Analysis and design process of a bi-membrane structure for micro-flow regulators

A bi-membrane structure is the main component of flow regulators for microfluidics with positive gain actuation. This microstructure is composed of two deformable circular membranes with different area tied by a rigid link that makes them move together. A comprehensive analysis of this microstructure is presented in this paper, which also provides an easy and practical design process in microsystems. The study is based on the microstructure behavior in typical microfluidic networks and is presented using dimensionless plots which have been obtained by numerical simulations based on finite element method performed by CoventorWare. The microstructure is defined using four dimensionless numbers for its seven dimensional parameters, and a dimensionless pressure. This fact represents the universal character of the design, dividing it into geometrical and material parts. The dimensionless pressure allows the use of any homogeneous and isotropic material in the design process of the devices. The values obtained from the plots are compared with simulation results using specific materials and dimensions and these comparisons present good agreement. Using the proposed analysis and design process, this sort of microstructures can be used by MEMS designers as standard components in microfluidic devices.