Impact Fatigue Life Assessment of Steam Pipeline Based on Transient Analysis

Fatigue life of high energy steam pipelines under shock loads is estimated based on static load, modal and transient response analysis. The time domain stress curve of pipelines under shock is obtained as the stress spectrum input for pipeline fatigue life prediction. The nCode fatigue analysis software is employed in the study cooperated with the impact fatigue damage model. The results show that the pipeline will experience multiple stress cycles under one impact load, and the maximum stress value exceeds 11% of the yield limit of the material. The impact fatigue life of the pipeline under transverse impact is 1.16×10
⁵
times. The maximum stress response of the pipe occurs after the forward triangular wave of the impact input and within the reverse triangular wave. The fixed end, elbow and tee of the pipeline are the stress concentration areas of the steam pipelines with the fatigue life of about 4×10
⁴
times.