Theoretical modeling of microfabricated beams with elastically restrained supports

A mathematical model is developed to analyze the mechanical behavior of step-up supports which typically result from surface micromachining. This model accounts for the finite stiffness of the step-up support, which is more accurately represented by an elastically restrained boundary condition rather than a fixed or built-in boundary condition. Based on the model developed, the deflection of cantilever and doubly-supported beams under arbitrarily located concentrated and distributed loads is determined for a wide range of beam geometries. In addition, the buckling load of doubly-supported beams with elastically restrained boundary conditions is analyzed. Finite element analysis verifies the accuracy of the models developed. The models show that significant error in predicting the beam mechanical behavior may result if the finite stiffness of the step-up support is not correctly modeled