Drill rod damping device based on bending beam semi-active nonlinear energy trap

Abstract

The invention relates to the technical field of drill rod vibration reduction, in particular to a drill rod vibration reduction device based on a bent beam semi-active nonlinear energy trap. The drill rod damping device based on the semi-active NES is suitable for deep hole machining and good in damping efficiency and comprises a connecting base, a mounting plate and NES components, and each NES component comprises a U-shaped auxiliary beam, an elastic main beam, a flexible hinge and a PID controller. Each U-shaped auxiliary beam is clamped in the corresponding annular groove, one end of each elastic main beam is fixed to the middle of a middle beam of the corresponding U-shaped auxiliary beam, the other end of each elastic main beam is fixed to the middle of the other side face of the flexible frame in the width direction, each U-shaped auxiliary beam is provided with a strain gauge, and the input end of the PID controller receives the multiple strain gauges. And the output end of the PID controller controls the plurality of piezoelectric ceramic stacks. The device is obvious in vibration suppression effect and suitable for drilling machining.

Description

Technical Field

[0001] The present invention relates to the technical field of drill pipe vibration reduction, and particularly to a drill pipe vibration reduction device based on a semi-active non-linear energy sink of a curved beam. Background Art

[0002] During the deep hole machining process, due to its special structure, classic problems in the machining process are formed: difficult vibration suppression, difficult guidance, difficult chip removal, difficult cooling and lubrication, low stiffness of the drill pipe system, etc. These problems have long troubled the deep hole machining industry, and during the machining process of ultra-large length-diameter ratio small deep holes, it is extremely vulnerable to external disturbances (such as drill pipe whirling, tool chatter, self-excited oscillation of cutting fluid, system forced vibration, etc.), which breaks the stable balance of the self-guiding part of the drill bit and exacerbates the non-linear vibration of the system. Currently, the vibration suppression methods used for deep hole machining have a narrow vibration suppression frequency band and the vibration suppression effect is not obvious. There is an urgent need for a simple and effective method to solve the non-linear vibration problem of ultra-large length-diameter ratio small deep holes machining.

[0003] As a non-linear passive vibration absorption device, the traditional Nonlinear Energy Sink (NES) has the advantage of being unaffected by external frequencies. It can control structural vibration through targeted energy transfer under broadband excitation and has good robustness. However, it should be noted that although the traditional NES can passively achieve vibration suppression in a relatively wide frequency band, its vibration reduction efficiency is sensitive to the uncertainty of system parameters and the amplitude of external excitation; while the semi-active NES has good parameter tuning ability and ideal vibration reduction effect, and has become the development trend of NES vibration suppression. Summary of the Invention

[0004] The purpose of the present invention is to provide a drill pipe vibration reduction device based on semi-active NES that is suitable for deep hole machining and has good vibration reduction efficiency, namely a drill pipe vibration reduction device based on a semi-active non-linear energy sink of a curved beam.

[0005] The present invention is implemented by adopting the following technical solutions: A drill pipe vibration damping device based on a semi-active non-linear energy sink of a curved beam, comprising a columnar connection base, a plurality of mounting plates, and multiple groups of NES components. An annular groove is provided in the axial middle of the connection base, and multiple groups of clamping grooves are evenly distributed circumferentially on the annular groove. Each group of clamping grooves includes two clamping grooves and are symmetrically distributed on the two side walls of the annular groove respectively. Both ends of each mounting plate are clamped on the two clamping grooves of each group of clamping grooves. Each group of NES components includes a U-shaped secondary beam with an arc-shaped longitudinal section, an arc-shaped elastic main beam, a flexible hinge, and a PID controller. Each U-shaped secondary beam is clamped in the annular groove. Each U-shaped secondary beam is located between two adjacent mounting plates. The opening of each U-shaped secondary beam faces the corresponding mounting plate direction, and both ends of it are respectively fixed to the left and right ends of the corresponding mounting plate. Each flexible hinge includes a rectangular flexible frame and a piezoelectric ceramic stack installed in the flexible frame and capable of expanding and contracting along the circumferential direction of the connection base. Each flexible frame is placed in the middle of the mounting plate, and both left and right ends of it are respectively fixed to both ends of the corresponding U-shaped secondary beam. The middle of one side surface in the width direction of each flexible frame is fixed to the corresponding mounting plate. One end of each elastic main beam is fixed to the middle of the middle beam of the corresponding U-shaped secondary beam, and the other end is fixed to the middle of the other side surface in the width direction of the corresponding flexible frame. Each U-shaped secondary beam is equipped with a strain gauge. The input end of the PID controller receives multiple strain gauges, and the output end of the PID controller controls multiple piezoelectric ceramic stacks to drive the corresponding flexible frame to expand and contract and deform.

[0006] Working principle: The structure involved in the present invention is a semi-active NES device. The U-shaped secondary beam is an additional mass, and the elastic main beam is a damping element and can provide non-linear stiffness. During use, one end of the columnar connection base is connected to the drill pipe, and the other end is connected to the drill bit. When the drill pipe vibrates, the strain gauge transmits the vibration signal to the PID controller. The PID controller outputs a certain voltage according to the vibration magnitude to control the expansion and contraction of the piezoelectric ceramic stack, causing it to generate displacement. After being amplified by the flexible frame, the flexible frame pushes the elastic main beam to bend and deform, generating non-linear stiffness. At this time, the elastic main beam forms an NES structure, and the drill pipe vibration is transferred to the elastic main beam. The elastic main beam bends and deforms in the circumferential direction. This process repeats continuously. When the vibration energy gradually decreases to a certain critical value, the system can no longer be captured by the next new resonance state. At this time, the system no longer meets the resonance capture condition. Therefore, most of the vibration energy will be consumed in the NES device and will not return to the main structure, thereby reducing the vibration generated by the drill pipe during machining. This structure can change the driving voltage of the piezoelectric ceramic stack through the PID controller, so that the elastic main beam generates different non-linear stiffnesses to achieve the suppression of different degrees of drill pipe vibration.

[0007] Furthermore, there is a circumferential spacing between the non-opening end of each U-shaped secondary beam and the adjacent mounting plate, which is convenient for disassembling and assembling the NES components.

[0008] Further, connecting plates for bolt connection with both ends of the mounting plate are fixed at both open ends of each U-shaped secondary beam, facilitating the installation and fixation of the U-shaped secondary beam.

[0009] Further, vertical limiting plates are fixed on three of the end faces of the mounting plate, namely the left limiting plate, the right limiting plate, and the middle limiting plate. The three limiting plates are integrally U-shaped and their openings are arranged towards the direction close to the corresponding U-shaped secondary beam. Two connecting plates on each U-shaped secondary beam are respectively clamped in the areas formed by the corresponding left limiting plate and the left end of the corresponding middle limiting plate, and the area formed by the corresponding right limiting plate and the right end of the corresponding middle limiting plate. The middle part of one side face in the width direction of each flexible frame is fixedly connected to the middle part of the corresponding middle limiting plate, making the structure specific and fixed.

[0010] Further, connecting blocks are fixed in the middle of the outer side faces of the four frame plates of each flexible frame, facilitating the fixation with the corresponding middle limiting plate, the elastic main beam, and both ends of the U-shaped secondary beam respectively.

[0011] Further, both side frame plates in the width direction of each flexible frame are V-shaped, facilitating telescopic deformation.

[0012] Further, a protective shell for waterproof encapsulation of the piezoelectric ceramic stack is adhesively fixed outside each flexible frame.

[0013] Further, the outer arc surfaces of the U-shaped secondary beam and the elastic main beam are concentric and have the same radius as the outer circumferential surface of the middle part of the connecting base, making the overall structure regular and occupying less space.

[0014] Further, there are three mounting plates and three groups of NES components, making the structure specific and standardized.

[0015] The beneficial effects produced by the present invention are as follows: Based on the semi-active non-linear energy sink, the present invention can effectively dissipate the energy generated from the vibration of the drill pipe, and the vibration suppression effect is relatively significant. Moreover, the non-linear stiffness in the non-linear energy sink of the bending beam can be indirectly changed by changing the driving voltage of the piezoelectric stack, thereby changing its vibration suppression ability in different frequency bands. The design of the present invention is reasonable, the structure is simple and effective, providing ideas and methods for the active vibration reduction method of the drill pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present invention and, together with the specification, are used to explain the principles of the present invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Schematic diagram of the overall structure of the present invention; Figure 2 Schematic diagram of the connection base structure; Figure 3 Schematic diagram of the structure of the U-shaped secondary beam and the elastic main beam; Figure 4 Schematic diagram of the structure of the mounting plate, left limit plate, right limit plate, and middle limit plate; Figure 5 Schematic diagram of the structure of the flexible frame; Figure 6 Schematic diagram of the assembly structure of a single set of NES components and the mounting plate; Figure 7 Schematic diagram of the assembly structure of three sets of NES components and three mounting plates; Figure 8 Drill pipe free vibration attenuation simulation with the NES components described in the present invention; Figure 9 Schematic diagram of the amplitudes of the drill pipe with the NES components described in the present invention and the drill pipe without the NES components.

[0019] In the figure: 1 - connection base, 2 - mounting plate, 3 - annular groove, 4 - card slot, 5 - U-shaped secondary beam, 6 - elastic main beam, 7 - flexible frame, 8 - piezoelectric ceramic stack, 9 - circumferential spacing, 10 - connecting plate, 11 - left limit plate, 12 - middle limit plate, 13 - right limit plate, 14 - connecting block, 15 - protective shell. Detailed implementation manners

[0020] In order to more clearly understand the above-mentioned objects, features, and advantages of the present invention, the following will further describe the solutions of the present invention. It should be noted that, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0021] In the description, it should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance. It should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0022] In the following description, many specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0023] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] As Figures 1 to 7 shown, a drill pipe vibration damping device based on a curved beam semi-active non-linear energy sink includes a columnar connection base 1, a plurality of mounting plates 2, and multiple groups of NES components. An annular groove 3 is provided in the axial middle of the connection base 1, and multiple groups of card slots 4 are circumferentially and evenly distributed on the annular groove 3. Each group of card slots 4 includes two card slots 4 and are symmetrically distributed on the two side walls of the annular groove 3 respectively. Both ends of each mounting plate 2 are clamped to the two card slots 4 of each group of card slots 4. Each group of NES components includes a U-shaped secondary beam 5 with an arc-shaped longitudinal section, an arc-shaped elastic main beam 6, a flexible hinge, and a PID controller. Each U-shaped secondary beam 5 is clamped in the annular groove 3. Each U-shaped secondary beam 5 is located between two adjacent mounting brackets. The opening of each U-shaped secondary beam 5 faces the corresponding mounting plate 2 and its two ends are respectively fixed to the left and right ends of the corresponding mounting plate 2. Each flexible hinge includes a rectangular flexible frame 7 and a piezoelectric ceramic stack 8 installed in the flexible frame 7 and capable of expanding and contracting along the circumferential direction of the connection base 1. Each flexible frame 7 is placed in the middle of the mounting plate 2 and its left and right ends are respectively fixed to the two ends of the corresponding U-shaped secondary beam 5. One side surface in the width direction of each flexible frame 7 is fixed to the corresponding mounting plate. One end of each elastic main beam 6 is fixed to the middle of the middle beam of the corresponding U-shaped secondary beam 5, and the other end is fixed to the middle of the other side surface in the width direction of the corresponding flexible frame 7. Each U-shaped secondary beam 5 is equipped with a strain gauge. The input end of the PID controller receives multiple strain gauges, and the output end of the PID controller controls multiple piezoelectric ceramic stacks 8 to drive the corresponding flexible frame 7 to expand and contract.

[0025] Working principle: The structure involved in the present invention is a semi-active NES device. The U-shaped secondary beam 5 is the additional mass, and the elastic main beam 6 is the damping element, which can provide non-linear stiffness. During use, one end of the columnar connection base 1 is connected to the drill pipe, and the other end is connected to the drill bit. When the drill pipe vibrates, the strain gauge transmits the vibration signal to the PID controller. The PID controller outputs a certain voltage according to the vibration magnitude to control the expansion and contraction of the piezoelectric ceramic stack 8, causing it to generate displacement. After being amplified by the flexible frame 7, the flexible frame 7 pushes the elastic main beam 6 to bend and deform, generating non-linear stiffness. At this time, the elastic main beam 6 forms an NES structure, and the drill pipe vibration is transferred to the elastic main beam 6. The elastic main beam 6 bends and deforms in the circumferential direction. This process cycles continuously. When the vibration energy gradually decreases to a certain critical value, the system can no longer be captured by the next new resonance state. At this time, the system no longer meets the conditions for resonance capture. Therefore, most of the vibration energy will be consumed within the NES device and will not return to the main structure, thereby reducing the vibration generated by the drill pipe during machining. This structure can change the driving voltage of the piezoelectric ceramic stack 8 through the PID controller, enabling the elastic main beam 6 to generate different non-linear stiffnesses and achieving the suppression of different degrees of drill pipe vibration.

[0026] During specific implementation, a circumferential spacing 9 is provided between the non-opening end of each U-shaped secondary beam 5 and the adjacent mounting plate 2 to facilitate the disassembly and assembly of the NES components.

[0027] During specific implementation, connecting plates 10 for bolt connection with both ends of the mounting plate 2 are fixed at both opening ends of each U-shaped secondary beam 5 to facilitate the installation and fixation of the U-shaped secondary beam 5.

[0028] During specific implementation, vertical limiting plates are fixed on three of the end faces of the mounting plate 2, namely the left limiting plate 11, the right limiting plate 13, and the middle limiting plate 12. The three limiting plates are integrally U-shaped and their openings are arranged towards the direction close to the corresponding U-shaped secondary beam 5. The two connecting plates 10 on each U-shaped secondary beam 5 are respectively clamped within the area formed by the corresponding left limiting plate 11 and the left end of the corresponding middle limiting plate 12, and within the area formed by the corresponding right limiting plate 13 and the right end of the corresponding middle limiting plate 12. One side surface in the width direction of each flexible frame 7 is fixedly connected to the middle of the corresponding middle limiting plate 12, making the structure specific and fixed.

[0029] During specific implementation, connection blocks 14 are fixed in the middle of the outer side surfaces of the four frame plates of each flexible frame 7 to facilitate the fixation with the corresponding middle limiting plate 12, the elastic main beam 6, and both ends of the U-shaped secondary beam 5 respectively.

[0030] During specific implementation, both side frame plates in the width direction of each flexible frame 7 are V-shaped to facilitate telescopic deformation.

[0031] In specific implementation, a protective case 15 for waterproof encapsulation of the piezoelectric ceramic stack 8 is adhesively fixed outside each flexible frame 7 with glue.

[0032] In specific implementation, the outer arc surfaces of the U-shaped secondary beam 5 and the elastic main beam 6 are concentric and have the same radius as the outer circumferential surface of the middle part of the connecting base 1, making the overall structure regular and occupying a small space.

[0033] In specific implementation, there are three mounting plates 2 and three groups of NES components, making the structure specific and standardized.

[0034] To verify the vibration suppression situation of the device, a free vibration decay simulation of the drill pipe is now carried out. As Figure 8 shown, it can be seen that the amplitude of the NES is sometimes high and sometimes low. When the first high amplitude of the NES appears, target energy transfer occurs to consume the vibration energy of the drill pipe, and the amplitude of the drill pipe with the NES decreases; then the amplitude of the NES decreases, and at this time the amplitude of the drill pipe with the NES will increase. This is because after the previous target energy transfer, due to the energy of the drill pipe system escaping from the vibration damping frequency band of the NES, the NES cannot capture the existing vibration form for vibration damping. At this time, after controlling the driving piezoelectric ceramic stack 8 through the PID controller to control the stiffness of the elastic main beam 6, the NES appears with a high amplitude again, and target energy transfer occurs again, and so on until it exceeds the variable stiffness ability range.

[0035] In addition, it can be seen from Figure 9 that the amplitude of the drill pipe with the NES is significantly lower than that of the drill pipe without the NES, and the vibration suppression effect is obvious. Thus, it can be proved that the device described in the present invention has a good vibration damping effect, and its structure is simple, occupies a small space, and is suitable for deep hole processing.

[0036] The above description is only the specific implementation manners of the present invention, enabling those skilled in the art to understand or implement the present invention. Although the foregoing embodiments have been described in detail, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A drill pipe vibration reduction device based on a bending beam semi-active nonlinear energy sink, characterized in that: The invention comprises a columnar connection base (1), a plurality of mounting plates (2), and a plurality of groups of NES components. An annular groove (3) is provided in the axial middle part of the connection base (1). The annular groove (3) is evenly distributed with a plurality of groups of slots (4) in the circumferential direction. Each group of slots (4) comprises two slots (4) which are symmetrically distributed on the groove walls on both sides of the annular groove (3). Both ends of each mounting plate (2) are fixed to the two slots (4) of each group of slots (4). Each group of NES components comprises a U-shaped sub-beam (5) whose longitudinal section is in the shape of an arc, an arc-shaped elastic main beam (6), a flexible hinge, and a PID controller. Each U-shaped sub-beam (5) is fixed in the annular groove (3). Each U-shaped sub-beam (5) is located between two adjacent mounting brackets. The opening of each U-shaped sub-beam (5) is arranged in the direction of the corresponding mounting plate (2), and its two ends are respectively connected to the corresponding mounting plate (2). The left and right ends are fixed, and each flexible hinge comprises a rectangular flexible frame (7) and a piezoelectric ceramic stack (8) installed in the flexible frame (7) and capable of being extended and retracted along the circumferential direction of the connection base (1). Each flexible frame (7) is placed in the middle of the mounting plate (2) and its left and right ends are respectively fixed to the two ends of the corresponding U-shaped auxiliary beam (5). The middle of one side surface in the width direction of each flexible frame (7) is fixed to the corresponding mounting plate. One end of each elastic main beam (6) is fixed to the middle of the middle beam of the corresponding U-shaped auxiliary beam (5), and the other end is fixed to the middle of the other side surface in the width direction of the corresponding flexible frame (7). Each U-shaped auxiliary beam (5) is installed with a strain gauge. The input end of the PID controller receives a plurality of strain gauges, and the output end of the PID controller controls the plurality of piezoelectric ceramic stacks (8) to drive the corresponding flexible frame (7) to extend and retract.

2. The drill pipe vibration reduction device based on a bending beam semi-active nonlinear energy sink according to claim 1 is characterized in that: A circumferential spacing (9) is provided between the non-open end of each U-shaped secondary beam (5) and the adjacent mounting plate (2).

3. The drill pipe vibration reduction device based on a bending beam semi-active nonlinear energy sink according to claim 2 is characterized in that: Connecting plates (10) for connecting to the two ends of the mounting plate (2) via bolts are fixed to both open ends of each U-shaped sub-beam (5).

4. The drill pipe vibration reduction device based on a bending beam semi-active nonlinear energy sink according to claim 3 is characterized in that: Three end surfaces of the mounting plate (2) are fixed with vertically arranged limit plates, which are respectively a left limit plate (11), a right limit plate (13), and a middle limit plate (12). The three limit plates are in a U-shape as a whole and their openings are arranged in a direction close to the corresponding U-shaped sub-beam (5). The two connecting plates (10) on each U-shaped sub-beam (5) are respectively clamped in an area formed by the corresponding left limit plate (11) and the left end of the corresponding middle limit plate (12), and in an area formed by the corresponding right limit plate (13) and the right end of the corresponding middle limit plate (12). The middle part of one side surface in the width direction of each flexible frame (7) is fixedly connected to the middle part of the corresponding middle limit plate (12).

5. The drill pipe vibration reduction device based on a bending beam semi-active nonlinear energy sink according to claim 4 is characterized in that: A connecting block (14) is fixed to the middle of the outer side surfaces of the four frame plates of each flexible frame (7).

6. The drill pipe vibration reduction device based on a bending beam semi-active nonlinear energy sink according to claim 5 is characterized in that: The frame plates on both sides in the width direction of each flexible frame (7) are both V-shaped.

7. The drill pipe vibration reduction device based on a bending beam semi-active nonlinear energy sink according to claim 6 is characterized in that: A protective shell (15) for waterproof packaging of the piezoelectric ceramic stack (8) is glued to the outside of each flexible frame (7).

8. The drill pipe vibration reduction device based on a bending beam semi-active nonlinear energy sink according to claim 7 is characterized in that: The outer arc surfaces of the U-shaped auxiliary beam (5) and the elastic main beam (6) are concentric and have the same radius as the outer circumferential surface of the middle portion of the connection base (1).

9. The drill pipe vibration reduction device based on a bending beam semi-active nonlinear energy sink according to claim 8, characterized in that: There are three mounting plates (2) and three groups of NES components.

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