发表机构
Kyoto University; Advanced Manufacturing Technology Institute, Kanazawa University; Kyoto MPI Inc.（京都大学; 金泽大学先进制造技术研究所; 京都MPI公司）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出一种基于取向动力学并隐含构象拉伸的偏应力本构方程，通过有效系数再现Cox-Merz等关系，并成功预测瞬态剪切、振荡剪切及单轴拉伸响应，为聚合物粘弹性提供新描述。
AI 中文摘要
我们提出了一种由取向动力学推导出的偏应力本构方程，同时隐含地保留构象拉伸的贡献。从哑铃模型出发，我们表明构象拉伸通过有效应力尺度和旋转扩散系数影响取向动力学，这两者决定了有效松弛时间。通过假设取向各向异性与拉伸状态之间的近似关系，推导出基于取向的方程。在所提出的框架内，恒定有效系数产生的稳态振荡剪切对应关系与经验性的Cox-Merz和Gleissle-Osaki关系密切相关。对于特定模型的有效系数，上对流Maxwell模型的特征是恒定松弛时间和稳态剪切下模量的增加，而具有Peterlin预平均的有限可延展性缩短了松弛时间并抑制了模量的增加。利用由稳态剪切状态确定的系数，所提出的方程成功再现了瞬态剪切、大幅振荡剪切和单轴拉伸下的应力响应。这些结果表明，构象拉伸对取向动力学的影响可以隐含地保留，提供了一种基于偏应力状态的本构描述，该状态可从标准流变测量中重建，并对拉伸如何进入聚合物粘弹性提供了物理解释。
英文摘要
We propose a deviatoric-stress constitutive equation derived from orientational kinetics, while implicitly retaining contributions from conformational stretch. Starting from the dumbbell model, we show that conformational stretch affects orientational dynamics through an effective stress scale and rotational diffusivity, which determine an effective relaxation time. The orientation-based equation is derived by assuming an approximate relation between orientational anisotropy and the stretch state. Within the proposed framework, constant effective coefficients yield steady-oscillatory shear correspondences closely related to the empirical Cox-Merz and Gleissle-Osaki relations. For model-specific effective coefficients, the upper-convected Maxwell model is characterized by a constant relaxation time and an increasing modulus under steady shear, whereas finite extensibility with Peterlin preaveraging shortens the relaxation time and suppresses the modulus increase. With coefficients determined from steady-shear states, the proposed equation successfully reproduces stress responses under transient shear, large-amplitude oscillatory shear, and uniaxial extension. These results show that the effects of conformational stretch on orientational kinetics can be retained implicitly, providing a constitutive description based on a deviatoric-stress state reconstructable from standard rheometry and a physical interpretation of how stretch enters polymer viscoelasticity.
Comments14 pages, 4 figures
