CN112161795A - A biaxial co-loading measurement device for wind turbine blade fatigue test - Google Patents

Abstract

The invention provides a double-shaft cooperative loading measuring device for a blade fatigue test of a wind driven generator, wherein a waving direction vibration exciter and a shimmy direction vibration exciter are arranged on a test blade, and a strain acquisition module is arranged on the test blade; the waving direction displacement sensor and the shimmy direction displacement sensor are respectively arranged on the waving direction vibration exciter and the shimmy direction vibration exciter and are used for collecting the amplitudes in the waving direction and the shimmy direction; the controller controls the waving direction vibration exciter and the shimmy direction vibration exciter under the instruction of the upper computer, and exciting forces are respectively applied to the test blade from the waving direction and the shimmy direction, so that the test blade generates resonance deformation to reach a test bending moment; the upper computer is connected with the data acquisition module through a wireless network. The invention adopts the data acquisition module of wireless transmission signals, not only realizes biaxial cooperative loading on the wind driven generator blade, but also meets the requirement of conveniently acquiring various mechanical data required by the test, and provides reliable experimental data for the fatigue test of the wind driven generator blade.

Description

A biaxial co-loading measurement device for wind turbine blade fatigue test

technical field

The invention belongs to the technical field of wind power blade fatigue test, and in particular relates to a biaxial coordinated loading measurement device for wind turbine blade fatigue test.

Background technique

As an important part of the development of new energy, wind power is a device that converts wind energy into electrical energy. As an important part of wind turbines, blades are crucial for blade reliability and life analysis, and life analysis is mostly Fatigue life, so the fatigue life analysis of the blade is an important part. At present, most foreign countries use hydraulic excitation and forced displacement method for fatigue excitation. The hydraulic excitation is to use the resonance principle in the two axial directions of the wind turbine blade, and use the hydraulic actuator to drive the mass block to generate the excitation force. The forced displacement law is the displacement calculated by the measured blade according to the design bending moment, forcing the blade to reach the displacement required for deformation to generate the test bending moment to complete the fatigue test. However, the above-mentioned methods are expensive and have strict requirements on the experimental site. In China, the motor drives the eccentric mass block to generate the exciting force to generate the fatigue loading bending moment. However, the method adopted in China is only for the excitation in a single direction, and cannot well fit the load condition of the blade in actual operation.

There are relatively few researches on the two-axis vibration excitation device of wind turbine blades in China, which are mainly similar to those in foreign countries, and the two-axis vibration is excited by hydraulic pressure. However, although the hydraulic excitation equipment has the advantages of stable excitation frequency and buffer energy absorption between the hydraulic cylinders, the excitation of several hydraulic cylinders will not cause major interference, and the output excitation force is stable. However, the hydraulic vibration excitation device requires high site requirements, high equipment cost, and is not easy to install and maintain. Another invention is a two-axial vibration excitation device driven by a motor, but in this invention, only two excitation sources are installed in one excitation position, which makes the coupling between the two motors more obvious.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: to provide a biaxial cooperative loading measuring device for wind turbine blade fatigue test, which can not only realize biaxial cooperative loading on wind turbine blades, but also can meet the requirements of convenient collection and testing laboratory. The required mechanical data can provide reliable experimental data for the fatigue test of wind turbine blades.

The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a biaxial coordinated loading measurement device for wind turbine blade fatigue test, the device includes a test blade, the root of the test blade is fixed by a fixed base, and the test blade The swing direction vibration exciter and the swing direction vibration exciter are arranged on the upper part, and the device is characterized in that: the device further includes a data acquisition module, a host computer and a controller; wherein,

The data collection module includes a strain collection module, a swing direction displacement sensor and a swing direction displacement sensor; the strain collection module is arranged on the test blade; the swing direction displacement sensor and the swing direction displacement sensor are respectively arranged on the swing direction vibration exciter and the swing direction displacement sensor. On the swing direction exciter, it is used to collect the amplitudes in the swing direction and the swing direction;

Under the instruction of the host computer, the controller controls the vibration exciter in the swing direction and the vibration exciter in the swing direction, and gives the test blade excitation force from the swing direction and the swing direction respectively, so that the test blade generates resonance deformation and reaches the test bending moment. ;

The upper computer and the data acquisition module are connected through a wireless network to obtain the experimental data of the experimental blade.

According to the above solution, the strain acquisition module includes a strain gauge and a wireless transmitter.

According to the above solution, the swing direction displacement sensor and the swing direction displacement sensor respectively include a gyroscope and a wireless transmitter.

According to the above scheme, the position of the strain gauge is set according to the following requirements:

According to the transient dynamic model of the blade model, a section with a larger strain change of the test blade is selected to arrange more dense strain gauges, and the larger strain change is a preset range, and the more denser is a preset range;

The other parts of the test blade are spaced with strain gauges.

According to the above scheme, the tip of the test blade is provided with a blade tip running trajectory acquisition module, which is connected to the upper computer through a wireless network.

According to the above solution, the blade tip running trajectory acquisition module includes a gyroscope and a wireless transmitter.

According to the above scheme, the swing direction vibration exciter includes a swing direction frequency converter, a swing direction motor, a swing direction reducer, a swing direction eccentric mass block, a swing direction rotary encoder and a swing direction counterweight; the swing direction exciter The swing direction fixture is rigidly fixed to the test blade, the upper end of the swing direction clamp is connected to the swing direction motor and the swing direction reducer, and the lower end of the swing direction clamp is fixed to the swing direction counterweight; the swing direction motor is connected to the swing direction through the power cord. The frequency converter is connected and controlled by the swing direction inverter; the swing direction eccentric mass block is set on the shaft end of the swing motor through the fixing part; the swing direction rotary encoder is connected with the main shaft of the swing direction reducer through the synchronous belt, and the swing direction rotary encoder The output end is connected with the upper computer through the wireless network.

According to the above solution, the structure of the vibration exciter in the swing direction is the same as that of the swing direction exciter.

According to the above scheme, the vibration exciter in the swing direction is set at a position 70% of the distance from the root of the test blade to be rigidly fixed, and the vibration exciter in the swing direction is set at a certain distance that does not interfere with the vibration exciter in the swing direction .

The beneficial effects of the invention are as follows: the data acquisition module of wireless transmission signal is adopted, which can not only realize biaxial coordinated loading on the wind turbine blades, but also can satisfy various mechanical data required for the convenient collection of the test, which is a good tool for wind turbine blades. The fatigue test provides reliable experimental data; at the same time, the wireless transmission signal reduces the deviation caused by the vibration of the data line during the test, and reduces the interference problem of the test blade on the data line during the test.

Description of drawings

FIG. 1 is a schematic structural diagram of a biaxial co-loading test device designed by the present invention.

Figure 2 is a schematic diagram of the structure of the swing direction exciter.

Figure 3 is a schematic diagram of the structure of the vibration exciter in the pendulum direction.

In the figure: Fixed base 1; Test blade 2; Strain acquisition module 3; Swing direction displacement sensor 4.1; Swing direction displacement sensor 4.2; Swing direction vibration exciter 5; Swing direction vibration exciter 6; Module 7; controller 8; host computer 9; swing direction motor 5.1; swing direction reducer 5.2; swing direction eccentric mass block 5.3; swing direction rotary encoder 5.4; swing direction frequency converter 5.5; swing direction counterweight 5.6; swing direction Direction fixture 10; Swing direction motor 6.1; Swing direction reducer 6.2; Swing direction eccentric mass block 6.3; Swing direction rotary encoder 6.4; Swing direction frequency converter 6.5; Swing direction counterweight 6.6; Swing direction Orientation fixture 11.

Detailed ways

The present invention will be further described below with reference to specific examples and accompanying drawings.

The present invention provides a biaxial coordinated loading measurement device for wind turbine blade fatigue test, as shown in Figures 1 to 3, comprising a test blade 2, the root of the test blade 2 is fixed by a fixed base 1, and the test blade 2 There is a swing direction vibration exciter 5 and a swing direction vibration exciter 6 , and the device also includes a data acquisition module, a host computer 9 and a controller 8 .

The data acquisition module includes a strain acquisition module 3, a swing direction displacement sensor 4.2 and a swing direction displacement sensor 4.1; the strain acquisition module 3 is arranged on the test blade 2; the swing direction displacement sensor 4.2 and the swing direction displacement sensor 4.1 are respectively provided The swing direction exciter 5 and the swing direction exciter 6 are used to collect the amplitudes in the swing direction and the swing direction.

Under the instruction of the host computer 9, the controller 8 controls the vibration exciter 5 in the swing direction and the vibration exciter 6 in the swing direction, and gives the test blade 2 an exciting force from the swing direction and the swing direction respectively, so that the test blade 2 generates a vibration force. The resonance deformation reaches the test bending moment.

The upper computer 9 is connected with the data acquisition module through a wireless network to obtain the experimental data of the experimental blade 2 . The test data collected by the data acquisition is transmitted to the host computer for display, and the mechanical changes of the blade during the test can be observed from time to time. It mainly outputs the rotational speed and phase of the exciter in the swing direction, the rotational speed and phase of the exciter in the swing direction, the stress and strain, the amplitude of the swing direction, the amplitude of the swing direction, and the change of the blade tip posture. These serve as important measurement data for the blade fatigue testing system.

Further, the strain acquisition module 3 includes a strain gauge and a wireless transmitter. The positions of the strain gauges are set according to the following requirements: According to the transient dynamic model of the blade model, select the section with the larger strain change of the test blade 2 to arrange the more dense strain gauges, and the larger strain change is preset. The said denser is a preset range; other parts of the test blade 2 are arranged with strain gauges at intervals. In order to ensure the accuracy of the collected data, the sampling frequency is required to be no less than 50 times the excitation frequency. According to this principle, the appropriate range of the data acquisition system is selected. The invention adopts wireless data acquisition, the acquisition end is arranged on the loading device, and the receiving end is arranged in other positions that do not interfere with the loading device, and the acquisition signal is transmitted through the wireless signal to reduce the cumbersome wiring problem of the whole device.

Further, the swing direction displacement sensor 4.2 and the swing direction displacement sensor 4.1 respectively include a gyroscope and a wireless transmitter. In this implementation, the installation positions of the two are respectively set at positions corresponding to the swing vibration exciter. The device collects the acceleration signal in the measurement direction of the test blade 2 and converts it into a displacement signal through integration. The displacement measured by the micro inertial navigation system is the amplitude of the blade.

Still further, the tip of the test blade 2 is provided with a blade tip running trajectory acquisition module 7, which is connected to the upper computer 9 through a wireless network. The blade tip running trajectory acquisition module 7 includes a gyroscope and a wireless transmitter. The sensor is connected with wireless data acquisition, transmits acceleration signal, and converts it into displacement signal through quadratic integration. The equipment mainly collects the running trajectory of the blade tip, which is compared with the running trajectory of the hydraulic biaxial loading device.

In this embodiment, the swing direction exciter 5 includes a swing direction inverter 5.5, a swing direction motor 5.1, a swing direction reducer 5.2, an eccentric mass block 5.3 in the swing direction, a swing direction rotary encoder 5.4 and a swing direction counterweight Block 5.6; the swing direction vibration exciter 5 is rigidly fixed to the test blade 2 by the swing direction clamp 10, the upper end of the swing direction clamp 10 is connected to the described swing direction motor 5.1 and the swing direction reducer 5.2, and the lower end of the swing direction clamp 10 is fixed to the described swing direction motor 5.1 and swing direction reducer 5.2. The swinging direction counterweight 5.6; the swinging direction inverter 5.5 is connected to the controller 8, the swinging direction motor 5.1 is connected to the swinging direction inverter 5.5 through the power cord and the frequency is controlled by the swinging direction inverter 5.5; the swinging direction eccentric mass block 5.3 is set on the shaft end of the swinging motor 5.1 through the fixing part; the swinging direction rotary encoder 5.4 is connected with the main shaft of the swinging direction reducer 5.2 through a synchronous belt, and the output end of the swinging direction rotary encoder is connected to the upper computer through a wireless network. The swing direction exciter 5 is used as the main exciter, and the installation position of the test blade 2 is not fixed, as long as the exciting force generated in the swing direction can meet the design bending moment of the fatigue test of each section of the blade. The cross section can contain more than 70% and can be used as the excitation point. In the present invention, the excitation point in the swing direction is set at a position 70% away from the root of the test blade 2 . The swing direction motor 5.1 provides driving force, and the swing direction reducer 5.2 reduces the starting speed and increases the torque, so as to avoid the problem that the swing direction eccentric mass 5.3 is too large to rotate. The eccentric mass block 5.3 for adjusting the swing direction is used to adjust the exciting force, and the swing direction inverter 5.5 is used to adjust the rotational speed of the swing direction motor 5.1 to reach the resonance frequency. The swinging direction counterweight 5.6 is used to adjust the bending moment distribution of the test blade 2 section. The centrifugal force generated by the swing direction exciter 5 by rotating in the swing direction is used as an exciting force.

The structure of the vibration exciter 6 in the swing direction is the same as that of the swing direction exciter. Specifically, the vibration exciter 6 in the swing direction includes a swing direction frequency converter 6.5, a swing direction motor 6.1, a swing direction reducer 6.2, an eccentric mass block 6.3 in the swing direction, a swing direction rotary encoder 6.4 and The swing direction counterweight 6.6; the swing direction vibration exciter 6 is rigidly fixed to the test blade 2 through the swing direction clamp 10, and the upper end of the swing direction clamp 11 is connected to the described swing direction motor 6.1 and the swing direction reducer 6.2, The lower end of the swing direction fixture 11 fixes the swing direction counterweight 6.6; the swing direction inverter 6.5 is connected to the controller 8 through a signal line, and the swing direction inverter 6.5 is connected to the swing direction reducer 6.2 through the swing direction reducer 6.2. The vibration direction motor 6.1 is connected; the swing direction eccentric mass block 6.3 is arranged at the main shaft end of the reducer; The terminal is connected with the host computer through wireless transmission. The setting of the excitation point in the swing direction is similar to that in the swing direction. Under the requirement of the test bending moment, the excitation point in the swing direction is set at a position 60% away from the blade root. The difference is that the centrifugal force generated by the vibration exciter 6 rotating in the swing direction is used as the excitation force source.

Since the two-direction exciter uses a motor to drive the eccentric mass block to rotate, the setting of the two exciter position points needs to consider the rotation range of the two rotating shafts to avoid interference leading to test accidents. The vibration exciter in the two directions of waving and pendulum is used as the loading device, which adopts the principle of resonance. When the blade is subjected to the excitation frequency close to its own natural frequency, the blade will produce resonance phenomenon. The resonance principle that needs to be avoided in industrial production is the core theory of this invention. When the blade resonates, the relatively small amount of energy absorbed by the blade causes a large deformation. In order to make the deformation meet the requirements of the test bending moment, the amplitude of the amplitude can be changed to achieve the required bending moment by changing the magnitude of the exciting force.

According to the fatigue test design requirements of the experimental blade, the appropriate eccentric mass block is selected to be installed on the two exciters, so that they can generate appropriate excitation force. The frequency converter connected to the vibration exciter in the direction of blade waving and swaying is controlled by the controller, and the excitation frequency is controlled by adjusting the rotational speed in the two directions and the initial phase. When the deceleration motor rotates and drives the eccentric mass block to rotate, a centrifugal force is generated, and the component force of the centrifugal force in the swing or swing direction is the exciting force, and the exciting force satisfies the law of the cosine function. The exciting force acts on the blade to generate a bending moment, which in turn causes a cosine change in the amplitude of the blade loading point. Among them, the strain gauge collects the stress and strain of each section, and the displacement changes in two directions, that is, the component of blade amplitude change, are collected by the two axial micro-INS; the blade tip is collected by the micro-INS at the blade tip. pose changes.

After the above-mentioned process is carried out for the loading device of the present invention, the design amplitude and the stress and strain in the two directions are inevitably changed. Ensure that the original operating frequency and phase of the main exciter remain unchanged, and adjust the frequency and phase of the slave exciter through the controller. According to the strain and displacement data measured in the swing direction and the swing direction displayed in the host computer as the adjustment basis, the bending moments generated by the two-way joint excitation are generally the same.

Specific example Implementation process: After the two fatigue loading devices are installed in the swing direction and swing direction of the blade, respectively, set the position of each sensor. First start the swing direction exciter (5) and the swing direction exciter (6), give the loading device an initial rotation speed n ₁ , n ₂ (obtained from the first-order natural frequency of the blade) and the bending moment required for the test According to the stress amplitude and amplitude corresponding to the bending moment of the fatigue test design, the frequency of the slave vibration exciter is adjusted so that in the After adjustment, the magnitude of the stress amplitude and amplitude generated by the biaxial synergistic loading is similar to the stress amplitude and amplitude of the blade swing direction alone; the stress amplitude and amplitude of the blade swing direction alone are close to each other. This realizes the test effect produced by biaxial co-loading and simultaneously satisfies the excitation effect of uniaxial swaying or swaying.

Compared with the traditional data line transmission, the wireless data acquisition reduces the workload of wiring, reduces the deviation caused by the tremor of the data line during the test, and reduces the damage of the blade during the test process. Interference problems caused by data lines. The strain gauge, the displacement sensor, the rotary encoder and the six-axis miniature inertial navigation unit in the present invention are all used with the matched wireless data acquisition.

The displacement sensor of the present invention adopts a six-axis miniature inertial navigation measurement unit, and its output signal is a three-axis acceleration, which is converted into a displacement signal through integration, thereby obtaining the displacement change in space, and can more truly reflect the operation of the blade during the test process. Trajectories and displacement increments in one direction.

Compared with other types of dual-degree-of-freedom loading devices, the present invention focuses on building a set of loading measurement devices, which can not only realize biaxial coordinated loading on wind turbine blades, but also meet the requirements of collecting various mechanical data for testing. , to provide reliable experimental data for the fatigue test of wind turbine blades.

Compared with the foreign hydraulic-driven biaxial loading device, the motor drive adopted in the present invention has lower cost and convenient maintenance.

The above embodiments are only used to illustrate the design ideas and features of the present invention, and the purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly, and the protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made according to the principles and design ideas disclosed in the present invention fall within the protection scope of the present invention.

Claims (9)

1. The utility model provides a biax is loading measuring device in coordination for aerogenerator blade fatigue test, this device is fixed through the unable adjustment base including experimental blade, the root of experimental blade, is equipped with on the experimental blade to wave orientation vibration exciter and the orientation vibration exciter that shimmys, its characterized in that: the device also comprises a data acquisition module, an upper computer and a controller; wherein,

the data acquisition module comprises a strain acquisition module, a waving direction displacement sensor and a shimmy direction displacement sensor; the strain acquisition module is arranged on the test blade; the waving direction displacement sensor and the shimmy direction displacement sensor are respectively arranged on the waving direction vibration exciter and the shimmy direction vibration exciter and are used for collecting the amplitudes in the waving direction and the shimmy direction;

the controller controls the swing direction vibration exciter and the shimmy direction vibration exciter under the instruction of the upper computer, and exciting force is respectively applied to the test blade from the swing direction and the shimmy direction, so that the test blade generates resonance deformation to reach a test bending moment;

the upper computer is connected with the data acquisition module through a wireless network to obtain test data of the experimental blade.

2. The apparatus of claim 1, wherein: the strain acquisition module comprises a strain gauge and a wireless transmitter.

3. The apparatus of claim 1, wherein: the flapping direction displacement sensor and the shimmy direction displacement sensor respectively comprise a gyroscope and a wireless transmitter.

4. The apparatus of claim 2, wherein: the position of the strain gauge is set according to the following requirements:

according to a transient dynamic model of a blade model, selecting a section with larger strain change of a test blade and arranging more densely strain gauges, wherein the strain change is a larger preset range, and the strain gauges are more densely arranged in the preset range;

the other parts of the test blades are provided with strain gauges at intervals.

5. The apparatus of claim 1, wherein: the tip of the test blade is provided with a blade tip running track acquisition module which is connected with an upper computer through a wireless network.

6. The apparatus of claim 5, wherein: the blade tip running track acquisition module comprises a gyroscope and a wireless transmitter.

7. The apparatus of claim 1, wherein: the flapping direction vibration exciter comprises a flapping direction frequency converter, a flapping direction motor, a flapping direction reducer, a flapping direction eccentric mass block, a flapping direction rotary encoder and a flapping direction balancing weight; the waving direction vibration exciter is rigidly fixed with the test blade through a waving direction clamp, the upper end of the waving direction clamp is connected with the waving direction motor and the waving direction reducer, and the lower end of the waving direction clamp is fixed with the waving direction balancing weight; the waving direction motor is connected with the waving direction frequency converter through a power line and is controlled by the waving direction frequency converter to control the frequency; the swing direction eccentric mass block is arranged at the rotating shaft end of the swing motor through a fixing piece; the main shaft of waving direction rotary encoder and waving direction reduction gear passes through the hold-in range and is connected, and the output of waving direction rotary encoder passes through wireless network and upper computer connection.

8. The apparatus of claim 7, wherein: the structure of the oscillation-swinging direction vibration exciter is the same as that of the swinging direction vibration exciter.

9. The apparatus of claim 7, wherein: the flapping direction vibration exciter is arranged at the position of the test blade, which is 70% away from the root part, and is rigidly fixed, and the shimmy direction vibration exciter is arranged at a certain distance which cannot interfere with the flapping direction vibration exciter.

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