Structure damage diagnosis method based on modality information

Abstract

This invention relates to a damage test method base on dynamic property of large-scale in active service structure. This invention utilizes mode information difference between fore-and-aft of damage to carry out damage orient and extent evaluating., utilize structural element stiffness matrix and mass matrix as diagnostic term, base on damage characterization vector to carry out one shot damage orient and extent of damage evaluating. This invention has no need of quality normalized mode of vibration, just utilize low-order mode information of fore-and-aft structural impair, could at the same time take into account of structural stiffness and qualitative change. The invention lends itself to mono damage and multifold damage behavior, be able to exactly locate out frame construction's damage position and extent of damage, possess certain practical application value.

Description

[0001] The invention relates to a damage detection method using modal information (cross-model cross-mode), in particular to a damage diagnosis method for marine engineering structures. Background technique [0002] Damage to large structures such as offshore platforms is inevitable during their service. The offshore platform structure has served in the harsh marine environment for a long time, and is subject to the interaction of various loads such as wind loads, wave loads, and ice loads, and sometimes it is also subject to unexpected shocks such as earthquakes, typhoons, tsunamis, and ship collisions. Due to its high cost and the nature of the work, once an accident occurs, it will not only bring immeasurable economic losses and casualties, but also cause serious pollution to the marine environment and cause adverse social and political impacts. [0003] Usually the damage of large structures is unavoidable during the service period of the structure. In order to ensure the...

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Problems solved by technology

[0004] The present invention solves the problems existing in the prior art that non-destructive detection of structural damage requires mass-normalized mode shapes and complete or high-order modal parameters, and the accuracy of damage degree evaluation is not high, and the change of structural unit mass is not considered. , a new method for structural damage diagnosis based on modal information is proposed. This method does not require mass-normalized mode shapes, but only uses low-order modal information before and after structural damage, and can consider changes in structural stiffness and mass at the same time

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