A study into the vibration behaviour of power ultrasonic devices for bone surgery

Nonlinear behaviour is known to exist in power ultrasonic systems. Multimodal responses, frequency modulations, hysteresis effects, bifurcations and chaos are amongst the nonlinear phenomena detected in tuned devices driven at high power.This paper investigates the effect of a cutting insert on the inherent nonlinear vibration behaviour of an ultrasonic transducer for bone surgery. The mode shape and operating mode of the tuned assembly have been simulated using finite element analysis (FEA) and validated by experimental modal analysis (EMA). The effects of temperature and power on the system nonlinear response characteristics have also been measured using a laser vibrometer (LDV) and a thermal imaging camera. Hints for the design of power ultrasonic devices with controlled vibration behaviour ensue from the work.