A method and apparatus for obtaining tightening torque coefficient based on finite element simulation analysis

Abstract

This invention provides a method and apparatus for obtaining tightening torque coefficients based on finite element simulation analysis. The method includes: assembling and tightening an aluminum alloy annular sleeve with a bolt of the same roughness level, recording the tightening torque value and the axial compression of the aluminum alloy annular sleeve; establishing a geometric model of the bolt and aluminum alloy annular sleeve using 3D modeling software and assembling them together; simulating the bolt and aluminum alloy annular sleeve assembly in finite element simulation software, calculating the axial preload required to generate the same axial compression; calculating the tightening torque coefficient corresponding to the roughness level of the mating surface based on the tightening torque value during operation and the axial preload value in the simulation, using the relationship between the two; and calculating the tightening torque coefficient for mating surfaces of other roughness levels using the same method. By combining simple tightening operations on ordinary test pieces with finite element simulation, tightening torque coefficients under different mating surface conditions can be obtained. The operation is simple, easy to master, and the data is reliable.

Description

Technical Field

[0001] This invention relates to the field of methods for determining tightening torque coefficient in the machinery industry, and particularly to a method and apparatus for obtaining tightening torque coefficient based on finite element simulation analysis. Background Technology

[0002] Bolted connections are common in mechanical products, and they relate to the tightness of the connection and the structural strength. Generally, it is required to increase the tightness of the connection while ensuring structural strength.

[0003] The tightness of a bolt connection is determined by the magnitude of the axial preload when the components are connected. For the same tightening torque, the resulting axial preload will differ depending on the roughness of the mating surfaces of the connecting parts. The tightening torque coefficient can be used to measure the roughness of the mating surfaces.

[0004] Currently, most methods for obtaining tightening torque coefficients rely on specialized equipment for measurement, which has limitations in practical application. Summary of the Invention

[0005] The purpose of this invention is to provide a method and device for obtaining tightening torque coefficient based on finite element simulation analysis. Specifically, it comprehensively utilizes the actual operation of bolt tightening and finite element simulation, and determines the tightening torque coefficient of the corresponding mating surface state according to the relationship between the tightening torque value and the axial preload value required for the two to achieve the same effect.

[0006] The first aspect of this invention provides a method for obtaining the tightening torque coefficient based on finite element simulation analysis, comprising the following steps: S1. Assemble the ring sleeve and bolt to be tested for tightening torque coefficient and tighten them together. Record the tightening torque value M and the axial compression amount ΔL of the ring sleeve. S2. Use 3D modeling software to create geometric models of the bolt and the ring sleeve to be tested for the tightening torque coefficient and assemble them together; S3. Simulate the geometric model of the bolt and the ring sleeve in the finite element simulation software to obtain the axial preload value F required to generate the axial compression amount ΔL; S4. Obtain the tightening torque coefficient based on the tightening torque value M and the axial preload value F.

[0007] Optionally, based on the tightening torque value M and the axial preload value F, a tightening torque coefficient is obtained, including: Based on the tightening torque value M and the axial preload value F, the tightening torque coefficient is obtained using the formula F=M / kd; Where k is the tightening torque coefficient and d is the nominal diameter of the bolt.

[0008] Optionally, after S1, the method further includes: Disassemble the ring sleeve and bolts to confirm that the axial length of the ring sleeve has not undergone plastic deformation.

[0009] Optionally, the method further includes: S5. For bolts and ring sleeves of the same size, obtain bolts with multiple roughness levels and ring sleeves with multiple end face roughness levels; S6. Pair bolts and ring sleeves of the same roughness level together and tighten them, and record the tightening torque value M for each roughness level when the axial compression amount ΔL of the ring sleeve is recorded. S7. Obtain the tightening torque coefficient for each roughness level based on the tightening torque value M and the axial preload value F.

[0010] It is understandable that, prior to S7, different axial preload values ​​F were obtained through simulation based on different axial compression amounts ΔL of the annular sleeve.

[0011] Optionally, the bolt head diameter is greater than twice the stud diameter; The inner diameter of the annular sleeve is slightly larger than the diameter of the bolt, and the outer diameter is slightly smaller than or equal to the diameter of the mating end face of the bolt head.

[0012] Optionally, the geometric dimensions of the bolt and the ring sleeve match the corresponding dimensions of the actual object; the thread feature of the bolt is replaced with a smooth surface.

[0013] Optionally, the annular sleeve is made of aluminum alloy.

[0014] Optionally, the roughness of the annular sleeve refers to the roughness of the two end faces of the annular sleeve.

[0015] A second aspect of the present invention provides a device for obtaining tightening torque coefficient based on finite element simulation analysis, for performing the method as described in any one of the first aspects.

[0016] This invention provides a method and apparatus for obtaining tightening torque coefficients based on finite element simulation analysis. It comprehensively utilizes the actual operation of bolt tightening with finite element simulation, and determines the tightening torque coefficients under different roughness mating surface conditions by analyzing the relationship between the required tightening torque and axial preload values ​​to achieve the same effect. This provides accurate and reliable data resources for product design and model simulation. The method combines simple tightening operations on ordinary test pieces with finite element simulation to easily, quickly, and accurately obtain tightening torque coefficients under different roughness mating surface conditions. The operation is simple, easy to master, and the data is reliable. The obtained series of tightening torque coefficient values ​​can be widely used as important data resources, avoiding blind data citation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a basic flowchart of the present invention; Figure 2 It is a geometric model of bolts and aluminum alloy ring fittings; Figure 3 This is a table of tightening torque coefficients. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0021] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0023] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0025] This invention provides a method for obtaining tightening torque coefficient based on finite element simulation analysis, comprising the following steps: S1. Assemble the annular sleeve and bolt to be tested for tightening torque coefficient and tighten them together. Record the tightening torque value. M Axial compression of the annular sleeve ΔL ; S2. Use 3D modeling software to create geometric models of the bolt and the ring sleeve to be tested for the tightening torque coefficient and assemble them together; S3. Simulate the geometric model of the bolt and the ring sleeve in finite element simulation software to obtain the axial compression amount. ΔL Required axial preload value F ; S4. Based on the tightening torque value M and axial preload value F To obtain the tightening torque coefficient.

[0026] By way of example, it can be understood that the present invention can also be used in other structures that can be screwed together.

[0027] For example, in one embodiment, this invention provides a method for obtaining the tightening torque coefficient based on finite element simulation, such as... Figure 1 and Figure 2 As shown, the method specifically includes: 1) Prepare several bolts with different roughness grades; 2) Prepare several aluminum alloy ring sleeves with different end face roughness; 3) Assemble the aluminum alloy annular sleeve with the same roughness level as in steps 1) and 2) with the bolt and tighten it, recording the tightening torque value. M Axial compression of aluminum alloy ring sleeve ΔL ; 4) Use 3D modeling software to create geometric models of the bolts and aluminum alloy ring sleeves and assemble them together; 5) Simulate the bolt and aluminum alloy ring sleeve assembly from step 4) in finite element simulation software to calculate the same axial compression. ΔL Required axial preload value F ; 6) According to the tightening torque value in step 3), M The axial preload value in step 5) of the simulation F Using the relationship between the two F = M / kd ( d (For the nominal diameter of the bolt), calculate the tightening torque coefficient corresponding to the mating surface of this roughness level. k ; 7) Calculate the tightening torque coefficient for mating surfaces with other roughness levels (including surfaces coated with lubricating oil or galvanized, etc.) using the same method.

[0028] The tightening torque coefficients under different roughness mating surface conditions can be obtained through the above steps.

[0029] In step 1), only the roughness of the bolt thread and the mating end face of the nut needs to be considered.

[0030] In step 1), it is recommended that the head diameter of the nut / bolt be greater than twice the diameter of the stud so that a sufficiently thick aluminum alloy annular sleeve can be fitted.

[0031] In step 2), only the roughness of the two end faces of the aluminum alloy annular sleeve needs to be considered.

[0032] In step 2), it is recommended that the inner diameter of the aluminum alloy annular sleeve should be slightly larger than the diameter of the stud, and the outer diameter should be slightly smaller than or equal to the diameter of the mating end face of the nut / bolt head.

[0033] In step 3), the roughness level of the bolt should be the same as that of the aluminum alloy annular sleeve.

[0034] In step 3), the required tightening torque value is... M The size of the load should not cause plastic deformation of the aluminum alloy annular sleeve. Whether plastic deformation has occurred can be determined by measuring the change in the axial length of the aluminum alloy annular sleeve before and after loading.

[0035] In step 4), the geometric model of the bolt and the aluminum alloy ring sleeve should match the actual object (except for the thread features), and the fit should be consistent with the fit in step 3).

[0036] In step 5), the applied preload may need to be adjusted repeatedly if necessary. FAdjust the size until the axial compression of the aluminum alloy annular sleeve is the same as that in step 3).

[0037] In step 7), the following tightening torque coefficient comparison table can be used as a reference, but is not limited to, for product design and simulation.

[0038] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A method for obtaining the tightening torque coefficient based on finite element simulation analysis, characterized in that, Includes the following steps: S1. Assemble the ring sleeve and bolt to be tested for tightening torque coefficient and tighten them together. Record the tightening torque value M and the axial compression amount ΔL of the ring sleeve. S2. Use 3D modeling software to create geometric models of the bolt and the ring sleeve to be tested for the tightening torque coefficient and assemble them together; S3. Simulate the geometric model of the bolt and the ring sleeve in the finite element simulation software to obtain the axial preload value F required to generate the axial compression amount ΔL; S4. Obtain the tightening torque coefficient based on the tightening torque value M and the axial preload value F.

2. The method for obtaining the tightening torque coefficient based on finite element simulation analysis according to claim 1, characterized in that, Based on the tightening torque value M and the axial preload value F, the tightening torque coefficient is obtained, including: Based on the tightening torque value M and the axial preload value F, the tightening torque coefficient is obtained using the formula F=M / kd; Where k is the tightening torque coefficient and d is the nominal diameter of the bolt.

3. The method for obtaining the tightening torque coefficient based on finite element simulation analysis according to claim 1, characterized in that, Following S1, the method further includes: Disassemble the ring sleeve and bolts to confirm that the axial length of the ring sleeve has not undergone plastic deformation.

4. The method for obtaining the tightening torque coefficient based on finite element simulation analysis according to claim 1, characterized in that, The method further includes: S5. For bolts and ring sleeves of the same size, obtain bolts with multiple roughness levels and ring sleeves with multiple end face roughness levels; S6. Pair bolts and ring sleeves of the same roughness level together and tighten them, and record the tightening torque value M for each roughness level when the axial compression amount ΔL of the ring sleeve is recorded. S7. Obtain the tightening torque coefficient for each roughness level based on the tightening torque value M and the axial preload value F.

5. The method for obtaining the tightening torque coefficient based on finite element simulation analysis according to claim 1, characterized in that, The bolt head diameter is greater than twice the bolt post diameter; The inner diameter of the annular sleeve is slightly larger than the diameter of the bolt, and the outer diameter is slightly smaller than or equal to the diameter of the mating end face of the bolt head.

6. The method for obtaining the tightening torque coefficient based on finite element simulation analysis according to claim 1, characterized in that, The geometric dimensions of the bolt and the ring sleeve match the corresponding dimensions of the actual object; the thread feature of the bolt is replaced with a smooth surface.

7. The method for obtaining the tightening torque coefficient based on finite element simulation analysis according to claim 1, characterized in that, The ring sleeve is made of aluminum alloy.

8. The method for obtaining the tightening torque coefficient based on finite element simulation analysis according to claim 1, characterized in that, The roughness of the annular sleeve refers to the roughness of the two end faces of the annular sleeve.

9. A device for obtaining tightening torque coefficient based on finite element simulation analysis, characterized in that, Used to perform the method as described in any one of claims 1-8.

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