Computation of full-field displacements in a scaffold implant using digital volume correlation and finite element analysis
Computation of full-field displacements in a scaffold implant using digital volume correlation and finite element analysis
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DOI：
10.1016/j.medengphy.2013.02.001
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发表时间：
2013-09-01
影响因子：
2.2
通讯作者：
Hild, F.
中科院分区：
文献类型：
--
作者：
Madi, K.;Tozzi, G.;Hild, F.
采用两种数字体积相关（DVC）方法测量了单轴压缩下支架植入体的三维位移，并与微有限元模型的测量结果进行了比较。DVC方法基于两种方法，一种是局部方法，它记录独立的小体积并产生不连续的位移场；一种全局方法，在整个感兴趣的体积上进行配准，导致连续的位移场。使用定制的微型压缩装置在微型计算机断层扫描（mu CT）室中对支架进行原位逐步压缩，并在感兴趣的步骤收集数据。在空间分辨率为32体素的情况下，两种方法的位移不确定性范围为0.006至0.02体素（即0.12-0.4 μ m），应变不确定性范围为60至600 μ epsilon，尽管全局方法具有较低的系统误差。通过增大单元尺寸，采用全局方法可以减小位移和应变的不确定性；并通过增加中介子卷的数量，采用局部化的方法。在主加载方向和横向加载方向上，DVC测量结果与有限元模拟结果吻合较好。该研究表明，使用DVC可以成功地获得体积应变测量，这可能是研究多孔植入物力学行为的有用工具。(c) 2013年度。Elsevier Ltd.出版。版权所有。
Measurements of three-dimensional displacements in a scaffold implant under uniaxial compression have been obtained by two digital volume correlation (DVC) methods, and compared with those obtained from micro-finite element models. The DVC methods were based on two approaches, a local approach which registers independent small volumes and yields discontinuous displacement fields; and a global approach where the registration is performed on the whole volume of interest, leading to continuous displacement fields. A customised mini-compression device was used to perform in situ step-wise compression of the scaffold within a micro-computed tomography (mu CT) chamber, and the data were collected at steps of interest. Displacement uncertainties, ranging from 0.006 to 0.02 voxel (i.e. 0.12-0.4 mu m), with a strain uncertainty between 60 and 600 mu epsilon, were obtained with a spatial resolution of 32 voxels using both approaches, although the global approach has lower systematic errors. Reduced displacement and strain uncertainties may be obtained using the global approach by increasing the element size; and using the local approach by increasing the number of intermediary sub-volumes. Good agreements between the results from the DVC measurements and the FE simulations were obtained in the primary loading direction as well as in the lateral directions. This study demonstrates that volumetric strain measurements can be obtained successfully using DVC, which may be a useful tool to investigate mechanical behaviour of porous implants. (C) 2013 IPEM. Published by Elsevier Ltd. All rights reserved.