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Duffing equation Lyapunov index based ultrasonic guided wave detection method

A technology of ultrasonic guided wave and detection method, which is applied in the direction of processing the response signal of detection, etc.

Active Publication Date: 2013-09-25
JINAN UNIVERSITY +2
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  • Abstract
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Problems solved by technology

[0006] The purpose of the present invention is to solve the above-mentioned defects in the prior art, and to provide an ultrasonic guided wave detection method based on the Duffin equation Lyapunov index, which can identify weak ultrasonic guided wave signals under strong noise and evaluate and locate different damage degrees , thereby improving the sensitivity of ultrasonic guided wave identification of small defects and effectively extending the detection range

Method used

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  • Duffing equation Lyapunov index based ultrasonic guided wave detection method
  • Duffing equation Lyapunov index based ultrasonic guided wave detection method
  • Duffing equation Lyapunov index based ultrasonic guided wave detection method

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Embodiment 1

[0047] Such as figure 1 As shown, it is the ultrasonic guided wave detection process of this embodiment, and the specific implementation process is as follows:

[0048] 1) Construct the Duffin oscillator signal detection system based on the Duffin equation, and calculate the Lyapunov exponent changing with the driving force F, the specific process is as follows:

[0049] a) Construct the Duffin oscillator signal detection system

[0050] The Duffin equation is a commonly used model in weak signal detection. The nonlinear system described by it exhibits a variety of nonlinear characteristics, including complex states of oscillation, bifurcation, and chaos. Its expression is:

[0051] x · · + k x · - x + x 3 = F cos ωt - - - ...

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Abstract

The invention discloses a Duffing equation Lyapunov index based ultrasonic guided wave detection method. The method comprises the following steps: 1, calculating to obtain the change Lyapunov index of a Duffing oscillator signal detection system with the driving force F; 2, inputting a Hanning window modulated ultrasonic guided wave signal to the Duffing oscillator signal detection system, and calculating to obtain the Lyapunov index of the Duffing oscillator signal detection system with the driving force F after the input of the ultrasonic guided wave signal; 3, selecting the driving force F corresponded by a largest absolute value of a difference between two L1 vales in the area having a product of the L1 value before the input of the ultrasonic guided wave signal and the L1 value after the input of the ultrasonic guided wave signal as the driving force of the Duffing oscillator signal detection system; 4, exciting the ultrasonic guided wave signal on a detected object, and obtaining a receiving signal through a receiver; and 5, inputting the receiving signal to the driving force selected Duffing oscillator signal detection system, determining the detected object is intact if L1 is greater than 0, and determining the detected object contains a defect if L1 is lower than 0.

Description

technical field [0001] The invention relates to an ultrasonic guided wave detection technology, in particular to an ultrasonic guided wave detection method based on the Duffin equation Lyapunov index, which belongs to the technical field of nondestructive testing. Background technique [0002] Ultrasonic guided wave testing technology is a new type of non-destructive testing technology. Using ultrasonic guided wave technology can not only realize fast and large-scale non-destructive testing of slender structures, but also can realize the detection of underground, underwater, under covering and under insulating layers, etc. Non-destructive testing of structures. The working principle of ultrasonic guided wave testing is: the ultrasonic guided wave is excited by the probe array located at one end of the structure. The guided wave fills the entire circumferential direction and the entire pipe wall thickness, and propagates far away. When a defect is encountered during the guide...

Claims

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Application Information

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IPC IPC(8): G01N29/44
Inventor 马宏伟张伟伟莫应强武静张喆斯林荣
Owner JINAN UNIVERSITY
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