WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
Browse
2 results
Search Results
Article Modal Characteristics of Fly Ash-Based Geopolymer Reinforced Concrete Columns under Dynamic Impact Loads(Techno-Press, 2026) Kucukgoncu, HurmetGeopolymer concrete (GPC) stands out as an environmentally friendly, sustainable structural material with superior mechanical and thermal properties, as an alternative to ordinary Portland cement (OPC) concrete. Due to this, investigating the dynamic properties of GPC materials is particularly crucial for structures subjected to vibration loads such as earthquakes. Therefore, eight heat-cured class F fly ash-based GPC and two OPC column specimens were subjected to modal tests using the Experimental Modal Analysis (EMA) method. Thus, the modal characteristics of columns produced from GPC were investigated and compared regarding reinforcement ratio, alkali activator ratio, and curing method. Furthermore, the dynamic properties of GPC and OPC columns were also compared. Additionally, the relationship between these columns' resonance frequencies, damping ratios, mode shapes, and mechanical properties was evaluated. The results show that although the resonance frequencies of OPC columns are 8.19% higher than those of GPC columns, their damping ratios are 13.01% lower. For GPC columns, the alkali activator ratio and curing method had a greater impact on the modal characteristics of the column samples than the reinforcement ratio. Besides, the relationship between strength and resonance frequency was closely related. In contrast, the damping ratio was closely related to the static modulus of elasticity and rigidity values. In particular, it was concluded that GPC columns had higher energy dissipation capacities, which was an important design parameter, under dynamic loads due to the high damping ratio.Article Axial Free Vibration Analysis of a Tapered Nanorod Using Adomian Decomposition Method(Techno-Press, 2025) Coskun, Safa B.; Kara, Ozge; Atay, Mehmet T.; Coçkun, Safa B.This study aimed to conduct an analysis of the axial free vibration of tapered nanorods based on nonlocal elasticity theory. The small-scale effect on the free axial vibration of a tapered nanorod was studied employing the Adomian decomposition method (ADM) and the finite difference method (FDM) as a checking tool where a contradiction existed between the results of this study and available results in one highly cited work in the literature, which was used for comparison purposes in this work. Different boundary conditions for the nanorod were considered: fixed-fixed nanorod, fixed-free nanorod, and fixed-linear spring nanorod. The governing equation of the problem is a variable coefficient differential equation for which analytical solutions are strictly limited. For this type of problem, analytical approximate methods are effective, and there are many studies available in the literature on the application of these methods to solve linear/nonlinear ordinary/partial differential equations. ADM is one of the methods and was successfully used in this study to analyze the free vibration of nanorods. The results obtained in this study have shown that the presented technique is so powerful and has potential for applications in nanomechanics based on nonlocal elasticity theory.