چكيده به لاتين
Abstract
With the growing importance of major structures and the need to maintain and care of
these structures, it is increasingly felt that aspects of preventing mortalities and
financial losses caused by the collapse of these structures are becoming increasingly
evident. Over the years, over time and under continuous loading, these structures may
be damaged and eventually destroyed by reaching the final capacity point. Therefore,
the study of the health monitoring of the structure at any one time and identifying the
potential damage at the earliest appearance of the genesis and its quick fixing is
necessary to reduce repair costs and prevent irreparable damage. So, various methods
have been introduced to identify damage in structures in recent years. In the meantime,
the methods of model updating have become more prominent in that they provide a
more complete state of the structure. These methods utilize the vibrational properties
of the structure and attempt to update a numerical model using the information of the
structure in hand and approach the current state of the structure.
The purpose of this thesis is to provide a suitable method for detecting damage in
structures, especially bulk structures, because of their large dimensions, they incur a
great deal of time and cost to detect damage. Therefore, the use of sensitivity analysis
for high speed and acceptable accuracy in detecting damage is considered. So, we will
provide an algorithm that, in order to reduce the time required for constructing the
structure, in a small number of steps, it is possible to achieve a precise answer. and
the modal characteristics of the structure (frequency and mode shape) will be used as
a parameter for indicating the current state of the structure for the more appropriate
physical concept and higher resistance to noise compared with the time information
(acceleration and displacement). In order to prove the efficiency of the proposed
algorithm, various examples will be presented for performance evaluation. Examples
include damage detection in a two-dimensional truss bridge and a two-dimensional 5-
span frame and a power transmission tower as standard structures across the country.
The results show the acceptable accuracy of the results of the algorithm, despite the
high noise in the structural input information.
Keywords: damage detection, finite element model updating, modal information,
sensitivity analysis
