Nonlinear ultrasonic detection method for evaluating thermo-oxidative ageing of organic material

A nonlinear ultrasonic and thermo-oxidative aging technology, which is applied in the analysis of solids using sonic/ultrasonic/infrasonic waves, which can solve the problems of complex detection devices and demanding excitation signal waveforms.

Inactive Publication Date: 2015-07-08
BEIJING UNIV OF TECH
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Problems solved by technology

However, the mixed-frequency nonlinear ultrasound has strict requirements on the waveform of t...

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  • Nonlinear ultrasonic detection method for evaluating thermo-oxidative ageing of organic material
  • Nonlinear ultrasonic detection method for evaluating thermo-oxidative ageing of organic material
  • Nonlinear ultrasonic detection method for evaluating thermo-oxidative ageing of organic material

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Embodiment Construction

[0055] Combine below Figure 1 to Figure 6 The implementation process of the thermal-oxidative aging damage detection method for organic polymer materials based on nonlinear ultrasonic technology is described in detail.

[0056] The organic material to be tested in this experiment is polymethyl methacrylate (commonly known as plexiglass, English abbreviation PMMA), its size is: length 200mm, width 25mm, height 50mm, and the shape is a cuboid. The thermal oxygen aging temperature is 80°C, and the interval between each measurement is 10 hours.

[0057] Step 1: Preparation of plexiglass test blocks with different thermal and oxygen aging damages. The vitrification temperature of plexiglass is 104°C, and its heat distortion temperature is about 96°C, so the setting temperature of the artificial accelerated aging test box is 80°C, and the ventilation rate is 10m per hour. 3 , each heating time is 10 hours.

[0058] Step 2: Test system construction and parameter setting.

[0059...

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Abstract

A nonlinear ultrasonic detection method for evaluating the thermo-oxidative ageing of an organic material comprises the following steps: building an organic material thermo-oxidative ageing damage nonlinear ultrasonic detection system based on a nonlinear acoustic detection system; respectively setting corresponding parameters of an excitation signal and a reception signal, and finely adjusting the corresponding parameters of the excitation signal and the reception signal by a time domain waveform signal observed and received by an oscilloscope; selecting the optimum work frequency range of a probe according to the frequency characteristic of the ultrasonic probe, and determining the initial frequency and the ending frequency of the swept frequency range; adjusting integrator gate parameters, carrying out frequency sweeping to obtain the change rule of an supersonic wave fundamental wave amplitude and a secondary harmonic amplitude with the frequency, and storing the change rule in a computer; calculating corresponding nonlinear coefficients of all frequency points in the swept frequency range, and calculating the accumulated nonlinear effect in the swept frequency range; and determining a corresponding relationship between the accumulated nonlinear effect and the thermo-oxidative ageing time of the organic material, and assessing the existence or not and the degree of the thermo-oxidative ageing damage of the organic material.

Description

technical field [0001] The invention relates to a nonlinear ultrasonic detection method for thermal oxygen aging damage of organic materials. The method can be used for nondestructive detection of organic material thermal oxygen aging damage and evaluation of aging degree, and belongs to the field of nondestructive testing. Background technique [0002] Organic polymer materials are widely used in various fields due to their light weight, strong plasticity, high strength, and corrosion resistance, such as municipal water supply pipe networks, external insulation materials for power systems, and basic support components for various instrument panels / panels, etc. . Due to the influence of environmental factors such as light, temperature, and oxygen, the physical and chemical properties of organic materials will undergo irreversible changes during processing, storage, and use, resulting in aging damage. The aging of organic materials will not only cause the deterioration of it...

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Application Information

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IPC IPC(8): G01N29/04
Inventor 焦敬品李亮樊仲祥何存富吴斌
Owner BEIJING UNIV OF TECH
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