Bolt pretightening force measurement method and verification method for the same

A technology of bolt pre-tightening force and measurement method, which is applied in the direction of force/torque/work measuring instrument, torque/torsional force measurement during tightening, force/torque/work measuring instrument calibration/testing, etc., can solve the hidden safety hazards of bolts, It can not effectively characterize the bolt pre-tightening force and the deviation of the bolt pre-tightening force, so as to achieve the effect of convenient operation.

Inactive Publication Date: 2017-11-17
STATE GRID CORP OF CHINA +2
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the uncertainty of the torque coefficient, the tightening torque cannot effectively represent the bolt pretightening

Method used

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  • Bolt pretightening force measurement method and verification method for the same
  • Bolt pretightening force measurement method and verification method for the same
  • Bolt pretightening force measurement method and verification method for the same

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Embodiment Construction

[0024] The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0025] A bolt is a mechanical part widely used in the mechanical field. It is usually a type of fastener consisting of a head and a screw. The screw is usually a cylinder with external threads. The head can be set into different shapes according to different needs, such as hexagonal head, round head, square head or countersunk head, etc. In practical applications, bolts need to be used in conjunction with nuts to fasten and connect two parts with through holes. Correspondingly, this connection method is called bolt connection, and bolt connection is a detachable connection.

[0026] In the process of tightening the bolts, the pre-tightening force generated between the bo...

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Abstract

The invention provides a bolt pretightening force measurement method and a verification method for the same. The bolt pretightening force measurement method comprises steps of using an electromagnetic ultrasonic thickness measurement technology to measure a first length of a bolt to be measured and a second length of the bolt to be measured after a nut is screwed and calculating a pretightening force on the bolt to be measured on the basis of a stress strain relation according to the first length and the second length. The bolt pretightening force measurement method does not have to install an additional device on the bolt to be measured, has a simple operation and can fast and accurate measure the pretightening force of the bolt. The invention also provides a verification method for the bolt pretightening force measurement method verifies that the bolt pretightening force measurement method can accurately detect the pretightening force of the bolt and provides a theoretic basis to the bolt pretightening force measurement method.

Description

technical field [0001] The invention relates to the technical field of connection of structural components, and more specifically, to a detection method and a verification method for the pretightening force of bolts. Background technique [0002] Bolt fastener connection is a way of connecting large structural components. In order to ensure the strength and rigidity of structural components, the pre-tightening force of bolts, especially high-strength bolts that can only be used once, is particularly important during installation. [0003] At present, the pretightening force measurement method used in the bolt installation process is torque measurement. Since the relationship between torque and preload is: [0004] T=K×p×d [0005] Among them, T is the tightening torque applied to the nut, the unit is N*m, K is the torque coefficient, p is the pretightening force on the bolt, the unit is N, and d is the bolt diameter, the unit is mm. The torque coefficient is the proportio...

Claims

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Application Information

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IPC IPC(8): G01L5/24G01L25/00
CPCG01L5/243G01L5/246G01L25/00
Inventor 李文波谢亿刘云龙沈丁杰龙毅
Owner STATE GRID CORP OF CHINA
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