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Steel and Composite Structures
  Volume 49, Number 6, December 25 2023 , pages 685-699
DOI: https://doi.org/10.12989/scs.2023.49.6.685
 


Damping characteristics of CFRP strengthened castellated beams
Cyril Thomas Antony Raj, Jyothis Paul Elanhikuzhy and Baskar Kaliyamoorthy

 
Abstract
    In recent years, Carbon Fibre Reinforced Plastic (CFRP) strengthening is found to be one of the best methods to strengthen steel structures. The fibrous bond can also influence the vibration characteristics of the strengthened element apart from its static strength enhancement property. The main objective of this study is to understand the influence of CFRP strengthening on the dynamic Behaviour of Thin-Webbed Castellated Beams (TWCBs). A detailed experimental investigation was carried out on five sets of beams with varying parameters such as domination of shear (Shear Dominant, Moment Dominant and Moment and Shear Dominant), sectional classification (Plastic and Semi-compact) and perforation geometries (ho/dwratio 0.65 and e/ho ratio 0.3). Free vibration analysis was carried out by exciting the simply supported TWCBs with an impact force generated by a ball dropped from a specific height. Logarithmic decrement method was used to obtain the damping ratio and natural frequencies of vibration were found by Fast Fourier Transform (FFT). Natural frequency showed an increase in a range of 10.5 - 55% for the different sets of castellated beams. An increase of 62.30% was noted in the damping ratio of TWCBs after strengthening which is an indication of improvement in the vibration characteristics of the beam.
 
Key Words
    castellated beam; CFRP; damping ratio; free vibration analysis; natural frequency; steel structure; strengthening; thin-webs
 
Address
Cyril Thomas Antony Raj: School of Civil Engg., SASTRA Deemed to be University, Thanjavur - 613401, Tamil Nadu, India

Jyothis Paul Elanhikuzhy and Baskar Kaliyamoorthy:Department of Civil Engg., National Institute Technology Tiruchirappalli, Tiruchirappalli – 620015, Tamil Nadu, India
 

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