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arXiv 2102.11018cond-mat.mtrl-sciphysics.data-an
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用高斯过程估计远场扫描X射线衍射中的晶内应变

Intragranular Strain Estimation in Far-Field Scanning X-ray Diffraction using a Gaussian Processes

Axel Henningsson, Johannes Hendriks

摘要:

提出并评价了一种基于扫描三维X射线衍射数据(scanning-3DXRD)估算多晶材料晶内应变场的新方法。在已知各向异性柔度的情况下,回归方法可以使线弹性应变场重建中的线动量和角动量保持平衡。通过使用高斯过程(GP),所提出的方法可以产生重建应变场的不确定性的空间估计。此外,可以通过超参数估计相对于测量来优化对空间平滑度的约束。这三个特征解决了针对先前现有的扫描3DXRD重建方法所讨论的弱点,并且因此提供了更鲁棒的应变场估计。该方法是双重验证,首先通过重建合成衍射数据,其次,通过重建以前研究的锡(Sn)颗粒嵌入在多晶试样。最近提出的代数反演技术实现重建的比较。结果发现,GP回归始终产生较低的均方根误差,平均绝对误差和最大绝对误差在所有六个组件的应变重建。

英文摘要:

A new method for estimation of intragranular strain fields in polycrystalline materials based on scanning three-dimensional X-ray diffraction data (scanning-3DXRD) is presented and evaluated. Given an apriori known anisotropic compliance, the regression method enforces the balance of linear and angular momentum in the linear elastic strain field reconstruction. By using a Gaussian Process (GP), the presented method can yield a spatial estimate of the uncertainty of the reconstructed strain field. Furthermore, constraints on spatial smoothness can be optimised with respect to measurements through hyperparameter estimation. These three features address weaknesses discussed for previously existing scanning-3DXRD reconstruction methods and, thus, offers a more robust strain field estimation. The method is twofold validated; firstly by reconstruction from synthetic diffraction data and, secondly, by reconstruction of previously studied tin (Sn) grain embedded in a polycrystalline specimen. Comparison against reconstructions achieved by a recently proposed algebraic inversion technique is also presented. It is found that the GP regression consistently produces reconstructions with lower root mean squared errors, mean absolute errors and maximum absolute errors across all six components of strain.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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