A Damage Identification Method for Simply Supported Concrete Beams Based on Nonlinear Vibration

Abstract

The invention provides a simply-supported concrete beam damage identification method based on nonlinear vibration, belonging to the technical field of concrete beam damage identification. A vibration exciter and a speed or acceleration sensor are installed in the span of a bridge. On the premise that the dynamic load of the vibration exciter does not cause new damage to a beam body, the frequency of the vibration exciter is changed and the amplitude of the speed or acceleration sensor is detected to get an amplitude-frequency curve. Then, the dimensionless nonlinear factor of the system is obtained through a nonlinear least square method, and the dimensionless nonlinear factor ratio of unit load is obtained on the basis. The damage condition of the bridge is assessed according to the magnitude of the dimensionless nonlinear factor ratio of unit load. The method has incomparable superiority in damage identification of a dynamic characteristic bridge in the absence of a reference model. Moreover, the method has the following advantages: the method is related to load amplitude; experimental installation is simple; and the method is easy to operate.

Description

technical field [0001] The invention relates to the technical field of damage identification of concrete beams, in particular to a damage identification method for simply supported concrete beams based on nonlinear vibration. Background technique [0002] In the field of civil engineering, the structure will be affected by the surrounding environment during use, such as corrosion, overload, strong wind, earthquake, fatigue and material aging, etc., which will lead to different degrees of damage and strength reduction of the structure. If the necessary maintenance is lacking, the damage will continue to accumulate and the strength will continue to decrease, causing the structure to collapse and damage, resulting in casualties and economic losses. Therefore, damage detection is essential for building structures that have been built and have been in service for many years. Since the benchmark model of a large number of building structures in the initial non-damage stage is unk...

AI Technical Summary

Problems solved by technology

A defect of the above-mentioned nonlinear vibration identification method based on simple harmonic vibration is that the obtained damage index is related to the load amplitude, and the damage index obtained by different load amplitude experiments is quite different, which makes the damage identification invalid.

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