A method to identify the damage degree of beam structure based on the change of deflection influence line

Abstract

A method for identifying the damage degree of a beam structure based on the amount of deflection influence line change, comprising the steps of: 1) using a piecewise quadratic function to represent the fitting curve of the influence line change amount; 3) Quantify the damage of the beam structure according to the fitting curve of the change amount of the influence line. The invention proposes a method for estimating the change of the bending stiffness based on the change of the deflection influence line, and then realizing the identification of the damage degree. By fitting the piecewise quadratic function, the change curve of the influence line is determined from the measured influence line change amount with noise, and the problem is simplified to the identification of the coefficient change amount of the quadratic term of several piecewise functions. By introducing a sparse regularization method, the matrix ill-conditioning of the inverse problem recognition equation is improved, which can ensure good robustness of the recognition. This method does not need to establish a finite element model, the damage index has a clear physical meaning, and has the advantages of being sensitive to local damage and having good noise resistance.

Description

technical field [0001] The invention relates to the field of engineering structure health monitoring, in particular to a method for identifying the damage degree of a beam structure based on the amount of deflection influence line change. Background technique [0002] An ideal structural damage identification method needs to construct a damage index that can reflect the inherent characteristics of the structure and is more sensitive to damage, and then judge whether the structure is damaged or not, the location and degree of damage according to the index, and estimate the remaining service life of the structure. The influence line is an inherent characteristic of the bridge structure, has a clear physical meaning, is sensitive to structural damage, and is suitable for development as a key indicator for evaluating the state of the bridge. As the structural performance of the bridge degrades during service, the influence line will also change in an unfavorable direction. By m...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that an accurate finite element model is required, which adds a lot of difficulty and additional errors to practical applications.

However, considering that the change of the influence line of the beam due to early damage is much smaller than the influence line itself, the curve fitting of the influence line enhances the noise resistance of the method, and it may also cause a large number of components of the influence line change containing damage information to be eliminated, making it difficult for less susceptibility to injury

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