Derrick steel structure damage identification method based on IMF (Intrinsic Mode Function) instantaneous energy curvature difference value

Abstract

The invention discloses a derrick steel structure damage identification method based on an IMF (Intrinsic Mode Function) instantaneous energy curvature difference value. The method comprises the following steps of: carrying out modal analysis on a derrick steel structure to determine the low-order vibration modal of the derrick steel structure, and carrying out transient dynamic analysis on the derrick steel structure to extract the vibration responses of different positions of the derrick steel structure; utilizing a band-pass filtering method to extract the low-order vibration signals of different positions of the derrick steel structure, carrying out EMD (Empirical Mode Decomposition) decomposition on the low-order vibration signals to select main IMF components, and adopting a central difference method to calculate the IMF instantaneous energy curvature; and taking the IMF instantaneous energy curvature difference value obtained before and after the derrick steel structure is damaged as a damage sensitive index so as to realize the identification and the analysis of derrick steel structure damage positions and degrees. By use of the method, only the low-order vibration information of the derrick steel structure needs to be used for realizing damage position identification, identification accuracy is high, and the problem that the damage can not be accurately identified since large complex steel structure high-order vibration information is difficult in obtaining is solved.

Description

technical field [0001] The invention relates to the technical field of signal processing, in particular to a method for identifying damage to a steel structure of a derrick based on an IMF instantaneous energy curvature difference using HHT signal feature extraction technology. Background technique [0002] With the development of signal processing technology, damage detection methods based on structural signal feature extraction are more and more widely used. Such methods use vibration sensors to collect the vibration response of structures, and adopt appropriate signal processing methods to extract damage sensitivity indicators, and then structures for damage detection or health monitoring. [0003] In 1998, N.E.Huang proposed the Hilbert-Huang Transform (HHT) method, and proved that it has stronger decomposition ability than the wavelet transform method HHT in many fields. The HHT method consists of two parts: empirical mode decomposition (EMD) and Hilbert transform. The...

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Problems solved by technology

However, in practical application testing, it is difficult to obtain high-order modal parameters of large and complex steel structures

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