Master Degree / Yüksek Lisans Tezleri

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

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Access Right: Open AccessSubject: search.filters.subject.Composite materials--Impact testing

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  • Master Thesis
    The Projectile Impact Responses of the Composite Faced Aluminum Foam and Corrugated Aluminum Sandwich Structures: a Comparative Study
    (Izmir Institute of Technology, 2011) Odacı, İsmet Kutlay; Güden, Mustafa; Odacı, İsmet Kutlay; Güden, Mustafa; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The projectile impact and energy absorption characteristics of the corrugated aluminum cored E-glass/polyester composite sandwich structures were determined at the impact velocities of 150 m/s. For comparison, E-glass/polyester sandwich structures cored with aluminum foam were also investigated. The test conditions were kept the same for each structure in order to identify the impact properties at the similar test conditions. The composite and the foam core composite sandwiches were produced by vacuum assisted resin transfer molding and the mechanical tests were performed on the composite and core samples based on ASTM. High strain rate tests were performed using a compression type Split Hopkinson Pressure Bar and drop weight test set-up. It was found that aluminum foam sandwich structures had higher ballistic limit and energy dissipating performance than corrugated aluminum sandwich structures; however, as the thickness of the face sheets increased the corrugated aluminum cores were observed to be more effective. The results showed that corrugated aluminum structures had the potentials to be used as core material in composite sandwich structures.
  • Master Thesis
    The Effects of Light-Weight Interface Material on the Stress Wave Propagation in the Multilayered Composite Armor System
    (Izmir Institute of Technology, 2011) Tunusoğlu, Gözde; Taşdemirci, Alper; Taşdemirci, Alper; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The main purpose of the current study is to investigate the effect of interlayer material on the ballistic performance of composite armor and stress wave propagation both experimentally and numerically. Three different interlayer materials, EPDM rubber, Teflon and Aluminum metallic foam, were tried. Relatively large pieces of the ceramic around the impact axis in the rubber interlayer configuration were observed while the ceramic layer was efficiently fragmented in Aluminum foam and Teflon interlayer configurations. Accordingly, more significant amount of delamination in composite layer of without interlayer, larger and deeper delamination in EPDM rubber configurations was observed while fewer amounts were observed on Teflon and Aluminum foam configurations .Also, all interlayers caused reduction in the magnitude of the stress transmitted to the composite backing plate, particularly Aluminum foam. However, EPDM rubber did not cause delay in the initial stress build-up in the composite layer, whereas Teflon (~15 ms) and Aluminum foam (~25 ms) caused a significant delay. Also, as ceramic was efficiently fragmented in Teflon and Aluminum metallic foam interlayer configurations, greater amount of projectile kinetic energy was absorbed in this layer, as a consequence, the remaining energy which was transmitted to composite backing plate was decreased. At this point, the effectiveness of Aluminum foam and Teflon were validated with conducting ballistic tests and corresponding numerical simulations and impact chamber tests. After this validation, the ballistic performance of aforementioned materials was compared at equal areal densities. Finally, Aluminum foam was found to be more effective interlayers in reducing the stress values transmitted to the composite backing plate and reduction of the damage imparted to this layer.