Acoustic Vibration Induced Fatigue in Welded Pipe Supports

High acoustic energy has the potential to cause vibration induced fatigue in a piping system at integral attachments such as welded pipe supports. Although recognized as a potential failure location, there is no established design curve and fatigue life equation among industry guidelines. In this paper, acoustic induced vibration (AIV) at welded supports is evaluated using Finite Element Analysis. Peak stress and the associated minimum fatigue life is calculated for various types of welded supports under the same acoustic excitation. By comparing the stress level to that of a branch connection, for which design limit for AIV have been published, the design limit and fatigue life equation for welded pipe supports is developed. The use of partial reinforcement pad to mitigate AIV risk is also discussed.