Device and method for detecting and eliminating residual stress of circumferential weld of wind power tower

Abstract

The invention provides a wind power tower drum circumferential weld residual stress detection and elimination device, and belongs to the field of metal surface machining.The device comprises two coaxial circular rings, a plurality of movable fixing frames arranged in the circumferential direction of the circular rings and a placement table, and the circular rings are provided with inner annular sliding grooves and outer annular sliding grooves which are coaxial; the placement table rotates along the inner annular sliding groove or the outer annular sliding groove, a plurality of pulleys matched with the inner annular sliding groove or the outer annular sliding groove are installed on the side edge of the placement table, an ultrasonic probe and an ultrasonic impact gun are fixedly installed on the placement table, and the residual stress is calculated according to the detection result of the ultrasonic probe. Adjusting the impact amplitude of the ultrasonic impact gun according to the residual stress; the invention further provides a detection elimination method. The residual stress at the weld joints of the inner wall and the outer wall of the wind power tower drum ring can be detected and eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of metal surface processing, and in particular to a device and method for detecting and eliminating residual stress in a girth weld of a wind power tower. Background Art

[0002] Ultrasonic waves can detect residual stress in welds. Ultrasonic impact therapy utilizes ultrasonic waves to impact the weld surface at high speed and high frequency, causing plastic deformation and reducing stress concentration. It can even create a compressive plastic deformation layer on the surface, effectively eliminating harmful residual stress in the weld area and introducing beneficial compressive stress, thereby significantly improving the fatigue strength of the specimen. Ultrasonic impact therapy can reduce metal surface roughness in the weld area, improve metal surface quality, reduce welding residual stress, change the surface metal structure in the affected area, and strengthen the weld area.

[0003] As the supporting structure of wind turbine generators, wind turbine towers have high requirements for strength and corrosion resistance. Ultrasonic impact testing can be applied to the girth welds of wind turbine towers to further enhance their strength.

[0004] In the prior art, the Chinese utility model patent "An ultrasonic strengthening and stress relief device for a tower" with announcement number CN219117518U discloses an ultrasonic strengthening and stress relief device for a tower, which uses an ultrasonic impact gun to eliminate stress at the welding point on the tower, supports the tower through a support mechanism, and uses the rotation of the support wheel to drive the tower to rotate to adjust the position of the weld scar on the side of the tower. At the same time, the ultrasonic impact gun is used to eliminate the stress of the annular weld scar. The ultrasonic impact gun is driven to move horizontally by the cooperation between the first motor, the first screw rod, and the first slider, thereby eliminating the stress of the horizontal weld scar. The height of the ultrasonic impact gun is adjusted by an electric push rod, so that it can adapt to towers with different outer diameters for support and stress relief.

[0005] However, the above-mentioned stress relief device can only eliminate the residual stress on the periphery of the wind turbine tower, and cannot detect and eliminate the residual stress at the weld on the inner wall of the wind turbine tower. In addition, the above-mentioned stress relief device does not have the ability to adjust the speed and needle diameter to impact the circumferential weld of the wind turbine tower according to the size of the residual stress. Summary of the Invention

[0006] The technical problem to be solved by the present invention is how to detect and eliminate the residual stress at the welds on the inner and outer walls of a wind turbine tower ring.

[0007] The present invention solves the above-mentioned technical problems through the following technical solutions: a device for detecting and eliminating residual stress in the ring weld of a wind turbine tower, the device comprising two coaxial circular rings, a plurality of movable fixed frames arranged along the circumference of the circular rings, and a placement platform, the circular rings are provided with a coaxial inner circular groove and an outer circular groove, the placement platform rotates along the inner circular groove or the outer circular groove, a plurality of pulleys cooperating with the inner circular groove or the outer circular groove are installed on the side of the placement platform, an ultrasonic probe and an ultrasonic impact gun are fixedly installed on the placement platform, the residual stress is calculated according to the detection results of the ultrasonic probe, and the impact amplitude of the ultrasonic impact gun is adjusted according to the residual stress.

[0008] Beneficial effects: The present invention adjusts the movable fixing frame according to the size of the wind turbine tower ring, fixes the circular ring on the outside or inside of the wind turbine tower ring, and then installs the pulley on the placement platform in the inner annular groove or the outer annular groove of the circular ring. When detecting and eliminating the residual stress of the weld on the outer wall of the wind turbine tower ring, the pulley is placed in the outer annular groove of the circular ring at the outer wall of the wind turbine tower ring. When detecting and eliminating the residual stress of the weld on the inner wall of the wind turbine tower ring, the pulley is placed in the inner annular groove of the circular ring at the inner wall of the wind turbine tower ring. The placement platform is equipped with an ultrasonic probe and an ultrasonic impact gun and rotates along the outer or inner ring of the wind turbine tower ring. The residual stress is calculated according to the detection result of the ultrasonic probe. The impact amplitude of the ultrasonic impact gun is adjusted according to the residual stress to fully eliminate the residual stress of the wind turbine tower ring weld. Changing the impact amplitude based on the residual stress data can effectively ensure the service life of the wind turbine tower ring weld.

[0009] Preferably, the two coaxial rings are fixedly connected via a plurality of connecting columns, the movable fixing frame is fixed to the connecting member via a fixing member, and the connecting member is fixed to the rings.

[0010] Beneficial effects: The present invention fixes the movable fixing frame on the connecting member through the fixing piece, and by loosening the fixing piece, the movable fixing frame is adaptively adjusted according to the size of the wind tower ring. When the end of the movable fixing frame abuts against the inner wall or outer wall of the wind tower ring, tightening the fixing piece can fix the circular ring on the inner ring or outer periphery of the wind tower ring, and then placing the placement platform on the circular ring can realize the detection and elimination of residual stress near the weld of the inner wall or outer wall of the wind tower ring.

[0011] Preferably, the movable fixing frame is U-shaped, and its two end surfaces are parallel to the axis of the ring.

[0012] Beneficial effect: The present invention sets the two end faces of the U-shaped movable fixing frame to be parallel to the axis of the circular ring, thereby ensuring that the movable fixing frame is adjusted during actual installation, and its end faces can fully fit and press against the inner wall or outer wall of the wind tower ring, thereby stably fixing the circular ring on the wind tower ring, thereby ensuring the stability and accuracy of the measurement of the entire device during the rotation process.

[0013] Preferably, the device further comprises a support rod and a lifting rod, the ultrasonic probe is fixed to one end of the lifting rod, the other end of the lifting rod is passed through the support rod, and the end of the support rod is fixed to the placement table.

[0014] Preferably, a plurality of weights are sleeved on the screw at one end of the ultrasonic impact gun, and an impact needle is installed at the other end of the ultrasonic impact gun through the impact head.

[0015] Beneficial effects: The present invention arranges a plurality of weights on the screw at one end of the ultrasonic impact gun. When in actual use, the plurality of weights are locked on the screw, and the impact load can be kept stable by adding or removing the weights.

[0016] Preferably, the ultrasonic impact gun is slidably mounted on the first slide rail through the first slider, and the end of the first slide rail is slidably mounted on the second slide rail through the second slider. The second slide rail is located on the upper surface of the placement table, and the second slide rail is perpendicular to the first slide rail and perpendicular to the rotating shaft connecting the two pulleys.

[0017] Beneficial effect: The present invention sets a first slide rail and a second slide rail in directions perpendicular to each other, so that the ultrasonic impact gun can be moved in the horizontal and vertical spaces, and the position of the ultrasonic impact gun can be adjusted according to the position of the weld to be detected and eliminated in the wind turbine tower ring.

[0018] The present invention also provides a method for detecting and eliminating residual stress in the girth weld of a wind turbine tower, using the device for detecting and eliminating residual stress in the girth weld of a wind turbine tower. The method comprises:

[0019] S1. Prepare two sets of devices of different specifications according to the size of the wind turbine tower ring, adjust the movable fixing frame, and place the rings of one set of devices on the outer wall of the wind turbine tower ring, and place the rings of the other set of devices on the inner wall of the wind turbine tower ring;

[0020] S2. When detecting and eliminating the residual stress of the weld on the outer wall of the wind turbine tower ring, the pulley is placed in the outer annular chute of the circular ring on the outer wall of the wind turbine tower ring; when detecting and eliminating the residual stress of the weld on the inner wall of the wind turbine tower ring, the pulley is placed in the inner annular chute of the circular ring on the inner wall of the wind turbine tower ring;

[0021] S3. Calculate the residual stress according to the detection results of the ultrasonic probe, and adjust the impact amplitude of the ultrasonic impact gun according to the magnitude and distribution of the residual stress.

[0022] Preferably, the residual stress is calculated according to the detection result of the ultrasonic probe as follows:

[0023]

[0024] Where σ is the residual stress, a positive value indicates compressive stress, a negative value indicates tensile stress, V is the velocity of the longitudinal wave propagating along the stress direction, V0 is the velocity of the longitudinal wave in the zero stress state, K is the acoustoelastic coefficient, λ and μ are the second-order elastic coefficients, and l and m are the third-order elastic coefficients.

[0025] Preferably, according to the size of the wind turbine tower ring, the fixing piece is loosened, the movable fixing frame is adjusted, and when the end of the movable fixing frame abuts against the inner wall or outer wall of the wind turbine tower ring, the fixing piece is tightened.

[0026] Preferably, the impact amplitude A of the ultrasonic impact gun is:

[0027]

[0028] Wherein, σ is the residual stress, r is the radius of the impact head, k is a coefficient related to material properties and impact conditions, f is the ultrasonic impact frequency, t is the ultrasonic impact time, m is the mass of the impact head, w is the angular frequency, w = 2πf, It is a normal distribution function that describes the attenuation of the impact load within the radius of the impact head. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a frame assembly in a device for detecting and eliminating residual stress in a girth weld of a wind turbine tower provided by an embodiment of the present invention;

[0030] Figure 2 A half-section view of a frame assembly in a device for detecting and eliminating residual stress in a girth weld of a wind turbine tower provided by an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of the installation of a detection component and a stress relief component in a device for detecting and relieving residual stress in a girth weld of a wind turbine tower provided by an embodiment of the present invention;

[0032] Figure 4 For the present invention Figure 3 A partial enlarged view of the installation position of the third slider;

[0033] Figure 5 A flow chart of a method for detecting and eliminating residual stress in a girth weld of a wind turbine tower provided by an embodiment of the present invention;

[0034] In the figure: 11 circular ring, 111 inner annular slide, 112 outer annular slide, 12 movable fixing frame, 13 connecting column, 14 fixing member, 15 connecting member, 21 placing table, 22 pulley, 23 first slider, 24 first slide rail, 25 second slider, 26 second slide rail, 27 driving motor, 28 third slider, 29 limiting plate, 31 ultrasonic probe, 32 supporting rod, 33 lifting rod, 41 ultrasonic impact gun, 42 weight, 43 screw, 44 impact head, 45 impact needle. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the following describes the technical solutions of the present invention clearly and completely with reference to specific embodiments and the accompanying drawings. It is obvious that the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] See also Figure 1-Figure 3 This embodiment provides a device for detecting and eliminating residual stress in a girth weld of a wind turbine tower, comprising:

[0037] The frame assembly includes two coaxial rings 11 and a plurality of movable fixing frames 12 arranged along the circumference of each ring 11. Figure 1 In the exemplary embodiment, four movable fixing frames 12 are provided on each circular ring 11, respectively located at 0 degrees, 90 degrees, 180 degrees and 360 degrees of the circular ring 11. The circular ring 11 is provided with a coaxial inner annular groove 111 and an outer annular groove 112. The two coaxial circular rings 11 are fixedly connected by a plurality of connecting columns 13. The movable fixing frame 12 is fixed to the connecting member 15 by a fixing member 14. The connecting member 15 is fixed to the circular ring 11. The movable fixing frame 12 is provided with a groove, and the connecting member 15 is provided with a through hole. The fixing member 14 can be a bolt. Through the combination of the bolt and nut, one end of the bolt is passed through the through hole of the connecting member 15 and installed in the groove. By loosening or tightening the bolt, the connecting member 15 and the movable fixing frame 12 can be moved relative to each other or fixedly connected. The circular ring 11 can be designed as a whole or as a detachable and assembled structure.

[0038] The present invention adjusts the movable fixing frame according to the size of the wind tower ring, fixes the circular ring on the outside or inside of the wind tower ring, and then installs the pulley on the placement platform in the inner annular groove or the outer annular groove of the circular ring. When detecting and eliminating the residual stress of the weld on the outer wall of the wind tower ring, the pulley is placed in the outer annular groove of the circular ring at the outer wall of the wind tower ring. When detecting and eliminating the residual stress of the weld on the inner wall of the wind tower ring, the pulley is placed in the inner annular groove of the circular ring at the inner wall of the wind tower ring. The placement platform is equipped with an ultrasonic probe and an ultrasonic impact gun and rotates along the outer periphery or inner ring of the wind tower ring. The residual stress is calculated according to the detection result of the ultrasonic probe, and the impact amplitude of the ultrasonic impact gun is adjusted according to the residual stress to fully eliminate the residual stress of the wind tower ring weld. Changing the impact amplitude based on the residual stress data can effectively ensure the service life of the wind tower ring weld.

[0039] The present invention fixes the movable fixing frame on the connecting member through a fixing piece, and by loosening the fixing piece, the movable fixing frame is adaptively adjusted according to the size of the wind turbine tower ring, so that the weld position can be accurately positioned. When the end of the movable fixing frame abuts the inner wall or outer wall of the wind turbine tower ring, tightening the fixing piece can fix the circular ring on the inner circle or outer periphery of the wind turbine tower ring, and then placing the placing platform on the circular ring can realize the detection and elimination of residual stress near the weld of the inner wall or outer wall of the wind turbine tower ring. In order to ensure the uniformity and consistency of the residual stress elimination of the device, it is necessary to ensure that the device is fixedly installed horizontally as much as possible. The device of the present invention has two groups when in use. The radius of the inner annular slide groove of one group of circular rings is larger than the maximum outer diameter of the circle where the wind turbine tower ring weld is located, and the radius of the outer annular slide groove of one group of circular rings is smaller than the minimum inner diameter of the circle where the wind turbine tower ring weld is located, which can ensure that the circular ring can be fixed and run at any layer of weld.

[0040] The movable fixing frame 12 is U-shaped, and its two end faces are parallel to the axis of the circular ring 11. In actual use, by pressing the end faces of the movable fixing frame 12 against the inner wall or outer wall of the wind turbine tower ring, the entire device can be well fixed on the wind turbine tower ring, thereby realizing the detection and elimination of residual stress at the weld of the wind turbine tower ring. Taking into account that the tower ring is narrow at the top and wide at the bottom, the adjustment parameters of the movable fixing frames on the two coaxial circular rings are different.

[0041] The connecting component includes a placement platform 21 and a plurality of pulleys 22 fixed on one side of the placement platform 21. Figure 3 In actual use, by installing a drive motor 27 on the placement platform 21, it is possible to drive multiple pulleys 22 to roll in the inner annular groove 111 or the outer annular groove 112, driving the placement platform 21 to move along the outer wall or inner wall of the wind tower ring.

[0042] The detection component includes an ultrasonic probe 31, a support rod 32, and a lifting rod 33 installed on the placement table 21. The ultrasonic probe 31 is fixed to one end of the lifting rod 33, and the other end of the lifting rod 33 is passed through the support rod 32. The end of the support rod 32 is fixed on the placement table 21.

[0043] The stress relief assembly includes an ultrasonic impact gun 41 and weights 42 installed on the placement table 21. The axis of the ultrasonic impact gun 41 is perpendicular to the upper surface of the placement table 21. Several weights 42 are mounted on a screw 43 at one end of the ultrasonic impact gun 41. The other end of the ultrasonic impact gun 41 is equipped with an impact needle 45 through an impact head 44.

[0044] The ultrasonic impact gun 41 is slidably mounted on the first slide rail 24 via the first slider 23. The end of the first slide rail 24 is slidably mounted on the second slide rail 26 via the second slider 25. The second slide rail 26 is located on the upper surface of the placement table 21. The second slide rail 26 is perpendicular to the first slide rail 24 and perpendicular to the rotating shaft 221 connecting the two pulleys 22. In actual use, two drive motors can be installed to drive the first slide rail 23 and the second slide rail 25 respectively. The first slide rail 24 is perpendicular to the upper surface of the placement table 21. When the first slide rail 23 slides in the first slide rail 24, it can drive the ultrasonic impact gun 41 to move in a direction perpendicular to the upper surface of the placement table 21, which is defined as the longitudinal direction. The second slide rail 26 is parallel to the upper surface of the placement table 21. When the second slide rail 25 slides in the second slide rail 26, it can drive the ultrasonic impact gun 41 to move in a direction parallel to the upper surface of the placement table 21, which is defined as the transverse direction. In this way, the ultrasonic impact gun 41 can be moved in both the transverse and longitudinal directions.

[0045] See also Figure 3 The sidewall of the ultrasonic impact gun 41 is fixedly mounted in the chute of the sidewall of the first slider 23 via the third slider 28. The third slider 28 is dovetail-shaped, and the chute of the sidewall of the first slider 23 is a dovetail groove that matches the third slider 28. By designing the chute of the third slider 28 and the sidewall of the first slider 23 into a dovetail shape, the stability of the installation of the ultrasonic impact gun 41 is achieved. Limiting plates 29 are also fixedly mounted at both ends of the matching dovetail groove of the third slider 28 to prevent the ultrasonic impact gun 41 from falling off in the natural state or working state.

[0046] See also Figure 4 The present invention also provides a method for detecting and eliminating residual stress in the girth weld of a wind turbine tower, using a device for detecting and eliminating residual stress in the girth weld of a wind turbine tower. The method comprises:

[0047] S1. Prepare two groups of devices with different specifications according to the outer diameter and inner diameter of the wind tower ring, loosen the fixing piece 14, adjust the movable fixing frame 12, and when the end of the movable fixing frame 12 abuts against the inner wall or outer wall of the wind tower ring, tighten the fixing piece 15, and place the circular rings in one group of devices on the outer wall of the wind tower ring, and place the circular rings in the other group of devices on the inner wall of the wind tower ring.

[0048] S2. When detecting and eliminating the residual stress of the weld on the outer wall of the wind tower ring, place the pulley in the outer annular groove of the circular ring on the outer wall of the wind tower ring. When detecting and eliminating the residual stress of the weld on the inner wall of the wind tower ring, place the pulley in the inner annular groove of the circular ring on the inner wall of the wind tower ring.

[0049] S3. Calculate the residual stress based on the detection results of the ultrasonic probe, and adjust the impact amplitude of the ultrasonic impact gun based on the residual stress. The specific calculation process includes the following:

[0050] S3.1. Measure residual stress using LCR waves. First, determine the incident angle of the ultrasonic probe 31, i.e., the first critical angle θ. LCR

[0051]

[0052] Among them, V1 is the longitudinal wave velocity of the wedge, V2 is the longitudinal wave velocity of the workpiece, L is the propagation sound path, and R is the curvature radius of the curved surface component, which is + for convex surfaces and - for concave surfaces.

[0053] S3.2. According to the theory of acoustic elasticity, the propagation velocity of elastic waves in stressed solid materials depends not only on the material's second-order and higher-order elastic constants and density, but also on the residual stress. The velocity of ultrasonic longitudinal waves propagating along the direction of residual stress changes with changes in stress. The relationship between the velocity of longitudinal waves propagating along the stress direction and the residual stress is:

[0054]

[0055] Where V is the longitudinal wave velocity propagating along the stress direction; V0 is the longitudinal wave velocity in the zero stress state; σ is the residual stress, a positive value indicates compressive stress, and a negative value indicates tensile stress; K is the acoustoelastic coefficient, and λ and μ are the second-order elastic coefficients, and l and m are the third-order elastic coefficients.

[0056] The relationship between the critical refracted longitudinal wave speed and the residual stress is:

[0057]

[0058] Where dV is the change in sound velocity and dσ is the change in stress.

[0059] get:

[0060]

[0061] Where t0 is the propagation time of the critical refracted longitudinal wave under zero stress state; dt is the change in propagation time of the ultrasonic critical refracted longitudinal wave within the propagation distance L due to stress.

[0062] S3.3. The motion equation of the ultrasonic impact load is used to describe the motion of the impact head 45 during the ultrasonic impact process. The motion equation can be expressed as:

[0063] X(t)=Asin(wt) (5)

[0064] Where X(t) is the displacement of the impact head at time t, t is the ultrasonic impact time, A is the ultrasonic impact amplitude, angular frequency w (w = 2πf), and f is the ultrasonic impact frequency, which represents the number of complete vibrations completed by the impact head per unit time.

[0065] During ultrasonic impact, the pressure load equation generated by the impact head on the component is:

[0066] F(t)=|4(πf) 2 mAsin(wt)| (6)

[0067] Where m is the mass of the impact head.

[0068] The impact head applies a pressure load to the component during ultrasonic impact. However, in actual applications, the impact load is applied over the entire radius of the impact head. To more accurately describe the distribution of the impact load, a normal distribution of the impact load within the impact radius is considered. The impact load expression F(t) is:

[0069]

[0070] Where: r is the radius of the ultrasonic impact head.

[0071] The above expression considers the distribution of the impact load within the radius of the impact head, where is a normal distribution function that describes the attenuation of impact load within the radius of the impact head. This expression assumes that the impact load is greatest at the center of the impact head and decays exponentially with increasing distance from the center. It more accurately predicts the impact load's effects on a component, especially when considering the uneven distribution of impact loads.

[0072] S3.4. During the ultrasonic impact time t, the material is subjected to multiple impacts. Assuming that the stress increments generated by each impact are linearly superimposed (the actual situation may be more complicated, this is a simplification), the relationship between the residual stress σ and the number of impacts n (n = ft), the maximum impact load, and the coefficient k is:

[0073] σ=knF(t) (8)

[0074] Where k is a dimensionless coefficient related to material properties and impact conditions. The coefficient k can be determined through experiments. The experimental steps are as follows:

[0075] Wind turbine tower material samples with known elastic modulus E and density ρ were selected, and an ultrasonic impact device was used to impact the samples with different amplitudes A, frequencies f and impact times t.

[0076] Based on ultrasonic testing, the residual stress σ of the impact is measured according to formula (2).

[0077] Substitute the test data into the formula The coefficient k is solved by data fitting method.

[0078] Combining formula (7) and formula (8), the residual stress σ can be obtained as follows:

[0079]

[0080] The ultrasonic shock amplitude A can be derived from the above expression:

[0081]

[0082] Working principle: The wind turbine tower ring weld residual stress detection and elimination device of the present invention is mainly used to detect and eliminate the residual stress at the wind turbine tower ring weld, and is mainly used to detect and eliminate the residual stress near the welding position of the two sections of wind turbine tower ring. The wind turbine tower ring has a cylindrical shape and a shape that is narrow at the top and wide at the bottom. In actual application, the device of the present invention usually requires two groups, which are used for detecting and eliminating the residual stress on the outer wall of the wind turbine tower ring and the outer wall weld respectively.

[0083] According to the outer diameter and inner diameter of the wind tower ring, two groups of devices with different specifications are prepared, the circular ring in one group of devices is placed on the outer wall of the wind tower ring, the fixing piece 14 is loosened, and the movable fixing frame 12 is adjusted. When the end face of the movable fixing frame 12 close to the center of the circular ring is close to the outer wall of the wind tower ring, the fixing piece 14 is tightened so that the end face of the movable fixing frame 12 close to the center of the circular ring is close to the outer wall of the wind tower ring, and the circular ring 11 is firmly fixed on the outer wall of the wind tower ring, and the circular ring in the other group of devices is placed on the inner wall of the wind tower ring, the fixing piece 14 is loosened, and the movable fixing frame 12 is adjusted. When the end face of the movable fixing frame 12 away from the center of the circular ring is close to the wind tower ring, the circular ring 11 is firmly fixed on the outer wall of the wind tower ring. When the inner wall of the wind tower ring is touched by the movable fixing member 14, the end face of the movable fixing frame 12 away from the center of the ring is close to the inner wall of the wind tower ring, and the ring 11 is firmly fixed to the inner wall of the wind tower ring; when it is necessary to detect and eliminate the residual stress of the weld on the outer wall of the wind tower ring, the pulley 22 is placed on the outer annular groove 112 of the ring 11 at the outer wall of the wind tower ring; when it is necessary to detect and eliminate the residual stress of the weld on the inner wall of the wind tower ring, the pulley 22 is placed on the inner annular groove 111 of the ring 11 at the inner wall of the wind tower ring; the residual stress is calculated according to the detection result of the ultrasonic probe 31, and the impact amplitude of the ultrasonic impact gun 41 is adjusted according to the residual stress.

[0084] The present invention sets a plurality of weights 42 on a screw rod 43 at one end of an ultrasonic impact gun 41. In actual use, the plurality of weights can be locked on the screw rod 43 by nuts, and the impact load can be kept stable by adding or removing the weights.

[0085] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. Wind turbine tower girth weld residual stress detection and elimination device, characterized by: The device comprises two coaxial circular rings (11), a plurality of movable fixed frames (12) arranged along the circumference of the circular rings (11), and a placement platform (21). The circular rings (11) are provided with a coaxial inner annular chute and an outer annular chute. The placement platform (21) rotates along the inner annular chute or the outer annular chute. A plurality of pulleys (22) cooperating with the inner annular chute or the outer annular chute are installed on the side of the placement platform (21). An ultrasonic probe (31) and an ultrasonic impact gun (41) are fixedly installed on the placement platform (21). Residual stress is calculated according to the detection result of the ultrasonic probe (31), and the impact amplitude of the ultrasonic impact gun (41) is adjusted according to the magnitude and distribution of the residual stress.

2. The device for detecting and eliminating residual stress in the girth weld of a wind turbine tower according to claim 1, characterized in that: Two coaxial circular rings (11) are fixedly connected via a plurality of connecting columns (13); a movable fixing frame (12) is fixed to a connecting member (15) via a fixing member (14); and the connecting member (15) is fixed to the circular rings (11).

3. The device for detecting and eliminating residual stress in the girth weld of a wind turbine tower according to claim 1, characterized in that: The movable fixing frame (12) is U-shaped, and its two end faces are parallel to the axis of the ring (11).

4. The wind turbine tower girth weld residual stress detection and elimination device according to claim 1, characterized in that: The device also includes a support rod (32) and a lifting rod (33). The ultrasonic probe (31) is fixed to one end of the lifting rod (33). The other end of the lifting rod (33) is inserted into the support rod (32). The end of the support rod (32) is fixed on the placement platform (21).

5. The wind turbine tower girth weld residual stress detection and elimination device according to claim 1 is characterized in that: A plurality of weights (42) are sleeved on a screw at one end of the ultrasonic impact gun (41), and an impact needle (45) is installed at the other end of the ultrasonic impact gun (41) through an impact head (44).

6. The wind turbine tower girth weld residual stress detection and elimination device according to claim 1, characterized in that: The ultrasonic impact gun (41) is slidably mounted on a first slide rail (24) via a first slider (23); the end of the first slide rail (24) is slidably mounted on a second slide rail (26) via a second slider (25); the second slide rail (26) is located on the upper surface of the placement table (21); and the second slide rail (26) is perpendicular to the first slide rail (24) and perpendicular to a rotation axis connecting the two pulleys (22).

7. A method for detecting and eliminating residual stress in a girth weld of a wind turbine tower, comprising: using the device for detecting and eliminating residual stress in a girth weld of a wind turbine tower according to any one of claims 1 to 6, characterized in that: Methods include: S1. According to the size of the wind turbine tower ring, two groups of devices of different specifications are prepared, and the movable fixing frame (12) is adjusted. The circular ring (11) of one group of devices is placed on the outer wall of the wind turbine tower ring, and the circular ring (11) of the other group of devices is placed on the inner wall of the wind turbine tower ring; S2. When detecting and eliminating the residual stress of the weld seam on the outer wall of the wind tower ring, the pulley (22) is placed in the outer annular chute of the circular ring on the outer wall of the wind tower ring; when detecting and eliminating the residual stress of the weld seam on the inner wall of the wind tower ring, the pulley (22) is placed in the inner annular chute of the circular ring on the inner wall of the wind tower ring; S3. Calculating the residual stress based on the detection result of the ultrasonic probe (31), and adjusting the impact amplitude of the ultrasonic impact gun (41) based on the magnitude and distribution of the residual stress.

8. The method for detecting and eliminating residual stress in the girth weld of a wind turbine tower according to claim 7, characterized in that: According to the size of the wind turbine tower ring, the fixing piece (14) is loosened, the movable fixing frame (12) is adjusted, and when the end of the movable fixing frame (12) abuts against the inner wall or outer wall of the wind turbine tower ring, the fixing piece (15) is tightened.

9. The method for detecting and eliminating residual stress in the girth weld of a wind turbine tower according to claim 7, characterized in that: The method for calculating residual stress based on the detection results of the ultrasonic probe is: Where σ is the residual stress, a positive value indicates compressive stress, a negative value indicates tensile stress, V is the velocity of the longitudinal wave propagating along the stress direction, V0 is the velocity of the longitudinal wave in the zero stress state, K is the acoustoelastic coefficient, λ and μ are the second-order elastic coefficients, and l and m are the third-order elastic coefficients.

10. The method for detecting and eliminating residual stress in the girth weld of a wind turbine tower according to claim 7, characterized in that: The impact amplitude A of the ultrasonic impact gun is: Wherein, σ is the residual stress, r is the radius of the impact head, k is a coefficient related to material properties and impact conditions, f is the ultrasonic impact frequency, t is the ultrasonic impact time, m is the mass of the impact head, w is the angular frequency, w = 2πf, It is a normal distribution function that describes the attenuation of the impact load within the radius of the impact head.

Images