Shear constrained layer damping type pulse magnet coil and preparation method thereof

Abstract

The present application provides a kind of shearing constrained layer damping formula pulse magnet coil and its preparation method, the pulse magnet coil includes: coil body, constitutes annular magnet structure;Insulating structure, the shape of structure is matched with the appearance of coil body, is wrapped outside coil body, is made of insulating material, for limiting the radial deformation of coil body;Viscoelastic damping layer, is arranged between coil body and insulating structure, wraps coil body, is made of viscoelastic material, the outer surface of coil body and the inner surface of insulating structure are fixedly connected with the two sides of viscoelastic damping layer respectively.Wherein, when coil body is passed into pulse current and generates vibration, viscoelastic damping layer generates shear deformation with the vibration of coil body and insulating structure, converts vibration mechanical energy into heat energy dissipation by viscoelastic material, simultaneously, the axial and radial vibration damping of coil body is reduced.The present application is simple in structure, and cost is lower, can consider radial and axial vibration damping fatigue resistance of pulse magnet coil.

Description

Technical Field

[0001] This invention relates to the field of damping and vibration reduction and magnet structure protection technology, and in particular to a shear-constrained layer damped pulse magnet coil and its preparation method. Background Technology

[0002] In numerous technological fields such as fusion engineering, magnetic confinement fusion devices, particle confinement and acceleration devices, and special motors, pulsed magnet coils are among the core and critical components. Their main function is to rapidly generate a high-intensity pulsed magnetic field by applying a large instantaneous current. Especially in FRC (Field Inversion) pulsed fusion devices, which represent an important research direction in magnetic confinement fusion, the performance requirements for pulsed magnet coils are even more stringent. The coils not only need to withstand the enormous impact of instantaneous large currents but must also ensure long-term stable operation to avoid structural failures that could affect the experimental and operational reliability of the entire device.

[0003] Specifically, when a pulsed magnet coil is in operation, a large instantaneous current with a high peak value and short duration needs to be supplied to its interior. This current is subjected to a Lorentz force in the magnetic field. Combined with the coil's structural characteristics and the instantaneous nature of the current, this generates a large-amplitude, radially outward instantaneous Lorentz force. This instantaneous Lorentz force acts directly on the coil body, causing radial expansion and deformation. After deformation, the coil's elastic recovery causes it to enter a state of repeated oscillation, thus creating continuous alternating stress. Under the long-term influence of this repeated oscillation and alternating stress, the pulsed magnet coil itself and its insulation layer will gradually suffer fatigue damage, manifesting as coil deformation or fatigue fracture, as well as aging, cracking, and detachment of the insulation layer. This not only significantly shortens the coil's lifespan, increases equipment maintenance costs and downtime risks, but the coil's oscillation can also affect the stability of the magnetic field, leading to a decrease in plasma confinement effectiveness and even causing the entire equipment to fail. Therefore, solving the problems of oscillation and fatigue damage in pulsed magnet coils is crucial to improving the operational reliability of such equipment.

[0004] To address the oscillation and fatigue damage issues of pulsed magnet coils, Chinese invention CN117795633A discloses an inertial damping segmented coil for generating high magnetic fields. This coil uses a metallic inertial damper as its structural element to limit the deformation of the magnet coil, concentrating the strain and vibration generated during coil operation onto the connecting bolts. A soft-hard material cross-laminated composite (such as a glass fiber and soft polymer cross-laminated composite) sandwiched between the metallic inertial dampers acts as an energy absorption element, damping and dissipating the vibration of the bolts, thus achieving vibration reduction and fatigue resistance. However, this vibration reduction scheme has significant limitations in practical applications. First, this scheme relies on a high-hardness metal as the inertial damper structure. In applications such as fusion devices and high-precision electromagnetic equipment, to avoid induced currents and magnetic interference in the metal structure, which could affect the electromagnetic performance of the coil and the operational accuracy of the equipment, a softer insulating material is typically required for the structure. Once the metal structure is replaced with an insulating structure, the stress distribution changes fundamentally. Strain and vibration are no longer concentrated on the bolts but are dispersed across the magnet coil and the insulating structure. In this case, the damping scheme originally designed for localized bolt vibration cannot function effectively, resulting in a significantly weakened vibration reduction effect that fails to meet the coil vibration reduction and fatigue resistance requirements in insulating structure scenarios. Furthermore, while the soft-hard interlayered composite used in this scheme can provide some damping under pressure, its complex manufacturing process, high production difficulty, and high cost severely limit its large-scale application. Secondly, this damping vibration reduction scheme only addresses the radial vibration of the coil, neglecting the fact that in certain designs (such as FRC devices), a radial magnetic field may exist at the magnet coil location, generating axial Lorentz forces and axial vibrations. Summary of the Invention

[0005] The purpose of this invention is to provide a shear-constrained layer damped pulse magnet coil and its preparation method to solve the above-mentioned problems. It can achieve coil vibration damping and dissipation without relying on a metal structure. It has a simple structure, lower cost, and can take into account both radial and axial vibration reduction and fatigue resistance of the pulse magnet coil, which can meet the application requirements of pulse magnet coils in multiple scenarios.

[0006] This invention proposes a shear-constrained layer damped pulse magnet coil, comprising: The coil body forms a ring-shaped magnet structure, which encloses a vacuum chamber. An insulating structure, whose shape matches the outer shape of the coil body, is wrapped around the outside of the coil body and is made of insulating material to limit the radial deformation of the coil body; A viscoelastic damping layer is disposed between the coil body and the insulating structure, wrapping the coil body, and is made of viscoelastic material. The two sides of the viscoelastic damping layer are fixedly connected to the outer surface of the coil body and the inner surface of the insulating structure, respectively. When a pulse current is applied to the coil body to generate vibration, the viscoelastic damping layer undergoes shear deformation along with the vibration of the coil body and the insulating structure. The viscoelastic material converts the mechanical energy of the vibration into heat energy for dissipation, while simultaneously reducing the axial and radial vibration of the coil body.

[0007] In one embodiment, the coil body, the viscoelastic damping layer, and the insulating structure are fixed together by at least one of the following methods: An adhesive is applied between the coil body and the viscoelastic damping layer, and between the viscoelastic damping layer and the insulating structure. The adhesive strength is not lower than the shear strength of the viscoelastic damping material. Bolt holes are provided at the ends of the insulating structure, the viscoelastic damping layer and the coil body, respectively, and the insulating structure, the viscoelastic damping layer and the coil body are pressed and fixed by insulating bolts. The coil body and the insulating structure are fixed by binding them with several insulating tapes on the outside. The number and position of the insulating tapes are set according to the shape and size of the coil body.

[0008] In one embodiment, the outer surface of the coil body is provided with a plurality of protrusions, which are embedded in the viscoelastic damping layer or penetrate the viscoelastic damping layer and then embedded in the insulating structure.

[0009] In one embodiment, the insulating bolt is a ceramic bolt, a titanium alloy bolt, or a non-magnetic metal bolt with an insulating sleeve.

[0010] In one embodiment, the coil body includes a main body portion forming a ring-shaped magnet structure to enclose a vacuum chamber, and an extension portion connected to the main body portion and extending from the main body portion in a direction away from the vacuum chamber; The bolt holes on the coil body are opened on the extension, and the insulating structure and the viscoelastic damping layer are respectively provided with bolt holes. The insulating structure, the viscoelastic damping layer and the coil body are pressed and fixed by the insulating bolts passing through the bolt holes of each layer.

[0011] In one embodiment, the main body of the coil body is composed of N segmented magnets spliced ​​together to form a ring magnet structure to enclose a vacuum chamber, where N≥2, and each segmented magnet has an extension at both ends extending away from the vacuum chamber. Adjacent segmented magnets are fixedly connected by insulating bolts on the extension, and an insulating partition is fixedly installed between the extensions of adjacent segmented magnets.

[0012] In one embodiment, the insulating structure that wraps the coil body or each segmented magnet is composed of multiple segmented insulating structures, and the viscoelastic damping layer that wraps the coil body or each segmented magnet is composed of multiple segmented viscoelastic damping bodies, with each segmented insulating structure and each segmented viscoelastic damping body correspondingly arranged. Each of the segmented insulating structures includes an insulating main body portion corresponding to the main body portion, and an insulating extension portion extending from both ends of the insulating main body portion in a direction away from the vacuum chamber; Each of the segmented viscoelastic dampers includes a damping main body portion corresponding to the main body portion, and a damping extension portion extending from both ends of the damping main body portion in a direction away from the vacuum chamber; Adjacent segmented insulating structures and adjacent segmented viscoelastic damping bodies are fixedly connected by insulating bolts.

[0013] In one embodiment, the insulating structure is made of glass fiber epoxy resin board, and the thickness of the insulating structure is designed according to the maximum Van Mieses stress generated when the coil body is energized, so that the amplitude of the maximum Van Mieses stress generated when the coil body is energized is less than the yield strength of the coil body. The viscoelastic damping layer is made of silicone rubber or polyurethane material, and the thickness of the viscoelastic damping layer is designed according to the size of the coil body, the load frequency, and the vibration reduction requirements.

[0014] This invention also proposes a method for preparing the shear-constrained layer damped pulse magnet coil as described above, comprising the following steps: Prepare or provide the coil body, viscoelastic damping layer material, and insulating structure according to the preset shape, structure, and size; Adhesive is applied to the outer surface of the coil body and the inner surface of the insulating structure; A viscoelastic damping layer material is placed between the coil body and the insulating structure, so that one side of the viscoelastic damping layer is bonded to the outer surface of the coil body and the other side is bonded to the inner surface of the insulating structure, forming a three-layer composite structure. The adhesive is cured by applying pressure to the three-layer composite structure through mechanical pressure.

[0015] In one embodiment, the mechanical pressurization method includes at least one of the following steps: Insulating bolts are installed and tightened at the pre-set bolt hole positions on the insulating structure, viscoelastic damping layer and coil body to compress the three-layer composite structure; Based on the preset number and position of the bundles, the outer side of the three-layer composite structure is bundled and fixed with insulating tape.

[0016] Compared with the prior art, the beneficial effects of the shear-constrained layer damped pulse magnet coil and its preparation method of the present invention are as follows: 1) This invention introduces the principle of confined layer damping (CLD), constructing a three-layer composite coil structure consisting of a coil body, a viscoelastic damping layer, and an insulating structure. It utilizes the shear deformation mechanism of the viscoelastic damping layer during overall structural vibration to achieve vibration reduction and energy dissipation. Under this vibration reduction principle, relatively soft insulating materials (such as fiberglass epoxy resin boards) can be used as the external confined structure, effectively avoiding the fatal problems such as induced current, magnetic interference, and creepage that inevitably arise with metal structures. This meets the stringent insulation and electromagnetic purity requirements of high-precision electromagnetic equipment.

[0017] 2) This invention employs a triple-layer composite fixing method of "adhesive bonding + bolt tightening + tape binding," ensuring an extremely tight connection between the three layers. This physically prevents relative slippage between interfaces, ensuring that the coil's minute vibrations are 100% converted into shear deformation of the damping layer. Simultaneously, the protruding design on the back of the coil body not only increases mechanical anchoring points but also creates multi-dimensional shear displacement differences locally, enhancing the shear damping effect of the coil's viscoelastic damping layer and thus achieving efficient suppression of both radial and axial vibrations.

[0018] 3) This invention does not rely on special compression damping composite materials with complex manufacturing processes, high production difficulty and high cost. It can achieve excellent vibration damping and fatigue resistance by using readily available and inexpensive viscoelastic materials with high dissipation factors such as silicone rubber or polyurethane. This effectively solves the problem of obtaining special vibration damping materials, greatly reduces the overall manufacturing cost of pulse magnet coils and significantly improves the feasibility of engineering implementation.

[0019] 4) The vibration reduction and fatigue resistance structure provided by this invention has strong engineering versatility and can be fully applied to the protection of magnet coils under instantaneous high current excitation. It can be applied not only to FRC (field inversion) pulsed fusion devices with extremely harsh operating conditions, but also to other types of magnetic confinement fusion devices, particle confinement or acceleration devices, and special motors and other cutting-edge fields involving pulsed magnet coils. It can fundamentally reduce fatigue damage to coil windings and insulation layers, significantly extend the service life of core components, and reduce equipment downtime risks and maintenance costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a shear-constrained layer damped pulse magnet coil according to an embodiment of the present invention; Figure 2This is a schematic diagram of the coil body in a shear-constrained layer damped pulse magnet coil according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the insulating structure in a shear-constrained layer damped pulse magnet coil according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the viscoelastic damping layer in a shear-constrained damped pulse magnet coil according to an embodiment of the present invention.

[0021] Figure Labels

[0022] 1. Coil body; 10. Segmented magnet; 101. Main body; 102. Extension; 103. Protrusion; 2. Insulating structure; 20. Segmented insulating structure; 201. Insulating main body; 202. Insulating extension; 3. Viscoelastic damping layer; 30. Segmented viscoelastic damping body; 301. Damping main body; 302. Damping extension; 4. Insulating bolt; 5. Insulating partition. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention more readily understood, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that while many specific details are set forth in the following description to provide a thorough understanding of the invention, the invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the invention; therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0025] Secondly, the phrase "an embodiment" or "an embodiment" in this application refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The phrases "in one embodiment" and "an embodiment" appearing in different places in this specification do not all refer to the same embodiment, nor are they embodiments that are mutually exclusive, either alone or selectively, with other embodiments. The terms "comprising" or "including" indicate the presence of the claimed feature but do not exclude the presence of one or more other features. The term "and / or" as used in this application includes any and all combinations of one or more of the related listed items.

[0026] This invention proposes a shear-constrained layer damped pulse magnet coil, see [link to relevant documentation]. Figure 1The system comprises a three-layer composite structure consisting of a coil body 1, an insulating structure 2, and a viscoelastic damping layer 3. Borrowing from the working principle of confined layer damping (CLD), it utilizes the shear energy dissipation characteristics of the damping layer to rapidly dissipate vibration energy, thus solving the technical challenge of weakened vibration reduction in scenarios with insulating structures. The coil body 1 forms a ring-shaped (e.g., circular ring, D-shaped ring, racetrack-shaped ring) magnetic structure to generate a magnetic field by introducing pulsed current. This ring-shaped magnetic structure encloses an FRC vacuum chamber to contain plasma or other charged particles. The insulating structure 2 matches the shape of the coil body 1, completely encasing it radially to ensure effective limitation of deformation in all parts of the coil and avoid localized stress concentration. Made of high-modulus insulating material, the insulating structure 2 acts as a confining layer, limiting the radial deformation of the coil body 1. It forcibly controls the maximum van der Mises stress amplitude generated during coil expansion within a safe range, preventing yielding plastic deformation of the coil body 1 and reducing the alternating stress amplitude, thereby reducing fatigue damage to the coil at its source. A viscoelastic damping layer 3 is disposed between the coil body 1 and the insulating structure 2, completely covering the contact surface between the coil body 1 and the insulating structure 2, without gaps or air bubbles, and is made of a viscoelastic material with a damping dissipation factor greater than 0.5. The two sides of the viscoelastic damping layer 3 are fixedly connected to the outer surface of the coil body 1 and the inner surface of the insulating structure 2, respectively, and cover the contact surfaces with the coil body 1 and the insulating structure 2, forming an integrated structure without relative slippage. When a pulse current (instantaneous large current) is applied to the coil body, the current experiences a large-amplitude, radially outward instantaneous Lorentz force in the magnetic field. This Lorentz force acts directly on the coil body, pushing the coil to tend to undergo radial expansion deformation. At this time, the insulating structure on the outside of the coil, with its own thickness and rigidity, forcibly restricts the radial expansion deformation of the coil, preventing excessive deformation, controlling the maximum Van Mises stress amplitude within a safe range, avoiding yielding plastic deformation of the coil body, and reducing the alternating stress amplitude, thereby reducing fatigue damage to the coil at its source. Due to the impact of the instantaneous Lorentz force on the coil, even under the constraint of the insulating structure, it will still produce slight radial vibrations and elastic recovery, resulting in repeated oscillations. At this time, since the coil body 1, the viscoelastic damping layer 3, and the insulating structure 2 are firmly connected without relative slippage, the vibration of the coil will cause the viscoelastic damping layer 3, which is bonded to it, to undergo slight displacement synchronously. Meanwhile, the other side of the viscoelastic damping layer 3 is firmly bonded to the insulating structure 2, and the movement of the insulating structure 2 will also cause the viscoelastic damping layer 3 to undergo slight displacement. Under the combined effect of the geometric asymmetry of the inner and outer layer structures and the material differences, different circumferential displacements will be generated between the two bonding surfaces during vibration, thereby forming a relative shear displacement difference on the upper and lower sides of the viscoelastic damping layer, forcing the viscoelastic damping layer to undergo strong shear deformation.During shear deformation, the molecular chains within viscoelastic materials undergo friction, slippage, and deformation, converting the mechanical energy generated by coil vibration into heat energy. This heat energy is then dissipated into the surrounding environment through heat conduction. As the vibration energy is continuously consumed, the oscillation amplitude of the coil gradually decreases until it stabilizes, significantly reducing the number and amplitude of alternating stress cycles experienced by the coil. This reduces fatigue damage to the coil windings and insulation structure, extending the service life of the coil body. When the coil body vibrates under axial Lorentz force, the damped pulse magnet coil structure of this application is nearly equivalent to CLD damping, directly generating strong damping layer shear in the axial direction, achieving simultaneous axial and radial vibration reduction of the coil body.

[0027] The coil body 1 is usually made of copper or other materials that have excellent electrical conductivity, thermal conductivity and certain mechanical toughness.

[0028] The insulating structure 2, acting as a rigid constraint to limit coil deformation, must simultaneously meet insulation requirements and prevent the generation of induced current and magnetic interference. Therefore, it needs to be made of insulating material with excellent insulation performance, moderate Young's modulus, and stable mechanical properties. Ideally, it should also have a large damping loss factor, combining rigidity and insulation to suit applications such as fusion devices and high-precision electromagnetic equipment. The Young's modulus of the insulating structure 2 is preferably not less than 10 GPa, more preferably not less than 20 GPa, to ensure sufficient support force to effectively limit the radial deformation of the coil body under the electromagnetic force generated by the pulsed current. Materials such as G10 (glass fiber epoxy resin board), G11, and FR5 are suitable. If the Young's modulus of the insulating material is too low, the insulating structure itself will deform significantly, failing to provide effective deformation constraint for the coil body, thus affecting the shear deformation effect of the damping layer. For example, G10 has a Young's modulus of approximately 15-30 GPa and can also play a certain auxiliary damping role during vibration, meeting the requirements of this invention.

[0029] The thickness of the insulating structure 2 is designed based on the maximum Van Mises stress generated when the coil body is energized. This ensures that the amplitude of the maximum Van Mises stress generated when the coil body is energized is less than the yield strength of the coil body. This guarantees that the stress generated by the insulating structure can sufficiently resist the instantaneous Lorentz force radially outward from the magnet coil, limiting the maximum radial deformation of the coil body and preventing yielding deformation. Simultaneously, it reduces the amplitude of alternating stress, minimizing fatigue damage. The specific thickness of the insulating structure 2 depends on the electromagnetic force. Considering a typical FRC forming region current of approximately 100kA, the thickness of the insulating structure should be greater than 50mm. Too thin a thickness will not effectively limit deformation, while too thick a thickness will increase the size and cost of the device. The thickness of the insulating structure can be designed using the following method: First, calculate the radial electromagnetic force distribution on the coil body based on the peak current and working magnetic field of the pulse magnet coil; second, establish a finite element analysis model including the coil body, viscoelastic damping layer, and insulating structure, and calculate the maximum Van Mieses stress of the coil body under different insulating structure thicknesses; finally, the minimum insulating structure thickness that makes the maximum Van Mieses stress amplitude of the coil body less than its yield strength can be selected as the design value.

[0030] The viscoelastic damping layer 3 should be made of a viscoelastic material with high dissipation factor / damping characteristics within the operating frequency and temperature range of the pulse magnet coil. The damping dissipation factor (tanδ) is preferably greater than 0.5, more preferably greater than 0.7. A higher dissipation factor results in more heat energy being converted per unit shear deformation, leading to a more significant vibration reduction effect. If the dissipation factor is too low, the viscoelastic damping layer will dissipate limited vibrational energy during shear deformation, failing to effectively attenuate the oscillations of the coil body and making it difficult to achieve the expected vibration reduction and fatigue resistance effects. High-damping polyurethane, high-damping silicone rubber, and butyl rubber are preferred viscoelastic materials. These materials possess excellent shear energy dissipation capabilities, dissipating a large amount of vibrational mechanical energy even under small shear deformations. Furthermore, they have simple manufacturing processes, controllable costs, and good compatibility with insulating structures and metal coil surfaces.

[0031] The thickness of the viscoelastic damping layer 3 is designed according to the size of the coil body, the load frequency, and the vibration reduction requirements to ensure that it can generate sufficient shear deformation to dissipate energy, without affecting the overall structural compactness due to excessive thickness. Preferably, the thickness of the viscoelastic damping layer is typically designed to be between 1 mm and 5 mm.

[0032] To prevent surface slippage between the coil body, viscoelastic damping layer, and insulating structure during coil vibration, and to ensure effective shear deformation of the damping layer, one embodiment of the present invention employs at least one of the following fixing methods to fix the coil body, viscoelastic damping layer, and insulating structure: 1) The coil body 1 and the viscoelastic damping layer 3, and the viscoelastic damping layer 3 and the insulating structure 2 are both coated with adhesive of uniform thickness for bonding. The bonding strength of the adhesive is not lower than the shear strength of the viscoelastic damping material to avoid peeling or falling off during use.

[0033] 2) Bolt holes are provided at the ends of the insulating structure 2, the viscoelastic damping layer 3, and the coil body 1, respectively. The insulating structure 2, the viscoelastic damping layer 3, and the coil body 1 are pressed and fixed together by insulating bolts 4. The insulating bolts 4 should be made of insulating material or non-magnetic metal material with insulating sleeve, such as ceramic bolts, titanium alloy bolts, or non-magnetic metal bolts with insulating sleeve, to avoid the bolt itself generating induced current in the alternating magnetic field.

[0034] 3) The coil body 1 and the insulating structure 2 are fixed by binding with a number of insulating tapes on the outside. The number and position of the insulating tapes are set according to the shape and size of the coil body 1 and other parameters. They are evenly bound at different circumferential positions to ensure that the clamping force is evenly distributed.

[0035] Preferably, the coil body 1, the viscoelastic damping layer 3, and the insulating structure 2 are connected and fixed together by a triple fixing method of adhesive bonding, insulating bolt tightening, and insulating tape binding, which strengthens the integrity of the three-layer structure, prevents surface slippage, and ensures the effectiveness of the damping layer in shear energy dissipation.

[0036] The adhesive should be selected to have good adhesion to the coil body material (such as copper), the viscoelastic damping layer material (such as silicone rubber or polyurethane), and the insulating structural material (such as G10). Epoxy resin adhesives, polyurethane adhesives, or acrylic adhesives are preferred. The adhesive strength should not be lower than the shear strength of the viscoelastic damping layer itself to ensure that no interface slippage occurs between the damping layer and the structures on both sides during vibration, thereby ensuring effective transmission of shear deformation. The thickness of the adhesive layer is preferably controlled between 0.05 mm and 0.5 mm, more preferably between 0.1 mm and 0.3 mm. If the adhesive layer is too thin, it may not be able to fully wet the bonding surface, leading to poor local adhesion; if the adhesive layer is too thick, the adhesive layer itself may become a weak point in shear deformation, affecting the shear energy dissipation effect of the damping layer.

[0037] Specifically, if the viscoelastic damping layer uses high-damping silicone rubber, a primer combined with instant adhesive can be used for bonding. Before bonding, the bonding surfaces of the metal coil body and the insulating structure can be polished to increase surface roughness, and the silicone rubber surface can be cleaned. Then, a primer is applied to the silicone rubber surface, and after waiting for about 30-60 seconds for evaporation, an instant adhesive of about 0.1 mm thickness is applied, followed by rapid pressing to fix it. If the viscoelastic damping layer uses butyl rubber or high-damping polyurethane, an epoxy resin adhesive of about 0.1 mm thickness can be used for curing and bonding.

[0038] The insulating tape should be made of materials with good insulation properties, certain mechanical strength, and weather resistance, preferably high-strength polyimide tape or fiberglass cloth tape. For pulse magnet coils used in nuclear fusion devices, considering the low temperature (liquid helium temperature range) and irradiation environment, low-temperature resistant and radiation-resistant polyimide tape is preferred. The tensile strength of the insulating tape should preferably be no less than 100 MPa to ensure sufficient clamping force during binding and fixing without easy breakage.

[0039] In one embodiment of the present invention, the outer surface of the coil body 1 is provided with a plurality of protrusions 103, see [reference]. Figure 2 The height of the protrusion 103 is less than the thickness of the viscoelastic damping layer 3, and it is embedded in the viscoelastic damping layer 3; or, its height is greater than the thickness of the viscoelastic damping layer 3, and it passes through the viscoelastic damping layer 3 and is embedded in the insulating structure 2. By adjusting the structural dimensions and fit of the protrusion 103, this application can flexibly adapt to complex stress conditions under different magnetic field distributions. Specifically, when the axial Lorentz force is small and can be supported by the insulating bolt 4, the height of the protrusion 103 on the outer surface of the coil body 1 can be less than the thickness of the viscoelastic damping layer 3. After being bonded to the viscoelastic damping layer 3, it is embedded in the viscoelastic damping layer 3. On the one hand, the protrusion structure breaks the original smooth contact surface, significantly increases the contact surface area between the coil body and the damping layer, and further improves the interlayer bonding strength. On the other hand, the protrusion forms a macroscopic "mechanical anchor point" inside the damping layer. When the coil body is excited to generate small radial or axial vibrations, these protrusions embedded in the damping layer will act like "stirring teeth", not only causing the overall damping layer to deform, but also forcing the viscoelastic material around the protrusion to undergo more complex and intense multidimensional shear deformation, thereby further enhancing the axial and radial shear energy dissipation effect. When the axial Lorentz force is large, the height of the protrusion on the outer surface of the coil body can be greater than the thickness of the viscoelastic damping layer. After assembly, it passes through the viscoelastic damping layer and is embedded in the matching groove reserved inside the inner side of the insulation structure, playing an auxiliary role in bearing the force and effectively improving the overall structure's ability to resist complex multidimensional stress conditions.

[0040] According to one embodiment of the present invention, the coil body 1 includes a main body 101 that forms a ring-shaped magnet structure to surround a vacuum chamber, and an extension 102 connected to the main body and extending outward from the main body in a direction away from the vacuum chamber for connecting a power supply cable. When the ring-shaped magnet structure formed by the coil body 1 is a circular ring magnet structure, the main body 101 is a circular ring coil, and the extension 102 is a structure connected to the main body and extending outward along the radial direction of the circular ring magnet structure. Bolt holes are formed on the extension 102 on the coil body 1, and bolt holes are correspondingly formed on the insulating structure 2 and the viscoelastic damping layer 3. The insulating structure, the viscoelastic damping layer, and the coil body are pressed and fixed by insulating bolts passing through the bolt holes of each layer.

[0041] In one embodiment of the present invention, the main body 101 of the coil body 1 is composed of N 1 / N segmented magnets 10 (e.g., arc-shaped), each segmented magnet 10 being an independent structure, forming a ring magnet structure to enclose a vacuum chamber, where N≥2. Each segmented magnet 10 has extensions at both ends extending away from the vacuum chamber to connect to a power supply cable, with adjacent extensions parallel to each other. When the ring magnet structure formed by the coil body 1 is a circular ring magnet structure, the main body 101 is composed of N (N≥2) arc-shaped coils joined circumferentially to jointly enclose a vacuum chamber. Each arc-shaped coil has extensions 102 extending radially outward along the circular ring magnet structure at both ends, with the extensions 102 of adjacent arc-shaped coils facing each other. Adjacent segmented magnets 10 are fixedly connected by insulating bolts 4 on the extensions, and insulating partitions 5 are fixedly provided between the extensions 102 of adjacent segmented magnets 10. This segmented structure not only allows for N times the driving voltage to generate a stronger magnetic field, or reduces the supply voltage of a single segment, but also lowers the machining precision requirements for large-size coils; if a segment suffers fatigue damage, it can be replaced individually, significantly reducing equipment maintenance costs and downtime.

[0042] In the shear damping method adopted in this application, since the ends of the 1 / N coil are fixed with insulating bolts, there is a significant difference in the degree of expansion and bending between the middle and both sides of the arc segment. Near the junction of the main body and the extension of the 1 / N coil, the magnet coil body and the insulating structure will produce a more significant deformation difference during vibration, thereby effectively enhancing the shear damping effect. At the same time, the overall deformation of the insulating structure fixed to it is relatively uniform. A more significant local displacement difference will be generated near the junction area between the main body and the extension of the segmented magnet. This displacement difference forces the viscoelastic damping layer located between the coil body and the insulating structure to produce stronger shear deformation in this local area, thereby converting more vibrational mechanical energy into heat energy dissipation. The segmented structure of this invention not only facilitates processing and manufacturing and individual maintenance, but also actively increases the deformation difference between the coil body and the insulating structure by fixing the ends, thereby strengthening the shear damping effect in key areas and further improving the overall vibration reduction and fatigue resistance performance of the coil.

[0043] For viscoelastic damping layers, the damping effect is strongest at the ends (where the extension meets the main body) due to greater deformation shear. Therefore, the damping effect is generally better when there are more coil segments. However, in practice, too many segments of the magnet coil may have some adverse effects, such as affecting the uniformity of the circumferential magnetic field. Therefore, this application further designs a structure that further segments the structure, aiming to generate additional damping layer ends without excessive segmentation of the magnet. Specifically, the insulating structure 2 surrounding the coil body or each segment of the magnet is composed of multiple segmented insulating structures 20, and the corresponding viscoelastic damping layer 3 is composed of multiple segmented viscoelastic damping bodies 30. Each segmented insulating structure 20 and each segmented viscoelastic damping body 30 are correspondingly arranged. That is, the insulating structure 2 and the viscoelastic damping layer 3 further divide each segmented magnet 10 into several segments, such as... Figure 3 , Figure 4 As shown, one-quarter of the coil body corresponds to two one-eighths of the insulating structure and a viscoelastic damping layer. Each segmented insulating structure 20 includes an insulating main body 201 corresponding to the main body 101, and insulating extensions 202 extending from both ends of the insulating main body 201 away from the vacuum chamber. Each segmented viscoelastic damping body 30 includes a damping main body 301 corresponding to the main body 101, and damping extensions 302 extending from both ends of the damping main body 301 away from the vacuum chamber. Adjacent segmented insulating structures and adjacent segmented viscoelastic damping bodies are fixedly connected by insulating bolts 4. An insulating partition 5 is also provided between adjacent segmented viscoelastic damping bodies 30, and the insulating partition 5 can be made of the same material as the insulating structure 2. The outstanding advantage of this "re-splitting" design is that, without interfering with the electromagnetic design of the internal magnet, the extension structure artificially enhances the circumferential asymmetry of the structure, thereby generating a stronger shear displacement difference and producing a stronger vibration damping effect.

[0044] This invention also proposes a method for preparing a shear-constrained layer damped pulse magnet coil, comprising the following steps: Step S1: Prepare components: Prepare or provide the coil body, viscoelastic damping layer material and insulating structure according to the preset shape, structure and size.

[0045] Step S2, Surface treatment and adhesive application: The bonding surfaces of the coil body and the insulation structure are polished to improve surface roughness and clean them. Then, adhesive is applied to the outer surface of the coil body and the inner surface of the insulation structure.

[0046] Step S3, Layered Assembly: Place the viscoelastic damping layer material between the coil body and the insulating structure, so that one side of the viscoelastic damping layer is bonded to the outer surface of the coil body and the other side is bonded to the inner surface of the insulating structure, forming a three-layer composite structure. During the bonding process, control the adhesive thickness to be uniform, and ensure that the viscoelastic damping layer fully covers the contact surfaces with the coil body and the insulating structure, without gaps or air bubbles, to ensure that the bonding strength of the bonding interface is not lower than the shear strength of the viscoelastic damping layer itself, and to avoid the damping layer peeling or falling off during use.

[0047] Step S4, Pressure Curing: Apply pressure to the three-layer composite structure by mechanical pressure to cure the adhesive and ensure a firm bond between the viscoelastic damping layer and the structures on both sides without relative slippage.

[0048] Step S5, Post-processing: Trim and inspect the overall structure after curing.

[0049] In one embodiment of the present invention, step S4 involves mechanical pressurization, which includes at least one of the following steps: Insulating bolts are installed and tightened at the pre-set bolt hole positions on the upper end of the insulating structure, viscoelastic damping layer and coil body to compress the three-layer composite structure. Based on the preset number and position of the bundles, the outer side of the three-layer composite structure is bundled and fixed with insulating tape to maintain a uniform distribution of the clamping force.

[0050] It should be noted that the terms "inner" and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. This expression is only for the purpose of making the description of the present invention simpler and more convenient, and does not indicate or imply that the component referred to must have a specific orientation or be constructed and operated in a specific orientation.

[0051] In addition, unless otherwise explicitly specified and limited, terms such as “connection” and “setup” should be interpreted broadly in this application. For example, “connection” 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 a direct connection or an indirect connection through an intermediate medium; it can also be a connection between the internal components of two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0052] Although the methods described above are illustrated and depicted as a series of actions for the sake of simplicity, it should be understood and appreciated that these methods are not limited by the order of the actions, as some actions may occur in a different order and / or concurrently with other actions from the illustrations and descriptions herein or not illustrated and described herein but which may be understood by those skilled in the art, according to one or more embodiments.

[0053] The constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., size, structure, shape and proportion, as well as parameter values, installation arrangements, use of materials, color, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application. For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of the elements may be inverted or otherwise changed, and the nature or number or position of the discrete elements may be altered or changed. Therefore, all such modifications are intended to be included within the scope of this invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Various corresponding modifications and variations can be made by those skilled in the art according to this invention without departing from the spirit and essence of the invention, but such corresponding modifications and variations should fall within the protection scope of this invention.

Claims

1. A shear-constrained layer damping pulsed magnet coil, characterized by, include: The coil body forms a ring-shaped magnet structure, which encloses a vacuum chamber. An insulating structure, whose shape matches the outer shape of the coil body, is wrapped around the outside of the coil body and is made of insulating material to limit the radial deformation of the coil body; A viscoelastic damping layer is disposed between the coil body and the insulating structure, wrapping the coil body, and is made of viscoelastic material. The two sides of the viscoelastic damping layer are fixedly connected to the outer surface of the coil body and the inner surface of the insulating structure, respectively. An adhesive is applied between the coil body and the viscoelastic damping layer, and between the viscoelastic damping layer and the insulating structure. The adhesive strength is not lower than the shear strength of the viscoelastic damping material. When a pulse current is applied to the coil body to generate vibration, the viscoelastic damping layer undergoes shear deformation along with the vibration of the coil body and the insulating structure. The viscoelastic material converts the mechanical energy of the vibration into heat energy for dissipation, while simultaneously reducing the axial and radial vibration of the coil body.

2. The shear-constrained layer damped pulse magnet coil according to claim 1, characterized in that, Bolt holes are provided at the ends of the insulating structure, the viscoelastic damping layer and the coil body, respectively, and the insulating structure, the viscoelastic damping layer and the coil body are pressed and fixed by insulating bolts.

3. The shear constrained layer damping pulsed magnet coil of claim 2, wherein, The outer surface of the coil body is provided with several protrusions, which are embedded in the viscoelastic damping layer or penetrate the viscoelastic damping layer and then embedded in the insulating structure.

4. The shear constrained layer damping pulsed magnet coil of claim 2, wherein, The insulating bolt is a ceramic bolt, a titanium alloy bolt, or a non-magnetic metal bolt with an insulating sleeve.

5. The shear-constrained layer damped pulse magnet coil according to claim 2, characterized in that, The coil body includes a main body that forms a ring-shaped magnet structure to enclose a vacuum chamber, and an extension that is connected to the main body and extends from the main body in a direction away from the vacuum chamber; The bolt holes on the coil body are opened on the extension, and the insulating structure and the viscoelastic damping layer are respectively provided with bolt holes. The insulating structure, the viscoelastic damping layer and the coil body are pressed and fixed by the insulating bolts passing through the bolt holes of each layer.

6. The shear-constrained layer damped pulse magnet coil according to claim 5, characterized in that, The main body of the coil is composed of N segmented magnets spliced ​​together to form a ring magnet structure to enclose a vacuum chamber, where N≥2. Each segmented magnet has an extension at both ends that extends away from the vacuum chamber. Adjacent segmented magnets are fixedly connected by insulating bolts on the extension, and an insulating partition is fixedly installed between the extensions of adjacent segmented magnets.

7. The shear-constrained layer damped pulse magnet coil according to claim 6, characterized in that, The insulating structure that encloses the coil body or each segmented magnet is composed of multiple segmented insulating structures, and the viscoelastic damping layer that encloses the coil body or each segmented magnet is composed of multiple segmented viscoelastic damping bodies. Each segmented insulating structure and each segmented viscoelastic damping body are correspondingly arranged. Each of the segmented insulating structures includes an insulating main body portion corresponding to the main body portion, and an insulating extension portion extending from both ends of the insulating main body portion in a direction away from the vacuum chamber; Each of the segmented viscoelastic dampers includes a damping main body portion corresponding to the main body portion, and a damping extension portion extending from both ends of the damping main body portion in a direction away from the vacuum chamber; Adjacent segmented insulating structures and adjacent segmented viscoelastic damping bodies are fixedly connected by insulating bolts.

8. The shear-constrained layer damped pulse magnet coil according to claim 1, characterized in that, The insulating structure is made of glass fiber epoxy resin board. The thickness of the insulating structure is designed according to the maximum Van Mieses stress generated when the coil body is energized, so that the amplitude of the maximum Van Mieses stress generated when the coil body is energized is less than the yield strength of the coil body. The viscoelastic damping layer is made of silicone rubber or polyurethane material, and the thickness of the viscoelastic damping layer is designed according to the size of the coil body, the load frequency, and the vibration reduction requirements.

9. The shear-constrained layer damped pulse magnet coil according to claim 1, characterized in that, The coil body and the insulating structure are fixed by binding them with several insulating tapes on the outside. The number and position of the insulating tapes are set according to the shape and size of the coil body.

10. A method for preparing a shear-constrained layer damped pulse magnet coil as described in any one of claims 1-9, characterized in that, Includes the following steps: Prepare or provide the coil body, viscoelastic damping layer material, and insulating structure according to the preset shape, structure, and size; Adhesive is applied to the outer surface of the coil body and the inner surface of the insulating structure; A viscoelastic damping layer material is placed between the coil body and the insulating structure, so that one side of the viscoelastic damping layer is bonded to the outer surface of the coil body and the other side is bonded to the inner surface of the insulating structure, forming a three-layer composite structure. The adhesive is cured by applying pressure to the three-layer composite structure through mechanical pressure.

11. The method for preparing a shear-constrained layer damped pulse magnet coil according to claim 10, characterized in that, The mechanical pressurization method includes at least one of the following steps: Insulating bolts are installed and tightened at the pre-set bolt hole positions on the insulating structure, viscoelastic damping layer and coil body to compress the three-layer composite structure; Based on the preset number and position of the bundles, the outer side of the three-layer composite structure is bundled and fixed with insulating tape.

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