Abstract: A new multi-scale model based on the energy conversation law is presented to calculate the static bending of a nanometer double clamped silicon beam.This model accounts for the discrete nature in the thickness of the beam and it can be used in the range of the nanometer scale to the micrometer scale.It is shown that the surface relaxation has a significant effect on the deflection behavior when the beam is scaled down to nanosize.Compared with the continuum theory in the micrometer scale,the multi-scale model agrees with the macro-model in the micrometer scale.

Key words: NEMS, beam, multi-scale, bending