Competition of strength and stress disorder in creep rupture.
Competition of strength and stress disorder in creep rupture.
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蠕变断裂中的力量竞争和应力紊乱。
DOI：
10.1103/physreve.85.016116
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
F. Kun
中科院分区：
文献类型：
--
作者：
Z. Halász;Z. Danku;F. Kun
基于一个局部载荷分担的亚临界断裂纤维束模型，我们证明了门限无序和非均匀应力场的相互作用导致了丰富的动力学过程。在该模型中，纤维要么由于立即断裂，要么由于缓慢的损伤过程而失效。当无序很强时，会产生大量的破坏，这些破坏会随机地扩散到整个系统；然而，对于弱无序，会形成一个单一的扩展裂纹，并以大量的局部爆发进行。裂纹的微观结构呈幂函数分布，这类似于扩散损伤区的渗流，但当单个裂纹占主导地位时，裂纹的微观结构变得更加陡峭。模拟结果表明，中断脉冲的大小分布和其间的等待时间具有与负载相关的截止值的幂函数形式。爆破尺寸指数与损伤过程无关，但它强烈依赖于外加载荷，最小值为1.75。等待时间分布对损伤过程的细节很敏感，随着爆破越来越多地集中在推进的裂纹前沿，等待时间的指数从2.0下降到1.4。
Based on a fiber bundle model of subcritical fracture with localized load sharing, we show that the interplay of threshold disorder and the inhomogeneous stress field gives rise to a rich dynamics with intriguing aspects. In the model, fibers fail either due to immediate breaking or to a slow damage process. When the disorder is strong, a large amount of damage occurs, which is randomly diffused over the system; however, for weak disorder, a single growing crack is formed, which proceeds in a large number of localized bursts. The microstructure of cracks is characterized by a power-law size distribution, which is analogous to percolation in the regime of diffusive damage; however, it becomes significantly steeper when a single crack dominates. Simulations showed that the size distribution of breaking bursts and of the waiting times in between have a power-law functional form with a load-dependent cutoff. The burst size exponent proved to be independent of the damage process; however, it strongly depends on the external load with a minimum value of 1.75. The waiting time distribution is sensitive to the details of the damage process with an exponent decreasing from 2.0 to 1.4 as bursts get more and more localized to an advancing crack front.