The effects of modal interactions and nonlinear response characteristics can hamper implementation of high power ultrasonic technologies, due to the resulting modal coupling, increased stress, audible noise levels and poor control of the operating response. These different adverse responses are illustrated by characterising the vibration behaviour of single-blade and multi-blade ultrasonic cutting systems. This paper proposes design strategies to eliminate the effects of modal interactions, by focusing on reducing the number of vibration modes, and to reduce the effects of nonlinear responses, by serial coupling of tuned components with appropriate cubic softening and hardening response characteristics.
Lucas, M., Cardoni, A., Lim, F. C. N., & Cartmell, M. P. (2003). Effects of modal interactions on vibration performance in ultrasonic cutting. CIRP Annals - Manufacturing Technology, 52(1), 193-196. https://doi.org/10.1016/S0007-8506(07)60563-0