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1.1 WHAT IS PIPING VIBRATION?
Piping vibration is simply the movement of pipe away from its static, at-rest position. Some vibration can be seen by the naked eye, some vibration can be felt or heard, and some vibration occurs only occasionally under certain operating conditions, and may not be recognized until a piping failure has occurred.
Piping vibration is simply the movement of pipe away from its static, at-rest position. Some vibration can be seen by the naked eye, some vibration can be felt or heard, and some vibration occurs only occasionally under certain operating conditions, and may not be recognized until a piping failure has occurred.
1.2 WHY SHOULD I CARE ABOUT PIPING VIBRATION?
21% of hydrocarbon releases are due to vibration-induced fatigue failures (UK Health & Safety Executive). These releases can have a significant impact on public and employee safety, the environment, production and financial performance.
The piping system is by far the leading source of failures in facilities (Marsh & McLennan). This is in part due to the sheer quantity of piping in facilities, but also due to inadequacies in integrity programs to consider vibration and fatigue. The situation is compounded by the fact that commonly used design codes do not consider vibration in detail.
Overall, only a small portion of piping is of high risk of failure, but identifying those high-risk locations is the challenge. Piping vibration risks can be identified at any stage of the asset lifecycle, but few companies have a systematic approach to evaluating these risks.
21% of hydrocarbon releases are due to vibration-induced fatigue failures (UK Health & Safety Executive). These releases can have a significant impact on public and employee safety, the environment, production and financial performance.
The piping system is by far the leading source of failures in facilities (Marsh & McLennan). This is in part due to the sheer quantity of piping in facilities, but also due to inadequacies in integrity programs to consider vibration and fatigue. The situation is compounded by the fact that commonly used design codes do not consider vibration in detail.
Overall, only a small portion of piping is of high risk of failure, but identifying those high-risk locations is the challenge. Piping vibration risks can be identified at any stage of the asset lifecycle, but few companies have a systematic approach to evaluating these risks.
1.3 WHAT PIPING IS MOST AT RISK?
Around 80% of vibration-induced failures are associated with small-bore connections (SBCs). This is due to several reasons:
Stress concentrations at the weld to the main pipe or vesselLarge unsupported valvesLack of evaluation of vibration and fatigue risk, beyond a reactive approach after a failureDisconnects between the SBC design intent and site fabrication, particularly regarding local support/bracing
The remaining 20% are generally associated with parent pipe girth weld failure.
Around 80% of vibration-induced failures are associated with small-bore connections (SBCs). This is due to several reasons:
Stress concentrations at the weld to the main pipe or vesselLarge unsupported valvesLack of evaluation of vibration and fatigue risk, beyond a reactive approach after a failureDisconnects between the SBC design intent and site fabrication, particularly regarding local support/bracing
The remaining 20% are generally associated with parent pipe girth weld failure.
🔼⬆️ Small-bore connections are high-risk locations for piping vibration
1.4 WHERE DOES PIPING VIBRATION COME FROM?
Two main factors affect vibration: the strength of the excitation and the flexibility of the piping system. Therefore, there are always two methods to solve piping vibration problems: reduce the level of excitation to which the piping system is exposed or support the piping systemso that it can withstand the applied dynamic forces.
The excitation mechanisms that cause vibration originate from three main sources:
Acoustic/pulsation – time-varying changes in fluid pressure
Momentum – time-varying changes in fluid density and velocity
Machinery – unbalanced forces from operating machinery.
Two main factors affect vibration: the strength of the excitation and the flexibility of the piping system. Therefore, there are always two methods to solve piping vibration problems: reduce the level of excitation to which the piping system is exposed or support the piping systemso that it can withstand the applied dynamic forces.
The excitation mechanisms that cause vibration originate from three main sources:
Acoustic/pulsation – time-varying changes in fluid pressure
Momentum – time-varying changes in fluid density and velocity
Machinery – unbalanced forces from operating machinery.
ANSYS Workbench Tutorial - Pipe Stress Analysis - Beam Modeling ⬇️⬇️