DIC-(Digital Image Correlation)-technique-based curvature modal damage recognition method

Abstract

The invention discloses a DIC-(Digital Image Correlation)-technique-based curvature modal damage recognition method. The method comprises the following steps of S1, applying a dynamic hammer excitation to a model of a truss structure, shooting an initial truss structure and the truss structure, to which the hammer excitation is applied, respectively by utilizing a DIC technique, so as to obtain time-sequence images of the deformation of the truss structure, meanwhile, measuring time-interval signals of the hammer excitation by utilizing a dynamic and static acquisition instrument, so as to obtain an exciting force curve, and carrying out correlation analysis treatment on the time-sequence images, so as to obtain a displacement curve; S2, enabling the obtained displacement curve and exciting force curve to correspond in accordance with a time order, importing into a dynamic signal test and analysis system, so as to obtain a frequency response function, and deriving the inherent frequency and the vibration modal of the truss structure according to the frequency response function; and S3, after the inherent frequency and the vibration modal are obtained, acquiring a difference value by using curvature modals to obtain a difference-value index of the curvature modals, and determining a difference between the curvature modals, before and after the deformation, of the truss structure, so as to judge whether the damage is generated to the truss structure, to position the damage and to judge the extent of the damage.

Description

technical field [0001] The present invention relates to the technical field of structural damage identification, and more specifically, relates to a curvature mode damage identification method based on DIC technology. Background technique [0002] In recent years, there have been countless accidents involving casualties and economic losses due to structural damage not being discovered and dealt with in time. If not found and dealt with in time, the consequences will be disastrous. Timely monitoring of the health of structures has important theoretical significance and significant socio-economic benefits. Curvature mode has attracted wide attention due to its ability to represent the local characteristic information of the structure and its sensitivity to damage. The industry has conducted a lot of research on structural damage identification using curvature mode. Although fruitful research results have been achieved, they mainly focus on numerical However, there are few exp...

AI Technical Summary

Problems solved by technology

[0003] Based on the traditional vibration measurement method, there are many uncertain factors in the acceleration time history response during the actual measurement, and the complete dynamic information of the structure cannot be obtained.

Arranging sensors on limited measuring points can only measure low-cost modes, and cannot measure the response on the rotational degree of freedom, and the measurement information is incomplete

This has led to the fact that the curvature modal damage identification index has hardly been applied in experiments and actual engineering based on traditional sensor measurement methods.

Moreover, traditional measurement methods (acceleration sensors, strain gauges, fiber gratings) are mostly contact-type, and the measurement layout is time-consuming and sometimes difficult to implement.

When using the curvature modal difference damage index to identify, the damage location can be judged by comparing the sudden change of the curvature modal difference before and after the damage, but this method needs to know the information of the complete structure, so the traditional measurement method affects the obtained curvature. The accuracy of the mode leads to poor damage identification, misjudgment and missed judgment

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