Nonlinear ultrasonic detection method for axial stress of bolt

A nonlinear ultrasonic and axial stress technology, applied in the direction of measuring force components, force/torque/work measuring instruments, measuring devices, etc., can solve the problem of inaccurate stress, simplify the measurement process, avoid measurement, and improve accuracy sexual effect

Inactive Publication Date: 2020-07-24
BEIJING INSTITUTE OF TECHNOLOGYGY
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Problems solved by technology

The traditional ultrasonic testing method evaluates the stress of the material through the relationship between sound velocity and stress. However, when the stress chan

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  • Nonlinear ultrasonic detection method for axial stress of bolt
  • Nonlinear ultrasonic detection method for axial stress of bolt
  • Nonlinear ultrasonic detection method for axial stress of bolt

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Embodiment Construction

[0072] The invention proposes a nonlinear ultrasonic detection method for the axial stress of bolts, with the purpose of accurately and quickly measuring the axial stress of bolts. The existing ultrasonic measurement method is mainly based on the principle of acoustic elasticity, relying on the change of sound velocity to judge the magnitude of the stress. However, when the stress changes by 100MPa, the sound velocity only changes by 0.01%. Therefore, it is not accurate enough to reflect the stress on the material through the change of wave velocity. . Based on the shortcomings of the existing methods, the present invention detects the axial stress of the bolt from the perspective of nonlinear response. The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0073] In the embodiment of the present invention, the method of the present invention is described by taking a bolt whose material is 45 steel, the ...

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Abstract

The invention provides a nonlinear ultrasonic detection method for axial stress of a bolt. The method comprises the following implementation steps: step A, establishing a relation model between a second harmonic amplitude and a fundamental wave amplitude on the basis of a propagation theory of ultrasonic waves in an isotropic medium to obtain an expression of relative nonlinear coefficients; stepb, carrying out an axial stress loading experiment on a bolt sample, carrying out nonlinear ultrasonic detection, and calculating relative nonlinear coefficients under different stress states; and step c, fitting the loaded axial stress and the corresponding relative nonlinear coefficients, determining an ultrasonic detection coefficient of the axial stress of the bolt, and finally obtaining a relational expression of the axial stress of the bolt and the relative nonlinear coefficients. By means of the steps, nonlinear ultrasonic detection of the axial stress of the bolt can be realized, the axial stress of the bolt can be rapidly and accurately detected with the method, and the accuracy and the practicability of the axial stress detection technology of the bolt are improved.

Description

[0001] 1. Technical field [0002] The invention provides a nonlinear ultrasonic detection method for bolt axial stress, which relates to the technical field of detection of bolt fasteners. [0003] 2. Background technology [0004] As a common fastener, bolts are widely used in aerospace, railway transportation, ship turbines, armored vehicles, civil manufacturing and other industrial fields due to their advantages of good connection performance, simple disassembly and low cost. Connection performance or sealing effect. During the service process, the bolts are required to maintain sufficient strength and rigidity to meet the stability requirements of the overall structure. However, during the working process, the bolt is inevitably affected by the axial force. As time accumulates, the overall performance of the bolt will degrade, which has a great impact on its service performance and service life. In extreme cases, the bolts may even break suddenly, causing major personnel...

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Application Information

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IPC IPC(8): G01L5/173
CPCG01L5/16
Inventor 潘勤学常梅乐李双阳徐晓宇潘瑞鹏张云淼
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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