A FREQUENCY-DOMAIN METHOD OF STRUCTURAL DAMAGE IDENTIFICATION FORMULATED FROM THE DYNAMIC STIFFNESS EQUATION OF MOTION

2002 ◽  
Vol 257 (4) ◽  
pp. 615-634 ◽  
Author(s):  
U. LEE ◽  
J. SHIN
Keyword(s):  
Frequency Domain ◽  
Structural Damage ◽  
Damage Identification ◽  
Dynamic Stiffness ◽  
Equation Of Motion ◽  
Frequency Domain Method ◽  
Domain Method ◽  
Structural Damage Identification

A Novel Frequency-Domain Method of Structural Damage Identification

2001 ◽  
Author(s):  
Usik Lee ◽  
Jinho Shin
Keyword(s):  
Frequency Domain ◽  
Structural Damage ◽  
Damage Identification ◽  
Dynamic Stiffness ◽  
Equation Of Motion ◽  
Frequency Domain Method ◽  
Response Functions ◽  
Structural Damage Identification ◽  
Measured Frequency Response ◽  
Frequency Domain Approach

Abstract This paper introduces a frequency-domain approach of structural damage identification method (SDIM). The present SDIM is formulated from the exact dynamic stiffness matrix (DSM) equation of motion and then applied to beam structures. The appealing features of the present SDIM are: (1) it needs the DSM only for intact structure, (2) the excitation forces and the measured frequency response functions (FRFs) of damaged structure are only the required input data, and (3) it can locate and quantify many local damages at a time. The feasibility of the present SDIM is verified through some numerically simulated damage identification tests.

scholarly journals Structural Damage Identification of Bridges from Passing Test Vehicles

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 4035 ◽  
Author(s):  
Yang Yang ◽  
Yuanhao Zhu ◽  
Li Wang ◽  
Bao Jia ◽  
Ruoyu Jin
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Least Squares Method ◽  
Field Tests ◽  
Bending Stiffness ◽  
Frequency Domain Method ◽  
Residual Vector ◽  
Test Vehicle ◽  
Domain Method ◽  
Structural Damage Identification

This paper presents two approaches for the structural damage identification of a bridge from the dynamic response recorded from a test vehicle during its passage over the bridge. Using the acceleration response recorded by the vibration sensors mounted on a test vehicle during its passage over the bridge, along with the computed displacement response, the bending stiffness of the bridge can be determined using either: (1) the frequency-domain method based on the improved directed stiffness method with the identified frequency and corresponding mode shape, or (2) the time-domain method based on the residual vector of the least squares method with a fourth-order displacement moment. By comparing the bending stiffness values identified from the vehicle-collected data for the bridge under the undamaged and damaged states that are monitored regularly by the test vehicle, the bridge damage location and severity can be identified. Through numerical simulations and field tests, the present approaches are shown to be effective and feasible.

Response-Only Frequency-Domain Method for Structural Damage Detection

2009 ◽  
Author(s):  
Shuncong Zhong ◽  
S. Olutunde Oyadiji
Keyword(s):  
Damage Detection ◽  
Frequency Domain ◽  
Natural Frequency ◽  
Structural Damage ◽  
Natural Frequencies ◽  
Frequency Domain Method ◽  
Structural Damage Detection ◽  
Frequency Curve ◽  
Domain Method ◽  
Auxiliary Mass

This paper proposes a response-only method in frequency domain for structural damage detection by using the derivative of natural frequency curve of beam-like structures with a traversing auxiliary mass. The approach just uses the response time history of beam-like structures and does not need the external source of force excitation. The natural frequencies of a damaged beam with a traversing auxiliary mass change due to change in flexibility and inertia of the beam as the auxiliary mass is traversed along the beam. Therefore the auxiliary mass can enhance the effects of the crack on the dynamics of the beam and, therefore, facilitating locating the damage in the beam. That is, the auxiliary mass can be used to probe the dynamic characteristic of the beam by traversing the mass from one end of the beam to the other. However, it is impossible to obtain accurate modal frequencies by the direct operation of the Fast Fourier Transform of the response data of the structure because the frequency spectrum can be only calculated from limited sampled time data which results in the well-known leakage effect. A spectrum correction method is employed to estimate high accurate frequencies of structures with a traversing auxiliary mass. In the present work, the modal responses of damaged simply supported beams with auxiliary mass are computed using the Finite Element Analysis. The graphical plots of the natural frequencies versus axial location of auxiliary mass are obtained. The derivatives of natural frequency curve can provide crack information for damage detection of beam-like structures. However, it is suggested that the derivative do not go beyond the third derivative of natural frequency curves to avoid the difference approximation error which will be magnified at higher derivative. The sensitivity of crack index for different noise, crack depth, auxiliary mass and damping ratio are also investigated. The simulated result demonstrated the efficiency and precision of the response-only frequency-domain method which can be recommended for the real application in structural damage detection.

scholarly journals A Reduced-Domain Method of Structural Damage Identification: Application to a Spectral Element Beam Model

2003 ◽  
Vol 10 (5-6) ◽  
pp. 313-324 ◽  
Author(s):  
Usik Lee
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Dynamic Stiffness ◽  
Experimental Tests ◽  
Element Model ◽  
Spectral Element ◽  
Beam Specimen ◽  
Identification Algorithm ◽  
Beam Model ◽  
Domain Method

Though there have been many efforts to make the inverse problem of damage identification small by reducing its finite element degrees-of-freedom, there have been few efforts to make it small by reducing its spatial domain of problem. Thus, as the extension of the author's previous work in which the damage identification algorithm was formulated from the dynamic stiffness equation of motion, the present study introduces a spectral element model (SEM)-based reduced-domain method (RDM) of damage identification. In the present RDM, a three-steps process is used to reduce the domain of problem by iteratively searching out and removing damage-free parts of structure in the course of the damage identification analysis. To validate the present RDM, numerically simulated damage identification tests are conducted. The experimental tests for a damaged cantilevered beam specimen show that the present RDM can fairly well locates and quantifies all local damages (i.e., slots) placed along the beam specimen.

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