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arXiv 1301.3574cond-mat.softcond-mat.dis-nn
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无序弹簧网络的动力学行为

Dynamical behavior of disordered spring networks

M. G. Yucht, M. Sheinman, C. P. Broedersz

摘要:

本文采用键稀释的渗流模型研究了二维三角形晶格中弹簧网络的动力学流变特性。流体动力学相互作用通过网络节点和均匀变形液体之间的Stokesian粘性耦合来实现。我们的模拟表明,在临界连接状态下,这些系统显示出弱的幂律流变性,其中复数剪切模量随频率缩放为G^* ~(i * omega)^Delta,其中Delta = 0.41,与Delta = 1/2的平均场预测不一致。临界状态下的弱幂律流变学可以从宏观流变学和非仿射应变波动之间的简单标度关系来理解,对于均衡网络,非仿射应变波动随着频率的消失而发散。我们扩展的动态有效介质理论,表明它定量地描述了一个稀释的三角形晶格远离均衡的流变学,虽然EMT正确地预测近均衡网络的流变学的标度形式,仍然存在定量的差距,由于平均场性质的EMT。令人惊讶的是,通过将流变学的临界标度与应变波动的临界标度联系起来,我们发现无序弹簧网络的动力学行为完全由在没有粘性相互作用的情况下控制弹性网络行为的临界指数决定。

英文摘要:

We study the dynamical rheology of spring networks with a percolation model constructed by bond dilution in a two-dimensional triangular lattice. Hydrodynamic interactions are implemented by a Stokesian viscous coupling between the network nodes and a uniformly deforming liquid. Our simulations show that in a critical connectivity regime, these systems display weak power law rheology in which the complex shear modulus scales with frequency as G^* ~ (i * omega)^Delta where Delta = 0.41, in discord with a mean field prediction of Delta = 1/2. The weak power law rheology in the critical regime can be understood from a simple scaling relation between the macroscopic rheology and the nonaffine strain fluctuations, which diverge with vanishing frequency for isostatic networks. We expand on a dynamic effective medium theory, showing that it quantitatively describes the rheology of a diluted triangular lattice far from isostaticity; although the EMT correctly predicts the scaling form for the rheology of near-isostatic networks, there remains a quantitative disparity due to the mean-field nature of the EMT. Surprisingly, by connecting this critical scaling of the rheology with that of the strain fluctuations, we find that the dynamical behavior of disordered spring networks is fully determined by the critical exponents that govern the behavior of elastic network in the absence of viscous interactions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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