Cutting Velocity Effects in Bone Sawing.
Pearlman, John.
2017-04-18T14:02:44.773Z
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Abstract: Thermal 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 accomp... read morelishing 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 - ID:
- 3x817015r
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