Hydrogels exhibit a wide range of responses to various stimuli, which makes them useful in myriad applications including the biomedical industry. To capture certain features of this varied response, several constitutive models have been proposed. However, few attempts have been made at the predictive modelling of temperature and moisture driven transition between fast and slowly relaxing states in physical hydrogels. We in this article focus on the changes that occur in the mechanical response due to such phase transitions. We propose a unified and thermodynamically consistent poro-visco-elastic framework for modelling the transition and the associated mechanical behaviour. Towards that, the effective temperature framework that has been previously exploited for such transitions by the authors and other researchers is used. The constitutive model is numerically solved for the uniaxial tensile response of equilibrated hydrogels and also validated against experimental data from the literature. It is also used for certain transient problems involving solvent diffusion with or without mechanical constrains. The aim of this exercise is to assess the predictive fidelity of the model against some standard poro-elastic problems and examine the influence of inter-molecular interactions on the saturation. The numerical studies are concluded with a set of simulations to showcase certain other capabilities of our approach such as modelling of visco-hyperelastic phase transitions. We also investigate through these simulations a few other coupling effects caused by changes in moisture, temperature, loading rates and prior ageing.

水凝胶对各种刺激表现出广泛的反应，这使其可用于包括生物医学行业在内的多种应用中。为了捕获这种变化响应的某些特征，已经提出了几种本构模型。然而，在物理水凝胶中快速和缓慢松弛状态之间温度和水分驱动的转变之间的预测模型方面，很少进行尝试。在本文中，我们重点讨论由于此类相变而导致的机械响应发生的变化。我们提出了一个统一的且热力学上一致的孔隙-粘弹性框架，用于对转变和相关的机械行为进行建模。为此，使用了作者和其他研究人员先前为此类转换所利用的有效温度框架。本构模型在数值上求解了平衡水凝胶的单轴拉伸响应，并针对文献中的实验数据进行了验证。它也可用于某些瞬态问题，涉及有或没有机械约束的溶剂扩散。本练习的目的是针对某些标准的孔隙弹性问题评估模型的预测保真度，并研究分子间相互作用对饱和度的影响。数值研究以一组模拟结束，以展示我们方法的某些其他功能，例如，粘超弹性相变建模。我们还通过这些模拟研究了由湿度，温度，负载率和先前老化引起的其他一些耦合效应。