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Low-temperature composite material storage box damage online identification method based on coupling electromechanical impedance

A technology of electromechanical impedance and composite materials, applied in the direction of material impedance, etc., can solve the problems of few applications, distortion of damage identification results, performance degradation of sensors and adhesives, etc.

Inactive Publication Date: 2019-04-09
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] During the cooling process of the tank structure, the sensor and the mounting adhesive may be damaged due to thermal stress, resulting in the failure of the impedance damage identification technology; under low-temperature loading conditions, the performance of the sensor and adhesive is prone to degradation due to stress, resulting in Damage identification results are distorted
Therefore, methods based on electromechanical impedance are often rarely used in structural damage identification in low temperature environments.

Method used

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  • Low-temperature composite material storage box damage online identification method based on coupling electromechanical impedance
  • Low-temperature composite material storage box damage online identification method based on coupling electromechanical impedance
  • Low-temperature composite material storage box damage online identification method based on coupling electromechanical impedance

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Embodiment

[0029] Such as Figure 2-Figure 5 The specific embodiment of the method disclosed by the invention comprises the following steps:

[0030] 1. Install a piezoelectric chip sensor on the surface of the composite laminate, and the sensor is connected to the impedance analyzer through a signal conversion switch;

[0031] 2. Install the test piece in the fixture;

[0032] 3. Use liquid nitrogen to create a low-temperature environment, and place the fixture in a low-temperature environment;

[0033] 4. The bending load is loaded in the middle section of the specimen, and the load continues to increase;

[0034] 5. Acquire the reference impedance signal, name it ImB and store it in the impedance signal space, and extract the signal characteristics such as the peak value of the real part, the slope of the imaginary part, and the frequency response of the real part, and name it MrB, SlB and FrB respectively, and store them in the Real part peak space, imaginary part slope space and ...

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Abstract

The invention discloses a low-temperature composite material storage box damage online identification method based on coupling electromechanical impedance. The method comprises the following steps: firstly, acquiring reference electromechanical coupling impedance information of a sensor network, and extracting real part and imaginary part signal characteristics; then, acquiring a current impedancesignal according to a time step and comparing the current impedance signal with a reference signal; if the root-mean-square deviation of the two sets of signals is smaller than a threshold value, stating that no damager appears, and if the deviation is larger than the threshold value, needing to further compare the signal characteristics of the peak value of the real part, the slope of the imaginary part, the frequency response of the real part and the like to determine the damage mode; and if the root-mean-square deviation of the sensors exceeding 30% of the total number in the sensor network is larger than the threshold value, affirming that a large-area damage occurs to the structure. According to the method in the invention, a hierarchical damage judgment-damage identification methodis adopted, so that the smoothness of monitoring is guaranteed, and accurate identification of the damage position, the type and the severity degree is guaranteed.

Description

technical field [0001] The invention relates to the technical field of low-temperature composite material storage tank damage, in particular to an online identification method for low-temperature composite material storage tank damage based on coupled electromechanical impedance. Background technique [0002] As the component with the largest weight and volume in the propulsion system of aerospace vehicles, cryogenic fuel tanks have become an important topic in the development of lightweight aerospace structures. Compared with the metal materials used in traditional storage tank structures, the occurrence and expansion of composite material damage is more subtle under low temperature conditions, resulting in sudden structural damage and failure. Therefore, online identification of damage to low-temperature composite material tanks is particularly important . Damage detection methods based on electromechanical coupling impedance have been widely used in the state assessment ...

Claims

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Application Information

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IPC IPC(8): G01N27/02
CPCG01N27/02
Inventor 武湛君高东岳马云龙郑跃滨张佳奇
Owner DALIAN UNIV OF TECH
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