Bolt joint clamping force testing method and system and storage medium

Abstract

The invention provides a bolt joint clamping force testing method and system and a storage medium, and the method comprises the steps: carrying out a tensile test on a bolt joint, and building a first relational expression between a tension value and the elongation of the bolt joint; assembling the bolt joint and the opponent part thereof, applying different torque values between the bolt joint and the opponent part thereof, recording the corresponding elongation of the bolt joint, and establishing a relational expression II between the torque values and the elongation of the bolt joint; a third relational expression between the tension value and the torque value is established according to the first relational expression and the second relational expression; and obtaining a torque value applied by the bolt joint and the opponent part in actual assembly, and calculating the clamping force of the bolt joint according to the relational expression III. According to the testing mode, the clamping force of the bolt joint can be obtained through direct conversion according to the torque value, and the defects in the prior art are overcome.

Description

Technical Field

[0001] This invention relates to the field of bolt connection technology, and specifically to a method, system and storage medium for testing the clamping force of a bolt joint. Background Technology

[0002] Bolted joints, as core components of mechanical connections, are widely used in critical fields such as aerospace, automotive manufacturing, energy equipment, and construction engineering. Their performance directly affects the reliability, safety, and service life of the overall structure, while clamping force (i.e., preload), as a core parameter of bolted connections, directly influences the joint's resistance to loosening, sealing performance, and fatigue resistance. However, accurate measurement of clamping force remains a significant challenge in existing technologies.

[0003] Currently, the industry generally relies on torque-clamping force conversion relationships (such as the torque method or the angle method). However, due to factors such as fluctuations in the friction coefficient and differences in the surface condition of the threaded pair, the clamping force estimation error can be as high as ±30%, making it difficult to meet the requirements of high-precision assembly. Secondly, although strain gauge or ultrasonic testing methods can directly reflect the clamping force, they require precision instruments and complex calibration procedures, and are sensitive to the operating environment (such as temperature and vibration interference), making them difficult to implement efficiently in industrial settings.

[0004] As industrial equipment evolves towards lighter weight and higher load capacity, the requirements for the reliability of bolted connections are becoming increasingly stringent. Developing a low-cost, high-precision clamping force testing method applicable to complex working conditions has become a core technological requirement for improving assembly quality and achieving predictive maintenance. Therefore, there is an urgent need for a bolt joint clamping force testing method, system, and storage medium. This should be achieved by innovating detection principles or integrating multi-physics coupling analysis to overcome existing technological bottlenecks and provide a scientific basis for the intelligent management and control of bolted connections. Summary of the Invention

[0005] The purpose of this invention is to provide a method for testing the clamping force of bolt joints, aiming to solve the problems of large errors and reliance on precision instruments in existing methods for testing bolt clamping force. The specific technical solution is as follows: A method for testing the clamping force of a bolted joint includes: Tensile tests were performed on the bolted joints to establish the tensile force values. Elongation of bolt joint Relational expression 1; Assemble the bolted joint with its mating parts, applying different torque values ​​between the bolted joint and its mating parts. Record the corresponding bolt joint elongation. Establish torque value Elongation of bolt joint Relational expression two; Establish the tension value based on relational expressions one and two. With torque value Relational expression three; Obtain the torque value applied to the bolt joint and the hand parts during actual assembly. The clamping force of the bolt joint is calculated based on relational expression three.

[0006] Preferred, in Select multiple torque values ​​within the range Apply the bolted joint between itself and its opposite part and record the corresponding bolted joint elongation. To establish torque value Elongation of bolt joint Relational expression two; where, This is the maximum torque value that the bolted joint can withstand.

[0007] Preferred, in Select at least two torque values ​​from the range. Apply the bolted joint between itself and its opposite part and record the corresponding bolted joint elongation. To establish torque value Elongation of bolt joint Relational expression two; where, This is the torque value corresponding to the maximum elastic deformation of the bolted joint.

[0008] Preferably, establish torque value Elongation of bolt joint The torque values ​​selected in the relationship expression two It exhibits a monotonically increasing trend.

[0009] Preferably, a non-contact extensometer is used to measure the elongation of the bolt joint. .

[0010] Preferred, establish and Relational expressions and and When the relationship expression is two, bolt joints of the same specification and batch are used respectively.

[0011] Preferably, in relational expression one and relational expression two, the bolt joint elongation in one of the relational expressions is... Substituting into another relational expression, we obtain the tensile force value. With torque value Relational expressions between the three.

[0012] Preferably, the tensile strength value Elongation of bolt joint The relational expression is one of Torque value Elongation of bolt joint The relational expression two is Tensile strength With torque value The relational expression three is .

[0013] The present invention also provides a bolt joint clamping force testing system, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the test method when running the computer program.

[0014] The present invention also provides a storage medium storing a computer program, which, when run, executes the aforementioned test method.

[0015] The application of the technical solution of the present invention has the following beneficial effects: The bolt joint clamping force testing method of the present invention innovatively utilizes the deformation characteristics of the bolt joint itself to realize the clamping force and torque values. The conversion between them can be achieved using the testing method of this invention based on the torque value. The clamping force of the bolt joint can be directly calculated, and the test method of the present invention is no longer affected by factors such as friction coefficient fluctuations and differences in the surface condition of the threaded pair. At the same time, it does not require precision instruments for testing, which solves the shortcomings of the existing technology and breaks through the technical bottleneck of existing bolt clamping force testing.

[0016] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart of the bolt joint clamping force testing method of the present invention; Figure 2 It is the tensile force value during the elastic deformation stage. Elongation of bolt joint A diagram illustrating the relationship between them. Detailed Implementation

[0018] To facilitate understanding of the present invention, a more complete description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0020] Example 1: See Figure 1 This embodiment provides a method for testing the clamping force of a bolt joint, including: S1. Conduct a tensile test on the bolted joint to establish the tensile force value. Elongation of bolt joint Relational expression 1; S2. Assemble the bolted joint with its mating parts, applying different torque values ​​between the bolted joint and its mating parts. Record the corresponding bolt joint elongation. Establish torque value Elongation of bolt joint Relational expression two; S3. Establish the tension value based on relational expression one and relational expression two. With torque value Relational expression three; S4. Obtain the torque values ​​applied to the bolt joints and the assembled parts during actual assembly. The clamping force of the bolt joint is calculated based on relational expression three.

[0021] The bolt joint clamping force test method in this embodiment will be described in detail below: Preferably, in step S1, a tensile test is performed on the bolt joint using a tensile testing machine, and the elongation of the bolt joint is measured using a non-contact extensometer (such as a video extensometer). The tensile testing machine and the non-contact extensometer are both existing products, so they will not be described in detail in this embodiment.

[0022] Among them, the tensile force value of the bolt joint This refers to the clamping force (i.e., preload) generated by the bolt joint during actual assembly. The tensile force on the bolt joint can be obtained through the tensile test in step S1. Elongation of bolt joint The relationship between them is used to obtain the tensile force value later. With torque value This provides the basis for the conversion between them.

[0023] Preferably, the "hand part" in step S2 refers to the part that is threadedly connected to the bolt joint, generally a nut or a workpiece with a threaded hole, etc. The bolt joint generates clamping force (i.e. preload) by threading with the hand part.

[0024] Furthermore, in this embodiment, a torque value is established. Elongation of bolt joint The torque values ​​selected in the relationship expression two It exhibits a monotonically increasing change; by applying different torque values ​​between the bolt joint and its counterpart. Record the corresponding bolt joint elongation. This allows us to obtain the torque value. Elongation of bolt joint The changing relationship between them.

[0025] Preferably, in order to obtain the ultimate case of the bolted joint, step S2 can be performed... Select multiple torque values ​​within the range Apply the bolted joint between itself and its opposite part and record the corresponding bolted joint elongation. To establish torque value Elongation of bolt joint Relational expression two; where, This represents the maximum torque value that the bolt joint can withstand. Since bolt joints are generally broken because the preload (i.e., clamping force) is too high, causing the bolt tensile stress to exceed the material's yield limit, resulting in irreversible plastic deformation or necking, the second relationship expression should cover both the elastic deformation and plastic deformation stages of the bolt joint.

[0026] Furthermore, by conducting a breakage test on the bolt joint, the maximum torque value that the bolt joint can withstand can be obtained. .

[0027] Furthermore, since bolt joints are not tightened to the point of breakage during actual assembly, they are generally kept within the range of elastic deformation to ensure the stability of the assembly structure and prevent bolt loosening. Therefore, step S2 can also be performed in... Select at least two torque values ​​from the range. Apply the bolted joint between itself and its opposite part and record the corresponding bolted joint elongation. To establish torque value Elongation of bolt joint Relational expression two; where, The torque value corresponding to the maximum elastic deformation of a bolted joint can be determined through a tensile test. The torque value at which the bolted joint achieves maximum elastic deformation can be found by gradually increasing the torque value. .

[0028] Preferred, establish and Relational expressions and and When using the second relationship expression, bolt joints of the same specification and batch are used to ensure the uniformity of the bolt joints and guarantee the tensile force value obtained subsequently. With torque value The relational expression three is accurate.

[0029] Preferably, in step S2, the torque value is selected. If a target torque value exists that needs to be tested, then the target torque value and the corresponding bolt joint elongation need to be tested. If no target torque value exists that needs to be tested, the value can be taken in a monotonically increasing manner within the range.

[0030] Furthermore, in step S2, a non-contact extensometer is also used to measure the elongation of the bolt joint. In particular, the non-contact extensometer used in steps S1 and S2 is preferably the same to prevent test errors caused by different non-contact extensometers.

[0031] Preferably, step S3 involves adjusting the bolt joint elongation in one of the relational expressions, either expression one or expression two. Substituting this into another relational expression yields the tensile force value. With torque value From the relationship expression three, the tensile force value can be further obtained. With torque value The curve relationship between them.

[0032] Preferably, the tensile force value is within the elastic deformation range of the bolt joint. Elongation of bolt joint The relational expression is one of ,like Figure 2 As shown; torque value Elongation of bolt joint The relational expression two is Tensile strength With torque value The relational expression three is The tensile force value can be directly obtained through relational expression three. With torque value Conversion between them, including tensile force value This refers to the clamping force (i.e., preload) of the bolt joint.

[0033] The test procedure for the bolt joint clamping force test method in this embodiment is as follows: 1. Mount the bolted joint for testing onto the tensile testing machine and zero the force value of the tensile testing machine; 2. Use a video extensometer to measure the original length of the bolt joint; 3. Perform a tensile test on the bolted joint and record the tensile force applied to the bolted joint. With elongation ; 4. Calculate the tensile force value With elongation Relational expression 1; 5. Secure the video extensometer by clamping the bolted joints and matching the other components. 6. Tighten the bolt joints at a uniform speed using a torque wrench. When the bolt joints are just properly engaged, reset the deformation value of the video extensometer to zero. 7. Continue tightening the bolt to the target torque value or break the bolt to obtain the torque value. With elongation Relational expression two; 8. Establish the tension value based on relational expression one and relational expression two. With torque value Relational expressions between the three.

[0034] The bolt joint clamping force testing method in this embodiment innovatively utilizes the deformation characteristics of the bolt joint itself to realize the clamping force and torque values. The conversion between them can be performed using the testing method in this embodiment based on the torque value. The clamping force of the bolt joint can be directly calculated. The test method in this embodiment is no longer affected by factors such as friction coefficient fluctuations and differences in the surface condition of the threaded pair. At the same time, it does not require precision instruments for testing, which solves the shortcomings of the existing technology and breaks through the technical bottleneck of existing bolt clamping force testing.

[0035] Example 2: This embodiment provides a bolt joint clamping force testing system, including a memory and a processor. The memory stores a computer program, and the processor executes the testing method in Embodiment 1 when running the computer program.

[0036] Example 3: This embodiment provides a storage medium storing a computer program, which, when run, executes the test method in Embodiment 1.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for testing the clamping force of a bolt joint, characterized in that, include: Tensile tests were performed on the bolted joints to establish the tensile force values. Elongation of bolt joint Relational expression 1; Assemble the bolted joint with its mating parts, applying different torque values ​​between the bolted joint and its mating parts. Record the corresponding bolt joint elongation. Establish torque value Elongation of bolt joint Relational expression two; Establish the tension value based on relational expressions one and two. With torque value Relational expression three; Obtain the torque value applied to the bolt joint and the hand parts during actual assembly. The clamping force of the bolt joint is calculated based on relational expression three.

2. The bolt joint clamping force testing method according to claim 1, characterized in that, exist Select multiple torque values ​​within the range Apply the bolted joint between itself and its opposite part and record the corresponding bolted joint elongation. To establish torque value Elongation of bolt joint Relational expression two; where, This is the maximum torque value that the bolted joint can withstand.

3. The bolt joint clamping force testing method according to claim 1, characterized in that, exist Select at least two torque values ​​from the range. Apply the bolted joint between itself and its opposite part and record the corresponding bolted joint elongation. To establish torque value Elongation of bolt joint Relational expression two; where, This is the torque value corresponding to the maximum elastic deformation of the bolted joint.

4. The bolt joint clamping force testing method according to claim 1, characterized in that, Establish torque value Elongation of bolt joint The torque values ​​selected in the relationship expression two It exhibits a monotonically increasing trend.

5. The bolt joint clamping force testing method according to claim 1, characterized in that, The elongation of the bolt joint was measured using a non-contact extensometer. .

6. The bolt joint clamping force testing method according to claim 1, characterized in that, Establish and Relational expressions and and When the relationship expression is two, bolt joints of the same specification and batch are used respectively.

7. The bolt joint clamping force testing method according to claim 1, characterized in that, In relational expressions one and two, the bolt joint elongation in one of the relational expressions is... Substituting into another relational expression, we obtain the tensile force value. With torque value Relational expressions between the three.

8. The bolt joint clamping force testing method according to claim 7, characterized in that: Tensile strength Elongation of bolt joint The relational expression is one of ; Torque value Elongation of bolt joint The relational expression two is ; Tensile strength With torque value The relational expression three is .

9. A bolt joint clamping force testing system, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the test method as described in any one of claims 1-8 when running the computer program.

10. A storage medium, characterized in that, The storage medium stores a computer program, which, when run, executes the test method as described in any one of claims 1-8.

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