Internal strains and stresses measured in cortical bone via high-energy X-ray diffraction
Internal strains and stresses measured in cortical bone via high-energy X-ray diffraction
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DOI：
10.1016/j.jsb.2005.08.003
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发表时间：
2005-10-01
影响因子：
3
通讯作者：
Stock, SR
中科院分区：
文献类型：
--
作者：
Almer, JD;Stock, SR
用高能同步辐射X射线衍射仪研究了在原位压缩载荷作用下的骨内应力。用80.7keV辐射研究了12~14岁比格犬腓骨的横截面，并用透射几何方法量化了碳酸化羟基磷灰石矿物相的内部应变和相应的应力。衍射图与列表图样一致，00.2/00.4和22.2衍射环附近的衍射光强分布与长骨轴向预期的00.1纤维织构一致。在测试之前，在试件中观察到沿骨骼纵轴的残余压应力：对于22.2，该应力等于-95兆帕，对于00.2/00.4，该应力在-160和-240兆帕之间。在-110 Mpa的压应力范围内采集了衍射图，在-100 Mpa的范围内，内应力与外加应力成比例增加，但增加的速度更快，对应于2.8倍于外加应力的矿物的应力集中。00.2和00.4衍射峰的宽度表明，垂直于00.1晶面的微晶尺寸从施加应力前的t=41 nm增大到施加应力前的t=44 nm，应力作用下的均方根应变(RMS)从加载前的2200 mU epsilon增加到最大施加应力时的4600 mU epsilon。变形完成后记录的卸载样品的小角X射线散射显示，胶原D周期为66.4 nm(沿骨轴线)。(C)2005 Elsevier Inc.保留所有权利。
High-energy synchrotron X-ray diffraction was used to study internal stresses in bone under in situ compressive loading. A transverse cross-section of a 12-14 year old beagle fibula was studied with 80.7 keV radiation, and the transmission geometry was used to quantify internal strains and corresponding stresses in the mineral phase, carbonated hydroxyapatite. The diffraction patterns agreed with tabulated patterns, and the distribution of diffracted intensity around 00.2/00.4 and 22.2 diffraction rings was consistent with the imperfect 00.1 fiber texture expected along the axis of a long bone. Residual compressive stress along the bone's longitudinal axis was observed in the specimen prior to testing: for 22.2 this stress equaled -95 MPa and for 00.2/00.4 was between -160 and -240 MPa. Diffraction patterns were collected for applied compressive stresses up to -110 MPa, and, up to about -100 MPa, internal stresses rose proportionally with applied stress but at a higher rate, corresponding to stress concentration in the mineral of 2.8 times the stress applied. The widths of the 00.2 and 00.4 diffraction peaks indicated that crystallite size perpendicular to the 00.1 planes increased from t = 41 nm before stress was applied to t = 44 nm at -118 MPa applied stress and that rms strain epsilon(rms) rose from 2200 mu epsilon before loading to 4600 mu epsilon at the maximum applied stress. Small angle X-ray scattering of the unloaded sample, recorded after deformation was complete, showed a collagen D-period of 66.4 nm (along the bone axis). (C) 2005 Elsevier Inc. All rights reserved.