Analysis of Transient Cutting Forces in Cortical Bone During Ultrasonically Assisted Cutting

Ultrasonically assisted cutting (UAC), a process characterized by high-performance material removal and enhanced surface finish, is widely employed in orthopedic surgery. However, variability in the mechanical properties of cortical bone may lead to unstable fractures and fluctuating cutting force during material removal, particularly under high-frequency vibration cutting. This study introduces a transient shear strength model that utilizes strain rate fluctuations to estimate cutting forces in the UAC process. The impact of varying osteon orientations and strain rate ranges on the yield strength of cortical bone is analyzed to elucidate changes in its mechanical properties under UAC conditions. Additionally, strain rates from conventional cutting (CC) and UAC, measured through digital image correlation (DIC), are compared with model predictions. The results demonstrate that the proposed model accurately predicts cutting forces and associated changes in thrust. This research offers a fresh insight into the dynamics of fluctuating forces during UAC, potentially inspiring advancements in orthopedic surgical instruments.