Yazar "Dağhan, Behçet" seçeneğine göre listele

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    Bifleks dişli zincir baklalarında elasto-plastik gerilme analizi
    (Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 1994-07-01) Dağhan, Behçet; Avcı, Ahmet
    Zincirler genellikle değişken yük altında, titreşimli ve darbeli olarak çalışırlar. Zincirlerin en zayıf elemanları baklalar ve rulolardır. Baklaların, kesit değişim bölgelerindeki kritik noktalarda gerilme yığılmaları ve bu yüzden bu bölgelerde plastik deformasyonlar ve çatlamalar olmaktadır. Böylece zincirlerin yorulma ömürleri kısalmaktadır. Dolayısıyla baklalardaki gerilme dağılımı bulunmalı ve kritik noktalar tespit edilmelidir. Bu çalışmada bifleks dişli zincir baklalarında gerilme analizi yapılarak kritik bölgeler tespit edilmiş ve gerilme dağılımları incelenmiştir. Bir zincir sisteminin ömrünün artırılabilmesi ve daha büyük yükleri taşıyabilmesi için çalışma yüklerine zıt yönde kalıcı gerilmeler oluşturulmuştur. Bu amaçla elasto-plastik genime analizi yapılmıştır. Problemin çözümü için sonlu elemanlar metodu kullanılarak bir bilgisayar programı geüştirilmiştir. Bu program ile gerek elastik bölgedeki, gerekse plastik bölgedeki gerilmeleri hesaplamak mümkündür. Plastik bölgedeki gerilmeleri bulurken von Mises akma kriteri kullanılmıştır. Sonuçlar tablo ve grafikler halinde verilmiştir. Ayrıca epoksi malzemeden zincir baklası numunesi hazırlanarak, fotoelastik metotla deneysel olarak gerilme dağılımı incelenerek, teorik sonuçlarla karşılaştuılrnıştır.
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    Elastic-Plastic Stress Analysis of Composite Beams Loaded by Bending Moment
    (Sage Publications Ltd, 2002) Sayman, Onur; Uyaner, Mesut; Dağhan, Behçet
    An elastic-plastic stress analysis is carried out in a thermoplastic composite cantilever beam loaded by a bending moment at the free end. The orientation angle is chosen as 0degrees, 15degrees, 30degrees and 45degrees. An analytical solution is performed for satisfying both the governing differential equation in the plane stress case and boundary conditions for small plastic deformations. The solution is carried out under the assumption of the Bernoulli-Navier hypotheses. It is found that the intensity of the residual stress component sigma(x) is maximum at the upper and lower surfaces. The beam material is assumed to be strain-hardening. The Tsai-Hill theory is used as a yield criterion. The displacement components are found in the elastic region.
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    Elastic-Plastic Stress Analysis of Thermoplastic Composite Beams Under Temperature Distributed Linearly
    (Sage Publications Ltd, 2002) Sayman, Onur; Karakuzu, Ramazan; Dağhan, Behçet; Koçak, Saim
    In this study, an elastic-plastic thermal stress analysis is carried out on a thermoplastic composite beam. Temperature is chosen to vary linearly along the sections of the beam. The beam is made of steel fibre thermoplastic matrix composite. It is fixed by two rigid planes at the ends. The solution is performed for 0degrees, 45degrees, 60degrees and 90degrees orientation angles. The orientation angle of 30degrees does not give any plastic yielding, for it melts before plastic yielding. The intensity of the residual stress component of sigma(x) is maximum at the upper and lower surfaces of the beam and is obtained to be the greatest for the orientation angle of 0degrees. The equivalent plastic strain is found to be the greatest for 0degrees and 60degrees orientation angles. Plastic yielding begins on the beam at the highest temperature for 45degrees orientation angle.
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    Fatigue behavior of surface-notched composite pipes repaired by composite patches
    (SAGE PUBLICATIONS LTD, 2013) Günaydın, Berrin; Dağhan, Behçet; Avcı, Ahmet
    This study investigated the effects of composite repair patches and number of patch layers on the fatigue behavior of surface-notched composite pipes. The pipes were repaired using glass/epoxy composite patches of two to seven layers. Failure modes were examined and S-N curves were plotted. Fatigue tests showed that the fatigue life of the repaired pipes was improved by increasing the number of patch layers. The seven-layer composite patch was most effective in preventing fatigue failure and increasing the fatigue life of the surface-notched pipes.
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    Fatigue Behaviour of Surface-Cracked Glass/Polyester Composite Plates
    (2012) Günaydın Akkuş, Berrin; Dağhan, Behçet; Önal, Gürol
    This paper reports on the fatigue behaviour of surface–cracked glass/polyester composite plates. The machined cracks have various aspect ratios (a/c) and depth ratios (a/t). The propagation behaviour of surface cracks and delamination are investigated under constant-amplitude (R ¼ 0) loading. The stress intensity factor, KI , is obtained using Newman–Raju and Paris and Sih equations, while Kdel is determined using equations given by Suo and Hutchinson and Bao et al. The results were plotted as curves of the typical relationship between the crack growth rate (dc/dN) and the stress intensity factor range (KI) and the delamination propagation rate (db/dN) and the delamination stress intensity factor range (Kdel). Material constants A and n were obtained according to the Paris–Erdoğan equation.