标题： 一种用于吸湿响应材料流变行为的统一模型 显示英文标题

标题： A Unifying Model for the Rheological Behavior of Hygro-responsive Materials

摘要： 湿度响应材料表现出复杂的结构-性能关系。 这些材料内部的水相互作用在不同的湿度和机械载荷下在其宏观变形和最终应用中起着关键作用。 虽然文献中已有多种模型，但许多模型缺乏对这些现象的全面物理理解。 在本研究中，我们引入了一种新的粘滑纤维束模型，该模型能够捕捉湿度响应材料的基本行为。 我们将与湿度相关的元件以及滑移应变的启动和松弛规则以及失效机制整合到纤维束模型所提供的统计方法中。 这些附加特性基于对纤维素材料的结构-性能关系的合理解释。 滑移应变由载荷和湿度的变化以及蠕变变形触发。 当受到湿度循环作用时，模型会积累滑移应变，从而产生机械吸附行为。 当载荷移除时，滑移应变部分得到松弛，随后的湿度循环会引发进一步的松弛，这与机械吸附材料的观察结果一致。 重要的是，这些滑移应变不被视为塑性应变；相反，它们是统一的、非线性的冻结应变，由各种刺激激活。 纤维的失效由允许从完整、损坏到失效状态进行集成模拟的临界滑移事件数定义。 我们研究了在相关参数范围内，湿度和机械载荷历史变化时这些模式之间的转变。 我们增强的粘滑纤维束模型提高了对湿度响应材料复杂行为的理解，并有助于建立更稳健的分析和解释其特性的框架。 显示英文摘要

摘要： Hygro-responsive materials exhibit a complex structure-to-property relationship. The interactions of water within these materials under varying hygric and mechanical loads play a crucial role in their macroscopic deformation and final application. While multiple models are available in literature, many lack a comprehensive physical understanding of these phenomena. In this study, we introduce a novel Stick-Slip Fiber Bundle Model that captures the fundamental behaviors of hygro-responsive materials. We incorporate moisture-dependent elements and rules governing the initiation and relaxation of slip strains as well as failure to the statistical approach offered by Fiber Bundle Models. The additional features are based on well-founded interpretations of the structure-to-property relationship in cellulosic materials. Slip strains are triggered by changes in load and moisture, as well as by creep deformations. When subjected to moisture cycles, the model accumulates slip strains, resulting in mechanosorptive behavior. When the load is removed, slip strains are partially relaxed, and subsequent moisture cycles trigger further relaxation, as expected from observations with mechanosorptive material. Importantly, these slip strains are not considered plastic strains; instead, they are unified, non-linear frozen strains, activated by various stimuli. Failure of fibers is defined by a critical number of slip events allowing for an integrated simulation from intact, via damaged, failed states. We investigate the transition between these regimes upon changes in the hygric and mechanical loading history for relevant parameter ranges. Our enhanced Stick-Slip Fiber Bundle Model increases the understanding of the intricate behavior of hygro-responsive materials and contributes to a more robust framework for analyzing and interpreting their properties.