Abstract
Fatigue cracks can be initiated at tee junction where fluids of different temperature flow in. In order to prevent the crack initiation, JSME issued the guideline for evaluating pipe system. In the guideline, the fatigue damage is estimated according to linear damage accumulation law, which is usually applied for low-cycle fatigue. In this study, problems to be solved were discussed to validate thennal stress and the fatigue damage assessment procedure of the JSIVIE guideline. Based on the analytical results for the thermal striping at a tee junction, the cyclic load was characterized. Then, loading patterns for simulating the fatigue damage were proposed. Possibility of introducing the crack growth analysis in the fatigue damage assessment was also discussed.