Determination of Elastic Modulus for Several Kinds of Micro Beams with Variable Moments of Inertia

摘要

In order to measure materials' elastic moduli according with their practical applications in MEMS, based on micro rectangle beam bending principle, the formulas to determining micro materials' elastic moduli were deduced for three kinds of micro cantilever beams with variable moments of inertia and three kinds of micro beams with variable moments of inertia under two-end supporting which were checked with ANSYS FE program and a theoretic material with elastic modulus of 190GPa and Poisson's ratio of 0.28. The elastic moduli obtained by the formulas according to the simulated results of the loads under a deflection of 10 μm for six kinds of micro beams are 191.2GPa, 192.2GPa, 192.4GPa, 188.6GPa, 182.9GPa,176.7GPa, respectively, and the maximum relative difference between the simulated elastic moduli and the theoretic elastic modulus is 6.4%. Besides, a series of bending simulations for he rectangle beams supported by Bases 1 and 2 with the different sizes was also done using ANSYS FE program. The simulation results showed that the elastic moduli determined by the formulas for micro rectangle beams without base(s) may be divided by a parameter equal to 0.866 or 0.845 for Base 1 or Base 2 in the interest of the actual elastic moduli.