论文标题
可逆塑料状态中无定形物质的异常柔软度
Anomalous softness in amorphous matter in the reversible plastic regime
论文作者
论文摘要
我们研究了一个无定形固体的整数自动机弹塑性模型，该模型受振幅$γ$的环状剪切作用。我们专注于中间体$γ_0<γ<γ_y$的可逆塑性状态，在瞬态后，系统将系统沉降到周期性的极限周期，并具有滞后，耗时的塑料事件，这些事件在整数周期数后重复。我们研究塑性应变速率，$ \ frac {dε} {dγ} $，（$γ$是施加的应变，$ε$是塑料菌株），并表明它由低$ frac {dγ; dampration and tarrivation and tarrivation and Truncation and tartication and tartical and Truncation and Truncation and tartical， $σ_*$，到具有较高$ \ frac {dε} {dγ} $的流动制度。我们表明，尽管将$γ$提高到$γ_0$以上，从而导致较低的终端状态能量，$ u _ {\ text {min}} $，以及相应地窄的压力分布，但令人惊讶的是，它导致较低的$γ_*$和$σ__*$。应力分布$ p（σ）$，也以$γ>γ_0$偏向。也就是说，RPR中的系统异常柔软且机械化。我们将其与应力分布中的新兴特征特征（$ p（σ）$，$σ_0$，它与$γ$无关，并表明$σ_0$ $σ_0$表示$γ$依赖性$σ_*_*$，$γ_*$，以及塑料量的质量损伤$ femittion $σ_0$。我们表明，磁滞的发生的特征是幂律缩放，表明二阶换档了$ε_p\ propto（γ-γ_0）^{1.2 \ pm0.1} $。我们认为，$σ_0$，相应地，RPR在$γ=γ_0$中的发作只是由所谓的Eshelby符号设置。此外，我们表明以$γ_0$的循环循环导致最大硬化状态。
We study an integer automaton elasto-plastic model of an amorphous solid subject to cyclic shear of amplitude $Γ$. We focus on the reversible plastic regime at intermediate $Γ_0<Γ<Γ_y$, where, after a transient, the system settles into a periodic limit cycle with hysteretic, dissipative plastic events which repeat after an integer number of cycles. We study the plastic strain rate, $\frac{dε}{dγ}$, (where $γ$ is the applied strain and $ε$ is the plastic strain) during the terminal limit cycles and show that it consists of a creeping regime at low $γ$ with very low $\frac{dε}{dγ}$ followed by a sharp transition at a characteristic strain, $γ_*$, and stress, $σ_*$, to a flowing regime with higher $\frac{dε}{dγ}$. We show that while increasing $Γ$ above $Γ_0$ results in lower terminal ground state energy, $U_{\text{min}}$, and a correspondingly narrower distribution of stresses, it, surprisingly, results in lower $γ_*$, and $σ_*$. The stress distribution, $P(σ)$, also becomes skewed for $Γ>Γ_0$. That is, the systems in the RPR are anomalously soft and mechanically polarized. We relate this to an emergent characteristic feature in the stress distribution, $P(σ)$, at a value, $σ_0$, which is independent of $Γ$ and show that $σ_0$ implies a relation between the $Γ$ dependence of $σ_*$, $γ_*$, and the amplitude of plastic strain, $ε_p$. We show that the onset of hysteresis is characterized by a power-law scaling, indicative of a second order transition with $ε_p\propto (Γ-Γ_0)^{1.2\pm0.1}$. We argue that $σ_0$ and, correspondingly, the onset of the RPR at $Γ=Γ_0$, is simply set by the so-called Eshelby-stress. Furthermore, we show that cycling at $Γ_0$ results in a maximally hardened state.
