Reconstruction of axisymmetric strain distributions via neutron strain tomography
Reconstruction of axisymmetric strain distributions via neutron strain tomography
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DOI：
10.1016/j.nimb.2011.09.012
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发表时间：
2012-01-01
影响因子：
1.3
通讯作者：
Korsunsky, Alexander M.
中科院分区：
文献类型：
--
作者：
Abbey, Brian;Zhang, Shu Yan;Korsunsky, Alexander M.
在一组特定的载荷条件下，预测结构部件的行为需要了解这些部件的剩余弹性应变分布。表征任何特定点处的3D应变状态涉及组成二阶应变张量的六个独立分量的测量。因此，绘制整个大体积的完整应变分布图提出了重大的实际挑战。这个问题的一个可能的解决方案是使用层析成像技术重建应变分量的3D变化。支撑这一想法的基本原理是，多分量应变张量可以从一组冗余的低阶投影数据中重建。在这里，我们证明了这一基本概念的两个样品：一个收缩配合的“环和插头”的样品，和一个喷雾淬火的圆柱体，都具有轴对称的内部应变分布。我们提出和对比不同的方法来应变断层扫描问题。这里描述的方法也可以很容易地应用于高能X射线衍射测量，并代表了朝着发展的断层重建框架的任意复杂的应变张量分布的重要一步。中子应变层析成像的主要好处是入射束流被更充分地利用，大大减少了数据收集时间。使用微通道板（MCP）中子探测器，可以实现0.1 mm量级的空间分辨率[1]。(C)2011 Elsevier B.V.保留所有权利。
Predicting the behaviour of structural components under a particular set of loading conditions requires knowledge of the residual elastic strain distribution throughout the bulk of these components. Characterising the 3D strain state at any particular point involves the measurement of six independent components which make up the second order strain tensor. Mapping the complete strain distribution throughout large volumes thus presents significant practical challenges. One possible solution to this problem is to reconstruct the 3D variation of strain components using tomographic techniques. The basic principle underpinning this idea is that the multi-component strain tensor can be reconstructed from a redundant set of lower order projection data. Here we demonstrate this fundamental concept for two samples: a shrink fit 'ring-and-plug' sample, and a spray-quenched circular cylinder, both possessing axially symmetric internal strain distribution. We present and contrast different approaches to the strain tomography problem. The methods described here can also be readily applied to high-energy X-ray diffraction measurements and represent an important step toward developing the tomographic reconstruction framework for strain tensor distributions of arbitrary complexity. The major benefit of neutron strain tomography is that the incident beam flux is utilised more fully, greatly reducing the data collection times. Using micro-channel plate (MCP) neutron detectors, a spatial resolution of the order of 0.1 mm can be achieved [1]. (C) 2011 Elsevier B.V. All rights reserved.