Yazar "Dere, Yunus" seçeneğine göre listele

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  • Küçük Resim Yok
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    Domain-by-domain algorithm for nonlinear finite-element analysis of structures
    (ASCE-AMER SOC CIVIL ENGINEERS, 2008) Dere, Yunus; Sotelino, Elisa D.
    Parallel and distributed computers have been shown to provide the necessary computational power to solve large-scale engineering problems. However, in order for this computation style to be effectively used, efficient computational algorithms must be devised. In this work, a domain-by-domain algorithm is developed for the parallel solution of nonlinear structural dynamics problems. In the proposed algorithm, the original structure is partitioned into a number of subdomains. Each subdomain is solved independently and, therefore, concurrently using a traditional direct-solution method. Finally, the solution for the interface degrees of freedom between neighboring subdomains is obtained by enforcing compatibility and equilibrium using an iterative procedure. The nonlinear version of the algorithm involves two iterations: The nonlinear dynamic equilibrium iteration and the interface equilibrium and compatibility iteration. The integration of these two iterations is investigated and two strategies are developed. It is found that the strategy in which the two iterations are isolated is the most efficient. As a demonstration, the fully nonlinear transient analysis of a 20-story model building is carried out. Excellent accuracy in the solution and significant speed up values are obtained.
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    Failure Prediction of Skewed Jointed Plain Concrete Pavements Using 3D FE Analysis
    (Pergamon-Elsevier Science Ltd, 2006) Dere, Yunus; Asgari, Alireza; Sotelino, Elisa D.; Archer, Graham C.
    A section of skewed jointed plain concrete pavements (JPCPs) that was constructed in the northern part of Indiana failed with premature transverse cracks. The cracks were observed within 3-4 years of construction. This research was performed to determine if the failure of the skewed JPCPs could have been predicted using a 3D finite element (FE) analysis. A representative 3D FE model was developed and analyzed using three different subgrade materials under traffic and nonlinear thermal loads. The dowel bars and aggregate interlock action were modelled at the skewed joints between adjacent concrete slabs. The effects of linear and nonlinear temperature gradients were compared with regard to the predicted failure of the pavements. The finite element analysis predicted not only the failure of the pavement, but also the correct orientation of the cracks.
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    STRENGTHENING AND SEISMIC PERFORMANCE IMPROVEMENT OF THE BUILDING OF CHAMBER OF ARCHITECTS IN AKSARAY (HISTORICAL IBRAHIM AGA MANSION)
    (INT SCIENTIFIC CONFERENCE SGEM, 2009) Sezer, Rifat; Yildiz, Mustafa; Dulgerler, O. Nuri; Kara, Nail; Dere, Yunus
    The historical Ibrahim Aga Mansion purchased by the Chamber of Architects of Aksaray and wished to be used as the service building for the chamber. In this study, the strengthening project before the restoration of the building was prepared. The building had no foundations under the stone walls and suffered from cracks and decaying of the wooden floors. Since the existing structural system did not allow restoration of the building, strengthening and redesign of the structural system was the main priority. In the retrofit project prepared, the exterior of the building is totally preserved, and the interior which had low load-carrying capacity and functionality is redesigned for more functionality and a new structural system made of reinforced concrete and steel members was proposed. The foundations were combined into a raft foundation, the basement walls were changed into shear walls, basement and ground floors designed as a reinforced concrete whereas the roof columns, beams and floors were designed as a steel system. The exterior walls and the interior structural system were anchored together in order to prevent possible settlements and deformations that may occur in the future. The prepared strengthening project has been put into practice and the construction work is still undergoing.
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    USE OF DIFFERENT SHAPED STEEL SLIT DAMPERS IN BEAM TO COLUMN CONNECTIONS OF STEEL FRAMES UNDER CYCLING LOADING
    (HONG KONG INST STEEL CONSTRUCTION, 2018) Koroglu, Mehmet Alpaslan; Koken, Ali; Dere, Yunus
    Following the Northridge and Kobe earthquakes, extensive research was conducted on the use of various materials and systems that will absorb the earthquake effects within the structure itself in order to improve the behavior of the steel structures under seismic effects. In this study, the use of seismic dampers at beam-column joints of steel-framed structures to prevent damage to the structural members by absorbing the energy of the lateral loads was investigated. Thus, it will be possible for the steel-framed structures to be put into service right after a damaging earthquake by only replacing the dampers attached to the joints as no damage will occur to the beams and columns. For this purpose, as a first step, dampers with ductile behavior were chosen through preliminary tests. Consistent with the results of the preliminary tests, a total of six full-scale corner beam-column joint test specimens were produced. Five specimens were attached various types of dampers m different sizes and one reference specimen was designed with regular end-plate connection. After the evaluation of the test results, valuable data on the load carrying and energy consumption capacities, stiffness characteristics and the general behavior of the specimens were obtained. In the analytical part of the study, analyses of the selected specimens were performed through ANSYS finite elements software package. The analytical and experimental results were compared and have been found very consistent with each other.
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    Yirmi katlı çelik bir bina çerçevesinin MIGI paralel işlem algoritması ile lineer olmayan dinamik analizi
    (Selçuk Üniversitesi Mühendislik-Mimarlık Fakültesi, 2004) Dere, Yunus
    Bu çalõşmada ilgili yönetmeliklere uygun olarak tasarlanmõş 20 katlõ çelik bir bina çerçevesinin lineer olmayan dinamik analizi paralel işlem yoluyla gerçekleştirilmiştir. Dinamik analiz için, Northridge depremi sõrasõnda Newhall istasyonunda ölçülmüş deprem ivmesi kayõtlarõnõn Doğu-Batõ bileşeni dikkate alõnmõştõr. Paralel işlem yöntemi olarak MIGI (Modified Iterative Group Implicit - Değiştirilmiş Döngülü Örtük Grup) algoritmasõ kullanõlmõştõr. İkinci derece etkiler (P-? etkisi) yanõnda malzemenin lineer olmayan davranõşõ da dikkate alõnmõştõr. Bina çerçevesi bir otomatik ayrõştõrõcõ kullanõlarak 2, 3, 4, 5 ve 6 farklõ çözüm bölgelerine ayrõlmõş ve analizler IBM SP süper bilgisayarõnda ve bir SUN iş istasyonlarõ ağõnda gerçekleştirilmiştir. Sayõsal sonuçlarõn incelenmesinden, MIGI algoritmasõnõn doğru sonuçlar verdiği, bunun yanõnda, birden fazla işlemci kullanõmõna izin vererek analiz performansõnõ önemli derecede artõrdõğõ görülmektedir. Ayrõca, işlemci sayõsõ arttõkça analizler çok daha kõsa sürede tamamlanabilmektedir.