Cutting Velocity Effects in Bone Sawing.
necrosis, or the death of living cells through excessive heating, occurs commonly while
cutting bone with the power saws used in orthopedic surgery. This effect has significant
repercussions in joint arthroplasty procedures, where the bone interface prepared by
sawing must remain viable. As a function of the energy expended during cutting, heat
generation may be reduced by a... read moreccomplishing the same for machining forces. In this
research, the effect of cutting speed on these forces was investigated in bovine bone.
An innovative experimental setup was used to simulate the distinctive conditions present
in power sawing. A linear relationship between tool forces and both cutting depth and
speed led to a two factor, two level design for the primary experiment. Results of this
trial indicated that speed had no statistically significant effect on either cutting or
thrust force. Thrust to cutting force ratios remained within a range of 1.4 - 1.8, with
resultant forces falling within 1.5 - 2.2 lbf. Per the experimental conditions, an
analytical model accounting for a tool with a cutting edge radius greater than cutting
depth was applied. The fit of the basic model was then improved by adding provisions
compensating for a plowing depth and a built up edge. In comparison to the empirical
trends, this refined model matched resultant forces well but remained in disagreement
for force ratios. Additionally, an unusually large plowed layer thickness of 60% the
uncut chip thickness was predicted, as well as a relatively low shear flow stress of 4.4
ksi. However, observed characteristics of built up edge behavior as well as the
sensitivity of the model to tool geometry led to the conclusion that these predictions
were not wholly unreasonable.
Thesis (M.S.)--Tufts University, 2011.
Submitted to the Dept. of Mechanical Engineering.
Advisor: Thomas James.
Committee: Anil Saigal, and K Subramanian.
Keywords: Mechanical engineering, Biomechanics, and Biomedical engineering.read less