摘要
对牛皮质骨在拉伸（Ⅰ型）、剪切（Ⅱ型）和撕裂（Ⅲ型）型载荷下的裂纹启裂韧性进行了研究。总数为130个紧凑拉伸试样，紧凑剪切试样和三腿型试样分别用于测量骨的拉伸型、剪切型和撕裂型启裂韧性。多试样柔度法用来测定当a／W＝0．55（a，裂纹长度，W，试样宽度）时的临界能量释放率（Gc）。临界应力强度因子（Kc）由a／W＝0．55的试样在试验中得到的临界载荷（PQ）来计算。为了考察骨力学性质的各向异性对于它的剪切型和撕裂型裂纹启裂韧性的影响，对骨试样的裂纹扩展方向平行于（纵向断裂）和垂直于（横向断裂）长骨的纵向轴线时的裂纹启裂韧性进行了比较。在纵向启裂情况下，拉伸型，剪切型和撕裂型临界能量释放率（Gc）分别为644±102，2430±836，and1723±486N／m。在横向断裂情况下，拉伸型，剪切型和撕裂型临界能量释放率（Gc）分别为1374±183，4710±1284，and4016±948N／m。统计分析表明，无论纵向断裂或横向断裂，皮质骨的剪切型和撕裂型裂纹启裂韧性显著高于其拉伸型裂纹启裂韧性。我们的结果同时也表明，皮质骨的结构使得它更有效地防止垂直于骨的纵向轴线的裂纹启裂和失稳扩展。
The fracture toughness at crack initiation was determined for bovine cortcal bone under tension(mode Ⅰ ), shear (mode Ⅱ ), and tear (mode Ⅲ ). A total of 130 compact tension specimens, compact shear specimens and triple pantleg specimens were used for the measurement of fracture toughness under tension, shear, andtear, respectively. Multiple-sample compliance method was utilized to measure the critical strain energy releaserate (Gc) at the a/W=0. 55 (crack length, a, to specimen width, W, ratio). The critical stress intensity factor(Kc) was also calculated from the critical loading (PQ) of the specimens at the a/W= 0. 55. The effect of theanisotropy of bone on its resistance to crack initiation under shear and tear loading was investigated as well. Thefracture toughness of bone with precrack orientations parallel (designed as longitudinal fracture) to and that withprecrack orientations normal (designed as transverse fracture) to the longitudinal axis of bone were compared. Inlongitudinal fracture, the critical strain energy release rates (Gc) of conical bone under tension, shear, and tearwere 644±102, 2430±836, and 1723±486 N/m, respectively. In transverse fracture, the critical strain energyrelease rates (Gc) of conical bone under tesion, shear, and tear were 1374± 183, 4710 ± 1284, and 4016± 948N/m, respectively. An analysis of variance demonstrated that the crack initiation fracture toughness of bone undershear and tear loading is significantly greater than that under tensile loading in both longitudinal and transversefracture. Our results also suggest that conical bone has been"designed" to prevent crack initiation in transversefracture under tension, shear, and tesar.
出处
《生物医学工程学杂志》
EI
CAS
CSCD
北大核心
1997年第3期199-204,共6页
Journal of Biomedical Engineering
