标题： 软聚合物断裂的建模 显示英文标题

标题： On modeling fracture of soft polymers

摘要： 软聚合物是自然界和工程材料中无处不在的材料，其性质从与速率无关到与速率有关，这取决于交联机制。 当前对于具有速率依赖性的软材料的断裂韧性测量在不同的加载轮廓和试样几何形状下是非唯一的。 关于在具有速率依赖性的软聚合物中建模断裂的研究仅限于特定的预裂纹几何形状。 对于软聚合子的断裂，还没有普遍接受的模型。 我们提出并展示了通过简单的均匀变形实验获得的应力功$\mathit{W}_{cr}$的临界值可以作为软聚合物断裂阻力的简单实验标量度量。 我们还开发了一个损伤模型，通过基于虚功率法的广义梯度损伤框架来预测软聚合物的断裂。 临界应力功的能量部分被提出作为损伤起始准则。 在模型中，材料强度，这是相场损伤模型的重要组成部分，被显式考虑。 通过将模型预测与不同材料（乙烯丙烯二烯单体 - EPDM，EPS25 塑性体，苯乙烯丁二烯橡胶 - SBR 和聚硼硅氧烷 - PBS）的实验结果、各种试样几何形状和加载条件进行比较，验证了该断裂模型，并证明其在弹性体和粘性软聚合物中都能很好地工作。 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 used as a simple experimental 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 based on the method of virtual power. The energetic part of the critical stress work is proposed as a damage initiation criterion. In the model, material strength, which is an important component of phase field damage models, is explicitly accounted for. The fracture model is validated and 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, styrene butadiene rubber - SBR, and polyborosiloxane - PBS), 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.