Static Analysis of Nano Fixed-Fixed Beam Based on Molecular Dynamics Simulation

In this paper, molecular dynamics simulation method is used to study static characteristic of nano fixed-fixed beam, which is used in nano-electric-mechanical switch. Firstly, model of solid beam and hollow beam are developed. The solid beam consists of 5times20times5 crystal cell, and dimension is 2.715 nm times 10.860 nm times 2.715 nm. For the hollow beam, its wall thickness is one crystal cell, the model consists of 5times20times5 crystal cells and 7times20times7 crystal cells. Then Tersoff potential function is used to compute the interaction of single crystal silicon atoms. The initial position is set on crystal lattice point and the initial speed is set to meet Boltzmann distribution. System freely calculates for period of time until it comes to balance. At last, beams are applied with external voltage to show bending deformation when the length of beam is 3.6 nm, 7 nm and 10 nm. Results show that: firstly, for solid beam, atom's position has a little deviation from the ideal lattice's position after relaxation, yet for hollow beam, the atom position is far from the ideal lattice and the section of beam is flat shape along diagonal line; then comparing simulation data with traditional theory data under uniform static load, it is found that two group data well conform to each other, only there are a few differences on the middle part of beam. The maximum difference is 0.050488 nm; at last, we discuss the effect for beam flexivity caused by length of beam. We found that the two end of beam only can affect no more than 2 nm long distance from the support base. More far from the support base is, the effect is less. So the longer nano beam is, the middle level distance is longer.