Bent-beam sensing with triple-beam tuning forks

A piezoelectric triple-beam tuning fork (TBTF) is presented as a force sensing element. Bent-beam sensing with large deformations is introduced as an alternative to conventional in-plane sensing with small deformations. Inertial force is applied to the tuning fork by a proof mass and it is demonstrated that bent-beam sensing results in several orders of magnitude increase in force sensitivity. The findings are verified by comparing the results of a tilting experiment to an analytical solution and finite element simulations. Five mode shapes of the TBTF are investigated and the resonance frequency of the proposed sensor mode is 265 kHz.