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Damage Detection in Steel Beams Subjected to Dynamic Loads Using Time Domain Response (Analytical & Experimental)

Fallahian, Saeed | 2017

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  1. Type of Document: Ph.D. Dissertation
  2. Language: English
  3. Document No: 50119 (53)
  4. University: Sharif University of Technology, International Campus, Kish Island
  5. Department: Science and Engineering
  6. Advisor(s): Joghataie, Abdolreza; Kazemi, Mohammad Taghi
  7. Abstract:
  8. Many structural systems may experience some local damage during their lifetime. If the local damage is not identified timely, it may lead to undesirable consequences. Vibration-based damage detection techniques of structures are global methods and are based on the assumption that damage alters both the physical properties, such as mass, stiffness and damping, as well as the dynamic properties of the structures. It is therefore feasible to utilize measured dynamic quantities, such as time histories, frequency response functions (FRFs) and modal parameters, from structural vibration to detect damage. Damage identification based on vibration characteristics is essentially a form of pattern recognition problems, which looks for the discrimination between two or more signal categories, e.g., before and after a structure is damaged, or differences in damage levels or locations. In this research, an efficient method is introduced to determine the location and extent of damage in the frame, beam and truss structures using time domain response and an optimization algorithm. First of all, the structural damage detection problem is formulated as a standard optimization problem. The objective function is defined using the acceleration of the real damaged structure and analytical model acceleration. Newmark method has been used in this research. To model the damage in numerical studies, the damage is simulated by reducing the stiffness of structural members. Then, the damage problem is converted to an optimization problem which is solved by teaching–learning-based optimization (TLBO) algorithm. Which determines the location and extent of damage in the structure. In order to show the capabilities of the proposed approach for identifying structural damage, five illustrative test examples are studied. The effect of noise in the measurements is also included. Laboratory test is used to assess the accuracy of the good performance of the proposed method. The results clearly show that the proposed method is a powerful method to detect single and multiple damage cases in structures
  9. Keywords:
  10. Analytical Modeling ; Damage Identification ; Time Domain Response ; Teaching and Learning Based Optimization

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