Uniform load surface curvature-based simply supported beam crack damage identification method

Abstract

The invention discloses a uniform load surface curvature-based simply supported beam crack damage identification method. The method includes the following steps that: the modal parameters of a simplysupported beam before and after the simply supported beam is damaged are obtained through testing, flexibility matrixes are calculated on the basis of frequencies and vibration modes; a uniform load is applied to the simply supported beam, and the uniform load is multiplied by the difference of the flexibility matrixes which are obtained before and after the simply supported beam is damaged, so that a corresponding displacement difference is obtained; the curvature of the displacement difference is obtained, and a uniform load surface curvature difference is obtained; a relation between the position of a crack and the uniform load surface curvature difference of adjacent measurement points is built based on a linear interpolation theory, so that the accurate positioning of the position ofthe crack can be realized; a uniform load surface curvature-based structural stiffness damage degree identification method is built on the basis of relations between displacement curvatures and structural stiffness and bending moment; and a relation between the height of the crack and a uniform load surface curvature is built through a series equivalent linear stiffness model, so that the quantification of the height of the crack can be realized. With the method of the invention adopted, the position and height of the crack of the simply supported beam can be accurately positioned and quantified. The method is applied to the damage degree evaluation of the structure of a simply supported beam.

Description

technical field [0001] The invention belongs to the field of structural health monitoring, and relates to beam structure non-destructive testing technology, in particular to a crack damage identification method of simply supported beams with uniform load surface curvature. Background technique [0002] The internal defects of the structure develop into cracks under the action of compound loads, and the expansion of cracks often causes major catastrophic accidents. Therefore, the detection and identification of cracks is of great significance to the normal use of structures and disaster prevention. The appearance of cracks in the structure causes the loss of local stiffness, changes the dynamic response of the system to a certain extent, and leads to changes in the natural vibration frequency and mode shape of the structure. Therefore, the change of the modal parameters before and after damage is used to detect the crack damage of the structure Widespread concern. For the vi...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the deficiency that the existing modal flexibility curvature damage index cannot quantitatively detect the crack height, the present invention provides a crack damage identification method for simply supported beams with uniform load surface curvature

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