Shock echo signal analysis method based on variational mode decomposition

Abstract

The invention discloses a shock echo signal analysis method based on variational mode decomposition, which comprises the following steps: 1) selecting measurement parameters and working parameters ofequipment according to requirements of field measurement environment, and collecting shock echo signals; 2) setting parameters in variational modal decomposition according to the shock echo signals; 3) decomposing the collected shock echo signals into several eigen modulus functions by a variational modal decomposition method to solve the variational problem; 4) using Hilbert transform to obtain the Hilbert time-frequency spectrum of the eigen modulus functions; 5) integrating the Hilbert time-frequency spectrum of different frequencies in the time domain to obtain the final marginal spectrum.The method identifies the defects of the concrete component by using the marginal spectrum of the shock echo signals, and can suppress the noise interference under strong noise, and achieves higher resolution compared with the traditional Fourier transform.

Description

technical field [0001] The invention relates to a shock echo signal analysis method based on variational mode decomposition, belonging to the technical field of civil and structural engineering detection. Background technique [0002] At present, some research has been done on the thickness and defect detection of concrete components using the shock echo method. Generally, the Fourier transform is used to solve the frequency spectrum characteristics of the vibration signal, and then the thickness of the concrete component is calculated according to the main frequency and apparent velocity. However, the actual shock echo signal is not a stationary signal, but a non-stationary signal. In actual engineering, the shock echo is not only reflected from the bottom plate but also reflected from the defect, which makes the Fourier transform spectrum often have multiple peaks, so the traditional Fourier transform is used. Difficult to correctly identify. The Hilber-Huang transform de...

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Problems solved by technology

However, the actual shock echo signal is not a stationary signal, but a non-stationary signal. In actual engineering, the shock echo is not only reflected from the bottom plate but also reflected from the defect, which makes the Fourier transform spectrum often have multiple peaks, so the traditional Fourier transform is used. difficult to correctly identify

The Hilber-Huang transform decomposes the non-stationary signal into a finite number of eigenmode functions, then Hilbert transforms the eigenmode functions, and then constructs the Hilbert amplitude spectrum of the signal, and finally obtains the marginal spectrum by integrating the Hilbert spectrum. Compared with the Fourier spectrum, it more accurately reflects the actual spectrum of the signal, but the Hilber-Huang transform empirical mode decomposition method often has problems such as mode aliasing and endpoint effects

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