Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Conference Object Citation - WoS: 1Citation - Scopus: 1Numerical and Experimental Studies of High Strain Rate Mechanical Behavior of E-glass/Polyester Composite Laminates(The American Society of Mechanical Engineers(ASME), 2010) Tunusoğlu, Gözde; Taşdemirci, Alper; Güden, Mustafa; Hall, Ian W.Quasi-static ∼10-3 s-1) and high strain rate (∼850 s-1) compression behavior of an E-glass/polyester composite was determined in the through-thickness and in-plane directions. In both directions, modulus and failure strength increased with increasing strain rate. Higher strain rate sensitivity for both elastic modulus and failure strength was observed in the in-plane direction. A numerical model was developed to investigate the compressive deformation and fracture of an E-glass/polyester composite. Excellent agreement was demonstrated for the case of high strain rate loading. Also, the fracture geometries were successfully predicted with the numerical model.Conference Object Off-Axis Properties of Cross-Ply Metal Matrix Composites at Quasi-Static and High Strain Rates(Elsevier Ltd., 2011) Hall, Ian W.; Taşdemirci, Alper; Kara, AliCylindrical samples of a 0/90° cross-ply Nextel 610™/A1-6061 (∼55Vf%) metal matrix composite have been subjected to compression testing at quasi-static and high strain rates over a range of angles between 0° and ±45° with respect to the principal fiber directions. The results, combined with testing in the longitudinal, transverse and through thickness directions, provide a detailed description of the response of such composites over a wide range of orientations. In addition, metallographic and fractographic studies along with high-speed camera records provide detailed information about the sequence of deformation events leading to fracture. Results confirm not only the strong dependence of mechanical properties upon orientation but also the critical importance of precise fiber alignment and processing in obtaining the desired theoretical properties. A misalignment of 10° was sufficient to cause an -40% decrease in maximum stress and the properties were found to vary by >70% over the orientations investigated. The high strain rate properties were generally significantly greater than those measured quasi-statically. A numerical model based on the commercial explicit finite element code LS-DYNA was used to investigate the compressive deformation and fracture of the composite. Experimental results are compared with those of the numerical model. © 2011 Published by Elsevier Ltd.Conference Object Citation - WoS: 3Citation - Scopus: 3Numerical Approach To Design Process of Armored Vehicles(The American Society of Mechanical Engineers(ASME), 2010) Erdik, Atıl; Kılıç, Namık; Güden, Mustafa; Taşdemirci, AlperToday, it is imperative that armored vehicles need advanced protection kits against anti-symmetric threats more than before. The primary goal of this study was to assess benefits of explicit hydrocodes for mine protection resistance of armored vehicles. An analysis of an armored vehicle under blast loading caused by high explosive (HE) detonation is presented with comparison to a full-scale test. The problem was examined using LS-DYNA which is an explicit non-linear finite element code. Multi Material Arbitrary Lagrangian Eulerian (MM-ALE) Fluid Structure Interaction Method was selected to model the explosion domain so as to observe advancing of the shock wave in the compressed air and to investigate the effects of blast on the vehicle structure after explosion. Johnson-Cook constitutive material model, Jones-Wilkins-Lee (JWL) and Linear Polynomial equation of states were used for the problem. Results show that numerical analysis was in good agreement with the experimental result.Conference Object Citation - WoS: 11Citation - Scopus: 18Experimental and Numerical Investigation of High Strain Rate Mechanical Behavior of a [0/45 - 45] Quadriaxial E-glass/Polyester Composite(Elsevier Ltd., 2011) Taşdemirci, Alper; Kara, Ali; Turan, Ali Kıvanç; Tunusoğlu, Gözde; Güden, Mustafa; Hall, Ian W.Quasi-static (10−3–10−1 s−1) and high strain rate (∼900 s−1) compression behavior of an E-Glass fiber woven fabric reinforced Polyester matrix composites was investigated by using a Shimadzu AG-I testing machine and a Split Hopkinson Pressure Bar apparatus in the Dynamic Testing and Modeling Laboratory of Izmir Institute of Technology. During the experiments, a high speed camera was used to determine deformation behavior. In both directions, modulus and failure strength increased with increasing strain rate. Higher strain rate sensitivity for both elastic modulus and failure strength was observed in the in-plane direction. Based upon these experimental data, a numerical model was developed using the commercial explicit finite element code LS-DYNA to investigate compressive deformation and damage behavior of composites. Excellent agreement was demonstrated for the case of high strain rate loading. Also, the fracture geometries were successfully predicted with the numerical model.