Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Subject: search.filters.subject.Strength of materials

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  • Master Thesis
    Impact Resistance of Steel Fiber Reinforced Concrete Slabs
    (Izmir Institute of Technology, 2015) Yaşayanlar, Süleyman; Saatcı, Selçuk
    As rare as it may seem, impact loads can act on a structure in its lifespan. For structures such as nuclear energy facilities, industrial facilities, and military buildings design for impact loads may be required. Steel fibers are increasingly used in the design and construction of such reinforced concrete structures. However, studies on the effect of steel fibers on the impact resistance of reinforced concrete structures are rare in the literature. This study investigates the global behavior of reinforced concrete slabs with different ratios of steel fibers under static and impact loading. 10 steel fiber reinforced concrete slabs with dimensions of 2150x2150x150 mm were tested with varying steel fiber volume ratios of 0.5 %, 1.0 % and 1.5 %. Specimens were manufactured as twins, as one to be tested under static loading and one to be tested under impact loading. Static tests were carried out by applying a static load at the midpoint with a hydraulic jack, whereas impact tests were applied through free falling drop-weights. Observed behavior and collected data were compared with companion studies of Batarlar (2013) and Arsan (2014), as they have used the same test setup with different parameters. As a result, it was seen that even steel a fiber addition of 0.5 % in volume was sufficient to provide a ductile behavior both under static and impact loading. Steel fibers significantly enhanced the impact behavior by increasing the strength and resiliency of the specimens.
  • Master Thesis
    Dynamic Force Measurement Techniques Split Hopkinson Pressure Bar Testing of Low Acoustic Impedance Materials Used as Armor Interlayer Materials
    (Izmir Institute of Technology, 2012) Turan, Ali Kıvanç; Taşdemirci, Alper
    GoreTM PolarchipTM heat insulating Teflon and Dow ChemicalsTM Voracor CS Polyurethane were characterized in this study by conducting compression tests at various strain rates. Quasi-static compression tests were done with a Shimadzu AG-X conventional test machine while two different modified Split Hopkinson Pressure Bar (SHPB) systems were used for dynamic compression tests. Since dynamic testing of soft materials with classical SHPB is problematic due to low signal levels and relatively higher signal to noise ratio, impact end of transmitter bar was modified with insertion of piezoelectric force transducers through the SHPB tests of Teflon, thus enabling the direct measurement of force on specimen. High strain tests of Polyurethane involved oscillations in both incident and transmitter bar signals. To overcome this, EPDM rubber pulse shaper was used through the SHPB tests of Polyurethane. Experimental results were used in numerical study as material model parameters and SHPB tests of both materials were simulated in LS-DYNA. Experimental study concluded strong strain rate dependency in both Teflon and Polyurethane, depicting an increase in maximum stress with the increase in strain rate. Numerical study showed a good correlation with experiments in terms of bar stresses and damage behavior of specimens, offering a solution to more complex problems that can be encountered in future studies.