Deformation analysis of a film-overlapped micro-pump membrane structure

Abstract

A novel approach is developed to study a film-overlapped membrane structure. Meanwhile,the established model is employed to design the micro-pump membrane structure and toevaluate its pumping efficiency. Two-dimensional coupling effects between the overlappingactuator films and the deformable membrane are thoroughly investigated, including theinfluences on the membrane from the overlapping films’ elongation effects, Poisson’s ratioeffects and shear strain effects. Overall deformations and interactions for the three-layermembrane structures are accurately calculated through exercising the developed model, incontrast to what difficulties are usually encountered in carrying out FEM methodswith very thin elements meshed for the actuator films. Furthermore, this studydemonstrates that the high stiffness of the actuating metal films needs to be reflected inthe equivalent stiffness of the membrane structures, especially when the sizes ofthe actuator films become compatible with the sizes of the membranes. Hence,the optimal micro-pumping efficiency of a membrane structure is acquired uponexercising the developed model, and larger sizes of the actuating films do notdefinitely obtain larger pumping efficiencies for the electromagnetically actuatedmicro-pumps.