Civil Engineering / İnşaat Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/13

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Author: search.filters.author.Aktaş, EnginPublisher: search.filters.publisher.John Wiley and Sons Inc.

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  • Article
    Citation - WoS: 12
    Citation - Scopus: 15
    Probabilistic Investigation of Error Propagation in Frequency Domain Decomposition-Based Operational Modal Analysis
    (John Wiley and Sons Inc., 2021) Hızal, Çağlayan; Aktaş, Engin
    Each operational modal analysis (OMA) technique may produce significant errors during the identification procedure due to the applied methodology, environmental/operational conditions, and instrumentation. Consequently, those errors can adversely affect the quality of identified parameters. In this context, this study aims at providing a comprehensive discussion on the propagation of predictions errors in the frequency domain OMA. To mitigate the prediction errors those considered to be induced by modeling and measurement errors, an extended formulation is presented based on a recently developed Modified Frequency and Spatial Domain Decomposition technique. A comprehensive investigation is presented for the probabilistic modeling of output power spectral density (PSD), considering prediction errors. Numerical and real data applications are conducted to show the effectiveness of the proposed methodology.
  • Article
    Citation - WoS: 108
    Citation - Scopus: 117
    Enhancement of Interlaminar Fracture Toughness of Carbon Fiber–epoxy Composites Using Polyamide-6,6 Electrospun Nanofibers
    (John Wiley and Sons Inc., 2017) Beylergil, Bertan; Tanoğlu, Metin; Aktaş, Engin
    In this study, carbon fiber–epoxy composites are interleaved with electrospun polyamide-6,6 (PA 66) nanofibers to improve their Mode-I fracture toughness. These nanofibers are directly deposited onto carbon fabrics before composite manufacturing via vacuum infusion. Three-point bending, tensile, compression, interlaminar shear strength, Charpy impact, and double cantilever beam tests are performed on the reference and PA 66 interleaved specimens to evaluate the effects of PA 66 nanofibers on the mechanical properties of composites. To investigate the effect of nanofiber areal weight density (AWD), nanointerlayers with various AWD are prepared by changing the electrospinning duration. It is found that the electrospun PA 66 nanofibers are very effective in improving Mode-I toughness and impact resistance, compressive strength, flexural modulus, and strength of the composites. However, these nanofibers cause a decrease in the tensile strength of the composites. The glass-transition temperature of the composites is not affected by the addition of PA 66 nanofibers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45244.