Abstract
Health monitoring of structures is gaining the interest of many engineers because of its role in early detection of structural damage. The commonly used damage detection techniques based on vibrations,require data from both pristine and damaged form of the structure to discriminate the damage. In most cases the data from pristine structure are not available. To make the process of damage detection baseline-free,the curvature mode shapes of the damaged structure are fitted with a smoothing polynomial curve. These smoothed curvature mode shapes can be further used as reference data.Among many damage detection methods, modal strain energy method has proven to be more effective as it considers the strain energy of the structure a teach mode.However, noise in the acquired response affects the success rate of the said method. To deal with this problem, a modification function is employed to amend the basic form of modal strain energy method. This modified modal strain energy method helped in giving damage indices which are less clouded with noisy peaks. However, it was still not able to detect and localize the damage with good accuracy. In this paper, along with this modified modal strain energy method which is made reference-free, a 2D Bayesian approach is presented. The approach uses the damage indices generated from the modified modal strain energy method and delivers an estimated damage index indicating the damage locations. The approach was tested for different scenarios of damage in terms of their severities, locality and noise levels and the results are compared with the published literature.
Natasha Waris, Ummul Baneen, Ayisha Nayyar. (2021) A Modified Reference-free Modal Strain Energy Method for Damage Identification in 2D Structures, Pakistan Journal of Engineering and Applied Sciences, Volume-28, Issue-1.
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