哈氏系统破坏的微观结构分析
Mechanical Failure in Haversian Systems on the Basis of Microstructure
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摘要: 本文旨在通过五个长骨试样在五个不同载荷等级(2KN,3KN,4KN,5KN和6KN)的抗压试验,观察哈氏系统(Haversian System)——哈氏骨板和哈氏管——的变化情况.由一组显微照片可以十分清晰地看出:(1)在载荷等级低的情况(2KN),哈氏管几乎与未受力时一样,哈氏骨板亦然;(2)在载荷等级高的情况,哈氏骨板最弱的部分最先变形;(3)随着载荷的增加,哈氏系统破坏的形式十分复杂,断裂总是发生在骨的结合缘处. 同时,测量了变形后的哈氏骨板和哈氏管的有关尺寸.对试验中所观察到的现象,用线性粘弹性力学的理论予以解释.最后提出了骨单位为纤维增强的厚壁筒模型.Abstract: The aim of this paper is to observe variations in the mechanical properties of Haversian systems including Haversian lamellae and canals,by means of the compressive test of five bone specimens subjected to different loads corresponding to 2KN,3KN,dKN,5KN and 6KN respectively. From a series of related microscopic pictures it is clearly seen that:(1) in the lower level of loading(2KN),the Haversian canals much the same as the one unsubjected to loads,and conditions of Harversian lamellae are also the same,but,the individual Harversian canal was slightly bent;(2) in the case of the higher levels of loading,it is first deformed in the weaked portion of the Haversian lamellae;(3) with increasing loads,the fracture shapes of the Haversian system are very complex,but the fractures always take place in the cement line between osteons.At the same time,deformed dimensions of the Harversian lamellae and canals were measured. The observed phenomena were qualitatively interpreted by the theory of the linear viscoelasticity.
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