Method for testing installation torque parameters of high-performance joint and conduit assembly under complex working conditions

Abstract

The invention provides a method for testing installation torque parameters of a high-performance joint and a conduit assembly under complex working conditions, which belongs to the technical field of testing and comprises the following steps: acquiring installation working condition information of a threaded joint and the conduit assembly; according to the installation working condition information, an installation pre-tightening force boundary is obtained through finite element simulation; obtaining a model calculation installation moment boundary through the constructed installation moment boundary calculation model; performing a simulation experiment according to the installation condition information to obtain a test installation torque boundary; acquiring a literature reference installation moment boundary according to the related standard file; and establishing a union set of a model calculation installation torque boundary, a test installation torque boundary and a literature reference installation torque boundary, obtaining a union set installation torque boundary, and carrying out test correction according to the installation working condition information to obtain the installation torque parameters of the high-performance joint and the conduit assembly under the complex working condition. According to the invention, the test cost can be effectively reduced, and the efficiency, accuracy and reliability of installation torque parameter determination are improved.

Description

Technical Field

[0001] This invention relates to the field of aerospace pipeline connection technology, specifically to a test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions. Background Technology

[0002] Piping connectors are fundamental electromechanical products for fluid transmission and power transfer in aerospace fluid systems. They serve as the airways and blood vessels of various aerospace vehicles, playing a crucial role in the safe and reliable operation of aerospace equipment. Installation torque parameters are critical in the design, verification, manufacturing, service, and maintenance of aerospace piping connectors. The rationality and accuracy of these parameters significantly impact the sealing performance, connection performance, and lifespan reliability of the piping products during service.

[0003] Aerospace piping connectors face a variety of complex load conditions during service, including high operating pressure, operating temperatures ranging from -55 to 650°C, vibration loads exceeding 20g, and pressure pulsation. High-performance connectors and conduit assemblies simultaneously require high reliability, long service life, lightweight design, and miniaturization. To meet maintenance requirements, they need to be reusable 8 to 25 times. To ensure reliable connections in these detachable piping products, the installation torque parameter range must be clearly specified in the product technical documents. Insufficient installation torque can cause leaks, while excessive torque can lead to excessive stress on the components, causing microcracks in the local structure and fatigue failure, failing to meet the product's full life-cycle requirements. Furthermore, excessive torque cannot meet the requirements for repeated disassembly and assembly. Simultaneously, the installation torque parameter should have a sufficient range to ensure the feasibility of the installation process. Otherwise, frequent installation-related leaks, damage, and fatigue failures during service will occur, making the installation torque "unusable" in actual installation. Therefore, determining a reasonable installation torque parameter range is one of the key indicators for the design and verification of piping connector products.

[0004] Currently, the installation torque parameters for pipe fittings are typically determined using two methods: one is through empirical methods, followed by verification through product qualification tests under standard laboratory conditions; the other is by approximating the maximum and minimum installation torque parameters through numerous experiments. However, the former method results in inaccurate determination of installation torque parameters, while the latter method involves time-consuming and costly testing.

[0005] Therefore, how to reliably and cost-effectively conduct installation torque parameter tests and obtain reasonable installation torque parameters is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions. This method utilizes finite element simulation to simulate the actual pressure, installation, and structural conditions of pipeline products. Based on the constructed boundary calculation model of installation torque, the method provides installation torque parameters under simulated conditions. By integrating model-calculated torque parameters, experimental installation torque parameters, and empirical installation torque parameters from literature, the method rapidly reduces the design and verification time for product installation parameters, lowers torque testing costs, guides the forward design of installation parameters for pipeline products, and improves the accuracy and reliability of determining installation torque parameters through a combination of simulation-based theoretical analysis and experimental verification.

[0007] Specifically, the present invention provides a test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions, which includes the following steps: S1. Obtain the installation condition information of the threaded connector and conduit assembly; the installation condition information includes product structure connection information, installation position information, installation lubrication information and installation environment information; S2. Based on the installation condition information, obtain the installation preload boundary through finite element simulation; S3. Based on the installation preload boundary, obtain the installation torque boundary calculated by the model through the constructed installation torque boundary calculation model; The boundary calculation model for the installation torque is as follows: T = (F - ( E x K x + E y K y + E α K y )) L z ; Where T is the installation torque boundary, F is the installation preload boundary, and n is the number of times the load range is obtained from the simulation; F G1 For the axial deformation load values ​​obtained from the simulation, L x1 For the corresponding F G1 The obtained angular displacement data; F G2 For the radial deformation load values ​​obtained from the simulation, L x2 For the corresponding F G2 The obtained angular displacement data; F G3 For the angle error load value data obtained from the simulation, L x3 For the corresponding F G3The obtained angular displacement data; Ex is the axial position error, Ey is the axial position error, E α Kx represents the angular position error; Kx is the projection component coefficient of the axial load in the direction of the installation preload, and Ky is the projection component coefficient of the radial load in the direction of the installation preload. α Lz is the projection component coefficient of the angular error load in the direction of the installation preload; Lz is the equivalent friction arm. S4. Conduct simulation experiments based on installation condition information to obtain the test installation torque boundary; S5. Obtain the reference installation torque boundary based on the relevant standard documents for threaded joints and conduit assemblies; S6. Establish the model to calculate the union of the installation torque boundary, the experimental installation torque boundary, and the literature reference installation torque boundary, and obtain the union installation torque boundary. S7. Perform experimental correction on the union installation torque boundary based on the installation condition information to obtain the installation torque parameters of high-performance joints and conduit assemblies under complex working conditions.

[0008] Preferably, the product structure connection information in S1 includes connector material, thread parameters, sealing surface shape, and sealing surface angle information; the installation position information includes installation angle deviation, axial deviation, and radial deviation information; the installation lubrication information includes conduit fluid medium and lubricant information; and the installation environment information includes installation environment information such as temperature, humidity, and internal pressure.

[0009] Preferably, the installation preload boundary in S2 includes a maximum installation preload and a minimum installation preload; the maximum installation preload is 80% of the maximum preload that does not cause material yielding in any of the connecting parts of the joint and conduit assembly during the finite element simulation installation process; the minimum installation preload is 120% of the preload when the contact stress of the sealing surface is greater than 50MPa and the width of the sealing surface of the assembly reaches 1mm.

[0010] Preferably, S3 includes: S31. Construct the boundary calculation model for installation torque; T = (F-( E x K x + E y K y + E α K y )) L z ; S32. Input installation environment information and installation lubrication information as the running background, perform finite element simulation, and for the connectors in the product structure connection information including dimensions, structure and material combination, fix them at the conduit end, and apply axial, radial and angular loads from the installation position information to the other end of the component, from 0% to 85% of the conduit yield limit load, and take n sets of data to obtain the load value data F. G11 To F Gn F G21 To F G2n F G31 To F G3n and the corresponding angular displacement data L x11 To L x1n L y21 To L y2n L α31 To L α3n ; S33. Obtain the axial position error Ex, axial position error Ey, and angular position error Eα through the installation position information; S34. Through finite element simulation, obtain the angle α0 between the axial direction of the connector and the theoretical axis after installation based on the position error, and calculate the projection component coefficients: Kx = cosα; Ky = sinα; Kα = sinα; S35. Determine the equivalent friction arm Lz based on the product structure connection information; + ; Where P is the thread pitch of the pipe fitting. The mean diameter of the pipe fitting thread. Correct the coefficient of friction between the pipe fitting and the outer nut. Correct the coefficient of friction for the contact surface between the sleeve and the outer nut; S36. Input the installation preload boundary data and the data required for the calculation model into the constructed installation torque boundary calculation model, and obtain the model to calculate the installation torque boundary.

[0011] Preferably, the friction coefficient of the contact surface between the S35 pipe fitting and the outer nut is modified. and the corrected friction coefficient of the contact surface between the sleeve and the outer nut They are respectively; =K h K r ; =K h K r ; in, The standard coefficient of friction between the pipe fitting and the outer nut contact surface. K is the standard friction coefficient of the contact surface between the sleeve and the outer nut. h K is the environmental condition correction factor. r This is a correction factor for lubrication conditions. , K h and K r Information was obtained by consulting relevant standard documents.

[0012] Preferably, S4 includes: S41. Based on the installation condition information, establish an environmental test chamber to simulate the environment; S42. Obtain the installation preload boundary of S2. In the environmental test chamber, select m groups of products to conduct installation tests under simulated working conditions. Measure the installation torque condition parameters under the conditions of maximum and minimum installation preload. Repeat the test multiple times and take the average value to determine the test installation torque boundary.

[0013] Preferably, step S5 specifically involves: consulting relevant standards and product manuals based on the product configuration to obtain the literature reference installation torque boundary for products under approximate working conditions.

[0014] Preferably, S7 includes: S71. Minimum installation torque for test correction; To simulate product operating conditions, select product group U and conduct Ux repeated assembly tests under the minimum installation torque condition in the union of installation torque boundaries to verify whether the airtightness and pressure resistance test requirements are met under the minimum installation torque. If not, continue to increase the standard torque until the installation torque of all products meets the test requirements, and determine it as the minimum installation torque boundary. S72, Test and correct the maximum installation torque; The initial installation torque condition is selected as 110% to 140% of the minimum installation torque in the union of installation torque boundaries to simulate product working conditions. Each time the standard torque is increased, Ux repeated assembly tests are performed to verify whether the U group of products meets the airtightness and pressure resistance test requirements under the current installation torque, until the maximum installation torque in the union of installation torque boundaries is reached. When one group of products fails to meet the airtightness and pressure resistance requirements during the process, the torque of the standard torque amount reduced by the standard multiple of the measured torque is taken as the maximum installation torque. If all test requirements are met, the maximum installation torque in the union of installation torque boundaries is the determined maximum installation torque. S73, Test and correction limit installation torque; The simulated product working conditions are tested by performing Ux repeated assembly tests starting from the maximum installation torque in the union of installation torque boundaries. This verifies whether the product meets the airtightness and pressure resistance test requirements under this installation torque, and whether disassembly is normal. If the requirements are met, the standard torque is increased and the test is continued. When one group of products fails to meet the airtightness and pressure resistance requirements or a disassembly failure occurs, this torque is the ultimate maximum installation torque.

[0015] Preferably, the standard torque is 0.5 N·m, and the standard multiple is 4 times.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention constructs an installation torque boundary calculation model, which calculates the installation torque boundary parameters of the simulation state based on installation working condition information. It shifts from the traditional "trial and error method" of a large number of experiments to "physically based precise experiments", which greatly reduces the number of test specimens and test rounds. At the same time, it avoids wasting experimental time in invalid low torque or destructive high torque ranges, thus improving experimental efficiency.

[0017] 2. This invention integrates the boundary parameters of calculated torque from the model, the boundary parameters of experimental installation torque, and the boundary parameters of empirical installation torque from the literature, and then verifies them from both ends, which greatly improves the verification efficiency. Furthermore, by combining simulation theoretical analysis and experimental verification with the same installation conditions, the accuracy and reliability of determining the installation torque parameters are improved. Attached Figure Description

[0018] Figure 1 This is a flowchart of the test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions according to the present invention; Figure 2 This is an overall structural diagram of an aviation detachable quick connector according to an embodiment of the present invention; Figure 3 This is a structural diagram of the conduit head in a detachable quick connector for aviation use according to an embodiment of the present invention; Figure 4 This is a structural diagram of the fitting of the conduit head and the conduit head in a detachable quick connector for aviation use according to an embodiment of the present invention; Figure 5 This is a schematic diagram of a typical catheter assembly and connector connection according to an embodiment of the present invention; Figure 6 This is a schematic diagram of a typical detachable threaded connector according to an embodiment of the present invention; Figure 7 This is a schematic diagram of a typical catheter assembly installation section according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the installation of a typical detachable threaded connector and conduit assembly according to an embodiment of the present invention; Figure 9This is a simulated stress diagram of a typical detachable threaded joint and conduit assembly mounting section according to an embodiment of the present invention; Figure 10 This is a diagram showing the equivalent plastic strain εp along the contact edge of the sealing area of ​​the connector according to an embodiment of the present invention. Figure 11 This is a diagram of the contact normal stress σN in the sealing surface area of ​​a connector according to an embodiment of the present invention. Figure 12 A typical axial and radial error diagram for the installation of a detachable threaded connector and conduit assembly according to an embodiment of the present invention; Figure 13 This is a schematic diagram of the installation of a typical detachable threaded connector and conduit assembly according to an embodiment of the present invention; Figure 14 This is a typical measurement diagram of the installation angle error of a detachable threaded connector and conduit assembly according to an embodiment of the present invention; Figure 15 This is a schematic diagram of an installation torque test of a typical detachable threaded joint and conduit assembly mounting section according to an embodiment of the present invention; Figure 16 This is a schematic diagram illustrating the process of obtaining the installation torque boundary of the model according to an embodiment of the present invention; Figure 17 This is a schematic diagram illustrating the process of obtaining installation torque parameters by experimentally correcting the boundary of the union installation torque according to an embodiment of the present invention.

[0019] Key reference numerals: 1. Conduit head, 11. Annular protrusion, 12. Sliding ring, 2. Double adapter, 21. Tube body, 22. Insertion, 23. Annular groove, 24. Threaded mounting part. Detailed Implementation

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0021] As attached Figure 1 As shown, this invention provides a test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions, which includes the following steps: S1. Obtain installation status information for threaded connectors and conduit assemblies; Installation condition information includes product structural connection information, installation position information, installation lubrication information, and installation environment information. Specifically: product structural connection information includes connector material, thread parameters, sealing surface shape, and sealing surface angle information; installation position information includes installation angle deviation, axial deviation, and radial deviation information; installation lubrication information includes conduit fluid medium and lubricant information; and installation environment information includes temperature, humidity, internal pressure, and other installation environment information.

[0022] S2. Based on the installation condition information, obtain the installation preload boundary through finite element simulation; The installation preload boundary includes the maximum installation preload and the minimum installation preload; the maximum installation preload is 80% of the maximum preload that does not cause material yielding in any of the connecting parts of the joint and conduit assembly during the finite element simulation installation process; the minimum installation preload is 120% of the preload when the contact stress of the sealing surface is greater than 50MPa and the width of the sealing surface of the assembly reaches 1mm.

[0023] S3. Based on the installation preload boundary, obtain the installation torque boundary calculated by the model through the constructed installation torque boundary calculation model, including: S31. Construct the boundary calculation model for installation torque; T = (F - ( E x K x + E y K y + E α K y )) L z ; Where T is the installation torque boundary, F is the installation preload boundary, and n is the number of times the load range is obtained from the simulation; F G1 For the axial deformation load values ​​obtained from the simulation, L x1 For the corresponding F G1 The obtained angular displacement data; F G2 For the radial deformation load values ​​obtained from the simulation, L x2 For the corresponding F G2 The obtained angular displacement data; F G3 For the angle error load value data obtained from the simulation, L x3 For the corresponding F G3 The obtained angular displacement data; Ex is the axial position error, Ey is the axial position error, E α Kx represents the angular position error; Kx is the projection component coefficient of the axial load in the direction of the installation preload, and Ky is the projection component coefficient of the radial load in the direction of the installation preload. α Lz is the projection component coefficient of the angular error load in the direction of the installation preload; Lz is the equivalent friction arm.

[0024] S32. Input installation environment information and installation lubrication information as the running background, perform finite element simulation, and for the connectors in the product structure connection information including dimensions, structure and material combination, fix them at one end of the conduit, and apply axial, radial and angular loads from the installation position information to the other end, from 0% to 85% of the conduit yield limit load, and take n sets of data to obtain the load value data F. G11 To F Gn F G21 To F G2n F G31 To F G3n and the corresponding angular displacement data L x11 To L x1n L y21 To L y2n L α31 To L α3n ; S33. Obtain the axial position error Ex, axial position error Ey, and angular position error Eα through the installation position information; S34. Through finite element simulation, obtain the angle α0 between the axial direction of the connector and the theoretical axis after installation based on the position error, and calculate the projection component coefficients: Kx = cosα; Ky = sinα; Kα = sinα; S35. Determine the equivalent friction arm Lz based on the product structure connection information; + ; Where P is the thread pitch of the pipe fitting. The mean diameter of the pipe fitting thread. Correct the coefficient of friction between the pipe fitting and the outer nut. The coefficient of friction is corrected for the contact surface between the sleeve and the outer nut.

[0025] Corrected friction coefficient between the pipe fitting and the outer nut contact surface and the corrected friction coefficient of the contact surface between the sleeve and the outer nut They are respectively; =K h K r ; =K h K r ; in, The standard coefficient of friction between the pipe fitting and the outer nut contact surface. K is the standard friction coefficient of the contact surface between the sleeve and the outer nut.h K is the environmental condition correction factor. r This is a correction factor for lubrication conditions. , K h and K r Information was obtained by consulting relevant standard documents.

[0026] S36. Input the installation preload boundary data and the data required for the calculation model into the constructed installation torque boundary calculation model, and obtain the model to calculate the installation torque boundary.

[0027] S4. Conduct simulation experiments based on installation condition information to obtain the test installation torque boundary; including: S41. Based on the installation condition information, establish an environmental test chamber to simulate the environment; S42. Obtain the installation preload boundary of S2. In the environmental test chamber, select m groups of products to conduct installation tests under simulated working conditions. Measure the installation torque condition parameters under the conditions of maximum and minimum installation preload. Repeat the test multiple times and take the average value to determine the test installation torque boundary.

[0028] S5. Obtain the reference installation torque boundary based on the relevant standard documents for threaded joints and conduit assemblies; Based on the product configuration, consult relevant standards and product manuals to obtain the literature reference installation torque boundary for products with similar operating conditions.

[0029] S6. Establish the model to calculate the union of the installation torque boundary, the experimental installation torque boundary, and the literature reference installation torque boundary, and obtain the union installation torque boundary. S7. The union installation torque boundary is experimentally corrected based on installation condition information to obtain the installation torque parameters for high-performance connectors and conduit assemblies under complex working conditions. This includes: S71. Minimum installation torque for test correction; To simulate product operating conditions, select product group U and conduct Ux repeated assembly tests under the minimum installation torque condition in the union of installation torque boundaries to verify whether the airtightness and pressure resistance test requirements are met under the minimum installation torque. If not, continue to increase the standard torque until the installation torque of all products meets the test requirements, and determine it as the minimum installation torque boundary. S72, Test and correct the maximum installation torque; The initial installation torque condition is selected as 110% to 140% of the minimum installation torque in the union of installation torque boundaries to simulate product working conditions. Each time the standard torque is increased, Ux repeated assembly tests are performed to verify whether the U group of products meets the airtightness and pressure resistance test requirements under the current installation torque, until the maximum installation torque in the union of installation torque boundaries is reached. When one group of products fails to meet the airtightness and pressure resistance requirements during the process, the torque of the standard torque amount reduced by the standard multiple of the measured torque is taken as the maximum installation torque. If all test requirements are met, the maximum installation torque in the union of installation torque boundaries is the determined maximum installation torque. S73, Test and correction limit installation torque; The simulated product working conditions are tested by performing Ux repeated assembly tests starting from the maximum installation torque in the union of installation torque boundaries. This verifies whether the product meets the airtightness and pressure resistance test requirements under this installation torque, and whether disassembly is normal. If the requirements are met, the standard torque is increased and the test is continued. When one group of products fails to meet the airtightness and pressure resistance requirements or a disassembly failure occurs, this torque is the ultimate maximum installation torque.

[0030] The standard torque can be 0.5 N·m, and the standard multiple can be 4 times.

[0031] As an example of an implementation of the present invention, an aviation connector and conduit assembly is provided, such as... Figure 2 and Figure 3 As shown, it includes a combined conduit 1 and a straight connector 2. The insertion end of the combined conduit 1 is provided with multiple stepped annular raised arc-conical surfaces 11 arranged along the axial direction. The sleeve 12 is connected to the conduit line through a groove by a rolling or extrusion process.

[0032] like Figure 3 As shown, the straight connector 2 includes a pipe body 21 and an outer nut 22 located at the first end of the pipe body 21. The inner wall of the outer nut 22 is provided with an annular groove 23 that matches the shape of the stepped annular protrusion 11. The conduit of the combined conduit 1 is inserted into the outer nut 22, and the stepped annular protrusion 11 engages with the annular groove 23 of the outer nut 22. The axial limiting and circumferential positioning of the combined conduit 1 and the straight connector 2 are achieved by the thread. The second end of the adapter 2 is a threaded mounting part 24.

[0033] like Figure 4 As shown, the central axis of the catheter head 1 coincides with the rotation axis of the double adapter 2, the inner wall of the through hole of the sleeve 12 is provided with a recessed area, and the outer wall of the catheter head 1 is deformed and protruded by rolling or extrusion process to connect with the sleeve.

[0034] The inner wall of the plug 22 of the adapter 2 is also provided with an internal thread, and the outer wall of the plug end of the conduit head 1 is also provided with an arc-conical guide. The inner wall of the plug end of the double adapter 2 is provided with a cone angle that matches the arc-conical guide. The internal thread in the outer nut 22 and the external thread of the plug interface of the adapter 2 are connected and tightened to achieve the connection and sealing between the arc surface of the conduit head 1 and the conical surface of the double adapter.

[0035] like Figure 16-17 As shown, this invention provides a test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions, which includes the following steps: Step 1: Obtain product operating condition information; Obtain product structural connection information including connector material, thread parameters, sealing surface shape, sealing surface angle, etc.; installation position information such as installation angle deviation, axial deviation, radial deviation, etc.; installation lubrication information such as conduit fluid medium and lubricant information; and installation environment information such as temperature, humidity, internal pressure, etc. Example: Conduit diameter: 6mm, material: titanium alloy TC4, thread: MJ12×1.25 thread, sealing surface spherical-conical seal, sealing surface angle 24°, installation angle deviation 0°, axial deviation 0.1mm, radial deviation 0mm, medium: hydraulic oil, lubricant: hydraulic oil, temperature: 70℃, humidity 60%, pressure: 10MPa.

[0036] Step 2: Create a digital prototype of the product; A typical catheter assembly structure is as follows Figure 5 As shown, the conduit and connector assembly consists of several spatially curved and straight sections. A simplified model of the connector and conduit assembly connections, simulating product operating conditions, is created using 3D modeling software. Typical detachable threaded connector and conduit assembly models and installation diagrams are shown below. Figure 6 , Figure 7 and Figure 8 As shown.

[0037] Step 3: Determine the boundary parameters of the preload through simulation; like Figure 9 As shown, the simulated product working condition information is obtained through finite element simulation. The maximum installation preload is 80% of the maximum preload that prevents any connector from yielding during the simulated installation process, and the minimum installation preload is 120% of the preload that makes the sealing surface width of the connector with a sealing surface contact stress greater than 50MPa reach 1mm. Example: such as Figure 10 The simulation model is used to apply pre-tightening force to both ends of the connector and record the equivalent plastic strain of the connector to simulate the tightening process. The equivalent plastic strain ε of the connector's sealing surface or any component is recorded. PWhen the preload exceeds the commonly used standard for judging plastic deformation by 0.2%, it is determined that plastic deformation has occurred. Record 80% of this preload as the maximum installation preload, and the maximum installation preload is 5kN.

[0038] like Figure 11 The simulation model shows that a pre-tightening force is applied to both ends of the connector, and the equivalent contact normal stress σ on the sealing surface of the connector is recorded. N The relationship curve between the sealing surface width and the maximum sealing surface width is used to ensure that the sealing surface width of the connector with a sealing surface contact stress greater than 50MPa reaches a preload of 1mm. The maximum preload parameter is taken as 120% of this preload, and the minimum installation preload is obtained as 2kN.

[0039] Step 4: Construct the installation torque boundary calculation model and calculate the theoretical installation torque boundary; T = (F - ( E x K x + E y K y + E α K y )) L z ; In the formula, T is the installation torque of the pipeline product; F is the preload of the pipeline product; Lz is the equivalent friction arm; substituting the installation preload calculated above, which is F, the maximum installation torque is calculated from the maximum preload, and the minimum installation torque is calculated from the minimum preload.

[0040] α is the deformation angle, Ex is the axial position error, Ey is the axial position error, Eα is the angular position error, Kx is the projection component coefficient of the axial load in the actual installation preload direction, Ky is the projection component coefficient of the radial load in the actual installation preload direction, and Kα is the projection component coefficient of the angular error load in the actual installation preload direction.

[0041] For connectors with defined dimensions, structure, and material combinations, with the conduit end fixed, axial, radial, and angular loads are applied to the other end of the assembly, ranging from 0% to 85% of the conduit's yield strength load. Five sets of data are collected, and the load values ​​F are obtained. G11 ~F G15 F G21 ~F G25 F G31 ~F G35 and the corresponding angular displacement data L x11 ~L x15 L y21 ~Ly25 L α31 ~L α35。 Axial error, radial error (e.g.) Figure 12 (as shown) and angular error (as shown) Figure 13 (As shown) During measurement, one end of the conduit can be placed in the correct installation position and fixed, the clamps and other connectors on the conduit can be loosened, and the axial, radial and angular deviations of the other end of the conduit connected to the connector can be checked.

[0042] After actual installation, the axial direction of the connector will have an angle α0 with the theoretical axis due to positional errors in the connection conditions. Figure 14 In the figure shown, Fx, Fy, and Fα represent the error loads caused by radial error, axial error, and angular error, respectively. The projection component coefficients on the theoretical axis can be obtained as Kx = cosα, Ky = sinα, and Kα = sinα.

[0043] + ; In the formula, P is the thread pitch of the pipe fitting, in mm; The thread pitch diameter of the pipe fitting is in mm; Correct the coefficient of friction between the pipe fitting and the outer nut. The coefficient of friction is corrected for the contact surface between the sleeve and the outer nut.

[0044] =K h K r ; =K h K r ; In the formula, The standard coefficient of friction between the pipe fitting and the outer nut contact surface. K is the standard friction coefficient of the contact surface between the sleeve and the outer nut. h K is the environmental condition correction factor. r This is a correction factor for lubrication conditions.

[0045] according to =6, with the following parameters: P=1.25mm; nominal thread diameter 12mm; =0.35; =0.35; ΔF =15N; After substituting the product structure parameters and the preload parameters calculated in step three, the minimum installation torque is 8.7 N·m and the maximum installation torque is 19.8 N·m.

[0046] Step 5: Obtain the test installation torque boundary; like Figure 15 As shown, following step three, three groups of products were selected for simulated installation tests to obtain the test preload boundary. One end of the conduit was connected to a force sensor and fixed, while the other end was connected to a connector. The other end of the connector was fixed to a fixture. The installation angle and positional error were simulated by adjusting the fixture position. An environmental test chamber was used to simulate the open environment. The test piece was installed by rotating the nut on the conduit using a torque wrench. The installation torque parameters were measured to meet the maximum and minimum installation preload conditions determined in step three. The test was repeated eight times for the three groups of products, and the average value was taken to determine the test installation torque parameters. For example, the average minimum installation torque was 7.0 N·m, and the average maximum installation torque was 18 N·m.

[0047] Simulations provide the ranges for maximum and minimum preload forces. The minimum torque ensures a seal, while the maximum torque does not cause damage. This principle guides the determination of the preload force range, as obtaining this range through testing would be labor-intensive. Using simulation results as a basis primarily aims to reduce the workload of laboratory verification in step five and lower testing costs. Furthermore, there are currently no readily available empirical ranges for preload forces; standard literature only specifies installation torque ranges. Based on the preload force obtained through simulation, two installation torques can be determined through model calculation and laboratory testing.

[0048] The former, the installation torque of the model takes into account the product's operating conditions and gives the range of installation torque on the simulation model, which is a theoretical value; The latter, laboratory testing plus environmental testing, selected typical parts for testing and took the average value, reflecting the actual manufacturing state, including the discreteness of dimensional tolerances, material and process performance, etc., which can serve as a supplement to theoretical values; The third is the installation torque obtained through empirical values ​​and by consulting similar standard documents. However, it can serve as an important reference, reflecting the status of previous verification of similar products.

[0049] By taking the union of these three torque ranges, and based on the torque calculated by the model, the discrete torque parameters caused by the actual manufacturing and connection processes are combined with the torque range of standard products with similar product configurations that have been verified, a comprehensive and accurate installation torque boundary value is obtained. On this basis, the minimum installation torque value is accurately found by successively increasing and verifying the minimum torque, and the maximum and ultimate torque values ​​are determined in turn. This avoids problems such as excessive experimental verification due to an excessively large experimental installation torque range, and insufficient product manufacturability due to an excessively small verification torque range.

[0050] Step Six: Obtain the standard document installation torque boundary; Based on the product configuration, consult relevant standards and product manuals to obtain empirical installation torque parameters for products under similar working conditions. For example, referring to HB 5970, the minimum average installation torque for DN6 titanium alloy connectors is determined to be 7.6 N·m, and the maximum average installation torque is 17 N·m. In the implementation of the above methods, finite element simulation uses the product structure to obtain the preload under standard working conditions; model torque calculation uses the product structure, installation position, environmental information, and lubrication information to obtain the model calculation torque range; test torque calculation uses the product structure, installation position, environmental information, and lubrication information to obtain the test torque range; manual lookup only involves product structure connection information, based on which manual standards are consulted.

[0051] Step 7: Verify the minimum installation torque; The minimum installation torque boundary A is obtained by taking the union of the installation torque boundaries determined in steps four, five, and six. Six groups of products are selected, and the product working conditions are simulated under the minimum installation torque condition for eight repeated assembly tests to verify whether the six groups of products meet the airtightness and pressure resistance test requirements under the minimum installation torque. If not, the installation torque A is increased by 0.5 N·m until all products meet the test requirements. N Determine the minimum installation torque boundary A N For example, if A = 7.0 N·m, A N =8.5 N·m.

[0052] Step 8: Verify the maximum installation torque; Step 8 verifies the maximum installation torque. The maximum installation torque boundary B is obtained by taking the union of the installation torque boundaries determined in Steps 4, 5, and 6, and is selected as 110%~140%A. N Eight repeated assembly tests were conducted to simulate the product's operating conditions using the initial installation torque condition. This verified whether six groups of products met the airtightness and pressure resistance test requirements under the maximum installation torque. If they met the requirements, the torque was increased by 0.5 N·m for further testing. When one group of products failed to meet the airtightness and pressure resistance requirements, the torque for that test was reduced by 2 N·m and taken as the maximum installation torque B. N If all test requirements are met, the installation torque B is taken as the maximum installation torque; for example, if B = 19.8 N m, the initial conditions are set at 140% of A. N =11.9 N·m, B N =16.9 N·m.

[0053] Step 9: Verify the ultimate installation torque; The maximum installation torque is the maximum torque used during normal installation, ensuring product performance and reliable performance through repeated disassembly and reassembly. The ultimate maximum installation torque is a specified limit; exceeding this torque will damage the product, causing performance issues or difficulties in assembly and disassembly.

[0054] The simulated product operating conditions are tested 8 times, starting from the maximum installation torque B, to verify whether the product meets the airtightness and pressure resistance requirements under this installation torque, and whether disassembly is normal. If the requirements are met, the torque is increased by 0.5 N·m for further testing. When one set of products fails to meet the airtightness and pressure resistance requirements or experiences a disassembly failure, this torque is considered the ultimate maximum installation torque C. N Obtain the minimum installation torque A. N Maximum installation torque B N Maximum installation torque C N The product installation torque parameters. For example, if B = 19.8 N·m, C N =24.8 N·m. Determine the minimum installation torque A. N =11.9 N·m, maximum installation torque B N =16.9 N·m, maximum installation torque C N =24.8 N·m.

[0055] This invention provides torque boundary parameters through finite element simulation and a constructed installation torque boundary calculation model. These parameters are then combined with subsequent experiments and standard literature torques to formulate a torque parameter testing method. On one hand, this significantly narrows the experimental scope, saving cost and time: the simulation model can calculate the theoretical lower and lower limits of the installation torque, reducing the number of test specimens and test cycles, while avoiding wasting time in ineffective low-torque or destructive high-torque ranges. On the other hand, it verifies simulation hypotheses and improves the model's iterative capabilities: Confirming boundary conditions: Experiments are the only standard for verifying the accuracy of simulation hypotheses (such as friction coefficient values ​​and contact stiffness); Correcting the friction coefficient: In simulations, the friction coefficient is usually a set value (e.g., 0.15). By comparing the simulated calculated torque with the measured torque, the actual friction coefficient can be deduced, making the next simulation model more accurate; Closed-loop calibration: Experimental data is used to "calibrate" the simulation model. Once the simulation proves accurate, future modifications can even rely entirely on simulation, eliminating the need for physical testing. Furthermore, it mitigates testing risks and prevents safety accidents: For high-pressure, high-temperature, or large structural components, directly and blindly conducting destructive tests is extremely dangerous. Using 110%~140% of the minimum installation torque boundary as the initial installation torque condition to simulate product operating conditions for testing and verification effectively prevents sample breakage, injury, or damage to the test bench.

[0056] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions, characterized in that, It includes the following steps: S1. Obtain the installation condition information of the threaded connector and conduit assembly; the installation condition information includes product structure connection information, installation position information, installation lubrication information and installation environment information; S2. Based on the installation condition information, obtain the installation preload boundary through finite element simulation; S3. Based on the installation preload boundary, obtain the installation torque boundary calculated by the model through the constructed installation torque boundary calculation model; The boundary calculation model for the installation torque is as follows: T=(F-( E x K x + E y K y + E α K y )) L z ; Where T is the installation torque boundary, F is the installation preload boundary, and n is the number of times the load range is obtained from the simulation; F G1 For the axial deformation load values ​​obtained from the simulation, L x1 For the corresponding F G1 The obtained angular displacement data; F G2 For the radial deformation load values ​​obtained from the simulation, L x2 For the corresponding F G2 The obtained angular displacement data; F G3 For the angle error load value data obtained from the simulation, L x3 For the corresponding F G3 The obtained angular displacement data; Ex is the axial position error, Ey is the axial position error, E α Kx represents the angular position error; Kx is the projection component coefficient of the axial load in the direction of the installation preload, and Ky is the projection component coefficient of the radial load in the direction of the installation preload. α Lz is the projection component coefficient of the angular error load in the direction of the installation preload; Lz is the equivalent friction arm. S4. Conduct simulation experiments based on installation condition information to obtain the test installation torque boundary; S5. Obtain the reference installation torque boundary based on the relevant standard documents for threaded joints and conduit assemblies; S6. Establish the model to calculate the union of the installation torque boundary, the experimental installation torque boundary, and the literature reference installation torque boundary, and obtain the union installation torque boundary. S7. Perform experimental correction on the union installation torque boundary based on the installation condition information to obtain the installation torque parameters of high-performance joints and conduit assemblies under complex working conditions.

2. The test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions according to claim 1, characterized in that, The product structure connection information in S1 includes connector material, thread parameters, sealing surface shape, and sealing surface angle information; installation position information includes installation angle deviation, axial deviation, and radial deviation information; installation lubrication information includes conduit fluid medium and lubricant information; and installation environment information includes installation environment information such as temperature, humidity, and internal pressure.

3. The test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions according to claim 1, characterized in that, The installation preload boundary in S2 includes the maximum installation preload and the minimum installation preload; the maximum installation preload is 80% of the maximum preload that does not cause material yielding in any of the connecting parts of the joint and conduit assembly during the finite element simulation installation process; the minimum installation preload is 120% of the preload when the contact stress of the sealing surface is greater than 50MPa and the width of the sealing surface of the assembly reaches 1mm.

4. The test method for installation torque parameters of high-performance joints and conduit assemblies under complex working conditions according to claim 2, characterized in that, S3 includes: S31. Construct the boundary calculation model for installation torque; T = (F-( E x K x + E y K y + E α K y )) L z ; S32. Input installation environment information and installation lubrication information as the running background, perform finite element simulation, and for the connectors in the product structure connection information including dimensions, structure and material combination, fix them at the conduit end, and apply axial, radial and angular loads from the installation position information to the other end of the component, from 0% to 85% of the conduit yield limit load, and take n sets of data to obtain the load value data F. G11 To F Gn F G21 To F G2n F G31 To F G3n and the corresponding angular displacement data L x11 To L x1n L y21 To L y2n L α31 To L α3n ; S33. Obtain the axial position error Ex, axial position error Ey, and angular position error Eα through the installation position information; S34. Through finite element simulation, obtain the angle α0 between the axial direction of the connector and the theoretical axis after installation based on the position error, and calculate the projection component coefficients: Kx = cosα; Ky = sinα; Kα = sinα; S35. Determine the equivalent friction arm Lz based on the product structure connection information; + ； Where P is the thread pitch of the pipe fitting. The mean diameter of the pipe fitting thread. Correct the coefficient of friction between the pipe fitting and the outer nut. Correct the coefficient of friction for the contact surface between the sleeve and the outer nut; S36. Input the installation preload boundary data and the data required for the calculation model into the constructed installation torque boundary calculation model, and obtain the model to calculate the installation torque boundary.

5. The test method for installation torque parameters of high-performance joints and conduit assemblies under complex working conditions according to claim 4, characterized in that, S35 middle tube joint and outer nut contact surface correction friction coefficient and the corrected friction coefficient of the contact surface between the sleeve and the outer nut They are respectively; =K h K r ; =K h K r ; in, The standard coefficient of friction between the pipe fitting and the outer nut contact surface. K is the standard friction coefficient of the contact surface between the sleeve and the outer nut. h K is the environmental condition correction factor. r This is a correction factor for lubrication conditions. , K h and K r Information was obtained by consulting relevant standard documents.

6. The test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions according to claim 1, characterized in that, S4 includes: S41. Based on the installation condition information, establish an environmental test chamber to simulate the environment; S42. Obtain the installation preload boundary of S2. In the environmental test chamber, select m groups of products to conduct installation tests under simulated working conditions. Measure the installation torque condition parameters under the conditions of maximum and minimum installation preload. Repeat the test multiple times and take the average value to determine the test installation torque boundary.

7. The test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions according to claim 1, characterized in that, Specifically, S5 involves consulting relevant standards and product manuals based on the product configuration to obtain the literature reference installation torque boundary for products under similar operating conditions.

8. The test method for installation torque parameters of high-performance joints and conduit assemblies under complex working conditions according to claim 1, characterized in that, S7 includes: S71. Minimum installation torque for test correction; To simulate product operating conditions, select product group U and conduct Ux repeated assembly tests under the minimum installation torque condition in the union of installation torque boundaries to verify whether the airtightness and pressure resistance test requirements are met under the minimum installation torque. If not, continue to increase the standard torque until the installation torque of all products meets the test requirements, and determine it as the minimum installation torque boundary. S72, Test and correct the maximum installation torque; Simulating product operating conditions, the initial installation torque condition is selected as 110% to 140% of the minimum installation torque in the union of installation torque boundaries. Each time the standard torque is increased, Ux repeated assembly tests are performed to verify whether the U group of products meets the airtightness and pressure resistance test requirements under the current installation torque, until the maximum installation torque in the union of installation torque boundaries is reached. When one group of products fails to meet the airtightness and pressure resistance requirements during the process, the torque of the standard torque amount reduced by the standard multiple of the measured torque is taken as the maximum installation torque. If all test requirements are met, the maximum installation torque in the union of installation torque boundaries is the determined maximum installation torque. S73, Test and correction limit installation torque; The simulated product working conditions are tested by performing Ux repeated assembly tests starting from the maximum installation torque in the union of installation torque boundaries. This verifies whether the product meets the airtightness and pressure resistance test requirements under this installation torque, and whether disassembly is normal. If the requirements are met, the standard torque is increased and the test is continued. When one group of products fails to meet the airtightness and pressure resistance requirements or a disassembly failure occurs, this torque is the ultimate maximum installation torque.

9. The test method for installation torque parameters of high-performance connectors and conduit assemblies under complex working conditions according to claim 8, characterized in that, The standard torque is 0.5 N·m, and the standard multiple is 4 times.

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