Time evolution of damage due to environmentally assisted aging in a fiber bundle model.
Time evolution of damage due to environmentally assisted aging in a fiber bundle model.
复制标题
纤维束模型中环境辅助老化造成的损伤的时间演变。
DOI：
10.1103/physreve.88.032802
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Lennartz-Sassinek S
中科院分区：
文献类型：
--
作者：
Lennartz-Sassinek S
复合材料中的损伤增长是一个复杂的过程，在科学和工程的许多领域都有兴趣。我们认为这个问题中的纤维束模型，纤维经历了一个老化过程，由于在化学活性环境中的局部作用应力驱动的损伤的积累。通过使纤维束承受恒定的外部载荷，当纤维上的载荷超过其各自的固有强度时，或者当累积的内部损伤超过随机阈值时，纤维失效。我们分析了在低的外部负荷下，老化的纤维占主导地位的断裂过程的时间演变。在平均场的限制，我们分析表明，老化系统不断加速的方式，其特征在于由一个奇异性，定义了故障时间的事件率的逆幂律。指数并不普遍，它取决于老化过程的细节。对于局部载荷分担，出现了一个更复杂的损伤过程，这是由不同的空间区域的系统具有不同程度的应力集中。分析计算表明，最终加速到全球失败之前，一个固定的累积损伤。当无序很强时，加速相具有与平均场极限相同的功能行为。计算机模拟验证了分析结果。
Damage growth in composite materials is a complex process which is of interest in many fields of science and engineering. We consider this problem in a fiber bundle model where fibers undergo an aging process due to the accumulation of damage driven by the locally acting stress in a chemically active environment. By subjecting the bundle to a constant external load, fibers fail either when the load on them exceeds their individual intrinsic strength or when the accumulated internal damage exceeds a random threshold. We analyze the time evolution of the breaking process under low external loads where aging of fibers dominates. In the mean field limit, we show analytically that the aging system continuously accelerates in a way which can be characterized by an inverse power law of the event rate with a singularity that defines a failure time. The exponent is not universal; it depends on the details of the aging process. For localized load sharing, a more complex damage process emerges which is dominated by distinct spatial regions of the system with different degrees of stress concentration. Analytical calculations revealed that the final acceleration to global failure is preceded by a stationary accumulation of damage. When the disorder is strong, the accelerating phase has the same functional behavior as in the mean field limit. The analytical results are verified by computer simulations.