Abstract: The stiffness and damping of sandwich damping metal bellows are researched by theory analysis, numerical simulation and experiment. Modal strain energy is induced. Finite element method (FEM) software ANSYS is chosen to analyze the loss factor and axis stiffness of bellows. The application of bellows in piping system is introduced. The mechanical performance of bellows considering fluid-solid interaction is simulated. A piping system simulation platform is put forward. The stiffness and damping of bellows in piping system are studied. Numerical analysis and simulation show the distributing of loss factor with wrinkle, layer and wall. It is usually practical for noise reduction to choose the bellows with more wrinkles, more layers, fewer wall of damping and metal. And the effects of wrinkle, elasticity module and wall on the compressed stiffness of bellows are studied. The results show that more wrinkles, fewer elastic modulus metal and fewer wall of bellows can improve the displacement compensation. The axis displacement with rates and pressure of flow are obtained too. The effect of pressure on stiffness and damping ratio is carried out by experimental method. All results give a theory base of optimizing design for sandwich damping metal bellows.

Key words: bellows;FEM;damping;stiffness;fluid-solid interaction