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Measurement method for influence of residual stress on bolt connection structure clamping force attenuation

A technology of residual stress and connection structure, applied in force/torque/work measuring instruments, using stable tension/pressure to test material strength, measuring devices, etc., can solve complex operations, low measurement accuracy, and inability to quantitatively analyze residual Problems such as the relationship between stress and bolt clamping force, to achieve accurate experimental results, accurate data, and improved precision

Inactive Publication Date: 2018-01-19
BEIJING UNIV OF TECH
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The present invention aims to solve the problems of complex operation, low measurement accuracy and inability to quantitatively analyze the relationship between residual stress and bolt clamping force in the existing method

Method used

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  • Measurement method for influence of residual stress on bolt connection structure clamping force attenuation
  • Measurement method for influence of residual stress on bolt connection structure clamping force attenuation
  • Measurement method for influence of residual stress on bolt connection structure clamping force attenuation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0022] Step 1: Divide N bolt fasteners of the same batch and the same material into M groups, with n pieces in each group, numbered Ⅰ, Ⅱ, Ⅲ, ..., and the corresponding axial connectors are numbered 1, 2 in sequence , ..., and ultrasonically cleaned them before the experiment.

[0023] Step 2: Apply a certain amplitude of exciting force and continuous vibration of frequency to the M group of bolts fixed on the vibrating table. At the same time interval, remove a group of bolts in sequence until all the bolts are removed.

[0024] Step 3: Set aside the experimental bolts of group M after vibration to release the residual stress in the experimental bolts. Then select 3 to 5 test points on the polished rod of each bolt in each group of experimental bolts, carry out the residual stress test through the X-ray residual stress tester, measure the residual stress in the circumferential and axial directions of each measuring point, and record, such as figure 2 shown.

[0025] Step 4...

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Abstract

The invention discloses a measurement method for the influence of residual stress on bolt connection structure clamping force attenuation. A device for realizing the method includes: a tensile testingmachine, a lower connecting piece, a nut, an eddy current displacement sensor, an upper connecting piece, a bolt, a pressure sensor, and a corresponding sensor data acquisition system and a computer,a 3D surface morphology measurement instrument, a digital display torque wrench, a vibration table, and an X ray residual stress tester. The 3D surface morphology measurement instrument is employed to acquire the three-dimensional morphology of a contact surface, vibratory stress relief process and the X ray residual stress tester are employed to acquire bolts that are made of a same material andhave different levels of residual stress, the tensile testing machine, the pressure sensor and the displacement sensor are combined to collect the data under the circumstances of a same pretighteningforce and specific amplitude circulating alternating load. The method can achieve quantitative analysis of the relationship between the two structures, provides the experimental basis for further study of the influence of residual stress on bolt connection structure clamping force attenuation, and has the characteristics of simple and quick operation and accurate measurement.

Description

technical field [0001] The invention relates to a method for measuring the effect of residual stress on the attenuation of clamping force of a bolt connection structure, belonging to the field of mechanical engineering and mechanics. Background technique [0002] Bolt relaxation is the process in which the clamping force of a bolt fastener with a certain pretightening force decreases under alternating load conditions, which is called bolt relaxation. There are many factors affecting bolt relaxation, one of which is that the residual stress on the machined surface of the bolt affects the initial pretightening force of the bolt and the attenuation of the clamping force under vibration conditions. [0003] There is residual stress in the processed surface quality of bolts. Residual stress is a force that exists inside the object in a balanced state, and it is also an unstable stress state. When the object is subjected to external force, the acting stress interacts with the resi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/08G01L5/00
Inventor 刘志峰张明洋蔡力钢李迎吕华峰徐文祥
Owner BEIJING UNIV OF TECH
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