Kumar D, Patinet S, Maloney C E, Regev I, Vandembroucq D, Mungan M
PMMH, CNRS, ESPCI Paris, Université PSL, Sorbonne Université, Université Paris Cité, Paris, France.
Northeastern University, Boston, Massachusetts 02115, USA.
J Chem Phys. 2022 Nov 7;157(17):174504. doi: 10.1063/5.0102669.
We develop a mesoscopic model to study the plastic behavior of an amorphous material under cyclic loading. The model is depinning-like and driven by a disordered thresholds dynamics that is coupled by long-range elastic interactions. We propose a simple protocol of "glass preparation" that allows us to mimic thermalization at high temperatures as well as aging at vanishing temperature. Various levels of glass stabilities (from brittle to ductile) can be achieved by tuning the aging duration. The aged glasses are then immersed into a quenched disorder landscape and serve as initial configurations for various protocols of mechanical loading by shearing. The dependence of the plastic behavior upon monotonous loading is recovered. The behavior under cyclic loading is studied for different ages and system sizes. The size and age dependence of the irreversibility transition is discussed. A thorough characterization of the disorder-landscape is achieved through the analysis of the transition graphs, which describe the plastic deformation pathways under athermal quasi-static shear. In particular, the analysis of the stability ranges of the strongly connected components of the transition graphs reveals the emergence of a phase-separation like process associated with the aging of the glass. Increasing the age and, hence, the stability of the initial glass results in a gradual break-up of the landscape of dynamically accessible stable states into three distinct regions: one region centered around the initially prepared glass phase and two additional regions characterized by well-separated ranges of positive and negative plastic strains, each of which is accessible only from the initial glass phase by passing through the stress peak in the forward and backward, respectively, shearing directions.
我们开发了一个介观模型来研究非晶材料在循环加载下的塑性行为。该模型类似于脱钉模型，由长程弹性相互作用耦合的无序阈值动力学驱动。我们提出了一种简单的“玻璃制备”方案，该方案使我们能够模拟高温下的热化以及零温度下的老化。通过调整老化持续时间，可以实现不同程度的玻璃稳定性（从脆性到韧性）。然后将老化后的玻璃浸入淬火无序势场中，并作为各种剪切机械加载方案的初始构型。恢复了塑性行为对单调加载的依赖性。研究了不同老化程度和系统尺寸下的循环加载行为。讨论了不可逆转变的尺寸和老化依赖性。通过对转变图的分析实现了对无序势场的全面表征，这些图描述了无热准静态剪切下的塑性变形路径。特别是，对转变图的强连通分量的稳定性范围的分析揭示了与玻璃老化相关的类似相分离过程的出现。增加初始玻璃的老化程度以及稳定性会导致动态可及稳定状态的势场逐渐分解为三个不同的区域：一个区域以最初制备的玻璃相为中心，另外两个区域的特征是正塑性应变和负塑性应变范围明显分开，每个区域只能通过分别在向前和向后剪切方向上通过应力峰值从初始玻璃相到达。
