%0 Journal Article
%T Structural Damage Detection Based on Modal Parameters Using Continuous Ant Colony Optimization
%A Aditi Majumdar
%A Bharadwaj Nanda
%A Dipak Kumar Maiti
%A Damodar Maity
%J Advances in Civil Engineering
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/174185
%X A method is presented to detect and quantify structural damages from changes in modal parameters (such as natural frequencies and mode shapes). An inverse problem is formulated to minimize the objective function, defined in terms of discrepancy between the vibration data identified by modal testing and those computed from analytical model, which then solved to locate and assess the structural damage using continuous ant colony optimization algorithm. The damage is formulated as stiffness reduction factor. The study indicates potentiality of the developed code to solve a wide range of inverse identification problems. 1. Introduction Structural health monitoring (SHM) has become an important area of research within the civil, mechanical, aerospace engineering community in recent years. Damage to structure may be caused as a result of normal operations, accidents, deterioration, or severe natural events such as earthquake and storms. Sometimes the extent and location of damage can be determined through visual inspection. But visual inspection technique has a limited capability to detect the damage, especially when the damage lies inside the structure and is not visible. So an effective and reliable global damage assessment methodology is necessary for determination of damage state particularly for these inaccessible regions. Modal parameters based damage detection method has several advantages over alternative techniques due to the fact that the modal parameters depend only on the mechanical characteristics of the structure and not on the excitation applied. Review of modal parameter based damage detection methods was carried out by Doebling et al. [1] and Fan and Qiao [2]. Since natural frequencies can be measured more easily than mode shapes and are less affected by experimental errors; it has been used as a probable damage indicator by many researchers [3, 4]. However, its application is somewhat limited due to its low sensitivity to damage; in particular when the damage is located at regions of low stress. Further, information regarding local damage is associated with higher modes which are difficult to extract experimentally and therefore are not available for damage detection. Alternately, since mode shape represents the relative displacement of all the parts of the structures for that particular mode, they can thereby provide the spatial information about sources of vibration changes. Damage in the structure changes the mode shape locally. The commonly used method for comparing two mode shapes is the modal assurance criterion (MAC) [5] value which
%U http://www.hindawi.com/journals/ace/2014/174185/