多孔颗粒材料压缩破坏的探讨
Approach to failure in porous granular materials under compression
摘要：
研究了单轴压缩下多孔颗粒材料模型的灾难性破坏.离散元计算模型用于模拟材料的微观结构和复杂的动力学和反馈，涉及局部断裂和裂纹噪声的产生。在应变控制加载下，微裂纹最初在整个样品上以不相关的方式成核。随着加载的进行，损伤局部化成与载荷方向成30-45度倾斜的狭窄损伤带。在损坏带内，材料被压碎成主要由细粉和一些较大碎片组成的分选不良的混合物。质量概率密度分布的颗粒在损伤区的指数为2.1的幂律，类似的值1.87推断从观察的磨损产品（凿）在自然和实验室故障的长度分布。辐射能量的动态爆发，类似于在多孔沉积岩的实验室实验中观察到的声发射，被确定为应力重新分布过程中出现的局部破裂的相关踪迹或级联。当系统接近宏观失效时，连续的爆发变得越来越相关。它们的粒度分布也是幂律的，在整个试验中平均的等效Gutenberg-Richter b值为1.22，在破坏时从3下降到0.5，所有这些都与在粒状砂岩样品的实验室试验中观察到的相似。损坏带本身的形成是由连续的突发和紧急事件的位置与相关维数为2.55，也类似于在实验室中观察到的（2.75和2.25之间）的幂律相关积分之间的平均距离的减少为标志。
英文摘要：
We investigate the approach to catastrophic failure in a model porous granular material undergoing uniaxial compression. A discrete element computational model is used to simulate both the micro-structure of the material and the complex dynamics and feedbacks involved in local fracturing and the production of crackling noise. Under strain-controlled loading micro-cracks initially nucleate in an uncorrelated way all over the sample. As loading proceeds the damage localizes into a narrow damage band inclined at 30-45 degrees to the load direction. Inside the damage band the material is crushed into a poorly-sorted mixture of mainly fine powder hosting some larger fragments. The mass probability density distribution of particles in the damage zone is a power law of exponent 2.1, similar to a value of 1.87 inferred from observations of the length distribution of wear products (gouge) in natural and laboratory faults. Dynamic bursts of radiated energy, analogous to acoustic emissions observed in laboratory experiments on porous sedimentary rocks, are identified as correlated trails or cascades of local ruptures that emerge from the stress redistribution process. As the system approaches macroscopic failure consecutive bursts become progressively more correlated. Their size distribution is also a power law, with an equivalent Gutenberg-Richter b-value of 1.22 averaged over the whole test, ranging from 3 down to 0.5 at the time of failure, all similar to those observed in laboratory tests on granular sandstone samples. The formation of the damage band itself is marked by a decrease in the average distance between consecutive bursts and an emergent power law correlation integral of event locations with a correlation dimension of 2.55, also similar to those observed in the laboratory (between 2.75 and 2.25).
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。
