Effect of Thinning on Fatigue Life Estimation of Elbows under In-Plane Cyclic Bending Moment

The safety of the piping systems used in any nuclear or thermal power plant is essential to the environment and also to the people involved. Pipe bends are one of the critical components of the piping system. Hence, fatigue life estimation becomes primary focus when the designing pipe bends for their safety limits. The current study uses finite element analysis and the revised manson universal slope method to estimate the life of elbows under in-plane opening and closing cyclic bending moment. The estimated fatigue life was compared with low-cycle fatigue tests in the literature. The displacement of 20 mm was given as input to estimate the number of cycles. The principal stresses were obtained on the highly strained node of the finite element model to locate the crack and its direction accurately. The elbows with thinning have a reduction in the fatigue life of about 19%.