniform pressure distribution on a large contact surface. This helps to ensure that the stress on each part of the composite material specimen 6 is relatively consistent during the bending fatigue loading process, avoids premature failure caused by local stress concentration, and thus more accurately simulates the stress situation in actual use. The fatigue loading device 2 uses three loading rates to test the composite material specimen 6. The three loading rates used in the bending test are 2 mm / min, 25 mm / min and 50 mm / min, respectively.
[0017] An acoustic emission device 7 is installed inside the protective housing 1. The acoustic emission device 7 comprises two sensors 701, two preamplifiers 702, and a PACSAMOS-48 acoustic emission instrument 703. The sensors 701 are piezoelectric ceramic sensors. Due to their high sensitivity, the piezoelectric ceramic sensors 701 can monitor subtle changes in wind turbine blades under fatigue loads in real time. By continuously monitoring the acoustic emission signals, the damage evolution of the blades at different loading stages can be understood, providing detailed data support for assessing the bending fatigue life of the blades. The preamplifiers 702, 703, and 704 are also included. The gain selector of 2 is set to 40dB, and the values of PDT, HDT and HLT are set to 50μs, 200μs and 300μs respectively. Two sensors 701 are installed at both ends of the composite material specimen 6. The two sensors 701 are fixed to the two loading fixtures 202 respectively. Each sensor 701 is connected to the preamplifier 702 through a signal line. The preamplifier 702 is connected to the acoustic emitter 703 through a data line. The two preamplifiers 702 are fixed to the two loading fixtures 202 respectively. The acoustic emitter 703 is fixed to the protective shell 1.
[0018] In use, first, rotate the two sets of nuts 4 to adjust the positions of the two loading clamps 202 according to the length of the composite material specimen 6. Then, activate the hydraulic cylinder 203 to lower the pressure-applying element 5, bringing it into contact with the composite material specimen 6. As pressure continues to be applied, the composite material specimen 6 will bend due to the pressure from the pressure roller 501 on the pressure-applying element 5. When the pressure-applying element 5 resets, the composite material specimen 6 resets as well. This process is then repeated. Since the two piezoelectric ceramic sensors 701 are placed at both ends of the composite material specimen 6, each sensor 701 is connected to the preamplifier 702 via a signal line. When the composite material specimen 6 is under fatigue load... When internal defects or damage occur, elastic waves are generated. The piezoelectric ceramic sensor 701 converts these elastic waves into weak electrical signals. The electrical signal output by the sensor 701 is transmitted to a preamplifier 702 connected to it. The preamplifier 702 amplifies the signal, and the gain selector is set to 40dB to significantly enhance the weak signal. Simultaneously, the preamplifier 702 processes the signal according to the set parameters PDT50μs, HDT200μs, and HLT300μs to determine the definition time, impact lock-in time, and impact end time of the wave impact, in order to accurately identify and process the acoustic emission signal. It should be noted that PDT50μs is the "Peak" parameter. HDT200μs is an abbreviation for "Definition Time," meaning the definition time for an impact is 50 microseconds. The definition time is a time parameter used to determine the start of an impact in an acoustic emission signal. When the signal exceeds a threshold and continues to rise within this time range, an impact can be considered to have begun. HDT200μs is an abbreviation for "Hitting Lockout Time," meaning the hit lockout time is 200 microseconds. The hit lockout time refers to the time range during which the system blocks subsequent signals and does not detect impacts to prevent the same impact from being detected multiple times after it is detected. HLT300μs is an abbreviation for "Hit Lockout Time." The abbreviation for "Time" indicates the impact end time. The amplified and processed signal is then transmitted via a data line to the acoustic emitter 703. The acoustic emitter 703 further processes and analyzes the received signal, including filtering, amplification, and digitization, to improve signal quality and resolution. The acoustic emitter 703 extracts parameters from the acoustic emission signal, such as amplitude, energy, and frequency, and identifies different failure modes and their damage evolution characteristics through data analysis algorithms. For example, based on the acoustic emission signals with specific characteristics generated by different failure modes, the type and extent of damage inside the composite material specimen 6 can be determined.Meanwhile, by analyzing the changing trend of continuously monitored acoustic emission signals, the damage evolution process of the specimen during fatigue can be understood, providing a basis for evaluating the fatigue performance of wind turbine blades. Through this connection and cooperative use, the piezoelectric ceramic sensor 701, preamplifier 702, and acoustic emission instrument 703 work together to detect and analyze the acoustic emission signals of the composite material specimen 6 under fatigue load, providing important data support for the fatigue test of wind turbine blades. Since the wind turbine blades are made of the same material as the composite material specimen 6, the bending fatigue value of the wind turbine blades can be determined based on the measured bending fatigue value of the composite material specimen 6. It should be noted that the fatigue loading device 2 uses three loading rates to test the composite material specimen 6. The three loading rates used in the bending test are 2 mm / min, 25 mm / min, and 50 mm / min, respectively. The composite material specimen 6 delaminated during the test is shown in the figure. Figure 3 As shown in the figure, the load and displacement curves of two composite specimens 6 under three loading rates are illustrated. The first peak value corresponds to the critical value for delamination initiation, and the second peak value represents the failure of the specimen. For the two specimens [0°16 / / 0°16] and [0° / 90°]4s / / [0° / 90°]4s, the first peak load under the loading rate is slightly smaller than the peak load under the quasi-static load. However, the crack propagation rate when delamination occurs in the [0° / 90°]4s / / [0° / 90°]4s specimen is faster than that in the [0°16 / / 0°16] specimen, indicating that the delamination resistance of the [0°16 / / 0°16] specimen is greater than that of the [0° / 90°]4s / / [0° / 90°]4s specimen. Traditional single loading rate test results have limitations because composite specimen 6 may exhibit different failure modes under different loading rates. Testing at three loading rates allows for cross-verification of test results. For example, at lower loading rates... At lower loading rates, composite specimen 6 may fail due to slow crack propagation, while at higher loading rates, it may experience instantaneous brittle fracture. If only a single loading rate is used, these different failure modes may be ignored. By testing at three loading rates, various failure conditions of the material can be captured more comprehensively, thereby improving the accuracy and reliability of fatigue performance evaluation of composite specimen 6, reducing evaluation errors caused by single test conditions, and simulating the stress conditions of composite specimen 6 under various actual working conditions through fatigue loading tests at three loading rates.
[0019] It should be noted that the end of the loading fixture 202 that contacts the composite material specimen 6 should be cylindrical. By setting it cylindrical, when the pressure roller 501 and the loading fixture 202 contact the specimen, they can provide a relatively uniform pressure distribution on a larger contact surface. This helps to ensure that the stress on each part of the composite material specimen 6 is relatively consistent during the bending fatigue loading process, avoids premature failure caused by local stress concentration, and thus more accurately simulates the stress situation in actual use.
[0020] Finally, the pressure roller 501 can be connected to an external motor. When the motor receives a start signal and begins to run, the motor's rotational motion is transmitted to the pressure roller 501, driving the pressure roller 501 to rotate around its axis. Since the pressure roller 501 is in direct contact with the composite material specimen 6 and its surface is treated with anti-slip material, friction is generated between the roller surface and the specimen during rotation. When the roller rotates, the friction is used to move the composite material specimen 6 on the loading fixture 202, thereby adjusting the position of the composite material specimen 6. It can precisely position itself at the optimal location required for fatigue testing. After the position of the composite material specimen 6 is adjusted, the motor stops working, and the pressure roller 501 also stops rotating. At this time, the hydraulic cylinder 203 starts working, driving the pressure element 5, which is equipped with the pressure roller 501, to descend until the pressure roller 501 contacts the composite material specimen 6 and applies pressure. During the repeated lifting and lowering of the hydraulic cylinder 203, the pressure roller 501 remains stationary, stably transmitting pressure to the composite material specimen 6, causing it to withstand periodic bending loads, thereby simulating wind turbine blades. The fatigue loads experienced during actual operation are then used to conduct fatigue tests. It should be noted that before the fatigue test, the position of the composite material specimen 6 is precisely adjusted by rotating the pressure roller 501. This ensures that the specimen's position on the loading fixture 202 is consistent for each test. This makes the initial stress state of each part of the specimen more stable and consistent when subjected to fatigue loads, avoiding uneven stress distribution caused by initial position deviations of the composite material specimen 6. This effectively improves the accuracy and repeatability of fatigue test results, providing a more reliable data basis for accurately evaluating the fatigue performance of wind turbine blades. Traditional methods require manual operation to adjust the position of the composite material specimen 6, which is cumbersome and time-consuming. The motor-driven adjustment method of the pressure roller 501 allows for quick and convenient adjustment of the specimen's position. Operators only need to control the start, stop, and direction of the motor to efficiently calibrate the specimen's position, shortening the preparation time before testing and improving the overall efficiency of the fatigue testing process. This helps to complete more sets of tests within a limited time, accelerating the progress of wind turbine blade fatigue performance research.
[0021] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A wind turbine blade fatigue testing apparatus comprising a containment enclosure (1), characterised in that: The inner wall of the protective shell (1) is provided with a fatigue loading device (2), the frame structure (201) of the fatigue loading device (2) is installed on the inner bottom wall of the shell, the loading clamp (202) of the fatigue loading device (2) is installed on the upper surface of the frame structure (201), the hydraulic cylinder (203) of the fatigue loading device (2) is installed on the inner top wall of the protective shell (1), the output end of the hydraulic cylinder (203) is fixedly provided with a pressure applying element (5), the bottom end of the pressure applying element (5) is provided with a pressure applying roller (501) for rotation, and the upper part of the loading clamp (202) is placed with a composite material test piece (6) for receiving fatigue load. The protective shell (1) is provided with an acoustic emission device (7), which comprises two sensors (701), two preamplifiers (702) and an acoustic emission instrument (703), the two sensors (701) are respectively installed on the two ends of the composite material test piece (6), each sensor (701) is connected with the preamplifier (702) through a signal line, and the preamplifier (702) is connected with the acoustic emission instrument (703) through a data line.
2. A wind turbine blade fatigue testing apparatus according to claim 1, wherein: The end of the loading clamp (202) in contact with the composite material test piece (6) is provided in a cylindrical shape.
3. The wind turbine blade fatigue testing apparatus of claim 1, wherein: The gain selector of the preamplifier (702) is set to 40dB, and the values of PDT, HDT and HLT are set to 50μs, 200μs and 300μs respectively.
4. A blade fatigue testing apparatus according to claim 1, wherein: The sensor (701) is a piezoelectric ceramic sensor (701).
5. The wind turbine blade fatigue testing apparatus of claim 1, wherein: The outer surface of the pressure applying roller (501) is provided with anti-skid lines.