A first estimation of prestress in so-called circularly fibered osteonic lamellae
A first estimation of prestress in so-called circularly fibered osteonic lamellae
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DOI：
10.1016/s0021-9290(99)00080-9
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发表时间：
1999-09-01
影响因子：
2.4
通讯作者：
Ascenzi, MG
中科院分区：
文献类型：
--
作者：
Ascenzi, MG
在长骨的各种层次结构中，预应力的存在和作用是长期存在的问题。在这项研究中，估计了人类骨骼微结构的一个组成部分--环形纤维骨板中存在的预应力和相关应变。这样的估计允许提出关于预应力形成和层板刚度的假设。对8个完全钙化的椎板进行了尺寸测量。这些尺寸，在与周围的交替骨分离之前，以及在通过隔离和轴向切面解除应变之后，提供了构建几何薄板模型的数据。材料模型基于关于片层结构的最可能的假设。这种几何-材料模型允许估计先前存在的应变。最大应变出现在剪切周向应变方向和法向轴向应变方向，平均分别为0.08和0.05。几何材料模型用未知的弹性模数来表示预应力。平均预应力值在剪切周向-轴向最大，补偿了该方向交替的骨量不足。预估的轴向预应力证实了长假想的交替骨预压，在低应力下，这种预压会阻碍横跨骨轴的胶原束区域的骨折。该模型的结果支持以下生物学假设的提出：(A)板层预应力发生在超分子水平，即通过本身可能受到预应力的胶原束；(B)与板层轴倾斜的胶原束负责剪切预应力；(C)预应力范围高达0.11 Gpa；以及(D)板层不如交替的骨质僵硬。(C)1999爱思唯尔科学有限公司。保留所有权利。
The existence and role of prestress in the various hierarchical structures of long bone are long standing questions. In this study, the prestress and associated strain that exist in a component of human bone microstructure, circularly fibered osteonic lamella, are estimated. Such estimates allow the formulation of hypotheses on prestress formation and lamellar stiffness. Dimensional measurements were obtained for eight fully calcified lamellae. These dimensions, before isolation from the surrounding alternate osteon and after strain relief by isolation and axial sectioning, furnish data upon which a geometric lamellar model is constructed. A material model is based on the most likely hypothesis as to lamellar structure. This geometric-material model allows estimation of the preexisting strain. The largest strains occur in shear circumferential-axial and normal axial strain directions, averaging 0.08 and 0.05, respectively. The geometric-material model expresses prestress in terms of as yet unknown elastic moduli. The average prestress magnitude is the largest in shear circumferential-axial direction, compensating for alternate osteon weakness in this direction. The estimated axial prestress confirms long hypothesized alternate osteon precompression, which impedes fractures of areas of collagen bundles transverse to the osteon axis at low stresses. The results of the model support the formulation of the following biological hypotheses: (a) lamellar prestress occurs at a supra-molecular level, namely through collagen bundles which are themselves likely to be prestressed; (b) collagen bundles oblique to the lamellar axis are responsible for shear prestress; (c) prestress ranges up to 0.11 GPa; and (d) the lamella is less stiff than alternate osteon. (C) 1999 Elsevier Science Ltd. All rights reserved.