Thermo-mechanical cyclic loading analysis of pipes with different type of defects: Temperature dependent properties

Shakedown and ratcheting behaviors of pipes under thermo-mechanical loading have an important role in their design. In this study, Plastic, Elastic shakedown and ratcheting limit of the pipelines with different types of defects were analyzed. The pipelines were subjected to the constant internal pressure and the cyclic thermal gradient. Different dimensions of these defects were also studied. Nonlinear kinematic hardening model of Armstrong-Frederick coupled with continuum damage mechanics was used and material properties were considered temperature-dependent. The unified Lemaitre's model was used in continuum damage mechanics. Interaction diagrams (Bree's diagram) of the defective pipelines were obtained and parametric studies involving different types and dimensions of part-through slot in the defective pipeline were investigated. Continuum Damage Mechanics was used to predict life time of some defected pipelines.