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Electromechanical impedance monitoring method of bolt pre-tightening force under vibration excitation

A technology of bolt pre-tightening force and electromechanical impedance, applied in the measurement of resistance/reactance/impedance, testing of mechanical parts, testing of machine/structural parts, etc., can solve the problem of insufficient sensitivity and achieve the effect of improving sensitivity

Inactive Publication Date: 2019-07-30
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In view of the above problems, the object of the present invention is to propose an electromechanical impedance monitoring method for bolt pretightening force under vibration excitation. loose monitoring

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  • Electromechanical impedance monitoring method of bolt pre-tightening force under vibration excitation
  • Electromechanical impedance monitoring method of bolt pre-tightening force under vibration excitation
  • Electromechanical impedance monitoring method of bolt pre-tightening force under vibration excitation

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Embodiment Construction

[0024] Now in conjunction with embodiment, accompanying drawing, the present invention will be further described:

[0025] Concrete steps of the present invention are as follows:

[0026] Step 1: Paste the piezoelectric ceramic PZT on one side of the bolt to be tested, the main deformation direction of the bolt and the PZT sheet is in line, and connect the lead-out line of the piezoelectric sheet to the impedance analyzer;

[0027] Step 2: Fix the vibrator under the structure to be tested and connect it with the signal amplifier and signal generator;

[0028] Step 3: The sweep frequency range of the impedance analyzer can be set to 30-500kHz. At the same time, the signal generator sends out a sinusoidal pulse signal with a fixed frequency (200-1000Hz is enough) as the input signal of the exciter. Change the pre-tightening force of the bolts so that it gradually changes from completely loose to fully tightened (the specific value depends on the bolt used). After changing the ...

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Abstract

The invention relates to an electromechanical impedance monitoring method of bolt pre-tightening force under vibration excitation. According to the method, a piezoelectric ceramic PZT is pasted to oneside of a to-be-detected bolt, main deformation directions of the bolt and the PZT are collinear, and an outgoing line of a piezoelectric patch is connected to an impedance analyzer; an exciter is fixed below a to-be-detected structure and is connected with a signal amplifier and a signal generator sequentially; a sweep frequency range of the impedance analyzer is set; meanwhile, the signal generator emits a sine pulse signal with fixed frequency to serve as an input signal of the exciter, and the bolt pre-tightening force is changed so that the bolt is changed step by step from a completely-loosened state to a completely-tightened state; and after the pre-tightening force is changed every time, the signal amplifier is started, and the exciter is made to excite the to-be-detected structure; impedance real-part data under different pre-tightening forces is collected, and the working condition under which the bolt is completely tightened is selected as a standard condition; a sensitivefrequency band is selected from the obtained impedance real-part data; a looseness index RMSD of the sensitive frequency band under the different pre-tightening forces is calculated; and the bolt looseness degree can be measured by use of the looseness index and the standard working condition.

Description

technical field [0001] The invention belongs to the field of structural health monitoring, and in particular relates to a high-sensitivity monitoring method for bolt pretightening force based on electromechanical impedance. Background technique [0002] The bolted connection structure is ubiquitous in spacecraft, it makes the structure easy to install or disassemble and plays a vital role in the component connection transfer load, but under the action of complex loads or after long-term service, the pretension of the bolted connection The force can drop or even disappear completely, which will seriously affect the safety of the spacecraft, so monitoring the preload force at the bolted joint is crucial. Electromechanical impedance technology has become an important identification method in the field of structural health monitoring because of its sensitive response and high reliability. [0003] At present, the electromechanical impedance method generally fixes the piezoelect...

Claims

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Application Information

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IPC IPC(8): G01M13/00G01R27/02
CPCG01M13/00G01R27/02
Inventor 杜飞邢思思徐超王晨柏绍波伍世伟
Owner NORTHWESTERN POLYTECHNICAL UNIV
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