A vibration isolation composite insulator cross arm

Abstract

The application discloses a kind of vibration isolation composite insulating cross arm, belong to power transmission and transformation equipment field, including cross arm main body, shell, damping core;Conductor is set to one end of cross arm main body by cable connector, the other end of cross arm main body is inserted into the inside of shell, and there is radial clearance between the outer wall of cross arm main body and the inner wall of shell;Tower side connector is assembled at the end of shell away from cross arm main body, and tower side connector is used to be fixedly connected with tower;The damping core is set to the inner cavity of shell and is located between cross arm main body and tower side connector, and damping core is sequentially divided into high stiffness support section, transition energy dissipation section and low stiffness vibration isolation section along the axial direction.The vibration isolation composite insulating cross arm sets gradient metamaterial connecting structure between cross arm main body and tower, can buffer and attenuate before dynamic load is transferred to tower, so as to reduce the vibration response of tower side connection area.

Description

Technical Field

[0001] This invention relates to the field of power transmission and transformation equipment technology, and in particular to a vibration-isolated composite insulating crossarm. Background Technology

[0002] Composite insulated crossarms are important load-bearing and insulation components in overhead transmission lines. They are usually installed between towers and conductors to support conductors, maintain electrical safety distances between conductors and towers, and bear the weight of conductors, wind loads, icing loads, and dynamic loads during operation.

[0003] However, in actual service, composite insulated crossarms are subjected to complex external environments for extended periods. Their tower-side connection ends must withstand bending moments, shear forces, and vibration loads transmitted from the crossarm itself. Especially under conditions of light wind vibration, conductor galloping, ice shedding impacts, and gusts, the periodic vibrations and transient impacts generated by the conductors are gradually transmitted along the conductor-side hardware and the composite insulated crossarm body to the tower-side connection area, making this area a concentration point for structural stress and vibration transmission. Under long-term alternating loads, problems such as localized stress concentration, loosening of connections, fatigue damage, and microcracks in the insulation material easily occur at the crossarm end connection hardware, fastening bolts, and composite material interfaces, thus affecting the long-term operational reliability of the composite insulated crossarm.

[0004] Existing methods for connecting composite insulated crossarms to the tower side mostly employ rigid fittings, connecting plates, bolts, or clamps for fixed connections, which have the following shortcomings: (1) Lack of vibration isolation design for the connection end of the tower side: Most existing composite insulated crossarms adopt rigid connection method. Under dynamic working conditions such as wind vibration, conductor galloping and ice falling impact, there is a lack of effective vibration isolation and energy dissipation path.

[0005] (2) High stress concentration and fatigue risk in the connection area: The connection end on the tower side is equivalent to the fixed end of the composite insulated crossarm, which is a key area for the transmission of bending moment and shear force. Traditional hardware connection has high stiffness, which easily causes the load to concentrate at the end of the crossarm, the connection plate and the vicinity of the bolts. After long-term service, it may cause bolt loosening, hardware fatigue or local damage to composite materials.

[0006] (3) Difficulty in balancing connection strength and vibration isolation performance: If a flexible pad or elastic buffer is simply added, although vibration transmission can be reduced to a certain extent, its load-bearing capacity, weather resistance and long-term stability are limited; if the connection stiffness is simply increased, the buffering capacity of the structure will be weakened. It is difficult to meet the comprehensive requirements of high load-bearing capacity, reliable connection and vibration attenuation at the same time.

[0007] (4) Lack of graded response capability: wind vibration, conductor galloping and ice impact have different amplitude and frequency characteristics. Traditional connection structures usually only exhibit a single stiffness response, making it difficult to achieve a graded working mechanism of "small vibration isolation, medium vibration energy dissipation, and large impact limit protection" according to the load amplitude change.

[0008] Therefore, it is necessary to propose a new structure that can be arranged at the side connection end of the composite insulated crossarm tower and has both connection bearing and gradient vibration isolation functions. Summary of the Invention

[0009] The purpose of this invention is to solve the problem that the existing composite insulated crossarm tower uses a rigid connection structure, which cannot take into account both the connection load-bearing capacity and the graded vibration isolation performance, and long-term vibration is prone to cause stress concentration in the connection area and fatigue damage to the hardware and composite materials.

[0010] To achieve the above objectives, the present invention employs the following technology: a vibration-isolated composite insulating crossarm, comprising a crossarm body, an outer shell, and a vibration-damping core; The conductor is installed at one end of the crossarm body through a cable connector, and the other end of the crossarm body extends into the interior of the outer shell, with a radial gap between the outer wall of the crossarm body and the inner wall of the outer shell; The tower side connector is assembled at the end of the outer shell away from the main body of the crossarm, and the tower side connector is used for fixed connection with the tower. The vibration damping core is disposed in the inner cavity of the outer shell and located between the crossarm body and the tower side connector. The vibration damping core is divided into a high stiffness support section, a transition energy dissipation section and a low stiffness vibration isolation section along the axial direction. The low stiffness vibration isolation section abuts against the end face of the crossarm body, and the high stiffness support section abuts against the tower side connector. The vibration damping core is formed by arranging negative Poisson's ratio honeycomb cells along the axial direction, and the parameters of the honeycomb cells vary with a gradient along the axial direction.

[0011] As a further description of the above technical solution: the porosity of the honeycomb cells in the high-rigidity support section is lower than that in the transition energy dissipation section, and the porosity of the honeycomb cells in the transition energy dissipation section is lower than that in the low-rigidity vibration isolation section. The honeycomb cell wall thickness of the high-stiffness support section is greater than that of the transition energy dissipation section, and the honeycomb cell wall thickness of the transition energy dissipation section is greater than that of the low-stiffness vibration isolation section.

[0012] As a further description of the above technical solution: after the vibration damping core is assembled, the vibration damping core continuously presses against the end of the crossarm body.

[0013] As a further description of the above technical solution: Under normal conditions, the offset of the crossarm body is less than the radial gap between the outer wall of the crossarm body and the inner wall of the outer shell, and the crossarm body does not contact the inner wall of the outer shell.

[0014] As a further description of the above technical solution: the end of the crossbeam body that extends into the outer shell is provided with a limiting boss, and the outer shell is integrally formed with a shoulder; The limiting boss and the shoulder work together to prevent the crossbeam body from axially dislodging outward from the outer shell.

[0015] As a further description of the above technical solution: the inner wall of the limiting boss and the shoulder and the outer wall of the crossbeam body all have radial clearance.

[0016] As a further description of the above technical solution: the open end of the outer shell is equipped with an elastic buffer rubber ring, which is sleeved on the outside of the crossarm body, and a gap is reserved between the inner hole of the rubber ring and the outer wall of the crossarm body.

[0017] As a further description of the above technical solution: the outer shell and the vibration damping core form a gradient connection structure, which is independently installed between the crossarm body and the tower without modifying the original structure of the crossarm body.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: This invention features an outer shell structure with an axially gradient honeycomb vibration-damping core between the composite insulated crossarm body and the tower-side connector. Compared to existing rigid connection structures, this structure achieves graded vibration attenuation and adapts to various dynamic operating conditions. The vibration-damping core is arranged with a high-stiffness support section, a transition energy-dissipating section, and a low-stiffness vibration-isolation section along an axial gradient, with the porosity and wall thickness of the honeycomb units gradually changing along the axial direction. When the line experiences low-frequency, small-amplitude vibrations in light winds, the low-stiffness vibration-isolation section preferentially undergoes micro-deformation to isolate the vibration. Under medium-amplitude conductor galloping conditions, the transition energy-dissipating section, in conjunction with the honeycomb units, dissipates vibration energy through bending and rotational deformation. Under significant impact loads from icing and strong gusts, the high-stiffness support section provides high-strength load-bearing capacity, working with the outer shell and fasteners to ensure overall connection stability, achieving a graded response of small-amplitude vibration isolation, medium energy dissipation, and large-amplitude load bearing.

[0019] The vibration and impact loads transmitted by the conductor are first buffered and attenuated by the vibration damping core before being transmitted to the tower side connectors and towers. This significantly reduces the alternating loads transmitted to the tower connection ends, reduces stress concentration at the crossarm root, tower side connecting hardware, and fastening bolts, lowers the risk of bolt loosening, hardware fatigue, and microcracks at the ends of composite materials, and extends the service life of the entire crossarm structure.

[0020] The high-rigidity support section near the tower ensures the overall compressive and impact resistance of the structure and guarantees stable installation and connection; the low-rigidity vibration isolation section near the crossarm end focuses on absorbing small vibrations; the intermediate transition energy dissipation section eliminates abrupt changes in stiffness and alleviates stress concentration, overcoming the contradiction of traditional structures where "rigid connections have no vibration reduction and flexible buffers have insufficient load-bearing capacity".

[0021] No changes are needed to the original processing structure and on-site installation method of the composite insulated crossarm. Only a shell and gradient vibration damping core combination structure are added at the crossarm tower end. It is suitable for the renovation of existing standard composite insulated crossarms and the use of new lines. The structure is simple and easy to mass-produce and assemble on-site. Attached Figure Description

[0022] Figure 1 A schematic diagram of the crossarm installation according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of a crossarm structure provided according to an embodiment of the present invention is shown; Figure 3 A partial cross-sectional schematic diagram provided according to an embodiment of the present invention is shown; Figure 4 A schematic diagram of the structure of the vibration damping core provided according to an embodiment of the present invention is shown; Figure 5 A schematic diagram of the installation of a conventional crossarm according to an embodiment of the present invention is shown; Figure 6 An installation top view of the vibration isolation and insulation crossarm provided according to an embodiment of the present invention is shown; Figure 7 A top view of the installation of a conventional crossarm according to an embodiment of the present invention is shown; Figure 8 A schematic diagram of a finite element analysis model provided according to an embodiment of the present invention is shown, wherein a is a finite element model of a cellular gradient vibration isolation structure and b is a traditional rigid connection finite element model; Figure 9 A comparison diagram of the force transmission rate frequency response curves provided according to an embodiment of the present invention is shown; Figure 10 A comparison diagram of the transient response to ice shedding impact provided according to an embodiment of the present invention is shown, where c is the time history of the ice shedding impact load, d is the force transmission response at the tower-side connection point, and e is the stress response of the tower-side connection section. Figure 11 A bar chart comparing key performance indicators provided according to embodiments of the present invention is shown.

[0023] Legend: 1. Crossarm body; 11. Limiting boss; 2. Cable connector; 3. Conductor; 4. Housing; 41. Shoulder; 5. Tower side connector; 6. Vibration damping core; 61. High-rigidity support section; 62. Transition energy dissipation section; 63. Low-rigidity vibration isolation section; 7. Tower; 8. Rigid connection section. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Reference Figures 1-4 This embodiment provides a vibration-isolated composite insulating crossarm, including a crossarm body 1, a cable connector 2, a conductor 3, a shell 4, a tower-side connector 5, a vibration-damping core 6, and a tower 7.

[0026] The conductor 3 of the transmission line is fixedly installed at the end of the crossarm body 1 away from the outer shell 4 through the cable connector 2; the other end of the crossarm body 1 extends into the inner cavity of the outer shell 4 through the opening end of the outer shell 4. A uniform radial gap is reserved between the outer wall of the crossarm body 1 and the inner wall of the outer shell 4. Under normal conditions, the crossarm body 1 is suspended and does not contact the inner wall of the outer shell 4.

[0027] The outer shell 4 is a square sleeve structure. The tower side connector 5 is assembled at the end of the outer shell 4 away from the crossarm body 1. The tower side connector 5 is fixed to the tower 7 by fasteners. The vibration damping core 6 is completely filled in the cavity inside the outer shell 4. The vibration damping core 6 is sandwiched between the flat end face of the crossarm body 1 and the tower side connector 5. The side of the vibration damping core 6 closest to the crossarm body 1 is a low-stiffness vibration isolation section 63. The front end face of the low-stiffness vibration isolation section 63 is completely attached to the end face of the crossarm body 1. The vibration damping core 6 is arranged axially as a high-stiffness support section 61, a transition energy dissipation section 62, and a low-stiffness vibration isolation section 63. The side of the vibration damping core 6 closest to the tower side connector 5 is the high-stiffness support section 61. The back of the high-stiffness support section 61 is tightly against the tower side connector 5. The transition energy dissipation section 62 is located between the high-stiffness support section 61 and the low-stiffness vibration isolation section 63.

[0028] The vibration damping core 6 is composed of several negative Poisson's ratio honeycomb units continuously arranged along the axial direction of the crossarm body 1. The axial mechanical gradient is achieved by changing the geometric dimensions, cell wall thickness, and porosity of the honeycomb units. The high-stiffness support section 61 has the lowest porosity and the thickest cell wall among the honeycomb units, the transition energy dissipation section 62 has intermediate porosity and cell wall thickness among the honeycomb units, and the low-stiffness vibration isolation section 63 has the highest porosity and the thinnest cell wall among the honeycomb units.

[0029] During assembly, one end of the vibration damping core 6 abuts against the inner wall of the outer shell 4. The vibration damping core 6 always presses against the end of the crossarm body 1, ensuring that the low-stiffness vibration isolation section 63 is tightly fitted with the end face of the crossarm body 1. All vibration loads are transmitted to the vibration damping core 6 only through the end face of the crossarm body 1 in one direction.

[0030] When the line operation generates light wind vibration, conductor galloping, and ice shedding impact, the vibration load is transmitted sequentially through conductor 3, cable connector 2, and crossarm body 1 to the vibration damping core 6. Under small-amplitude, high-frequency micro-vibration conditions, the low-stiffness vibration isolation section 63 preferentially undergoes micro-deformation to absorb vibration. Under medium-amplitude vibration, the transition energy dissipation section 62 honeycomb unit dissipates vibration energy through bending, rotation, and compression deformation. When encountering instantaneous large-amplitude impacts from ice shedding and strong gusts, the high-stiffness support section 61 provides high-strength compressive support, and all vibration energy is attenuated inside the vibration damping core 6 before being transmitted to the tower-side connector 5 and tower 7, significantly reducing the risk of fatigue damage in the connection area.

[0031] The end of the crossarm body 1 that extends into the outer shell 4 is integrally formed with a limiting boss 11. The inner cavity of the outer shell 4 is integrally formed with a shoulder 41, which is located on the inner wall of the outer shell 4. The limiting boss 11 and the shoulder 41 only serve to limit the crossarm body 1 axially, preventing the crossarm body 1 from being pushed out of the outer shell 4 by the vibration damping core 6. The four inner side walls of the limiting boss 11 and the shoulder 41 are all reserved with radial gaps from the four outer walls of the crossarm body 1. The side walls do not contact each other. Only under extreme working conditions can the edge of the end of the crossarm body 1 briefly make axial contact with the limiting boss 11 or the shoulder 41.

[0032] The outermost opening of the outer shell 4 is equipped with an elastic buffer rubber ring. The elastic buffer rubber ring is sleeved on the outside of the crossarm body 1. The inner hole size of the elastic buffer rubber ring is larger than the cross section of the crossarm body 1. A gap is reserved between the inner wall of the rubber ring and the outer wall of the crossarm body 1. This is used to buffer the lateral displacement of the crossarm body 1 under strong wind and large swing conditions, and to prevent the crossarm edges from directly hitting the shoulder 41, causing material damage and abnormal noise.

[0033] The outer shell 4 and the internal vibration-damping core 6 together form a gradient metamaterial connection structure. This structure is independently installed between the crossarm body 1 and the tower 7, without the need to cut or modify the original shape of the crossarm body 1, and is fully compatible with the existing standard installation dimensions of composite insulated crossarms. Under normal operating conditions, the self-weight of the crossarm body 1, the self-weight of the conductor 3, and the icing and wind loads generate a downward bending moment. The honeycomb units of the vibration-damping core 6 undergo elastic deformation, generating an upward lifting reaction force that counteracts the downward tendency of the end of the crossarm body 1. The downward offset of the crossarm body 1 is less than the preset radial gap, and the crossarm body 1 is suspended throughout its entire length, without frictional contact with the inner wall of the outer shell 4.

[0034] Analysis Model and Parameter Setting To verify the vibration isolation advantages of the honeycomb gradient vibration isolation structure of this invention compared with traditional rigid connection, a one-dimensional beam element finite element model was established, and modal analysis, frequency response analysis and transient impact analysis were performed on the two connection schemes.

[0035] Finite element model of cellular gradient vibration isolation structure as follows Figure 8 As shown, the connecting section has a total length of 200mm, an outer diameter of 80mm, and an effective cross-sectional area of ​​approximately 11.8cm² for the inner annular honeycomb structure.2 The honeycomb core adopts a negative Poisson's ratio re-entrant honeycomb configuration, with three gradient sections along the axial direction: (1) low-stiffness vibration isolation section (70mm long, 0.6mm thick cell wall, 12mm cell edge length, t / l=0.050); (2) transition energy dissipation section (70mm long, 1.2mm thick cell wall, t / l=0.100); (3) high-stiffness support section (60mm long, 2.0mm thick cell wall, t / l=0.167). The honeycomb substrate is aluminum alloy (E_s=70GPa, ρ=2700kg / m). 3 ).

[0036] The traditional rigid connection model uses 8 rigid connection sections (solid steel flanges) with the same outer diameter for connection (E=210GPa, ρ=7850kg / m). 3 The crossarm is 200mm long. An additional equivalent mass of 350kg is added to the crossarm end (including the crossarm body, conductor, and icing equivalent mass). Fixed constraints are used at the tower side ends.

[0037] Cellular equivalent mechanical parameters were calculated based on Gibson-Ashby cellular theory: Where C=12 is the dominant deformation coefficient for re-entrant honeycomb bending. Equivalent density is calculated based on relative density: The equivalent parameters for each segment are shown in Table 1.

[0038] Table 1. Equivalent mechanical parameters of the honeycomb gradient structure Through series equivalent calculation, the overall equivalent stiffness of the cellular gradient structure is k_eq=1.54MN / m, which is only 1 / 804 of that of the rigid connection, providing a flexible foundation for vibration isolation.

[0039] Modal analysis results The modal analysis results are shown in Table 2. The first natural frequency of the honeycomb gradient structure is 10.80 Hz, which is much lower than the 298.94 Hz of the rigid connection. According to the vibration isolation principle, when the excitation frequency exceeds √2 times the natural frequency (approximately 15.3 Hz), the structure enters the vibration isolation frequency band. Therefore, the honeycomb structure has good isolation capability against wind vibrations above 15 Hz and high-frequency vibration loads, while the rigid connection has almost no vibration isolation effect below 300 Hz.

[0040] Table 2 Comparison of the first 5 natural frequencies (Hz) of the two structures Frequency response analysis A unit harmonic force load was applied to the crossarm ends of both structures, and the force transmission ratio (transmitted force / applied force) at the tower-side connection points was calculated. The results are as follows: Figure 9 As shown, within the 1–200 Hz frequency band, the force transmissibility of the rigid connection remains close to 1.0 (0 dB), indicating that it transmits the entire vibration load with almost no attenuation. The cellular gradient structure exhibits a resonance peak near its natural frequency (approximately 11 Hz), but its transmissibility drops rapidly above 15 Hz, demonstrating significant vibration isolation characteristics.

[0041] Table 3 shows the comparison of transmissibility under typical vibration conditions. In the 30Hz aerodynamic vibration band, the force transmissibility of the honeycomb structure is 0.166 (-15.6dB), with an attenuation of 83.6% compared to the rigid connection; in the 50Hz high-frequency aerodynamic vibration band, the transmissibility drops to 0.054 (-25.4dB), with an attenuation of 94.8%; in the 100Hz band, the transmissibility is only 0.013 (-37.7dB), with an attenuation of 98.8%. These results indicate that the honeycomb gradient structure has excellent isolation performance for high-frequency vibration loads in transmission lines.

[0042] Table 3 Comparison of Force Transmission Rate under Typical Conditions Note: 10Hz is close to the first natural frequency of the honeycomb structure (10.80Hz), which is in the resonant amplification region. This frequency band corresponds to conductor galloping conditions. In actual engineering, the damping characteristics of the transition energy dissipation section are used to suppress the resonance amplitude. The design target frequency band for vibration isolation structures is above 15Hz for light wind vibrations and high-frequency impacts.

[0043] Transient analysis of icing shedding impact Ice shedding is a typical transient impact condition in transmission lines. The impact load is set as a half-sine pulse with a peak value of 8.0 kN and a pulse width of 15 ms, applied to the crossarm end. The time-domain response of the two structures is calculated using the Newmark-β stepwise integration method, with a time step of 0.1 ms and a total duration of 0.5 s.

[0044] Figure 10 (c) is the time history curve of the impact load. Figure 10 (d) Comparison of the time history of the force transmitted at the connection point on the tower side: the peak force transmitted by the rigid connection is 239.4kN, while the peak force transmitted by the honeycomb gradient structure is 165.2kN, a decrease of 31.0%. Figure 10 (e) Comparison of stress time history of the connection section: the peak stress of the rigid connection is 203.2 MPa, and the peak stress of the honeycomb structure is 140.3 MPa, both decreasing by 31.0%. In addition, the RMS transmission force of the honeycomb structure is 21.65 kN, which is 26.8% lower than that of the rigid connection (29.58 kN). This indicates that the honeycomb structure not only reduces the peak impact force, but also dissipates vibration energy through the bending deformation of the honeycomb wall, thus accelerating the decay of free vibration.

[0045] Comprehensive comparison of key indicators Figure 11 Table 4 summarizes the key performance indicators of the two structures. The cellular gradient structure is significantly superior to the traditional rigid connection in core indicators such as force transmission rate, impact transmission force, and stress in the connection section.

[0046] Table 4. Comprehensive Comparison of Key Performance Indicators Analysis Conclusion Finite element analysis results show that the honeycomb gradient vibration isolation structure involved in this invention has the following advantages compared with traditional rigid connections: (1) Low-frequency flexible vibration isolation: The first-order natural frequency of the honeycomb structure is reduced to 10.80Hz, which shifts the vibration isolation starting frequency down to about 15Hz, covering the main frequency band of wind vibration (5~50Hz). The first-order frequency of the rigid connection is as high as 298.94Hz, and it has no vibration isolation capability in the engineering vibration frequency band.

[0047] (2) High-frequency vibration isolation: The force transmission rate is reduced by 83.6% in the 30Hz micro-wind vibration band, 94.8% in the 50Hz band, and 98.8% in the 100Hz band, which is significantly better than the near-full transmission of rigid connections.

[0048] (3) Impact load reduction: Under the impact condition of ice shedding, the peak transmission force on the tower side is reduced by 31.0%, the peak stress of the connection section is reduced by 31.0%, and the RMS transmission force is reduced by 26.8%, which effectively protects the connection area on the tower side.

[0049] (4) Advantages of gradient segmented design: The low stiffness segment provides a flexible vibration isolation foundation, the transition energy dissipation segment dissipates vibration energy through the bending deformation of the honeycomb wall, and the high stiffness segment ensures reliable connection and load bearing with the tower side. The three segments work together to realize the integrated function of "vibration isolation - energy dissipation - load bearing", overcoming the contradiction that traditional rigid connection cannot take into account both load bearing and vibration isolation.

[0050] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A vibration-isolation composite insulating crossarm, characterized in that, Includes the crossbeam body (1), the outer shell (4), and the vibration damping core (6); The conductor (3) is set at one end of the crossarm body (1) through the cable connector (2), and the other end of the crossarm body (1) extends into the interior of the outer shell (4), and there is a radial gap between the outer wall of the crossarm body (1) and the inner wall of the outer shell (4); The tower side connector (5) is assembled on the end of the outer shell (4) away from the crossarm body (1), and the tower side connector (5) is used to fix the connection with the tower (7); The vibration damping core (6) is disposed in the inner cavity of the outer shell (4) and located between the crossarm body (1) and the tower side connector (5). The vibration damping core (6) is divided into a high stiffness support section (61), a transition energy dissipation section (62), and a low stiffness vibration isolation section (63) along the axial direction. The low stiffness vibration isolation section (63) abuts against the end face of the crossarm body (1), and the high stiffness support section (61) abuts against the tower side connector (5). The vibration damping core (6) is formed by arranging negative Poisson's ratio honeycomb units along the axial direction, and the parameters of the honeycomb units vary with a gradient along the axial direction. The porosity of the honeycomb cells in the high-rigidity support section (61) is lower than that in the transition energy dissipation section (62), and the porosity of the honeycomb cells in the transition energy dissipation section (62) is lower than that in the low-rigidity vibration isolation section (63). The cell wall thickness of the high-stiffness support section (61) is greater than that of the transition energy dissipation section (62), and the cell wall thickness of the transition energy dissipation section (62) is greater than that of the low-stiffness vibration isolation section (63).

2. The vibration-isolation composite insulating crossarm according to claim 1, characterized in that, After the vibration damping core (6) is assembled, the vibration damping core (6) continuously presses against the end of the crossbeam body (1).

3. The vibration-isolation composite insulating crossarm according to claim 1, characterized in that, Under normal conditions, the offset of the crossarm body (1) is less than the radial gap between the outer wall of the crossarm body (1) and the inner wall of the outer shell (4), and the crossarm body (1) does not contact the inner wall of the outer shell (4).

4. The vibration-isolation composite insulating crossarm according to claim 1, characterized in that, The end of the crossbeam body (1) that extends into the outer shell (4) is provided with a limiting boss (11), and the outer shell (4) has a shoulder (41) integrally formed inside. The limiting boss (11) and the shoulder (41) cooperate to restrict the crossbeam body (1) from axially dislodging outward from the outer shell (4).

5. The vibration-isolation composite insulating crossarm according to claim 4, characterized in that, The inner walls of the limiting boss (11) and the shoulder (41) and the outer wall of the crossbeam body (1) all have radial gaps.

6. The vibration-isolation composite insulating crossarm according to claim 1, characterized in that, The outer shell (4) is equipped with an elastic buffer ring at the open end. The elastic buffer ring is sleeved on the outside of the crossarm body (1), and a gap is reserved between the inner hole of the ring and the outer wall of the crossarm body (1).

7. The vibration-isolation composite insulating crossarm according to claim 1, characterized in that, The outer shell (4) and the vibration damping core (6) form a gradient metamaterial connection structure. This gradient metamaterial connection structure is independently installed between the crossarm body (1) and the tower (7) without altering the original structure of the crossarm body (1).

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