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Structural Engineering and Mechanics
  Volume 65, Number 1, January10 2018 , pages 043-51
DOI: https://doi.org/10.12989/sem.2018.65.1.043
 


Analysis of thermal and damage effects over structural modal parameters
Fabricio A. Ortiz Morales, Alexandre A. Cury and Ricardo A. Fiorotti Peixoto

 
Abstract
    Structural modal parameters i.e. natural frequencies, damping ratios and mode shapes are dynamic features obtained either by measuring the vibration responses of a structure or by means of finite elements models. Over the past two decades, modal parameters have been used to detect damage in structures by observing its variations over time. However, such variations can also be caused by environmental factors such as humidity, wind and, more importantly, temperature. In so doing, the use of modal parameters as damage indicators can be seriously compromised if these effects are not properly tackled. Many researchers around the world have found numerous methods to mitigate the influence of such environmental factors from modal parameters and many advanced damage indicators have been developed and proposed to improve the reliability of structural health monitoring. In this paper, several vibration tests are performed on a simply supported steel beam subjected to different damage scenarios and temperature conditions, aiming to describe the variation in modal parameters due to temperature changes. Moreover, four statistical methodologies are proposed to identify damage. Results show a slightly linear decrease in the modal parameters due to temperature increase, although it is not possible to establish an empirical equation to describe this tendency.
 
Key Words
    structural health monitoring; modal parameters; thermal effect; damage detection; structural dynamics
 
Address
Fabricio A. Ortiz Moralesand Ricardo A. Fiorotti Peixoto: Department of Civil Engineering, Federal University of Ouro Preto, Ouro Preto, MG, Brazil
Alexandre A. Cury: Department of Applied and Computational Mechanics, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
 

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