Abstract
Damage identification based on the change of dynamic properties is an issue worthy of attention in structure safety assessment, nevertheless, only a small number of discontinuous members in existing structure are damaged under service condition, and the most remaining members are in good condition. According to this feather, we developed an effective damage location and situation assessment algorithm based on residual mode vector with the first mode information of targeted structure, which utilized the quantitative relationship between first natural modes of global structure with the change of the element stiffness. Firstly, the element damage location is determined with exploitation of the sparseness of element stiffness matrices based on the discontinuity of damaged members. Then, according to the distribution characteristics of the corresponding residual mode vector, the nodal equilibrium equation about the damage parameter is established based on the residual mode vector, and the damage coefficients of structural elements are evaluated with the proposed equations. Two numerical examples are given to verify the proposed algorithm. The results showed that the proposed damage identification method is consistent with the preset damage. It can even accurately identify large-degree damages. The proposed algorithm only required the first-order modal information of the target structures and held few requirements of analysis resource; hence when compared with existing methods, it has obvious advantages for structural damage identification.
Highlights
Structural damage identification technology shows its strong vitality in many engineering fields such as civil engineering, mechanical engineering, and aerospace engineering, which has benefited from the combination with modal measurement technology and finite-element analysis [1,2,3]
Various damage location and detection technologies have been developed based on structural vibration properties. e principle for vibration-based damage identification is that the damage-induced changes in the physical properties of element stiffness will cause detectable changes in system modal properties
Damage detection methods have been developed for the identification of damage directly based on measured mode shapes or mode shape curvatures [8,9,10]
Summary
Structural damage identification technology shows its strong vitality in many engineering fields such as civil engineering, mechanical engineering, and aerospace engineering, which has benefited from the combination with modal measurement technology and finite-element analysis [1,2,3]. The authors develop a damage detection method originally proposed by Kaouk et al based on the residual mode equation with only the first order of structure mode information. E residual mode vector is developed based on the residual mode equation for structural element damage detection, in which the relationship between the stiffness matrix of damaged element and first-order mode information is derived from the residual mode equation. Step 2: locating the damage element in structure and filter Arrange the elements in the residual mode vector in the descending order of their absolute values. Step 3: Verifying the results of location identification List the elements in residual mode vector after filtering according to their corresponding structural elements. It should be noted that for the absolute value of residual mode vector from large to small, the number of the corresponding abscissa in Figure 3 of each ordered element of residual mode vector must be marked first before the sorting, which is important for the subsequent damage detection work. en, according to Step 3, obtain the location map of damage element as shown in Figure 4. e abscissa is the number of degrees of freedom of Eigenvector
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