A study of higher modes of buckled SiC beams for stress based sensing applications

Presence of compressive residual stresses beyond a critical value leads to the buckling of suspended fixed-fixed MEMS beams. While theoretical studies on the vibrational behaviour of these buckled structures exist in the literature, very few experimental investigations on such micromechanical structures have been reported. In this work, we have studied the dependence of the first four natural frequencies of buckled silicon carbide (SiC) beams on axial load in a non-dimensional parameter space. Measured results are compared against theoretical estimates from exact analytical formulations reported in literature and a good match is observed. Based on these observations we propose to exploit the characteristics of even and odd modes for potential applications. Further we show that it is possible to tune the sensitivity of the odd-modes of vibration by controlling the geometry and material properties of the beam. (C) 2016 The Authors. Published by Elsevier Ltd