In this paper, a Helmholtz-potential-based thermodynamic approach was developed for modelling fluids that exhibit both yielding and thixotropic behavior. The yielding behavior was captured using a framework of multiple natural configurations. The thixotropy was described using a structural parameter. The Helmholtz potential is made a function of a structural parameter and a stretch quantity, and the rate of dissipation was made to depend on the rate of change of the natural configuration and the time derivative of the structural parameter. The final constitutive equations were obtained by maximizing the rate of dissipation with the reduced dissipation equation as a constraint. For experimental corroboration of the model, steady-shear and step-shear experiments were performed using cement paste. The predictions from the model were found to match well with the experimental data. Finally, the different model variants that can also be obtained using the presented framework are discussed.

在本文中，开发了一种基于亥姆霍兹势的热力学方法来对表现出屈服和触变性的流体进行建模。使用多个自然配置的框架捕获了屈服行为。触变性是用结构参数描述的。亥姆霍兹势是结构参数和拉伸量的函数，耗散率取决于自然构型的变化率和结构参数的时间导数。通过以降低的耗散方程为约束条件使耗散率最大化来获得最终的本构方程。为了验证模型，使用水泥浆进行了稳定剪切和阶梯剪切实验。发现该模型的预测与实验数据非常吻合。最后，讨论了也可以使用提出的框架获得的不同模型变体。