A study of the progression of damage in an axially loaded Branta leucopsis femur using X-ray computed tomography and digital image correlation.
A study of the progression of damage in an axially loaded Branta leucopsis femur using X-ray computed tomography and digital image correlation.
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作者：
Mustansar Z;McDonald SA;Sellers WI;Manning PL;Lowe T;Withers PJ;Margetts L
本文采用X射线计算机断层扫描跟踪的力学响应的脊椎动物（藤壶鹅）的长骨受到轴向压缩载荷，这是逐渐增加，直到失败。将加载装置安装在X射线计算机断层扫描系统中，以便在加载期间记录骨内部（松质骨或小梁）结构的三维（3D）图像的延时序列。在骨的松质部分观察到五种不同类型的变形机制。这些是（i）开裂，（ii）变薄，（iii）细胞壁和支柱撕裂，（iv）切口形成，（v）颈缩和（vi）屈曲。结果强调，骨经历脆性（缺口形成和开裂），韧性（变薄，撕裂和颈缩）和弹性（屈曲）变形模式。利用数字图像相关技术对混凝土的渐进变形开裂进行了详细的研究。由此产生的应变图是一致的机制发生在一个较细的长度尺度。本文是第一个捕捉到的时间推移的三维图像的整个长骨受到负载，直到失败。这些结果为研究人员提供了一个独特的参考，他们对骨骼如何对负荷做出反应感兴趣。对于那些使用计算机建模的人来说，这项研究不仅为验证和验证他们的模拟提供了定性信息，而且还强调了骨的本构模型需要考虑许多不同的变形机制。
This paper uses X-ray computed tomography to track the mechanical response of a vertebrate (Barnacle goose) long bone subjected to an axial compressive load, which is increased gradually until failure. A loading rig was mounted in an X-ray computed tomography system so that a time-lapse sequence of three-dimensional (3D) images of the bone’s internal (cancellous or trabecular) structure could be recorded during loading. Five distinct types of deformation mechanism were observed in the cancellous part of the bone. These were (i) cracking, (ii) thinning (iii) tearing of cell walls and struts, (iv) notch formation, (v) necking and (vi) buckling. The results highlight that bone experiences brittle (notch formation and cracking), ductile (thinning, tearing and necking) and elastic (buckling) modes of deformation. Progressive deformation, leading to cracking was studied in detail using digital image correlation. The resulting strain maps were consistent with mechanisms occurring at a finer-length scale. This paper is the first to capture time-lapse 3D images of a whole long bone subject to loading until failure. The results serve as a unique reference for researchers interested in how bone responds to loading. For those using computer modelling, the study not only provides qualitative information for verification and validation of their simulations but also highlights that constitutive models for bone need to take into account a number of different deformation mechanisms.