Akademik Veri Yönetim Sistemi
Tezin Türü: Doktora
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Makina Mühendisliği Bölümü, Türkiye
Tezin Onay Tarihi: 2018
Öğrenci: MEHMET NURULLAH BALCI
Danışman: SERKAN DAĞ
Özet:The main aim of this study is to analyze the dynamic frictional contact problem of layered and functionally graded materials. Investigating contact problems including dynamic effects has a significant importance in mechanical engineering applications since many contact problems arise between moving structures. In moving contact problems, speed of the punch may not be so small to ignore dynamic effects. Hence, contact problem should be examined using elastodynamics theory. In this study, both frictional moving contact problems of homogenous elastic coatings and functionally graded coatings pressed by a moving rigid punch with various punch profiles are considered. The rigid punch is pressed against the coating and it moves at a constant subsonic speed. Governing partial differential equations are solved analytically using Galilean and Fourier transformation techniques. Displacement fields in both coating and the substrate are found by applying boundary and interface continuity conditions. Equations for the mixed boundary value problem is reduced to a singular integral equation of the second kind including unknown normal contact stress. The singular integral equation is solved numerically using a suitable expansion-collocation technique and normal contact stress is found. A verification study for elastostatic contact analysis is carried out using computational results generated by the use of finite element method. A verification study for elastodynamic contact analysis is conducted by utilizing available results in the literature. Consequently, the influences of punch profile, punch sliding speed, material inhomogeneity, coefficient of friction and coating thickness on contact stresses and punch stress intensity factors are investigated.