Method for identifying damage degree of beam structure based on deflection influence line variation

Abstract

The invention discloses a method for identifying the damage degree of a beam structure based on deflection influence line variation. The method comprises the following steps of 1) representing an influence line variation fitting curve by using a piecewise quadratic function; 2) identifying the fitting curve of the influence line variation based on a sparse regularization method; and 3) quantifyingthe damage of the beam structure according to the fitting curve of the influence line variation. The invention provides a method for estimating the flexural rigidity change amount based on deflectioninfluence line change so as to realize the damage degree identification. Through the piecewise quadratic function fitting, an influence line change curve is determined from the actually measured influence line change amount with noise, and the problem is simplified into the identification of a plurality of piecewise function quadratic term coefficient change amounts. By introducing a sparse regularization method, the matrix ill-conditioned condition of an inverse problem identification equation is improved, and good robustness of identification can be ensured. According to the method, a finite element model does not need to be established, damage indexes have definite physical significance, and the method has the advantages of being sensitive to local damage and good in noise immunity.

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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