Dimensionless Bending Rigidity Ratio and Material Dependency of Microbeams with Size Effects

Abstract

AbstractMicrobeams are extensively used for many applications in the MEMS/NEMS industry. The structural material properties modulate the performance of the beam-based resonators in microscale. In the current analysis, the flexural behaviour of microbeams subjected to various structural materials is analysed and the bending rigidity, the most significant flexural parameter associated with it, is investigated. As the device dimensions are scaled down, nonclassical continuum theories are applicable in structural domain to represent its dynamic characteristics. The current analysis incorporates modified couple stress theory as the chosen nonclassical elasticity theory to accurately model the vibrating microbeams with five different structural materials: Si, polySi, GaAs, diamond and SiC. In the analysis, the impacts of scaling effect on bending rigidity ratio of microbeams are investigated. Quality factor limited by thermoelastic damping (QTED) is an important performance parameter of resonating microstructures and found to be depending on the flexural characteristics. The variation of bending rigidity ratio with Poisson’s ratio is also investigated. The material order in which bending rigidity varies with dimensionless length parameter is explored for the five structural materials. The size effect parameter (l/h) increases the bending rigidity ratio and eigenfrequencies according to our study. The simulations have been conducted numerically using MATLAB 2015a. The structural materials with high bending rigidity ratio can be chosen for developing low energy dissipation MEMS/NEMS-based resonators in today’s leading edge technologies like IoT and 5G networks.KeywordsMicrobeam resonatorsSize effectsDimensionless length scale parameterDimensionless bending rigidity ratioPoisson’s ratio