List of Articles Modal parameters

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  1 - Review of damage detection methods based on modal parameters
  Ehsan Jamshidi Bahram Jamshidi Fatemeh Taghi Khaki Alireza Arghavan
  One of the common methods of structural damage detections and identification of location and severity of the damage in structures is investigation of changes in modal parameters before and after damage. These methods which are mostly based on optimization techniques use More

  One of the common methods of structural damage detections and identification of location and severity of the damage in structures is investigation of changes in modal parameters before and after damage. These methods which are mostly based on optimization techniques use an objective function based on natural frequencies and mode shapes. This paper reviews previous researches in damage detection techniques based on modal parameters and common objective functions used in the optimization stage in the damage detection process. To this end, damage detection methods based on natural frequency, mode shape, curvature mode shape and both of mode shape and natural frequency are reviewed. In the following, due to high importance of objective function in the damage detection process, objective functions based on modal assurance criterion, flexibility matrix and natural frequency and mode shapes are compared Manuscript profile
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  2 - Effect of crack location and severity on modal parameters of a cantilever beam
  Ehsan Jamshidi Bahram Jamshidi Fatemeh Taghi Khaki Alireza Arghavan
  One of the common methods of structural damage detections in structures is investigation of changes in modal parameters before and after damage. These methods which are mostly based on optimization techniques use an objective function based on natural frequencies and mo More

  One of the common methods of structural damage detections in structures is investigation of changes in modal parameters before and after damage. These methods which are mostly based on optimization techniques use an objective function based on natural frequencies and mode shapes. Success in detection of location and severity of the damage in these methods is severely a function of sensitivity of the objective function to the damage. As the objective function itself is function of natural frequencies or mode shapes or both of them, it is necessary that the sensitivity of modal parameters to damage location and severity is investigated. To this end, a cantilever beam is simulated numerically in this paper. Changing the location and severity of the damage, the effect of them on natural frequencies and mode shapes is studied. The results show that by increasing damage severity, natural frequencies decrease. On the other hand, moving the crack from the fix end to the free end of the cantilever beam, changes in the natural frequencies does not obey a specific pattern and for a crack of constant severity, decrement of natural frequencies from intact beam depends on the location of crack on the beam. Also it is observed that as the cracks approaches to the fix end, decrement of natural frequencies increased. The results show that the sensitivity of mode shapes to crack is low in beam. Therefore it is recommended to use natural frequencies or both natural frequencies and mode shapes together in objective functions. Manuscript profile
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  3 - A Comparative study of common objective functions based on modal parameters in structural damage detection
  Ehsan Jamshidi Bahram Jamshidi Fatemeh Taghi Khaki Alireza Arghavan
  Choosing appropriate objective function is necessary for detection of damage location and severity. To this end, objective functions based on modal parameters such as mode shapes and natural frequencies are combined with other objective functions capable to detect damag More

  Choosing appropriate objective function is necessary for detection of damage location and severity. To this end, objective functions based on modal parameters such as mode shapes and natural frequencies are combined with other objective functions capable to detect damage location. Then the location and severity of damage is obtained using optimization techniques. In this paper a cantilever beam is simulated numerically in MATLAB software using finite element method and then single and multi-objective genetic algorithms with different objective functions based on modal parameters are used to detect damage location and severity. To compare different objective functions, the effect of coordinate incompleteness, frequency range of interest and also environmental noise on the obtained results is studied. Manuscript profile
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  4 - The Identification of the Modal Parameters of Orbital Machines using Dynamic Structural Approach
  Hossein Pirzadeh Alireza Mohammadion Armen Adamian
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