Summary
In this study, we investigate the nonlinear dynamics of an in-plane rotational disc mass sensor. The proposed structure not only benefits from the low damping ratio thanks to the in-plane motion, but also tackles the position dependency of the added mass due to the ring structure of the central disc. The sensor is supported by fully clamped cantilever beams and is subjected to harmonic base excitation. The governing equations of motion are derived using the Lagrangian method. The resulting reduced-order model manifests as a nonlinear Duffing-type equation, incorporating a non-homogeneous term arising from the base excitation. Subsequently, we numerically integrate the equation of motion over time to analyse the impact of added mass on the central disc. The results show that the sensor offers 4 Hz resolution of mass detection for an added mass of 500 fg.
