Civil Engineering / İnşaat Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/13

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  • Book Part
    Citation - Scopus: 4
    Application of Fuzzy Logic in Water Resources Engineering
    (Elsevier, 2022) Tayfur, Gökmen
    This chapter introduces the fundamentals of fuzzy logic (FL), fuzzy sets, and fuzzy model components such as the fuzzification, the fuzzy rule base, the fuzzy inference engine, and the defuzzification. The processes of the fuzzy model components are presented by working on the examples from the water resources engineering application problems. This chapter also discusses the merits and the shortcomings of the fuzzy modeling. Hydrological processes have inherent source of uncertainty, for which the fuzzy set theory can be an effective solution tool. © 2023 Elsevier Inc. All rights reserved.
  • Book Part
    Citation - Scopus: 1
    Developments in Sediment Transport Modeling in Alluvial Channels
    (Elsevier, 2022) Tayfur, Gökmen
    This chapter discusses the developments in the mathematical modeling of sediment transport dynamics in alluvial channels. Starting with early experimental and empirical studies, it goes on to treating the processes in 1D, 2D, and 3D uniform sediment transport. Finally, it describes the treatment of the processes in 3D nonuniform sediment transport considering turbulence effects. While introducing the advancements in mathematical modeling of the dynamics, the chapter also discusses the outstanding issues like the treatment of the particle fall velocity, the particle velocity, and sediment transport rate function. © 2023 Elsevier Inc. All rights reserved.
  • Book Part
    Citation - Scopus: 3
    Real-Time Flood Hydrograph Predictions Using Rating Curve and Soft Computing Methods (ga, Ann)
    (Elsevier, 2022) Tayfur, Gökmen
    This chapter introduces hydraulic and hydrologic flood routing methods in natural channels. It details hydrological flood routing methods of the Rating Curve and Muskingum. Based on the rating curve method (RCM), it presents real-time flood hydrograph predictions using the genetic algorithm (GA-based RCM) model. In addition, it presents how to make real-time flood hydrograph predictions using the artificial neural network (ANN). The chapter briefly introduces the basics of GA and details how to calibrate and validate the GA-based RCM model using measured real-time flood hydrographs. Similarly, after giving the basics of ANN, it shows how to train and test the ANN model using measured hydrographs. Real hydrograph simulations by the RCM, GA-based RCM, and ANN are presented, and merits of each model are discussed. © 2023 Elsevier Inc. All rights reserved.
  • Conference Object
    Citation - WoS: 2
    Citation - Scopus: 2
    A Case Study on the Selection of Optimum Loop Units for the Deployable Arch Structures Exposed To Lateral and Non-Uniform Gravity Loads
    (Elsevier, 2020) Yuceturk, K.; Aktas, E.; Maden, F.; Gur, S.; Mitropoulou, C. C.
    Radially deployable arches may be created by using various types of units. However, for any deployable structure to be constructed in real life, it should satisfy the structural regulations and codes. Despite various advantages from architectural perspective, deployable structures are weak to satisfy the operational code limits when compared to trusses with similar height and span. Therefore, weight minimization is very important to reduce the dead loads of the structure which facilitates the code-conformance of the structure. The optimization of the deployable structures requires an initial selection of the loop types to define the structure parametrically. An initial selection strategy depending on the loads on the structure is important to increase the efficiency of optimization process. Under uniform gravity loads, optimum arrangement for each unit type converges to a similar point. However, in the real world, the loads on the arches are not always uniform and the structure is exposed to nonuniform loadings such as point loads or lateral loads. This work focuses on the performance of various arches with different unit types under lateral and non-uniform vertical loads. Different lateral load and non-uniform gravity loading scenarios are created. For each scenario, the arches with different units are analyzed. In all cases, clear span and height are kept as same. The performance of an arch with a specific unit type for a given load is measured with a score that includes the deformations and the weight of the structure. All the members are assumed to be circular hollow sections with variable diameter and thickness to have a meaningful weight comparison between structures. This work intends to define an initial selection guide for deployable arches under typical non-uniform and lateral loading conditions. (C) 2020 The Authors. Published by Elsevier B.V.
  • Conference Object
    Citation - WoS: 2
    Citation - Scopus: 3
    Micromechanical Modeling of Inter-Granular Localization, Damage and Fracture
    (Elsevier, 2018) Yalçınkaya, Tuncay; Özdemir, İzzet; Fırat, Ali Osman; Tandoğan, İzzet Tarık
    The recent developments in the production of miniaturized devices increases the demand on micro-components where the thickness ranges from tens to hundreds of microns. Various challenges, such as size effect and stress concentrations at the grain boundaries, arise due to the deformation heterogeneity observed at grain scale. Various metallic alloys, e.g. aluminum, exhibit substantial localization and stress concentration at the grain boundaries. In this regard, inter-granular damage evolution, crack initiation and propagation becomes an important failure mechanism at this length scale. Crystal plasticity approach captures intrinsically the heterogeneity developing due to grain orientation mismatch. However, the commonly used local versions do not possess a specific GB model and leads to jumps at the boundaries. Therefore, a more physical treatment of grain boundaries is needed. For this purpose, in this work, the Gurtin GB model (Gurtin (2008)) is incorporated into a strain gradient crystal plasticity framework (Yalcinkaya et al. (2011), Yalcinkaya et al. (2012), Yalcinkaya (2017)), where the intensity of the localization and stress concentration could be modelled considering the effect of grain boundary orientation, the mismatch and the strength of the GB. A zero thickness 12-node interface element for the integration of the grain boundary contribution and a 10-node coupled finite element for the bulk response are developed and implemented in Abaqus software as user element subroutines. 3D grain microstructure is created through Voronoi tessellation and the interface elements are automatically inserted between grains. After obtaining the localization, the mechanical behavior of the GB is modelled through incorporation of a potential based cohesive zone model (see Park et al. (2009), Cerrone et al. (2014)). The numerical examples present the performance of the developed tool for the intrinsic localization, crack initiation and propagation in micron-sized specimens. (C) 2018 The Authors. Published by Elsevier B.V.