Acoustic Induced Vibration

Acoustic Induced Vibration (AIV), Acoustic Fatigue

INERTANCE has performed Acoustic induced vibration (AIV) for piping system, and has provided the best solution to prevent the likelihood of acoustic fatigue failure caused by acoustic excitation as per Energy institute guidelines.

O-let Design for Acoustic induced vibration
O-let Design for Acoustic induced vibration

INERTANCE has a capability to perform below kinds of acoustic induced vibration analysis.

  • Acoustically induced vibration (AIV)
  • Acoustic fatigue in pipes
  • High frequency acoustic excitation source
  • Sound power level (PWL)
  • Small bore connection analysis
  • Pressure let-down device (Control valve, pressure relief valve, pressure safety valve, orifice, etc)
  • As per API 521, Concawe report no, 85/82
  • Pipe geometry parameter
  • Pipe energy parameter (Mach number)
  • Noise calculation as per IEC
  • Likelihood of failure assessment
  • Acoustic induced vibration control measures
  • Fitting type: Weldolet, sweepolet, equal tee, reduced tee, nipolet, latrolet, etc
  • Gusset support, reinforced pad, etc
  • Energy institute guideline, Guidelines for the avoidance of vibration induced fatigue failure in process pipework, 2nd edition
  • Detail FEA assessment
AIV Fatigue Assessment
AIV Fatigue Assessment
Assessment as per Energy Institute Guidelines

Pressure reducing system such as control valve and pressure safety valve in piping system is subject to rapidly decreasing pressure by flow restriction, which create the high velocity fluid, turbulent mixing and may cause the acoustic energy. The sound power levels are calculated as per process condition, and it is key parameters in problem concerning acoustically induced vibration.

Sound power level as per Energy Institute guidelines
Sound power level as per Energy Institute guidelines
Pipe Geometry for Acoustic Fatigue Control

Pipe diameter and thickness has to be checked in order to screen the potential fatigue failure caused by acoustic induced vibration, as the fatigue failure is more prevalent with thin wall and large diameter pipe. The acoustic energy generated from pressure let-down device is propagated to downstream piping system, and the fitting type and branch size have to be evaluated on the piping discontinuities location.

O-let type for Acoustic fatigue control
O-let type for Acoustic fatigue control

* Kinds of fitting type for acoustic induced vibration: Equal tee, Reduced tee, Lateral, Inserted weldolet, Latrolet, Weldolet, Reinforcing pad, Vesselet, Nipoflange, Nipolet, Sweepolet

High Frequency Acoustic Excitation

Acoustic spectrum of pressure let-down device generally have a broad band range with peak frequency in excess of 1000 Hz, which is radiated into the downstream piping. This kinds of high frequency acoustic excitation is the main reasons for acoustic fatigue failure, and the mitigation measures has to be considered to minimize the piping system stress.

Finite element analysis for AIV (Acoustic excitation)
Finite element analysis for AIV (Acoustic excitation)

INERTANCE has a capability regarding noise and vibration engineering, and our experts are familiar with assessment of Acoustic induced vibration (Acoustic fatigue) study. For further information, contact us at (admin@inertance.com).

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