Synchrotron X-ray characterization of crack strain fields in polygranular graphite
Synchrotron X-ray characterization of crack strain fields in polygranular graphite
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DOI：
10.1016/j.carbon.2017.08.075
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发表时间：
2017-11-01
期刊：
影响因子：
10.9
通讯作者：
Marrow, T. J.
中科院分区：
文献类型：
--
作者：
Barhli, S. M.;Saucedo-Mora, L.;Marrow, T. J.
本文研究了多颗粒各向同性核石墨（一种准脆性材料）中裂纹在稳定断裂扩展过程中的应变场。同步辐射X射线计算机断层扫描和应变映射衍射相结合的数字体积相关和相位一致性图像分析，以提取全场位移和弹性晶体应变。测量的位移场进行了分析，使用有限元方法提取的弹性应变能释放率作为J-积分。非线性性质描述了微裂纹对断裂过程区弹性模量的影响。当使用非线性模型时，预测和测量的弹性应变场的良好协议的分析进行了验证。I型裂纹扩展的本征临界弹性应变能释放率约为200 J·m（-2）。(C)2017爱思唯尔有限公司版权所有
The strain field of a crack in polygranular isotropic nuclear graphite, a quasi-brittle material, has been studied during stable fracture propagation. Synchrotron X-ray computed tomography and strain mapping by diffraction were combined with digital volume correlation and phase congruency image analysis to extract the full field displacements and elastic crystal strains. The measured displacement fields have been analysed using a Finite Element method to extract the elastic strain energy release rate as a J-integral. Non-linear properties described the effect of microcracking on the elastic modulus in the fracture process zone. The analysis was verified by the good agreement of the predicted and measured elastic strain fields when using the non-linear model. The intrinsic critical elastic strain energy release rate for mode I crack propagation is approximately 200 J m(-2). (C) 2017 Elsevier Ltd. All rights reserved.