Instantaneous frequency-based wood structure damage acoustic emission nondestructive detection method

Abstract

The invention discloses an instantaneous frequency-based wood structure damage acoustic emission signal identification and stress nondestructive detection method. The method comprises the following steps: (1) with a wood structure dimension lumber as a research object, a corresponding sensor is installed to build a wood bending damage acoustic emission acquisition system, and acoustic emission signals in a wood damage process are obtained; (2) the acquired acoustic emission signals are subjected to filtering and wavelet decomposition, thereby realizing preprocessing of original signals; (3) the signals after wavelet reconstruction are subjected to EMD decomposition to obtain an acoustic emission waveform for Hilbert transform; (4) according to the frequency domain characteristics of the acoustic emission reconstruction waveform, the characteristic frequencies of different acoustic emission events are determined; and (5) the number of different types of acoustic emission events is counted through the instantaneous frequency, a corresponding event occurrence density is calculated, and finally, by using the acoustic emission event occurrence density and the change condition, the stress state in the wood damage process is evaluated. The method is simple and easy, and real-time dynamic damage monitoring and identification on the internal damages of a wooden structure building can becarried out.

Description

technical field [0001] The invention relates to the technical field of damage identification in industrial production, in particular to an acoustic emission non-destructive detection method for wooden structure damage based on instantaneous frequency. Background technique [0002] At present, large-scale venues built with wood-structured timber as the core have been gradually promoted. At present, wood-structured building materials have been widely valued in many companies, factories and manufacturing industries. In my country, about 75% of houses and entertainment places are built with wood. At the same time, neighboring countries such as Thailand, Myanmar, Laos and other Southeast Asian countries have successively implemented wood structure buildings, such as gymnasiums, swimming pools and hospitals. At this stage, wooden structure buildings have become a hot topic in recent years. Therefore, it is necessary to carry out real-time and effective condition monitoring and str...

AI Technical Summary

Problems solved by technology

This kind of internal local stress concentration caused by environmental changes is the direct factor leading to the plastic deformation of wood, which not only reduces the life of the material, but even causes irreversible damage to some buildings

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