AMOLF, 1098 XG Amsterdam, The Netherlands;
AMOLF, 1098 XG Amsterdam, The Netherlands.
Proc Natl Acad Sci U S A. 2021 Dec 14;118(50). doi: 10.1073/pnas.2111436118.
The nonlinear response of driven complex materials-disordered magnets, amorphous media, and crumpled sheets-features intricate transition pathways where the system repeatedly hops between metastable states. Such pathways encode memory effects and may allow information processing, yet tools are lacking to experimentally observe and control these pathways, and their full breadth has not been explored. Here we introduce compression of corrugated elastic sheets to precisely observe and manipulate their full, multistep pathways, which are reproducible, robust, and controlled by geometry. We show how manipulation of the boundaries allows us to elicit multiple targeted pathways from a single sample. In all cases, each state in the pathway can be encoded by the binary state of material bits called hysterons, and the strength of their interactions plays a crucial role. In particular, as function of increasing interaction strength, we observe Preisach pathways, expected in systems of independently switching hysterons; scrambled pathways that evidence hitherto unexplored interactions between these material bits; and accumulator pathways which leverage these interactions to perform an elementary computation. Our work opens a route to probe, manipulate, and understand complex pathways, impacting future applications in soft robotics and information processing in materials.
受迫复杂材料的非线性响应——无序磁体、非晶态介质和褶皱薄片——具有复杂的转变途径，在这些途径中，系统会在亚稳态之间反复跳跃。这些途径编码了记忆效应，可能允许信息处理，但缺乏用于实验观察和控制这些途径的工具，而且其全部范围尚未得到探索。在这里，我们引入了波纹弹性薄片的压缩，以精确观察和控制它们完整的、多步骤的途径，这些途径具有可重复性、稳健性，并且可以通过几何形状进行控制。我们展示了如何通过操纵边界，从单个样本中引出多种目标途径。在所有情况下，途径中的每个状态都可以通过称为滞后器的材料位的二进制状态来编码，并且它们之间相互作用的强度起着至关重要的作用。特别是，随着相互作用强度的增加，我们观察到了 Preisach 途径，这在独立切换滞后器的系统中是预期的；观察到了在这些材料位之间存在迄今未探索的相互作用的混乱途径；以及利用这些相互作用来执行基本计算的累加器途径。我们的工作为探索、操纵和理解复杂途径开辟了道路，这将对软机器人和材料中的信息处理的未来应用产生影响。
