Mechanical Engineering / Makina Mühendisliği

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

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2008 - 200912010 - 20131

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Author: search.filters.author.Gültürk, ElifPublication Index: search.filters.publicationIndex.WoS

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  • Article
    Citation - WoS: 24
    Citation - Scopus: 26
    Diatom Frustule-Filled Epoxy: Experimental and Numerical Study of the Quasi-Static and High Strain Rate Compression Behavior
    (Elsevier Ltd., 2008) Taşdemirci, Alper; Yüksel, Sinan; Karsu, Deniz; Gültürk, Elif; Hall, Ian W.; Güden, Mustafa
    In this study, centric type diatom frustules obtained from a diatomaceous earth filter material were used as filler in an epoxy resin with a weight percentage of 15% in order to assess the possible effects on the compressive behavior at quasi-static and high strain rates. The high strain rate testing of frustule-filled and neat epoxy samples was performed in a split-Hopkinson pressure bar (SHPB) set-up and modeled using the commercial explicit finite element code LS-DYNA 970. Result has shown that 15% frustule filling of epoxy increased both modulus and yield strength values at quasi-static and high strain rates without significantly reducing the failure strain. Microscopic observations revealed two main deformation modes: the debonding of the frustules from the epoxy and crushing/fracture of the frustules. The modeling results have further confirmed the attainment of stress equilibrium in the samples in SHPB testing following the initial elastic region and showed good agreement with the experimental stress–time response and deformation sequence of the samples in high strain rate testing.
  • Article
    Citation - WoS: 20
    Citation - Scopus: 21
    Calcined and Natural Frustules Filled Epoxy Matrices: the Effect of Volume Fraction on the Tensile and Compression Behavior
    (Elsevier Ltd., 2013) Gültürk, Elif; Güden, Mustafa; Taşdemirci, Alper
    The effects of calcined diatom (CD) and natural diatom (ND) frustules filling (0–12 vol.%) on the quasistatic tensile and quasi-static and high strain rate compression behavior of an epoxy matrix were investigated experimentally. The high strain rate testing of frustules-filled and neat epoxy samples was performed in a compression Split Hopkinson Pressure Bar set-up. The frustules filling increased the stress values at a constant strain and decreased the tensile failure strains of the epoxy matrix. Compression tests results showed that frustules filling of epoxy increased both elastic modulus and yield strength values at quasi-static and high strain rates. While, a higher strengthening effect and strain rate sensitivity were found with ND frustules filling. Microscopic observations revealed two main compression deformation modes at quasi-static strain rates: the debonding of the frustules from the epoxy and/or crushing of the frustules. However, the failure of the filled composites at high strain rates was dominated by the fracture of epoxy matrix.