Large Deformation of Rubber Sleeves in Valves Using Strongly Coupled Fluid-Structural Interaction

In fluid power systems, the design of seals and flow paths play a vital role. For example, important design parameters are flow rate and forces on features such as spools to guarantee valve switching processes and computational analysis has become an important tool in the design process. The different numerical methods have evolved in separate restricted physical domains, each characterized by its unique challenges. Typical pneumatic flow regimes for example are governed by turbulent, compressible and oftentimes supersonic effects. The analysis of seal structures in pneumatic components by use of nonlinear structural FEA often exhibits large deformations, nonlinear material laws and body interactions by contact. These properties impose tight demands on the already isolated analysis of these distinct physical mechanisms. Naturally, phenomena and behaviour attributed to the interaction of these systems can only be revealed by properly modelling thesevery interacting mechanisms. A telling example is the fluttering of an annular seal due to transonic and transient interactions of the air flow and the rubber structure.Under unfavourable circumstances this seal ruptures and might even be extricated,leading at worst to the failure of the device or even the complete system.