Mechanical Engineering / Makina Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4129

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Institution Author: search.filters.institutionAuthor.Beylergil, BertanScopus Q: search.filters.scopusQuartile.Q2

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  • Article
    Citation - WoS: 8
    Citation - Scopus: 8
    Free Vibration Analysis of Damaged Composite Beams
    (Techno Press, 2015) Cünedioğlu, Yusuf; Beylergil, Bertan
    In this study, free vibration analyses of symmetric laminated cantilever and simply supported damaged composite beams are investigated by using finite element method (FEM). Free vibration responses of damaged beams are examined using Euler Bernoulli beam and classical lamination theories. A computer code is developed by using MATLAB software to determine the natural frequencies of a damaged beam. The local damage zone is assumed to be on the surface lamina of the beam by broken fibers after impact. The damaged zone is modeled as a unidirectional discontinuous lamina with 0 degrees orientations in this study. Fiber volume fraction (v(f)), fiber aspect ratio (L-f/d(f)), damage length (L-D) and its location (lambda/L), fiber orientation and stacking sequence parameters effects on natural frequencies are investigated. These parameters are affected the natural frequency values significantly.
  • 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.
  • Article
    Citation - WoS: 23
    Citation - Scopus: 23
    Free Vibration Analysis of Laminated Composite Beam Under Room and High Temperatures
    (Techno Press, 2014) Cünedioğlu, Yusuf; Beylergil, Bertan
    The aim of this study is to investigate the effects of the beam aspect ratio(L/h), hole diameter, hole location and stacking layer sequence ([0/45/-45/90]s, [45/0/-45/90]s and [90/45/-45/0]s) on natural frequencies of glass/epoxy perforated beams under room and high (40, 60, 80, and 100°C) temperatures for the common clamped-free boundary conditions (cantilever beam). The first three out of plane bending free vibration of symmetric laminated beams is studied by Timoshenko's first order shear deformation theory. For the numerical analyses, ANSYS 13.0 software package is utilized. The results show that the hole diameter, stacking layer sequence and hole location have important effect especially on the second and third mode natural frequency values for the short beams and the high temperatures affects the natural frequency values significantly. The results are presented in tabular and graphical form. © 2014 Techno-Press, Ltd.