Unified finite element method for analyzing vibration and noise in 3-D piping system with liquid-pipe coupling

Using the unified FEM, this paper aims to analyze vibration and noise in practical piping system which consists of equipments and fittings and perhaps owns branch structure, considering the interaction between internal liquid and pipe structure. The theoretical basis for modeling piping system and the analytical expressions of stiffness matrices of typical components, as well as the transformation formulation introducing test data of mechanical and acoustic impedance of flexible components into FE analysis, are presented in this paper in details. Through a complicated examples, the roles of pressure vessel and flexible components in reducing vibration and noise transmission are investigated.