Cutting Behavior of Cortical Bone in Different Bone Osteon Cutting Angles and Depths of Cut

• Published in: Chinese journal of mechanical engineering Vol. 35; no. 1; pp. 91 - 12
• Main Authors: Luo, Yuanqiang, Ren, Yinghui, Shu, Yang, Mao, Cong, Zhou, Zhixiong, Bi, Z. M.
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01-12-2022; Springer Nature B.V; SpringerOpen
• Edition: English ed.
• Subjects: Anisotropic materials; Bone cutting surgery; Chip formation; Crack initialization and propagation; Crack propagation; Cracking (fracturing); Cutting force; Cutting parameters; Design parameters; Electrical Machines and Networks; Electronics and Microelectronics; Engineering; Engineering Thermodynamics; Fracture toughness; Fractures; Heat and Mass Transfer; Instrumentation; Machines; Manufacturing; Mathematical models; Mechanical Engineering; Original Article; Orthogonal cutting models; Power Electronics; Processes; Processing of Biological Tissue; Propagation; Shearing; Theoretical and Applied Mechanics; Orthogonal cutting models; Bone cutting surgery; Chip formation; Crack initialization and propagation; Anisotropic materials; Fracture toughness
• ISSN: 1000-9345; 2192-8258
• DOI: 10.1186/s10033-022-00769-2

Cortical bone is semi-brittle and anisotropic, that brings a challenge to suppress vibration and avoid undesired fracture in precise cutting process in surgeries. In this paper, a novel analytical model is proposed to represent cortical bone cutting processes. The model is utilized to predict the chip formations, material removal behavior and cracks propagation under varying bone osteon cutting angles and depths. Series of orthogonal cutting experiments were conducted on cortical bone to investigate the impact of bone osteon cutting angle and depth of cut on cutting force, crack initialization and propagation. The observed chip morphology highly agreed with the prediction of chip formation based on the analytical model. The curly, serrated, grainy and powdery chips formed when the cutting angle was set as 0°, 60°, 90°, and 120°, respectively. Cortical bone were removed dominantly by shearing at a small depth of cut from 10 to 50 μm, and by a mixture of pealing, shearing, fracture and crushing at a large depth of cut over 100 μm at different bone osteon angles. Moreover, its fracture toughness was calculated based on measured cutting force. It is found that the fluctuation of cutting force is suppressed and the bone material becomes easy to remove, which attributes to lower fracture toughness at bone osteon cutting angle 0°. When the cutting direction develops a certain angle to bone osteon, the fracture toughness increases then the crack propagation is inhibited to some extent and the fluctuation of cutting force comparatively decreases. There is a theoretical and practical significance for tools design and operational parameters choice in surgeries.