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• MakaleAçık Erişim2024/r/gumushane/20068
  Gümüşhane ilinde deprem ivme ve manyetik alan istasyonlarının kurulumu ve işletilmesi

  Öztürk, Serkan; Maden, Nafiz; Beker, Yasemin; Sari, Mahmut; Pehlivan, Levent

  Bu çalışmada, Kuzey Anadolu Fay Zonu (KAFZ) üzerinde meydana gelen bir depremden Gümüşhane ilinin etkilenme derecesini belirlemek üzere deprem ivme kayıt cihazlarının yerleştirilmesi ve Güneşte meydana gelen fırtınalar nedeniyle yer Manyetik alanındaki değişimleri gözlemlemek amacıyla 3 bileşen Flux-Gate manyetometrenin kurulumu amaçlanmıştır. Deprem ivme kayıt cihazlarının (3 adet); Gümüşhane ili için önem taşıyan Karaca Mağarası ve Kürtün hidroelektrik santrali ile KAFZ’na yakınlığından dolayı Şiran MYO’na kurulması uygun görülmüştür. Flux-gate Manyetometresi ise Gümüşhane Merkez ilçede kurulmuştur. KAFZ üzerinde meydana gelen bir depremden Kelkit, Şiran ve Köse ilçeleri daha çok etkilenirken Torul ve Kürtün ilçeleri daha az etkilenmektedir. Gümüşhane’nin 17 km kuzeybatısında yer alan Karaca Mağarası bölgemizin önemli turizm merkezlerinden birisidir. Kürtün ilçesinde, Harşit nehri üzerinde kurulu olan Kürtün Hidroelektrik santrali enerji amaçlı olarak hizmet vermesi yanında baraj gölü üzerinde balık üretimine ve su sporları yapılmasına imkân sunmaktadır. Güneşte aniden gelişen çok şiddetli patlamalar dünyaya ulaştıklarında elektrik ve iletişim hatlarını kesilebilmekte, radyo haberleşmesinde bozulmalara ve radyasyona sebep olmaktadır. Gümüşhane kurşun, çinko, bakır, altın ve gümüş gibi değerli metaller açısından oldukça yüksek bir potansiyele sahiptir. Bu tür maden yataklarının belirlenmesinde Jeofizik yöntemlerden bir tanesi olan Manyetik yöntem oldukça başarılı bir şekilde kullanılmaktadır. Bu yöntemde arazide ölçü alınırken yer manyetik alanının sürekli kaydedilmesine hizmet edecektir.

  İncele
• MakaleAçık Erişim2024/r/gumushane/11741
  In-plane crushing behavior and energy absorption of CFRP honeycombs with different core topologies

  Pehlivan, Levent; Baykasoğlu, Cengiz

  The in-plane crushing behavior and energy absorption performance of carbon fiber reinforced polymer (CFRP) honeycombs with different core topologies were experimentally investigated under uniaxial loading conditions. Three types of CFRP honeycomb core topologies (i.e. circular, square and hexagonal) with different cell wall thicknesses and heights were considered in the designs. The honeycomb samples were fabricated by the molding and bonding process, which is widely used in the easy, fast and economical manufacturing of thin-walled honeycomb structures. A total of twenty-seven sample groups were experimentally tested for each loading condition, in which honeycomb samples with different core topologies were designed to have almost the same weights for a meaningful comparison. The experimental results revealed that all honeycomb designs have higher in-plane compression strength in the expansion direction, and hexagonal honeycombs showed the highest strength and energy absorption performance in both directions due to their stable load-carrying capacity and outstanding force efficiency. In particular, the experimental findings showed that the crushing strength and the specific energy absorption of CFRP honeycomb structures can be improved up to 6.1 and 4.2 times, respectively, by properly adjusting the cell wall thickness and height parameters. The results also revealed that the proposed lightweight CFRP honeycombs with the structural densities of 155–283 kg/m3 showed better in-plane crushing performance than many competing cellular topologies.

  İncele
• MakaleAçık Erişim2021/r/gumushane/13228
  Estimation of ground types in different districts of Gümüşhane province based on the ambient vibrations H/V measurements

  Öztürk, Serkan; Beker, Yasemin; Sari, Mahmut; Pehlıvan, Levent

  In this study, an attempt was made to estimate the ground types for Torul, Kürtün, Kelkit, Şiran and Köse districts of Gümüşhane, Turkey, by analyzing the predominant frequency and H/V ratio from microtremor data through the single station microtremor H/V ratio of Nakamura technique. For all districts, predominant frequencies show a general distribution between 1.36 and 9.84 Hz, H/V ratios between 1.01 and 9.58. According to these variations, three transient zones can be suggested as i) Z1, stiff rock composed of gravel, sand and other soils mainly consisting of tertiary or older layers with period of 0.1 to 0.2s, ii) Z2, sandy gravel, stiff sandy clay, loam or sandy alluvial deposits whose depths are 5m or greater with period of 0.2 to 0.4s, and iii) Z3, standard grounds other than type Z1, Z2 or Z4 (alluvial deposits whose depths are 5m or greater) with period of 0.4 to 0.8s. These r esults s uggest that p redominant period obtained from predominant frequency shows significant changes based on the soil formation, and H/V ratio highly corresponds to these subsurface properties. Soil-structure interaction can also be evaluated by considering these results and possible resonance risk can be investigated for building resonant frequency in these residential districts in the next. Thus, this type of application and evaluation of microtremor data may provide primary and useful information for other geophysical, geological and geotechnical studies such as planning the seismic resistant infrastructure, detecting the small-scale seismic risks and making a suitable and reliable seismic hazard microzonation in Gümüşhane. Copyright 2021, Yıldız Technical University.

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  İncele
• MakaleYayıncıda açık erişim2019/r/gumushane/15248
  An experimental study on the compressive response of CFRP honeycombs with various cell configurations

  Pehlivan, Levent; Baykasoğlu, Cengiz

  The experimental investigation on the compressive response of carbon fiber reinforced polymer (CFRP) honeycombs with various cell configurations was carried out in the present work. The CFRP honeycomb specimens were manufactured by corrugation technique, in which the prepreg CFRP sheets were first corrugated into the certain shape using corrugated aluminum moulds under heat and pressure, and then the corrugated CFRP sheets were glued and stacked to construct honeycomb specimens. Twenty-seven groups of specimens were experimentally tested to examine the effects of cell geometry (i.e., square, circular, and hexagonal), cell wall thickness and height on the quasi-static out-of-plane crushing performance of the honeycombs. The square, circular, and hexagonal honeycomb specimen groups were designed to have almost the same weights. The results showed that the cell wall thickness is an significant parameters on the overal crushing response of the CFRP honeycombs while the out-of-plane compressive strenght of the honeycombs is generally independent of the height. It is observed that the hexagonal specimen groups have generally superior crushing performance in comparison with the square and circular counterparts due to their large double foil bonding surfaces. The experimental results also revealed that the crushing properties of the honeycomb structures with the core densities of 157–282 kg/m 3 could be increased more than two times with the appropriate selection of cell configurations.

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