标题： 软聚合物断裂建模 显示英文标题

标题： On modeling fracture of soft polymers

摘要： 软聚合物在自然界和工程材料中无处不在，其特性从与速率无关到与速率有关，这取决于交联机制。 当前的断裂韧性测量对于与速率有关的软材料来说，在不同的加载轮廓和试样几何形状下是不唯一的。 关于与速率有关的软聚合物断裂建模的研究仅限于特定的预裂纹几何形状。 对于软聚合物的断裂，还没有普遍接受的模型。 我们提出并展示了通过简单均匀变形实验获得的应力功临界值$\mathit{W}_{cr}$可以作为软聚合物断裂阻力的标量度量。 我们还开发了一个损伤模型，通过广义梯度损伤框架预测软聚合物的断裂。 $\mathit{W}_{cr}$的能量部分被提出作为损伤起始准则。 通过将模型预测与不同材料（乙烯丙烯二烯单体 - EPDM，EPS25热固性树脂，聚硼硅氧烷）的实验结果进行比较，该断裂模型被证明在弹性体和粘性软聚合物中都能很好地工作，涉及多种试样几何形状和加载条件。 该模型能够预测关键的物理现象和微观结构物理量，例如软聚合物断裂过程中的亚链解离能。 显示英文摘要

摘要： Soft polymers are ubiquitous materials in nature and as engineering materials with properties varying from rate-independent to rate-dependent depending on the crosslinking mechanisms. Current fracture toughness measures are non-unique for rate-dependent soft materials for varying loading profiles and specimen geometries. Works on modeling fracture in rate-dependent soft polymers are limited to specific pre-cracked geometries. There is no generally agreed-upon model for the fracture of soft polymers. We propose and show that a critical value of stress work $\mathit{W}_{cr}$ obtained from simple homogeneous deformation experiments can be a scalar measure of fracture resistance in soft polymers. We also develop a damage model to predict fracture in soft polymers through a generalized gradient damage framework. The energetic part of $\mathit{W}_{cr}$ is proposed as a damage initiation criterion. The fracture model is demonstrated to work well for both elastomers and viscous soft polymers by comparing model predictions against experimental results for different materials (ethylene propylene diene monomer - EPDM, EPS25 vitrimer, polyborosiloxane), a variety of specimen geometries, and loading conditions. The model is able to predict key physical phenomena and microstructural physical quantities, such as subchain dissociation energy during the fracture of soft polymers.