Comparison of finite element method and applied element method used in structural engineering mechanics
Tez Türü: Doktora
Tezin Yürütüldüğü Kurum: Çukurova Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği, Türkiye
Tez Danışmanı: Prof. H. Murat Arslan
Tezin Onay Tarihi: 2023
Tezin Dili: İngilizce
Desteklendiği Program: Diğer
Özet:
| This study aims to compare the effectiveness of two different engineering methods, the Finite Element Method (FEM) and the relatively new Applied Element Method (AEM), in analyzing progressive collapse of reinforced concrete (RC) structures. Specifically, a five-span five-bay RC structure model was created and analyzed using SAP2000 and ELS programs. The study investigates the effect of different slab thicknesses and types on the progressive collapse process, as well as the impact of varying damping ratios. In total, 54 scenarios were created, consisting of 2 distinct engineering methods, 6 different slab models, 3 varying slab thicknesses, and 3 different damping ratios. For each analysis, a three-stage column pull was executed at 3-second time intervals. The displacement values of the corner column after removing three columns were compared in both programs. In SAP2000, five different slab types were analyzed, while the ELS program used cube- or cuboid-shaped elements connected by springs in three directions. A "thin structure correction factor" was applied to each slab piece in the ELS program to consider both shear and flexure behavior inside the elements. AEM allows particles to separate from each other, while FEM uses linear elements and is associated with the distributed plasticity concept (fiber hinges). The findings of the study were presented in graphical form, comparing the performance of FEM and AEM. The results indicate that the AEM model is more rigid, with models damped within a short period of time (around 0-1 seconds), while the FEM-based models took almost 2-3 seconds to damp. Due to its rigidity, the ELS model provides results closer to the SAP2000 shell-layered model. Increasing the slab thickness has a greater impact on the rigidity of the SAP2000 model, providing and contributing more to its resilience. Conversely, in the AEM-based solid model, an increase in deck weight leads to more displacement. Overall, the study demonstrates that both methods are suitable for progressive collapse analysis, with the AEM method being a useful alternative to FEM, especially in cases where the structures are highly rigid or there are many element removal from the structure in terms of computational time. The results of this study provide valuable insights into the application of AEM in structural engineering, which may help to improve the design and safety of RC structures in the future. |