A coarse-grained bead-spring-dashpot chain model with the dashpots representing the presence of internal friction is solved exactly numerically for the case of chains with more than two beads. Using a decoupling procedure to remove the explicit coupling of a bead’s velocity with that of its nearest neighbors, the governing set of stochastic differential equations are solved with Brownian dynamics simulations to obtain material functions in oscillatory and steady simple shear flow. Simulation results for the real and imaginary components of the complex viscosity have been compared with the results of previously derived semi-analytical approximations, and the difference in the predictions is seen to diminish with an increase in the number of beads in the chain. The inclusion of internal friction results in a nonmonotonous variation of the viscosity with shear rate, with the occurrence of continuous shear-thickening following an initial shear-thinning regime. The onset of shear-thickening in the first normal stress coefficient is pushed to lower shear rates with an increase in the internal friction parameter.

中文翻译：

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具有波动内摩擦的 Rouse 模型

对于具有两个以上珠子的链子的情况，粗粒度珠子-弹簧-缓冲器链模型用表示内摩擦存在的缓冲器精确地数值求解。使用解耦程序去除珠子速度与其最近邻居速度的显式耦合，随机微分方程组用布朗动力学模拟求解，以获得振荡和稳定的简单剪切流中的材料函数。复数粘度的实部和虚部的模拟结果已与先前推导的半分析近似的结果进行了比较，并且预测的差异随着链中珠子数量的增加而减小。内摩擦的加入导致粘度随剪切速率的非单调变化，在初始剪切稀化状态后发生连续的剪切稠化。随着内摩擦参数的增加，第一法向应力系数中剪切增稠的开始被推到较低的剪切速率。