Abstract Bending of micron-scale cantilevers with or without initial notch is simulated by finite element and their fracture is assessed using either the coupled criterion or a cohesive zone model. The fracture toughness and strength of UO2 single grain specimens with several crystal orientations are determined by means of inverse identification based on experimental tests at the micron-scale. Irradiation causes a decrease in fracture toughness from around 10 J/m2 to around 5 J/m2, whereas the strength variation remains in the order of magnitude of the measurement uncertainty. Premature fracture may occur in presence of a pore provided it is located close enough to the specimen surface undergoing tension, the resulting failure force decreasing with increasing pore size. A network of small porosities located on the fracture surface induces a decrease in the failure force which magnitude mainly depends on the total surface fraction and on the porosity locations rather than on the porosity size.

中文翻译：

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UO2 微米级试样断裂：孔隙率的参数识别和影响。

摘要 通过有限元模拟了带有或不带有初始缺口的微米级悬臂梁的弯曲，并使用耦合准则或内聚区模型对其断裂进行了评估。基于微米尺度的实验测试，通过逆识别的方法确定了具有多种晶体取向的UO2单晶试样的断裂韧性和强度。辐照导致断裂韧性从约 10 J/m2 降低到约 5 J/m2，而强度变化仍保持在测量不确定度的数量级。存在孔隙时可能会发生过早断裂，前提是它离承受张力的试样表面足够近，由此产生的破坏力随着孔径的增加而减小。