In-service bolt axial force detection method, detection system and detection device

A detection method and bolt shaft technology, applied to measuring devices, force/torque/work measuring instruments, measuring torque/torsion force during tightening, etc., can solve the problems of low measurement accuracy and large measurement error, and achieve high precision and measurement small error effect

Active Publication Date: 2018-09-25
BEIJING JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the existing ultrasonic stress measurement technology only considers the influence of the material constant of the bolt on the axial force of the

Method used

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  • In-service bolt axial force detection method, detection system and detection device
  • In-service bolt axial force detection method, detection system and detection device
  • In-service bolt axial force detection method, detection system and detection device

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0046] Example 1:

[0047] figure 1 It is a flow chart of the method for detecting the axial force of the bolt in service provided in the first embodiment of the present invention. Such as figure 1 As shown, an in-service bolt axial force detection method, the detection method includes:

[0048] Step 11: Obtain the bolt diameter, thread diameter, sound velocity before force, the axial length of the nut, the length of the screw, the length of the bolt force zone, the measured axial force of the bolt sample under different loads, and the The ultrasonic transit time and ultrasonic transit time-axial force model corresponding to the actual measured axial force, wherein the bolt sample and the in-service bolt to be tested are of the same specification, and the number of bolt samples is greater than or equal to 3 .

[0049] The ultrasonic transit time-axial force model is:

[0050] Among them, t represents the ultrasonic transit time, L d Represents the length of the nut force zone, v re...

Example Embodiment

[0059] Example 2:

[0060] figure 2 It is a structural block diagram of a system for detecting the axial force of an in-service bolt provided by Embodiment 2 of the present invention. Such as figure 2 As shown, an in-service bolt axial force detection system, the detection system includes:

[0061] The input quantity acquisition module 21 is used to acquire the bolt diameter, thread diameter, sound velocity before force, nut axial length, screw length, bolt force zone length, and actual measurement of the bolt sample under different loads Axial force, ultrasonic transit time corresponding to the actual measured axial force, ultrasonic transit time-axial force model, wherein the bolt sample and the in-service bolt to be tested are of the same specification, and the bolt sample The number is greater than or equal to 3.

[0062] The ultrasonic transit time-axial force model is:

[0063] Among them, t represents the ultrasonic transit time, L d Represents the length of the nut force ...

Example Embodiment

[0072] Example 3:

[0073] image 3 It is a schematic diagram of the structure of a detection device for the axial force of an in-service bolt provided in Embodiment 3 of the present invention. Such as image 3 As shown, an in-service bolt axial force detection device includes: an oscilloscope 31, a host 32, a computer 33, a pre-attenuation and low-pass filter module 34, an ultrasonic excitation device 35 and an ultrasonic receiver 36; among them,

[0074] The ultrasonic excitation device 35 and the ultrasonic receiver 36 are arranged oppositely on both sides of the bolt 30 to be tested in service, and the signal output end of the host 32 is connected to the pre-attenuation and low-pass filter module 34 through a coaxial cable. The input end of the pre-attenuation and low-pass filter module 34 is connected to the ultrasonic excitation device 35, and the ultrasonic receiving device 36 is connected to the input end of the host 32; the signal of the host 32 The monitoring port is con...

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Abstract

The invention discloses an in-service bolt axial force detection method, a detection system and a detection device. The detection method comprises steps: the bolt diameter of a bolt sample, a thread diameter, a sound velocity before force, a nut axial length, a screw rod length, a bolt force bearing area length, actually-measured axial forces of the bolt sample under different loads, ultrasonic transit time corresponding to the actually-measured axial force, and an ultrasonic transit time-axial force model are acquired; according to the bolt diameter, the thread diameter, the sound velocity before force, the nut axial length, the screw rod length, each actually-measured axial force, the ultrasonic transit time and the ultrasonic transit time-axial force model, a soft measurement expressionis determined; and by adopting the soft measurement expression, the axial force of the to-be-detected in-service bolt is calculated. The detection method provided in the invention not only takes intoaccount the influences of material constants of the bolt on the bolt axial force, but also takes into account influences of the length of the nut force bearing area and a nut force bearing area internal axis normal stress factor on the bolt axial force, the axial force of the in-service bolt can be effectively measured, the measurement errors are small, and the precision is high.

Description

technical field [0001] The invention relates to the technical field of ultrasonic detection, in particular to a detection method, detection system and detection device for the axial force of in-service bolts. Background technique [0002] As a fixed connection structure with simple structure and convenient disassembly and assembly, bolts are widely used in large-scale infrastructure and complete sets of equipment such as bridges and petrochemicals. Once the bolt connection fails, it will cause structural instability and even catastrophic accidents. Therefore, in order to ensure the reliability and safety of the connection structure, the pretightening force of the connection bolts must be strictly controlled, and the working stress of the bolts must be monitored online if necessary. The reliability of the bolted connection depends on whether the axial preload of the bolt (referred to as the axial force) is appropriate. Improper axial force can cause the nut to loosen or the...

Claims

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Application Information

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IPC IPC(8): G01L5/24
CPCG01L5/246
Inventor 姚凯李益铭赵欣欣刘晓光胡所亭赵泽宇韩易成张钰萍
Owner BEIJING JIAOTONG UNIV
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