Carrier modulation nonlinear ultrasonic guided wave damage detection method

A non-linear ultrasonic and damage detection technology, applied in the analysis of solids using sonic/ultrasonic/infrasonic waves, processing response signals of detection, instruments, etc., can solve problems such as affecting accuracy, achieve accurate detection, and reduce costs.
CN110108802AActive Publication Date: 2019-08-09SOUTH CHINA UNIV OF TECH
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Patent Information

Authority / Receiving Office
CN Β· China
Current Assignee / Owner
SOUTH CHINA UNIV OF TECH
Publication Date
2019-08-09

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Abstract

The invention discloses a carrier modulation nonlinear ultrasonic guided wave damage detection method, comprising the following steps: selecting a high-low frequency component according to frequency response characteristic of a detection object, and performing delayed time processing on the high-low frequency component and combining with a low frequency component to form a modulated carrier signal; performing signal acquisition by adopting a single excitation-single reception mode, exciting the modulated carrier signal containing a high frequency component and the low frequency signal by virtue of a single-excitation transducer, generating nonlinear modulation effect by the carrier signal by virtue of interaction with damage during propagation, and acquiring by a reception transducer by virtue of a transmission method; according to arrival time of the high frequency component and time when an end surface reflects an echo, intercepting the signal and analyzing, performing filtering andnormalization processing on the signal, then decomposing a received signal by adopting an empirical mode decomposition method, and according to decomposed IMF frequency spectrum information, selectingIMF components containing a base frequency and a nonlinear frequency component and performing signal reconstruction; and extracting a difference frequency component of a high-frequency modulation sidelobe and a low-frequency modulation sidelobe, namely a nonlinear component, calculating a nonlinear coefficient, and evaluating material damage degree by taking a nonlinear coefficient of zero damageas a benchmark.
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Description

technical field

[0001] The invention relates to the technical fields of non-destructive testing technology and structural health monitoring, in particular to a damage detection method of carrier modulation nonlinear ultrasonic guided wave. Background technique

[0002] Large-scale engineering structures such as aerospace vehicles, bridge engineering, ship engineering, and oil pipelines are in long-term service and are affected by the external environment, such as fatigue, corrosion effects, and material aging. Defects will inevitably form on the surface or inside of the structure. The occurrence of defects severely damages the structural integrity of engineering materials, resulting in a sharp decline in their performance, which can lead to serious accidents in actual use. In order to avoid sudden accidents, structural health monitoring technology has been widely concerned and developed. Structural health monitoring (SHM for short) is an online monitoring technology that co...

Claims

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