Abstract Explaining crack propagation in uniaxially compressed brittle solids is challenging because the complexity of such fracture makes it impossible to estimate the compressive capacity of a solid subjected to uniaxial compression using a well-defined, widely applicable formula. Localized tension is typically generated at the tip of a void in a solid under uniaxial compression, so we focus here on the geometrical possibilities of internal cavities and the impact of that geometry on crack propagation in a uniaxially compressed linear brittle solid. The study includes a review of the current understanding and limitations of knowledge of fracture in uniaxial compression and Finite Element based analyses of different initial void/cavity geometries and their impact on crack propagation. Analysis of crack propagation is carried out in terms of the mode I stress intensity factors associated with cracks propagating from different initial voids. Despite the analyses being limited to 2D, novel observations are discussed about the nature of crack propagation in uniaxial compression, confirming the complexity of this type of failure. The width (direct relationship), height (inverse relationship), size (direct relationship) and shape of the void are shown to be important in triggering crack propagation, but not the width-to-height ratio. An initial horizontal elliptical void with the major axis parallel to the applied compression and a minor axis 1/20 the length of the major axis was found to be the most critical void in terms of the likelihood to trigger cracks in uniaxial compression. Vertical elliptical voids were found to be less critical than all the other voids studied. The applicability of a stress intensity vs fracture toughness approach, as used to predict failure in tensile stress fields, is questioned.

中文翻译：

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初始缺陷形状和尺寸对单轴压缩线性脆性材料裂纹扩展的影响

摘要 解释单轴压缩脆性固体中的裂纹扩展具有挑战性，因为这种断裂的复杂性使得无法使用定义明确、广泛适用的公式来估计经受单轴压缩的固体的压缩能力。局部张力通常在单轴压缩下固体中的空隙尖端产生，因此我们在这里重点讨论内腔的几何可能性以及该几何形状对单轴压缩线性脆性固体中裂纹扩展的影响。该研究包括对单轴压缩中断裂知识的当前理解和局限性的回顾，以及基于有限元分析的不同初始空隙/腔几何形状及其对裂纹扩展的影响。裂纹扩展的分析是根据与从不同初始空隙传播的裂纹相关的模式 I 应力强度因子进行的。尽管分析仅限于 2D，但讨论了关于单轴压缩中裂纹扩展的性质的新观察结果，证实了此类故障的复杂性。空隙的宽度（直接关系）、高度（反比关系）、尺寸（直接关系）和形状在触发裂纹扩展方面很重要，但宽度与高度的比率并不重要。就在单轴压缩中引发裂纹的可能性而言，初始水平椭圆空隙的长轴平行于施加的压缩，短轴长度为长轴的 1/20，被发现是最关键的空隙。发现垂直椭圆空隙比所有其他研究的空隙都不太重要。用于预测拉伸应力场中的失效的应力强度与断裂韧性方法的适用性受到质疑。