Odd elasticity
Odd elasticity
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DOI：
10.1038/s41567-020-0795-y
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发表时间：
2020-03-02
期刊：
影响因子：
19.6
通讯作者：
Vitelli, Vincenzo
中科院分区：
文献类型：
--
作者：
Scheibner, Colin;Souslov, Anton;Vitelli, Vincenzo
被动固体不能通过任何准静态的变形循环对其周围环境做功。这个属性对允许的弹性模量有很强的限制。在这篇文章中，我们表明，静态弹性模量完全没有被动弹性可以产生主动，非保守的微观相互作用。这些有效模量进入静态弹性模量张量的反对称（或奇数）部分，并量化沿沿着准静态应变循环提取的功的量。在二维各向同性介质中，除了体模量和剪切模量外，还出现了两个手征奇弹性模量。我们讨论微观实现，包括网络的虎克弹簧增强与积极的横向力和非互惠的积极铰链。使用粗粒度的微观模型，数值模拟和连续方程，我们发现的现象，从拉胀行为引起的奇数模量的弹性波传播过阻尼介质中的自维持主动应变周期。我们的工作揭示了二维和三维活动固体的非厄米力学，这些活动固体保持线性动量，但表现出非互易的线性响应。活动，非保守的相互作用可以产生弹性模量，这在平衡时是禁止的，并进入刚度张量的反对称部分。由此产生的固体作为分布式弹性引擎，可以通过准静态应变循环对周围环境做功。
A passive solid cannot do work on its surroundings through any quasistatic cycle of deformations. This property places strong constraints on the allowed elastic moduli. In this Article, we show that static elastic moduli altogether absent in passive elasticity can arise from active, non-conservative microscopic interactions. These active moduli enter the antisymmetric (or odd) part of the static elastic modulus tensor and quantify the amount of work extracted along quasistatic strain cycles. In two-dimensional isotropic media, two chiral odd-elastic moduli emerge in addition to the bulk and shear moduli. We discuss microscopic realizations that include networks of Hookean springs augmented with active transverse forces and non-reciprocal active hinges. Using coarse-grained microscopic models, numerical simulations and continuum equations, we uncover phenomena ranging from auxetic behaviour induced by odd moduli to elastic wave propagation in overdamped media enabled by self-sustained active strain cycles. Our work sheds light on the non-Hermitian mechanics of two- and three-dimensional active solids that conserve linear momentum but exhibit a non-reciprocal linear response.Active, non-conservative interactions can give rise to elastic moduli that are forbidden in equilibrium and enter the antisymmetric part of the stiffness tensor. The resulting solids function as distributed elastic engines that can perform work on their surroundings through quasistatic strain cycles.