Acoustic Fatigue Assessment of Piping System Components by Finite Element Analysis

Abstract

High levels of acoustic energy can be produced at the downstream of pressure-reducing valves, pressure safety valves and control valves in piping systems. The presence of acoustic pressure waves and their coupling with the piping wall flexural modes of vibration can result in high levels of dynamic stresses, which cause acoustic fatigue failure at points of discontinuities on the pipe wall. This work presents a procedure for the assessment of the acoustic fatigue of different piping components by the application of finite element analysis. The piping system process data is used to generate the acoustic pressure and acoustic power spectrum at the downstream of the pressure-reducing valve. This acoustic power spectrum is taken to act at a finite element model of the piping system. Dynamic analysis, by use of power spectrum and harmonic analysis, is performed to obtain the response dynamic stresses, which are used for the fatigue evaluation of the piping component. The methodology presented can be applied during the engineering phase in the design and stress analysis of piping components in critical services subjected to acoustic fatigue as well as in the detailed evaluation of the different proposed acoustic fatigue design solutions.