Uncertainties in the thermal fatigue assessment of pipes under turbulent fluid mixing using an improved spectral loading approach

The results of the proposed method are less conservative than results of similar methods in the literature. This is expected, since the proposed method accounts for a much wider variability and more physical description of the fluid temperatures. Further, the reduction in the conservatism is effectively compensated through the ability to assess the uncertainties inherent in the calculations of fatigue life time. The proposed assessment could be straightforwardly extended to other fatigue design rules and, with the use of finite elements, to possibly nonlinear behavior and discontinuous shapes of the pipes. In this way the proposed improved thermal fatigue assessment of pipes could facilitate further development of currently very scarce and simple design rules for thermal fatigue.