Damage Identification Method with Structural Frequency Data from Modal Test

Du Jian-Hua,Zhao Yangdong,Ouyang Zhiwei

doi:10.26552/com.c.2009.1.50-54

Du Jian-Hua, Zhao Yangdong + Show 1 more

Open Access

https://doi.org/10.26552/com.c.2009.1.50-54

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Abstract

Testing and analysis technology based on vibration mode is a common method to structural health monitoring and checking. This paper deduces the damage factor used for structural damage evaluation based on test frequency of structure, makes a finite element numerical simulation using ANSYS software and model test to a pressure pipe. Here a stiffness reduction method is utilized to reproduce the damage state of a single-point and multiple-point, damage identification is carried out with a FEM model of redundant pipe. Meanwhile, a model experiment system is designed to validate the efficiency of damage factor with cutting-groove to simulate damage states. Numerical and experimental results show the proposed damage factor is theoretically breviate, simple realization and high-accuracy performance, therefore, it has a good usage prospect in the implementation of structural damage monitoring and identification.

Highlights

Technology of structural experiment modal analysis is an important measure for structural damage evaluation, which is based on a modal analysis, predicts and evaluates a variation of physical parameter according to the variation of a modal characteristic of pre-damage and post-damage of the structure [1]
The development and application of technology of structural experiment modal analysis is restricted because the modal data beyond all freedoms can not be measured in view of incompleteness of test data on spot
This paper deduces the evaluation method based on the variation ratio of squared frequency and the validity is checked from a numerical simulation and model experiment test validation

Summary

Introduction

Technology of structural experiment modal analysis is an important measure for structural damage evaluation, which is based on a modal analysis, predicts and evaluates a variation of physical parameter according to the variation of a modal characteristic of pre-damage and post-damage of the structure [1]. The damage position can be identified and damage degree can be evaluated according to the variation ratio of squared frequency of each mode. From the figures we know that damage in different positions has different effect on the variation ratio of squared frequency of the structure and relates with the connection conditions of the structure with other structure. With the damage position away from the fixed end, the value of the variation ratio of squared frequency ␩ decreases gradually and increases again at the supported end. The variation ratio of squared frequency because the information of the whole structure can be expressed by the information of the elements [6]

Test system

Damage simulation

Data processing and result analysis

Conclusion