论文标题
对数与安德拉德的瞬态蠕变：弹性应力重新分布的作用
Logarithmic vs Andrade's transient creep: the role of elastic stress redistribution
论文作者
论文摘要
蠕变被定义为时间依赖性变形和发生的破裂过程，发生在构成的材料中，其恒定应力小于其无时间独立的强度。这种时间依赖性通常归因于局部变形事件的热激活。蠕变的现象学的特征是几种无处不在但经验的流变学和缩放定律。在加载开始后，我们将重点放在主要的蠕变上，为此，观察到应变率的功率定律衰减，指数p在0.4和1之间变化，该上限定义了所谓的对数蠕变。尽管这种现象学已有一个多世纪的著名，但像安德拉德（Andrade）一样（p <1）蠕变的物理起源尚不清楚和辩论。在这里，我们表明p <1值来自热激活与弹性应力重新分布之间的相互作用。后者刺激了连续事件之间等待时间的缩短，这与物质损害有关，并且可能在高温和/或应力下引起了变形事件的雪崩。
Creep is defined as time-dependent deformation and rupture processes taking place within a material subjected to a constant applied stress smaller than its athermal, time-independent strength. This time-dependence is classically attributed to thermal activation of local deformation events. The phenomenology of creep is characterized by several ubiquitous but empirical rheological and scaling laws. We focus here on primary creep following the onset of loading, for which a power law decay of the strain-rate is observed, with the exponent p varying between '0.4 and 1, this upper bound defining the so-called logarithmic creep. Although this phenomenology is known for more than a century, the physical origin of Andrade-like (p <1) creep remains unclear and debated. Here we show that p <1 values arise from the interplay between thermal activation and elastic stress redistribution. The latter stimulates creep dynamics from a shortening of waiting times between successive events, is associated to material damage and possibly, at high temperature and/or stresses, gives rise to avalanches of deformation events.
