Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Havacılık ve Uzay Mühendisliği Bölümü, Türkiye
Tezin Onay Tarihi: 2012
Öğrenci: MERT ATASOY
Danışman: ALTAN KAYRAN
Özet:Analysis of aircraft structures are mainly performed by assuming that the structure behaves linearly. In linear finite element analysis, it is assumed that deformations are small, thus geometric nonlinearity can be neglected. In addition, linear analysis assumes that linear constitutive laws applicable, implying that material nonlinearity can also be neglected. One very common type of nonlinearity is associated with the boundary conditions. Contact between two deformable bodies or between a deformable and rigid body are typical examples of nonlinearity associated with boundary conditions. Linear structural analysis, in general, does not include contact analysis. Simplicity of linear analysis in terms modeling, interpreting the results and solution time makes the linear analysis approach very convenient in preliminary design and analysis stage of aircraft structures. However, simplicity of linear analysis may result in unconservative results which may occur due to neglecting the true nonlinear behavior of the structure. In this thesis, one such nonlinear e ect called prying load e ect on the tensile connections is studied. The e ect of prying load on structures are initially described by referencing the analytical approaches presented in the literature. Finite element models of typical bolted connections such as L and T type are generated for various combinations of the chosen design parameters such as bolt diameter, flange thickness, washer diameter and edge distances. Parametric modeling approach is used to perform the high number of finite element analysis which involve contact for the purpose of calculating the prying load. Comparative study of the e ect of prying load is then conducted by also including the results presented in the literature. Comparisons of the prying load are done with the experimental results presented in the literature. Series of finite element analyses are preformed for various cases such that e ect of geometrical variables and bolt preload on prying ratio can be understood. According to the results obtained, it is concluded that main factors e ecting the prying ratio are the distance of bolt center to the clip web, flange thickness of the clip and preload on the bolt where the e ect of edge distance of the bolt is insignificant.