Structural damage assessment using FRF employing particle swarm optimization

This paper evaluates the use of Frequency Response Function (FRF) with the help of Particle Swarm Optimization (PSO) technique, for structural damage detection and quantification. The robustness and efficiency of the above method has been established after comparing results between the two methods namely Genetic Algorithm (GA), and PSO, considering natural frequencies as response quantities. The performance of these methods has been evaluated for beam and plane frame structures with various damage scenarios. FRF based damage detection technique is employed subsequently along with PSO. It is observed that the use of FRF as response of damaged structure has led to better accuracy, since it contains data related to mode shape in addition to natural frequencies. The early detection of structural damage is one of the major challenges in the aerospace, civil and mechanical industries. The early damage detection helps in reducing the down time, to evaluate the safety and to prevent catastrophic events. Also it plays a major role in real time monitoring and reporting. Damage may be defined as any deviation in the structure's original geometric or material properties that may cause undesirable stresses, displacements, or vibrations in the structure. Damage in the structure may be caused due to various reasons, such as: deterioration and degradation of structures, fatigue failure, cracks inside the material due to manufacturing defect, accidental damage, earthquake in civil structures, flutter effect in aerospace, mechanical vibrations, etc. A number of researchers have proposed several methods in literature during last two decades to detect and assess damage in various types of structures. Yuen [1] examined changes in the mode shape and mode-shape-slope parameters. Farhat and Hemez [2] minimized the norm of the Residual Force Vector (RFV) by updating both stiffness elemental and mass parameters in a sensitivity-based algorithm. Yang [3] proposed a numerical technique for structural damage detection using modal residual force criteria and matrix disassembly technique. Pandey and Biswas [4] identified the damage in beam-type structures using changes in the flexibility matrix of the structure. Salawu and Williams [5] using a comprehensive literature review, established some conclusion about damage detection through changes in frequency. In general frequency changes alone do not necessarily imply the damage existence. Sampaio et al. [6] used a FRF curvature method for detection, localization, and extent of damage in the bridge structure. Lee and Shin [7] used FRF data measured from the damaged structure as the input data. Link [8] in …