Finite element analysis of nanostructures with roughness and scratches

Finite element analysis facilitates optimal design of MEMS/NEMS devices for reliability. A finite element method (FEM) was developed to analyze the effect of types of surface roughness and scratches on stresses of nanostructures. Beams with surface roughness in the form of semicircular and grooved asperities in varying numbers in the longitudinal direction were considered. In the transverse direction semicircular asperities and scratches in varying numbers and with different pitch were modeled. Furthermore semicircular asperities were truncated both in longitudinal and transverse direction and analyzed. It was observed that the asperities and scratches increase the bending tensile stresses which could lead to failure of MEMS/NEMS devices. The beam material was assumed to be purely elastic, elastic-plastic and elastic-perfectly plastic to observe the variations in the bending stresses and displacements for both smooth nanobeam and nanobeam with defined roughness. The results of the analysis can be useful to designers to develop the most suitable geometry for nanostructures.