Investigation of Slugging

Vibrations was observed on an installation and an analysis was performed to determine the likelihood of fatigue failure. Team Stressman was sent measurements and video. The motion was due to slugging in the pipe. Based on this input we investigated dynamical stresses. These stresses were checked against DNVGL-RP-0005 fatigue curves, design life factors and stress concentration factors. 

The result showed that 85% of the fatigue life was used. This gave a shorter life span than what was less than the desired one. Two solutions were proposed. The first was to clamp the pipe near the motion. The second option was to reduce the flow since this had shown a great reduction of the vibrations.