Elastic-plastic solutions of a long tube subjected to a temperature cycle

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Mühendislik Bilimleri Bölümü, Türkiye

Tezin Onay Tarihi: 2014

Öğrenci: YASEMİN KAYA

Danışman: AHMET NEDİM ERASLAN

Özet:

In many engineering applications, cylindrical structures are often subjected to various temperature fluctuations. When the temperature gradient is high enough, the thermal stresses build up in the structure and these stresses may cause the permanent deformation of the body. Therefore, determination and detailed understanding of the thermoelastoplastic stresses in the cylindrical elements are an important issue of engineering design to predict the failures and improve the safety and reliability of the products. To that end, in this thesis, an uncoupled thermo-elastoplastic problem of a long tube subjected to a temperature cycle from its inner surface is solved. The stress boundary conditions treated are those of stress-free at the inner wall while the outer wall is rigidly constrained. It is presumed that the tube is in a state of generalized plane strain and obeys Tresca’s yield criterion and its associated flow rule. After the temperature cycle is applied, the tube experienced three stages; purely elastic, elastic-plastic and finally unloading stage. The analytical formulation of these stages are obtained and the corresponding time-dependent stress, strain and displacement distributions are plotted during the temperature cycle. The formulation of the problem and the subsequent solutions are cast in general terms and the results may be adapted to a variety of specific applications. In this context, the present research study will make a theoretical contribution to the literature by giving analytical solution to the problem of thermo-elastoplastic thick-walled tube subjected to temperature cycle.