Crimping process simulation method

Abstract

The invention discloses a crimping process simulation method, comprising the following steps: step S10, establishing a mechanical simulation model of a to-be-crimped product, the to-be-crimped product comprising an insulating tube, a flange sleeving the outer periphery of the end portion of the insulating tube, and a support member arranged on the inner periphery of the end portion of the insulating tube; s20, in the mechanical simulation model, technological parameters are changed, crimping simulation and external force simulation are carried out, and stress data of the to-be-crimped product are obtained; and S30, performing comparative analysis to obtain target process parameters. According to the crimping process simulation method, the length difference between the supporting piece and the flange and the distance between the end, close to the flange plate, of the first sub-crimping area and the flange plate can be simulated and researched; the distance between the other end, far away from the flange plate, of the second sub-crimping area and the end face, far away from the flange plate, of the flange cylinder is respectively related to the stress borne by the insulating tube and the flange after crimping, so that optimal process parameters are quickly obtained, and the quality stability of crimping products is ensured.

Description

Technical Field

[0001] The present application relates to the field of power transmission and transformation insulation technology, and in particular to a crimping process simulation method. Background Art

[0002] Currently, most hollow composite insulator structures fail at the connection between the flange and the insulating tube, a difficult point in insulator processing. Insulating tubes are typically made of composite materials, and common methods for connecting composite materials are gluing and crimping. Gluing involves using high-strength adhesives such as epoxy resin to form a glue interface between the inner surface of the flange and the outer surface of the insulating tube to complete assembly. While this method can simultaneously meet connection strength and sealing requirements, the adhesive takes a long time to cure, making it inconvenient for on-site operations. Furthermore, most glue-attached structures fail to fully utilize the optimal performance of the insulating tube or flange. This means that the composite insulator may experience structural failure under conditions where the mechanical strength, such as bending, tensile, or compressive strength, is lower than the insulating tube's own strength. The crimping process is typically used for solid composite rods. Currently, during the crimping process for hollow insulating tubes, there is a lack of unified process standards for parameters such as flange length and the distance between the crimping zone and the flange. This makes it difficult to ensure the quality and stability of the crimped products, and can easily lead to tube rupture, compromising the product's strength and sealing requirements. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the main purpose of this application is to provide a crimping process simulation method that can quickly determine the target process parameters and ensure the quality stability of the crimped products.

[0004] In order to solve the above technical problems, the technical solution adopted in this application is: a crimping process simulation method, comprising the following steps: Step S10: establishing a mechanical simulation model of the product to be crimped, the product to be crimped including an insulating tube, a flange sleeved on the outer periphery of the end of the insulating tube, and a support member arranged on the inner periphery of the end of the insulating tube; Step S20: in the mechanical simulation model, changing the process parameters and performing crimping simulation and external force simulation to obtain stress data of the product to be crimped; Step S30: comparative analysis to obtain target process parameters.

[0005] Among them, step S10 also includes: step S101: establishing geometric models of the flange, insulating tube and support respectively, and assembling them to obtain an assembly of the product to be crimped; step S102: defining simulation parameters of the assembly, the simulation parameters including mesh properties, material properties, analysis steps, contact, coupling constraints, boundary conditions, loads, and failure criteria.

[0006] Among them, the external force simulation is a bending simulation, and the analysis steps include the first crimping analysis step, the first unloading analysis step, the second crimping analysis step, the second unloading analysis step, and the bending analysis step; the load includes the first crimping load, the second crimping load, and the bending load. The first crimping load and the second crimping load are both set to 250 MPa, and the bending load is set to 60 kN.

[0007] Wherein, step S20 also includes step S201: in the mechanical simulation model, changing the length difference between the support and the flange and performing simulation, and the length difference is set to -40 mm, 0 mm, 20 mm, and 40 mm respectively.

[0008] Wherein, step S20 also includes step S202: in the mechanical simulation model, changing the first crimping distance and performing simulation, and the first crimping distance is set to 15 mm, 20 mm, and 25 mm respectively.

[0009] Wherein, step S20 further includes step S203: in the mechanical simulation model, changing the second crimping distance and performing simulation, and the second crimping distance is set to 0 mm, 5 mm, and 10 mm respectively.

[0010] Wherein, step S20 also includes step S204: in the mechanical simulation model, changing the cross-sectional shape tolerance of the insulating tube and performing simulation, and the cross-sectional shape tolerance is set to 0 mm and 5 mm respectively.

[0011] Wherein, step S20 also includes step S205: after the simulation, obtaining first stress data on the insulating tube and second stress data on the flange.

[0012] Wherein, step S30 further includes step S301: comparing the first stress data and the second stress data under each process parameter according to the simulation results, and analyzing and determining the target process parameters.

[0013] Among them, in the target process parameters, the difference in length between the support member and the flange is 0-20 mm, the first crimping distance is 15 mm-25 mm, and the second crimping distance is 5 mm-10 mm.

[0014] The beneficial effect of the present application is that the crimping process simulation method of the present application can simulate and study the relationship between the difference in length between the support and the flange, the distance between the end of the first sub-crimping area close to the flange and the flange, and the distance between the other end of the second sub-crimping area away from the flange and the end face of the flange tube away from the flange, and the stress on the insulating tube and the flange after crimping, thereby quickly obtaining the optimal process parameters and ensuring the quality stability of the crimped products. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without inventive efforts. Among them:

[0016] Figure 1 is a partial cross-sectional view of a composite insulator 100 according to an embodiment of the present application;

[0017] Figure 2 is a cross-sectional view of a flange 120 in one embodiment of the present application;

[0018] Figure 3 is a top view of the flange 120 in one embodiment of the present application;

[0019] Figure 4 This is a cross-sectional view of a composite insulator 100 before crimping in one embodiment of the present application;

[0020] Figure 5 1 is a cross-sectional view of the composite insulator 100 after crimping in one embodiment of the present application. DETAILED DESCRIPTION

[0021] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0022] See Figure 1 A composite insulator 100 includes an insulating tube 110, an shed (not shown) located on the outer periphery of the insulating tube 110, and two flanges 120 respectively provided at both ends of the insulating tube 110. The insulating tube 110 is a hollow circular tube. Support members 130 are provided inside both ends of the insulating tube 110. The support members 130 are solid cylindrical structures. The support members 130 are coaxially arranged with the insulating tube 110 and extend inward from the ends of the insulating tube 110. The outer diameter of the support member 130 matches the inner diameter of the insulating tube 110. The flanges 120 are crimped onto the outer sides of the ends of the insulating tube 110, so that the insulating tube 110, the support members 130, and the flanges 120 are tightly connected. The composite insulator 100 of the present application utilizes a support member 130 to achieve crimping of the hollow insulating tube 110 and the flange 120, thereby ensuring the connection strength and sealing between the two, effectively preventing failure of the composite insulator 100 at the connection between the flange 120 and the insulating tube 110, and fully utilizing the structural strength of the composite insulator 100. Compared with traditional gluing technology, it eliminates the long glue curing process and improves production efficiency.

[0023] Combine Figure 2 and Figure 3 As shown, the flange 120 includes a flange tube 121 and a flange disc 122. The flange tube 121 is a hollow cylindrical structure that is sleeved onto the end of the insulating tube 110. The inner diameter of the flange tube 121 matches the outer diameter of the insulating tube 110. In this embodiment, the flange disc 122 is disc-shaped, with a diameter greater than the outer diameter of the flange tube 121, and the flange disc 122 completely covers one end of the flange tube 121. In other embodiments, the flange disc can also be annular, with an inner diameter smaller than the inner diameter of the flange tube and an outer diameter greater than the outer diameter of the flange tube, that is, the flange disc can partially cover one end of the flange tube. The flange disc 122 is provided to cover one end of the flange tube 121, mainly for connecting with other flanges with fasteners such as bolts, thereby facilitating the installation of the composite insulator 100. The other end of the flange barrel 121 away from the flange disc 122 is provided with an inner fillet with an arc radius of 2 to 3 mm. When the flange barrel 121 and the insulating tube 110 are assembled, the inner fillet can serve as a guide for expanding the diameter, allowing the flange barrel 121 to be more smoothly fitted onto the insulating tube 110, significantly improving assembly efficiency. Furthermore, the inner fillet can prevent structural wear caused by sharp edges, thereby extending the service life of the composite insulator 100. Preferably, the flange 120 further includes a plurality of reinforcing ribs 123. The reinforcing ribs 123 are plate members, arranged along the radial direction of the flange 120 and simultaneously connecting the flange barrel 121 and the flange disc 122. The plurality of reinforcing ribs 123 are evenly distributed along the circumference of the flange 120. The provision of the reinforcing ribs 123 can indirectly increase the contact area between the flange barrel 121 and the flange disc 122, thereby improving the strength of the flange 120. In this embodiment, six reinforcing ribs 123 are provided. These six reinforcing ribs 123 are arranged on the outer circumference of the flange cylinder 121 along the radial direction of the flange cylinder 121. The provision of six reinforcing ribs 123 can improve the strength of the flange 122 and reduce the thickness requirement of the flange 122, thereby saving material and reducing the weight of the composite insulator 100. In other embodiments, the number of reinforcing ribs may be four, five, seven, or more, or the number of reinforcing ribs may be eliminated, as long as the flange strength requirements are met. This is not a limitation herein.

[0024] In one embodiment, the flange sleeve 121, flange plate 122, and reinforcing ribs 123 can be separately formed and then connected by welding or other processes. Alternatively, the flange sleeve 121, flange plate 122, and reinforcing ribs 123 can be integrally cast to further enhance the overall stability and mechanical strength of the flange 120. In other embodiments, the flange sleeve, flange plate, and reinforcing ribs can also be formed by other methods as long as the flange strength is guaranteed, and this is not limited here.

[0025] Insulation tube 110 is a hollow circular tube formed by winding or pultrusion of a fiber-reinforced composite material. This provides excellent mechanical strength and dielectric properties. The inner diameter of flange 121 matches the outer diameter of insulation tube 110 for ease of assembly. Specifically, the outer diameter of insulation tube 110 is slightly smaller than the inner diameter of flange 121, allowing flange 121 to be smoothly fitted around the outer ends of insulation tube 110, facilitating subsequent crimping of flange 120 onto the outer ends of insulation tube 110. In one embodiment, the outer diameter of the insulating tube 110 is 0.1 to 0.5 mm smaller than the inner diameter of the flange tube 121, for example, 0.1 mm, 0.2 mm or 0.5 mm, so that the flange tube 121 and the insulating tube 110 can move relative to each other to adjust the position of the flange tube 121 on the insulating tube 110, thereby ensuring that the flange 120 can be put in place; at the same time, by pre-setting the gap, even if there is a radial processing error between the flange 120 and the insulating tube 110, it is not easy to cause product assembly failure, thereby reducing processing difficulty and improving fault tolerance.

[0026] Combine Figure 4 and Figure 5 As shown, the support member 130 is a solid cylindrical structure. The support member 130 is made of a fiber-reinforced composite material, the same material as the insulating tube 110. The same material has highly consistent hardness, ductility, and deformation characteristics. This ensures that the deformation behavior of the support member 130 and the insulating tube 110 remains synchronized during the crimping process, avoiding local stress concentration or cracking caused by asynchronous deformation of different materials, thereby ensuring the quality of the composite insulator 100. In addition, when designing the crimping process parameters, there is no need to consider the difference in thermal expansion coefficients of different materials, which greatly reduces the design complexity. Of course, in other embodiments, the support member can also be made of other insulating materials with a radial elastic modulus of 10 to 20 GPa, as long as it can support the crimping of the hollow insulating tube and the flange. This is not limited here.

[0027] In this embodiment, both ends of the support member 130 are provided with a 3mm×45° chamfer. When the support member 130 and the insulating tube 110 are assembled, the chamfer can serve as a guide for reducing the diameter, allowing the support member 130 to be more smoothly placed into the inner cavity of the insulating tube 110, significantly improving assembly efficiency. In addition, the chamfer can also prevent structural wear caused by sharp edges, thereby extending the service life of the composite insulator 100. In other embodiments, the chamfers at both ends of the support member can also be set to other sizes and angles, such as 1mm×45°, 2mm×45°, 1mm×60°, 2mm×60°, 3mm×60°, 1mm×30°, 2mm×30°, 3mm×30°, etc., as long as it facilitates the assembly of the support member and the insulating tube, and is not limited here.

[0028] The support member 130 is located within the inner cavity of the insulating tube 110, with one end of the support member 130 flush with the end of the insulating tube 110. The outer diameter of the support member 130 matches the inner diameter of the insulating tube 110, allowing the support member 130 to be smoothly positioned within the insulating tube 110. Specifically, the outer diameter of the support member 130 is 0.1 to 0.5 mm smaller than the inner diameter of the insulating tube 110, for example, 0.1 mm, 0.2 mm, or 0.5 mm. This allows the support member 130 and the insulating tube 110 to move relative to each other to adjust their relative positions, thereby ensuring that the support member 130 can be installed in place. Furthermore, the preset gap can prevent friction between the support member 130 and the insulating tube 110 during assembly, reducing assembly difficulty.

[0029] When the insulating tube 110, flange 120, and support member 130 are assembled in place, the support member 130 is coaxially arranged in the inner cavity of the insulating tube 110, and the ends of the two are flush; the flange tube 121 is coaxially sleeved on the outer periphery of the end of the insulating tube 110, and the flange 122 abuts the end faces of the insulating tube 110 and the support member 130 at the same time. Due to the existence of the assembly gap, the axes of the insulating tube 110, flange 120, and support member 130 may be slightly offset, but the extrusion between the components during crimping will correct the degree of coaxiality. A sealing structure (not shown in the figure) is provided at the connection between the other end of the flange tube 121 away from the flange 122 and the insulating tube 110. The sealing structure includes a sealing ring and a sealant. In this embodiment, the cross-section of the sealing ring is circular and is sleeved on the outer periphery of the insulating tube 110. When the flange tube 121 is sleeved on the outer periphery of the insulating tube 110, the sealing ring can simultaneously abut the outer periphery of the insulating tube 110 and the inner periphery of the flange tube 121, and the sealing ring is close to the other end of the flange tube 121 away from the flange plate 122. At this time, the sealing ring is in a compressed state, thereby isolating the interior of the insulating tube 110 from the outside air, preventing external dust, water vapor and other impurities from entering the insulating tube 110 through the connection between the insulating tube 110 and the flange tube 121, and ensuring the electrical stability of the composite insulator 100. In other embodiments, the cross-section of the sealing ring can also be rectangular or other shapes, as long as it can isolate the interior of the insulating tube from the outside air, and there is no limitation here. Furthermore, to further enhance the sealing performance of the composite insulator 100, a sealant is provided at the connection between the other end of the flange tube 121 away from the flange plate 122 and the insulating tube 110. The sealant fills the gap between the flange tube 121 and the insulating tube 110 and covers the connection between the end face of the flange tube 121 away from the flange plate 122 and the insulating tube 110, thereby providing a sealed connection between the sealing ring, the flange tube 121, and the insulating tube 110. This further prevents external dust, moisture, and other impurities from entering the insulating tube 110, thereby preventing the internal insulating environment of the composite insulator 100 from exchanging with the external environment, thereby ensuring the electrical stability of the composite insulator 100. The sealing structure of the present application, which simultaneously provides a sealing ring and sealant, achieves a better sealing effect and increases the reliability of the composite insulator 100.

[0030] In this embodiment, the sealing ring is made of EPDM rubber, which has good aging resistance, particularly slow stress relaxation, long service life, and can maintain good sealing performance during its long-term operation. The sealant uses a resin-based adhesive, which has excellent bonding ability and ensures a stable bonding effect; at the same time, the resin-based adhesive has extremely high mechanical strength after curing, ensuring the long-term reliability of the sealant. In other embodiments, the sealing ring can also be made of fluorosilicone rubber, nitrile rubber, hydrogenated nitrile rubber, etc., and the sealant can also be made of polyurethane, polytetrafluoroethylene, etc.; alternatively, the sealing structure can also include only the sealing ring or only the sealant or other structures, as long as the sealing can be achieved, there is no limitation here.

[0031] The flange 120, the insulating tube 110 and the support member 130 are connected by crimping technology, which can be specifically achieved by a crimping device. The crimping device includes a driving mechanism, an annular crimping mechanism, and a plurality of pressing blocks. The plurality of pressing blocks are arranged on the inner circumference of the annular crimping mechanism along the radial direction, and the plurality of pressing blocks are evenly distributed along the circumference of the annular crimping mechanism. The pressure surface of the pressing block matches the outer contour of the flange tube 121. During the crimping operation, the assembled flange 120, the insulating tube 110 and the support member 130 are placed in the annular crimping mechanism, and the pressing block is aligned with the target crimping area on the flange tube 121. The driving mechanism drives the plurality of pressing blocks to move synchronously toward each other along the radial direction of the annular crimping mechanism to form a centripetal extrusion force, and continuously squeeze the flange tube 121 until the flange 120, the insulating tube 110 and the support member 130 are crimped together. Preferably, eight pressing blocks are provided, and the radial angle θ between adjacent pressing blocks is 45°, so that the extrusion force generated by the annular crimping mechanism can be evenly loaded along the circumference of the flange tube 121, avoiding eccentric deformation caused by unilateral pressure and ensuring the quality of crimping; the shape of the crimping surface of the pressing block matches the outer peripheral contour of the flange tube 121, and can convert point loads into surface loads, so that the stress distribution at the interface between the flange tube 121, the insulating tube 110 and the support member 130 is uniform. Compared with traditional gluing technology, the crimping technology applies a uniform extrusion force to form a close contact between the flange 120, the insulating tube 110 and the support member 130, generating a large friction force, which significantly improves the tensile strength and shear strength of the connection parts of the three; moreover, the crimping process can be completed using only a dedicated crimping tool, which is easy to operate, eliminates the long glue curing process, greatly shortens the assembly time, and improves production efficiency.

[0032] The flange barrel 121 is provided with a target crimping area that mates with the insulating tube 110 and is used to effectively connect the flange barrel 121 and the insulating tube 110. This target crimping area is annular, located on the outer periphery of the flange barrel 121 and coaxially arranged with the flange barrel 121. Specifically, the target crimping area is the outer surface area of ​​the flange barrel 121 along its axial direction. Within this target crimping area, a plurality of evenly distributed pressure blocks apply circumferential compressive force, ensuring uniform force throughout the crimping process on the flange barrel 121, the insulating tube 110, and the support member 130, thereby ensuring a reliable connection among the three.

[0033] The length of the flange tube 121 is positively correlated with the area of ​​its target crimping zone, so as to ensure the crimping effect. When the length of the flange tube 121 exceeds a certain limit, its target crimping zone is too large, which will cause the crimping device to be unable to complete the fixed connection of the flange 120, the insulating tube 110 and the support member 130 through one crimping. In order to ensure the crimping effect, a stepwise crimping method is adopted, that is, only a part of the target crimping zone is crimped each time. Specifically, the target crimping zone includes a number of sub-crimping zones, and any two adjacent sub-crimping zones overlap 0 to 20 mm along the axial direction of the insulating tube 110, so that the target crimping zone on each flange tube 121 is continuous and has no gaps. If the axial overlap area of ​​any two adjacent sub-crimping zones along the insulating tube 110 is less than 0, that is, the target crimping zone is not continuous, the crimping effect will be weakened, and the reliability of the connection will be greatly reduced; if the axial overlap of any two adjacent sub-crimping zones along the insulating tube 110 is greater than 20 mm, it will lead to too many crimping times, extending the crimping time and reducing production efficiency. Therefore, any two adjacent sub-crimping areas overlap by 0 to 20 mm along the axial direction of the insulating tube 110, which can ensure a reliable connection between the flange tube 121, the insulating tube 110 and the support member 130, and the crimping efficiency is higher than when any two adjacent sub-crimping areas do not overlap.

[0034] The solid support member 130 prevents the hollow insulating tube 110 from excessive deformation during the crimping process, thereby ensuring product quality. After crimping, the insulating tube 110 deforms and contracts until it fits tightly against the support member 130. Simultaneously, the flange tube 121 deforms and contracts until it fits tightly against the insulating tube 110, forming contact surfaces with a certain pressure between the flange 120 and the insulating tube 110, and between the insulating tube 110 and the support member 130. This contact surface provides sufficient interfacial pressure and friction, thereby ensuring the strength of the connection between the three, preventing failure at the connection between the flange 120 and the insulating tube 110 during operation of the composite insulator 100 and fully utilizing the structural strength of the composite insulator 100.

[0035] The present application also provides a crimping process simulation method for obtaining target process parameters through simulation to crimp a product to be crimped, specifically including steps S10 to S30. The crimping process simulation process of the composite insulator 100 is described below as an example.

[0036] Step S10: Establish a mechanical simulation model of the product to be crimped, where the product to be crimped includes an insulating tube 110 , a flange 120 sleeved on the outer periphery of the end of the insulating tube 110 , and a support member 130 arranged on the inner periphery of the end of the insulating tube 110 .

[0037] In the present application's crimping process simulation method, the primary focus is on the crimping process between the insulating tube 110, flange 120, and support member 130. Therefore, in this step, the structure of the composite insulator 100 to be crimped is simplified during modeling. Specifically, the mechanical simulation model of the product to be crimped only establishes the structure of one end of the composite insulator 100, specifically including the insulating tube 110, flange 120 disposed at one end of the insulating tube 110, and support member 130 disposed at the same end of the insulating tube 110. By simplifying the mechanical simulation model, the amount of data required for the simulation and the computational complexity are significantly reduced, enabling the simulation to be completed in a shorter time and improving work efficiency.

[0038] In this step, establishing a mechanical simulation model of the product to be crimped specifically includes steps S101 to S102.

[0039] Step S101: geometric models of the flange 120 , the insulating tube 110 and the support member 130 are respectively established, and the geometric models are assembled to obtain an assembly of the product to be crimped.

[0040] Specifically, a geometric model of flange 120, insulating tube 110, and support member 130 was established. Insulating tube 110 has inner and outer diameters of 130 mm and 147 mm, respectively, and a length of 1436 mm. Support member 130 has a diameter of 130 mm. Flange tube 121 has an inner diameter of 147 mm. Support member 130 is positioned within the inner cavity of one end of insulating tube 110, and flange 120 is positioned on the outer periphery of insulating tube 110, corresponding to support member 130, to obtain an assembly of the product to be crimped. It is understood that the specific dimensional parameters of flange 120, insulating tube 110, and support member 130 can be adjusted according to specific simulation requirements and are not limited here.

[0041] Step S102: defining simulation parameters of the assembly, including mesh properties, material properties, analysis steps, contacts, coupling constraints, boundary conditions, loads, and failure criteria.

[0042] In this step, simulation parameters of the assembly are defined, which specifically includes steps S1021 to S1028.

[0043] Step S1021: Define the mesh properties of the assembly. Specifically, hexahedral elements are used to discretize the assembly structure to improve computational efficiency. Meshing is performed on the flange 120, the insulating tube 110, and the support 130. The meshing technology for the flange 120 uses a swept mesh and neutral axis algorithm, with a global mesh edge length of 6 and a wall thickness of the flange tube 121 set to four layers. The meshing technology for the insulating tube 110 uses a structured mesh with a global mesh edge length of 10 and a wall thickness of five layers. The meshing technology for the support 130 uses a structured mesh with a global mesh edge length of 10.

[0044] Step S1022: Define the material properties of the assembly. Specifically, the material properties can be defined with reference to the material of the composite insulator 100 in actual production. Among them, the flange 120 is defined to be made of Q355 steel, with a Young's modulus of 210 GPa and a Poisson's ratio of 0.3, and the flange 120 is defined to have plastic deformation properties. Please refer to Table 1 for specific settings. The insulating tube 110 and the support member 130 are defined to be made of glass fiber reinforced plastic, and both are defined as anisotropic materials and perfectly elastic materials. Anisotropic materials refer to materials with different elastic constants along the fiber direction and in the direction perpendicular to the fiber direction; perfectly elastic materials refer to materials that can completely restore their original shape after the external force causing the deformation is removed. And in the simulation software, engineering constants are used to define the material properties of the insulating tube 110 and the support member 130. Please refer to Table 2 for specific settings.

[0045] Table 1 Relationship between stress and plastic strain of flange 120 after exceeding yield strength

[0046] Stress (MPa) Plastic strain 355 0 620 0.2 930 0.4

[0047] Table 2 Material properties of the insulating tube 110 and the support member 130

[0048] Young's modulus (MPa) Shear modulus (MPa) Poisson's ratio <![CDATA[E1=53000]]> <![CDATA[G 12 =5000]]> <![CDATA[Nu 12 =0.26]]> <![CDATA[E2=20000]]> <![CDATA[G 13 =5000]]> <![CDATA[Nu 13 =0.26]]> <![CDATA[E3=20000]]> <![CDATA[G 23 =7692]]> <![CDATA[Nu 23 =0.3]]>

[0049] Step S1023: Define the loads. The loads include a first crimping load, a second crimping load, and an external force load. Both the first and second crimping loads are set to 250 MPa. The external force load is a bending load, set to 60 kN. In the crimping simulation, staged crimping is used. The target crimping area includes a first sub-crimping area and a second sub-crimping area. The first and second sub-crimping areas overlap by 0 to 20 mm along the axial direction of the insulating tube 110. The first sub-crimping area is close to the flange 122, while the second sub-crimping area is farther away from the flange 122. The first crimping load is applied to the first sub-crimping area, and the second crimping load is applied to the second sub-crimping area. The first and second crimping loads are surface loads, specifically radially uniformly distributed compressive loads, applied to the first sub-crimping area and the second sub-crimping area, respectively. The bending load is applied to the top of the insulating tube 110 to test the bending bearing capacity of the insulating tube 110. The bending load is a point load.

[0050] Step S1024: Define analysis steps. Specifically, the simulation is defined as five steps, including a first crimping analysis step, a first unloading analysis step, a second crimping analysis step, a second unloading analysis step, and an external force analysis step. The first crimping analysis step involves applying a first crimping load within the first sub-crimping area, while the first unloading analysis step involves removing the first crimping load. The second crimping analysis step involves applying a second crimping load within the second sub-crimping area, while the second unloading analysis step removes the second crimping load. The external force analysis step is a bending analysis step, i.e., applying a bending load to the insulating tube 110. Each complete simulation involves performing two crimping simulations and one external force simulation on the mechanical simulation model. The first crimping simulation includes the first crimping analysis step and the first unloading analysis step, while the second crimping simulation includes the second crimping analysis step and the second unloading analysis step. The external force simulation includes the external force analysis step.

[0051] Step S1025: Define the contact of the assembly. Specifically, the contact analysis uses the penalty function algorithm and the normal contact algorithm, and the friction coefficient of each contact surface is set to 0.1. The end surface of the support 130 that is flush with the end of the insulating tube 110 is defined as the bottom of the support 130, the end surface of the flange 122 covering the flange cylinder 121 is defined as the bottom of the flange 120, the end surface of the end of the insulating tube 110 equipped with the support 130 is defined as the bottom of the insulating tube 110, and the inner wall of the flange cylinder 121 is defined as the inner wall of the flange 120. Four pairs of contacts are defined, namely, the bottom of the support 130 and the bottom of the flange 120, the bottom of the insulating tube 110 and the bottom of the flange 120, the outer wall of the insulating tube 110 and the inner wall of the flange 120, and the outer wall of the support 130 and the inner wall of the insulating tube 110. In the assembly, the bottom of the support member 130 contacts the bottom of the flange 120 , the bottom of the insulating tube 110 contacts the bottom of the flange 120 , the outer wall of the insulating tube 110 contacts the inner wall of the flange 120 , and the outer wall of the support member 130 contacts the inner wall of the insulating tube 110 .

[0052] Step S1026: Define coupling constraints for the assembly. Specifically, define the end face of the insulating tube 110 not fitted with the support member 130 as the top of the insulating tube 110, and define the center of the circle at the top of the insulating tube 110 as the center point. To facilitate the application of a bending load to the top of the insulating tube 110, couple the top of the insulating tube 110 to the center point using full kinematic coupling, with the bending load applied to the center point.

[0053] Step S1027: Define boundary conditions for the assembly. The first boundary condition is defined as securing a portion of the end face of flange 122. Specifically, in each analysis step, flange 122 is secured away from and not covering the portion of the end face of flange cylinder 121 to prevent movement or rotation. The second boundary condition is defined as securing the top of insulating tube 110. Specifically, in the first crimping analysis step, the first unloading analysis step, the second crimping analysis step, and the second unloading analysis step, the top of insulating tube 110 is secured to prevent movement or rotation. During the external force analysis step, the top of insulating tube 110 is unsecured.

[0054] Step S1028: Define the failure criteria of the assembly. Specifically, failure refers to the failure of the insulating tube 110 or the failure of the flange 120 or the contact slip failure between the flange 120 and the insulating tube 110. The failure of the insulating tube 110 refers to the shear cracking of the insulating tube 110, and the judgment is based on whether the shear stress of the insulating tube 110 exceeds 75MPa; the failure of the flange 120 refers to the cracking of the flange 120, and the judgment is based on whether the structural equivalent stress of the flange 120 exceeds the tensile strength of Q355 steel 600MPa; the contact slip failure between the flange 120 and the insulating tube 110 refers to the unstoppable relative slip between the flange 120 and the insulating tube 110, and the judgment is based on whether the unstoppable relative slip between the flange 120 and the insulating tube 110.

[0055] The establishment of the above-mentioned mechanical simulation model can be achieved by using any mechanical simulation software in the prior art, and no specific limitation is made here.

[0056] Step S20: In the mechanical simulation model, process parameters are changed and crimping simulation and external force simulation are performed to obtain stress data of the product to be crimped.

[0057] In this embodiment, the external force simulation is a bending simulation, so the aforementioned external force load is set as a bending load, and the external force analysis step is set as a bending analysis step. In other embodiments, the external force simulation can also be set as a tensile simulation, a compression simulation, a torsion simulation, etc. according to the simulation requirements. As long as the specific settings of the external force load and the external force analysis step are adjusted accordingly, no specific restrictions are made here.

[0058] In this step, the mechanical simulation model is simulated multiple times. A complete simulation includes the following: First, a mechanical simulation model of the product to be crimped is established and assembled to obtain an assembly of the product to be crimped. Second, in the first crimping analysis step, a portion of the end face of the flange 122 is fixed and the top of the insulating tube 110 is fixed, and a first crimping load is applied within the first sub-crimping zone. In the first unloading analysis step, a portion of the end face of the flange 122 is fixed and the top of the insulating tube 110 is fixed, and the first crimping load is removed. In the second crimping analysis step, a portion of the end face of the flange 122 is fixed and the top of the insulating tube 110 is fixed, and a second crimping load is applied within the second sub-crimping zone. In the second unloading analysis step, a portion of the end face of the flange 122 is fixed and the top of the insulating tube 110 is fixed, and the second crimping load is removed. In the bending analysis step, only a portion of the end face of the flange 122 is fixed and a bending load is applied to the top of the insulating tube 110. Finally, first stress data on the insulating tube 110 and second stress data on the flange 120 are obtained. The first stress data and the second stress data are analyzed, specifically, the first stress data is the fiber shear stress, and the second stress data is the Mises equivalent stress, so as to obtain the influence of the mechanical simulation model structure on the stress. Specifically, the method includes steps S201 to S204.

[0059] Step S201: In a mechanical simulation model, the length difference L between the support member 130 and the flange 120 is changed and a simulation is performed. The length difference L can be set to -40 mm, 0 mm, 20 mm, or 40 mm.

[0060] Step S202: In the mechanical simulation model, the distance between the end of the first sub-crimping area close to the flange 122 and the flange 122 is defined as a first crimping distance M. The first crimping distance M is changed and a simulation is performed. The first crimping distance M can be set to 15 mm, 20 mm, or 25 mm.

[0061] Step S203: In the mechanical simulation model, the distance between the other end of the second sub-crimping area away from the flange 122 and the end face of the flange tube 121 away from the flange 122 is defined as the second crimping distance N. The second crimping distance N is changed and a simulation is performed. The second crimping distance N can be set to 0 mm, 5 mm, or 10 mm.

[0062] Step S204: During actual crimping, due to manufacturing process variations, the cross-section of the insulating tube 110 along its radial direction may be non-circular. Therefore, in the mechanical simulation model, the cross-sectional shape tolerance of the insulating tube 110 is varied and simulated. The cross-sectional shape tolerance is specifically defined as the maximum difference between any two mutually orthogonal diameters along any radial cross-section of the insulating tube 110. The cross-sectional shape tolerance can be set to 0 mm or 5 mm. Specifically, when the cross-sectional shape tolerance is 0 mm, the cross-section of the insulating tube 110 along its radial direction is circular. When the assembly clearance is 5 mm, the cross-sectional shape of the insulating tube 110 along its radial direction is non-circular.

[0063] The process of obtaining stress data of the product to be crimped specifically includes step S205: after simulation, obtaining first stress data on the insulating tube 110 and second stress data on the flange 120 .

[0064] It is understandable that after each step of changing the process parameters in steps S201 to S204, step S205 can be executed to obtain corresponding data, and the execution order of steps S201 to S204 can be adjusted according to specific needs and is not specifically limited here.

[0065] In a specific application scenario, in the first simulation, the length of flange 120 was fixed (set to 160 mm), while the length of support member 130 was varied to 120 mm, 160 mm, 180 mm, and 200 mm. This allowed the length difference L between support member 130 and flange 120 to be set to -40 mm, 0 mm, 20 mm, and 40 mm, respectively. After the simulation, first stress data on insulating tube 110 and second stress data on flange 120 were obtained. The results are shown in Table 3.

[0066] Table 3: First stress data and second stress data when L takes different values

[0067] L value (mm) First stress data (MPa) Second stress data (MPa) -40 67.9 572.8 0 44.7 467.2 20 44.2 464.3 40 45.9 465.8

[0068] By comparison, it can be seen that when the value of L is -40 mm, the first stress data on the insulating tube 110 and the second stress data on the flange 120 are both large, the stress on the insulating tube 110 and the flange 120 is large, there is a risk of excessive plastic deformation, and failure is prone to occur; when the value of L is 40 mm, the length of the support 130 is large and the cost is high; therefore, when the value of L is 0 to 20 mm, the first stress data on the insulating tube 110 and the second stress data on the flange 120 are both small, which can control the cost while reducing the stress on the insulating tube 110 and the flange 120, thereby ensuring product quality.

[0069] In the second simulation, the length of the first sub-crimping area was set to 45 mm, and the values ​​of M were selected as 15 mm, 20 mm, and 25 mm. After the simulation, the first stress data on the insulating tube 110 and the second stress data on the flange 120 were obtained, and the results are shown in Table 4.

[0070] Table 4: First stress data and second stress data when M takes different values

[0071] M value (mm) First stress data (MPa) Second stress data (MPa) 15 71.03 478.2 20 74.14 466.4 25 77.88 463.5

[0072] A comparison shows that when M is set to 15 mm, 20 mm, and 25 mm, the first stress data on insulating tube 110 and the second stress data on flange 120 are similar. Therefore, the value of M has little effect on the stresses on insulating tube 110 and flange 120. Therefore, based on this simulation, M is set to 15 to 25 mm.

[0073] In the third simulation, the length of the second sub-crimping zone was set to 45 mm, and the values ​​of N were selected as 0 mm, 5 mm, and 10 mm. After the simulation, the first stress data on the insulating tube 110 and the second stress data on the flange 120 were obtained, and the results are shown in Table 5.

[0074] Table 5: First stress data and second stress data when N takes different values

[0075] N value (mm) First stress data (MPa) Second stress data (MPa) 0 77.88 463.5 5 74.14 466.4 10 71.03 478.2

[0076] A comparison shows that when N is set to 0 mm, 5 mm, and 10 mm, the first stress data on the insulating tube 110 and the second stress data on the flange 120 are similar. Therefore, the value of N has little effect on the stresses on the insulating tube 110 and flange 120. However, when N is set to 0 mm, actual crimping becomes more difficult. Therefore, to facilitate crimping, N is set to 5 mm to 10 mm.

[0077] In the fourth simulation, the cross-sectional shape tolerances of the insulating tube 110 were selected to be 0 mm and 5 mm, respectively. In the external force simulation, a bending load was applied until failure occurred to obtain the bearing capacity of the insulating tube 110. The results are shown in Table 6.

[0078] Table 6 Bearing capacity of insulation tube 110 with different cross-sectional shape tolerances

[0079] Assembly clearance (mm) Insulation tube 110 bearing capacity (kN) 0 45.97 5 41.90

[0080] It can be seen from the comparison that the cross-sectional shape tolerance has little effect on the bearing capacity of the insulating tube 110 , that is, there is no need to consider the cross-sectional shape tolerance of the insulating tube 110 .

[0081] Step S30: Comparative analysis to obtain target process parameters, specifically including step S301: comparing the first stress data and the second stress data under each process parameter according to the simulation results, and analyzing and determining the target process parameters.

[0082] Combined with the analysis, the target process parameters are determined as follows: L value is 0~20mm, M value is 15mm~25mm, and N value is 5mm~10mm.

[0083] To verify the accuracy of the simulation, the insulation tube 110, flange 120, and support member 130 were prepared and crimped according to the target process parameters obtained from the simulation. Then, a load failure test was conducted, and the relevant test data was recorded. The simulation and test results were compared and analyzed. Specifically,

[0084] S1: Provide an insulating tube 110, two support members 130, and two flanges 120. The flange 120 includes a flange cylinder 121 and a flange plate 122. The flange cylinder 121 is a hollow cylindrical structure. The flange plate 122 covers one end of the flange cylinder 121. The inner diameter of the flange cylinder 121 matches the outer diameter of the insulating tube 110. The outer diameter of the support member 130 matches the inner diameter of the insulating tube 110.

[0085] Specifically, an insulating tube 110, two support members 130, and two flanges 120 are prepared according to the size of the composite insulator 100 to be prepared. The outer diameter of the insulating tube 110 is 0.1 to 0.5 mm smaller than the inner diameter of the flange tube 121, so that the flange tube 121 and the insulating tube 110 can move relative to each other to adjust the position of the flange tube 121 on the insulating tube 110, thereby ensuring that the flange 120 can be installed in place. The outer diameter of the support member 130 is 0.1 to 0.5 mm smaller than the inner diameter of the insulating tube 110, so that the support member 130 and the insulating tube 110 can move relative to each other to adjust their relative positions, thereby ensuring that the support member 130 can be installed in place.

[0086] The support member 130 is a solid cylindrical structure. The length of the support member 130 is 10 to 20 mm longer than the length of the flange tube 121. Chamfers are prepared at both ends of the support member 130. The chamfers can serve as a guide for reducing the diameter, so that the support member 130 can be placed more smoothly into the inner cavity of the insulating tube 110, significantly improving the assembly efficiency; and the chamfers can also avoid structural wear caused by sharp edges, thereby extending the service life of the composite insulator 100.

[0087] Furthermore, an shed is prepared on the outer circumference of the insulating tube 110 .

[0088] S2: Place the two support members 130 into the inner cavities at both ends of the insulating tube 110 respectively, so that one end of the two support members 130 is flush with the two end portions of the insulating tube 110 respectively.

[0089] When the insulating tube 110 and the support member 130 are assembled in place, the support member 130 is approximately coaxially disposed in the inner cavity of the insulating tube 110 , and the ends of the two are flush.

[0090] S3: Sleeve the two sealing rings on the outer circumference of the insulating tube 110 so that they are located in the target crimping areas of the two flanges 120 respectively.

[0091] The sealing ring has a circular cross section and is sleeved on the outer circumference of the insulating tube 110. The sealing ring is made of EPDM rubber or other rubber.

[0092] The flange barrel 121 is provided with a target crimping area that mates with the insulating tube 110 and is used to effectively connect the flange barrel 121 and the insulating tube 110. The target crimping area is annular and located on the outer periphery of the flange barrel 121 and is coaxial with the flange barrel 121. In other words, the target crimping area is the outer surface area of ​​the flange barrel 121 along its axial direction.

[0093] The distance between the end of the target crimping zone closest to flange 122 and flange 122 is 15-25 mm. This ensures a good crimping effect while minimizing the crimping stress on flange 120, preventing damage to flange 120 during the crimping process and ensuring product quality. The distance between the other end of the target crimping zone, away from flange 122, and the end face of flange tube 121, away from flange 122, is 5-10 mm. This ensures a good crimping effect while minimizing the crimping stress on insulating tube 110, preventing damage to insulating tube 110 during the crimping process and ensuring product quality.

[0094] S4: The flange cylinders 121 of the two flanges 120 are sleeved on the outer peripheries of both ends of the insulating tube 110 , and the end surfaces of the insulating tube 110 and the supporting member 130 that are flush with each other are in contact with the flange plates 122 .

[0095] When the flange tube 121 is sleeved on the outer periphery of the insulating tube 110, the sealing ring abuts against the outer periphery of the insulating tube 110 and the inner periphery of the flange tube 121 at the same time, and the sealing ring is close to the other end of the flange tube 121 away from the flange plate 122. At this time, the sealing ring is in a compressed state.

[0096] S5: Perform crimping operation in the target crimping area to firmly connect the insulating tube 110, the support member 130, and the flange 120.

[0097] The crimping operation is achieved through a crimping device, which applies radial extrusion force in the target crimping area, ensuring that the flange tube 121, the insulating tube 110 and the support member 130 are evenly stressed during the entire crimping process, thereby ensuring the connection reliability of the three.

[0098] In one embodiment, when the length of the flange tube 121 exceeds a certain limit, staged crimping is performed. The target crimping area consists of several sub-crimping areas, with any two adjacent sub-crimping areas overlapping by 0-20 mm along the axial direction of the insulating tube 110, ensuring a continuous, gap-free target crimping area across the entire flange tube 121. Staged crimping is performed, with crimping performed on only one sub-crimping area at a time, until all sub-crimping areas are crimped.

[0099] Furthermore, after step S5 or before step S1 , step S6 may be included: welding a plurality of reinforcing ribs 123 on the flange 122 , the reinforcing ribs 123 simultaneously connecting the flange tube 121 and the flange 122 , and the plurality of reinforcing ribs 123 are evenly distributed along the circumference of the flange 120 .

[0100] The provision of the reinforcing ribs 123 can indirectly increase the contact area between the flange cylinder 121 and the flange plate 122, thereby improving the strength of the flange 120. Six reinforcing ribs 123 or any other number can be provided as long as the overall stability of the flange 120 can be enhanced.

[0101] After step S5, step S7 may be further included: using sealant to fill the gap between the flange tube 121 and the insulating tube 110, and covering the connection between the end surface of the flange tube 121 away from the flange plate 122 and the insulating tube 110, so that the two are further sealed and connected.

[0102] S8: Conduct load destruction test and record relevant test data.

[0103] Specifically, according to the target process parameters obtained by the simulation, three test pieces were prepared using the above steps. A load failure test was performed on each test piece by applying a load, and the failure load, the failure strength of the insulating tube 110, and the failure mode were recorded, as shown in Table 7.

[0104] Table 7 Load failure test data record

[0105]

[0106] In the prior art, when the insulating tube and the flange are glued together, the concentrated load force on the insulating tube is 24kN, and the failure mode is based on the failure of the glue. From the above test results, it can be seen that after the insulating tube 110 and the flange 120 are crimped together according to the target process parameters obtained by simulation, the external force that the insulating tube 110 can withstand is improved compared to the glue connection. The finished crimped product is mainly the destruction of the insulating tube 110, which shows that the crimping connection can fully utilize the strength of the insulating tube 110. It further shows that the crimping process simulation method of the present application can quickly obtain the optimal process parameters to ensure the quality stability of the crimped products.

[0107] The beneficial effect of the present application is that compared with the prior art, the crimping process simulation method of the present application can simulate and study the relationship between the difference in length between the support and the flange, the distance between the end of the first sub-crimping area close to the flange and the flange, and the distance between the other end of the second sub-crimping area away from the flange and the end face of the flange tube away from the flange, and the stress on the insulating tube and the flange after crimping, thereby quickly obtaining the optimal process parameters and ensuring the quality stability of the crimped products.

[0108] The above is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A crimping process simulation method, characterized in that: The following steps are involved: Step S10: establishing a mechanical simulation model of a product to be crimped, wherein the product to be crimped includes an insulating tube, a flange sleeved on the outer periphery of an end portion of the insulating tube, and a support member provided on the inner periphery of the end portion of the insulating tube; Step S20: In the mechanical simulation model, changing process parameters and performing crimping simulation and external force simulation to obtain stress data of the product to be crimped; Step S30: comparative analysis to obtain target process parameters.

2. The crimping process simulation method according to claim 1, wherein: The step S10 further includes: Step S101: establishing geometric models of the flange, the insulating tube, and the support respectively, and assembling them to obtain an assembly of the product to be crimped; Step S102: defining simulation parameters of the assembly, wherein the simulation parameters include mesh properties, material properties, analysis steps, contact, coupling constraints, boundary conditions, loads, and failure criteria.

3. The crimping process simulation method according to claim 2, wherein: The external force simulation is a bending simulation; the analysis steps include a first crimping analysis step, a first unloading analysis step, a second crimping analysis step, a second unloading analysis step, and a bending analysis step; the load includes a first crimping load, a second crimping load, and a bending load, the first crimping load and the second crimping load are both set to 250 MPa, and the bending load is set to 60 kN.

4. The crimping process simulation method according to claim 1, wherein: The step S20 further includes a step S201: in the mechanical simulation model, changing the length difference between the support member and the flange and performing a simulation, wherein the length difference is set to -40 mm, 0 mm, 20 mm, and 40 mm, respectively.

5. The crimping process simulation method according to claim 1, wherein: The step S20 further includes a step S202: in the mechanical simulation model, changing the first crimping distance and performing a simulation, wherein the first crimping distance is set to 15 mm, 20 mm, and 25 mm respectively.

6. The crimping process simulation method according to claim 1, wherein: The step S20 further includes a step S203: in the mechanical simulation model, changing the second crimping distance and performing simulation, wherein the second crimping distance is set to 0 mm, 5 mm, and 10 mm respectively.

7. The crimping process simulation method according to claim 1, wherein: The step S20 further includes a step S204: in the mechanical simulation model, changing the cross-sectional shape tolerance of the insulating tube and performing simulation, wherein the cross-sectional shape tolerance is set to 0 mm and 5 mm respectively.

8. The crimping process simulation method according to claim 1, wherein: The step S20 further includes a step S205: obtaining first stress data on the insulating tube and second stress data on the flange after the simulation.

9. The crimping process simulation method according to claim 8, wherein: The step S30 further includes step S301: comparing the first stress data and the second stress data under each of the process parameters according to the simulation results, and analyzing and determining the target process parameters.

10. The crimping process simulation method according to claim 1, wherein: In the target process parameters, the difference in length between the support member and the flange is 0 to 20 mm, the first crimping distance is 15 to 25 mm, and the second crimping distance is 5 to 10 mm.

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