Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Article Citation - WoS: 71Citation - Scopus: 81The Impact Responses and the Finite Element Modeling of Layered Trapezoidal Corrugated Aluminum Core and Aluminum Sheet Interlayer Sandwich Structures(Elsevier Ltd., 2013) Kılıçaslan, Cenk; Güden, Mustafa; Odacı, İsmet Kutlay; Taşdemirci, AlperThe impact responses of brazed and adhesively bonded layered 1050 H14 trapezoidal corrugated aluminum core and aluminum sheet interlayer sandwich panels with 3003 and 1050 H14 aluminum alloy face sheets were investigated in a drop weight tower using spherical, flat and conical end striker tips. The full geometrical models of the tests were implemented using the LS-DYNA. The panels tested with spherical and flat striker tips were not penetrated and experienced slightly higher deformation forces and energy absorptions in 0°/90° corrugated layer orientation than in 0°/0° orientation. However, the panels impacted using a conical striker tip were penetrated/perforated and showed comparably smaller deformation forces and energy absorptions, especially in 0°/90° layer orientation. The simulation and experimental force values were shown to reasonably agree with each other at the large extent of deformation and revealed the progressive fin folding of corrugated core layers and bending of interlayer sheets as the main deformation mechanisms. The experimentally and numerically determined impact velocity sensitivity of the tested panels was attributed to the micro inertial effects which increased the critical buckling loads of fin layers at increasingly high loading rates.Article Citation - WoS: 21Citation - Scopus: 25Quasi-Static and Dynamic Crushing of Empty and Foam-Filled Tubes(Springer Verlag, 2001) Hall, Ian W.; Ebil, Özgenç; Güden, Mustafa; Yu, C.-J.Metallic foam-filled tubes and their empty counterparts have been tested at quasi-static and dynamic strain rates in order to determine their energy absorption capabilities. Data from the Split-Hopkinson Pressure Bar have been used to generate force vs. displacement curves that are somewhat analogous to pseudo-engineering stress-strain curves. Force balance calculations have also been made. These results indicate that, on an equal weight basis, foam-filled tubes offer greater energy absorption capability than empty tubes at quasi-static strain rates. However, the benefit of foam filling does not appear to be extended to strain rates of the order of 200–500 s−1. Force balance calculations are shown to have potential as a method for monitoring the crushing of metallic foams at high strain rate.Article Citation - WoS: 11Citation - Scopus: 14Quasi-Static and Dynamic Compression Behaviour of an Fptm Alumina-Reinforced Aluminium Metal Matrix Composite(Springer Verlag, 1998) Güden, Mustafa; Hall, Ian W.An aluminium metal matrix composite reinforced with continuous unidirectional α-alumina fibres has been compression tested at quasi-static and dynamic strain rates. In the transverse direction, the composite showed increasing flow stress (at 5% strain) and maximum stress within the studied strain rates, 10−3−3 × 103 s−1. In the longitudinal direction, the maximum stress of the composite increased similarly with increasing strain rates within the range 10−5−7 × 102 s−1. It is shown that, if brooming of the sample ends can be suppressed, the failure stress of the composite in longitudinal compression increases significantly. Metallographic observations reveal the typical modes of damage initiation in the composite.Article Citation - WoS: 30Citation - Scopus: 33Processing and Compression Testing of Ti6al4v Foams for Biomedical Applications(Springer Verlag, 2009) Dizlek, Mustafa Eren; Güden, Mustafa; Türkan, Uğur; Taşdemirci, AlperOpen cell Ti6Al4V foams (60% porosity) were prepared at sintering temperatures between 1,200 and 1,350 °C using ammonium bicarbonate particles (315–500 μm) as space holder. The resulting cellular structure of the foams showed bimodal pore size distribution, comprising macropores (300–500 μm) and micropores (1–30 μm). Compression tests have shown that increasing sintering temperature increased the elastic modulus, yield and compressive strength, and failure strain of foams. The improvements in the mechanical properties of foams prepared using smaller size Ti64 powder with bimodal particle distribution were attributed to the increased number of sintering necks and contact areas between the particles. Finally, the strength of foams sintered at 1,350 °C was found to satisfy the strength requirement for cancellous bone replacement.Article Citation - WoS: 32Citation - Scopus: 37Modeling Quasi-Static and High Strain Rate Deformation and Failure Behavior of a (±45) Symmetric E-glass/Polyester Composite Under Compressive Loading(Elsevier Ltd., 2013) Kara, Ali; Taşdemirci, Alper; Güden, MustafaQuasi-static (1 × 10−3–1 × 10−2 s−1) and high strain rate (∼1000 s−1) compressive mechanical response and fracture/failure of a (±45) symmetric E-glass/polyester composite along three perpendicular directions were determined experimentally and numerically. A numerical model in LS-DYNA 971 using material model MAT_162 was developed to investigate the compression deformation and fracture of the composite at quasi-static and high strain rates. The compressive stress–strain behaviors of the composite along three directions were found strain rate sensitive. The modulus and maximum stress of the composite increased with increasing strain rate, while the strain rate sensitivity in in-plane direction was higher than that in through-thickness direction. The damage progression determined by high speed camera in the specimens well agreed with that of numerical model. The numerical model successfully predicted the damage initiation and progression as well as the failure modes of the composite.