AI 中文总结
该研究采用内聚力区相场模型，揭示颗粒填充聚合物中弱界面可诱导中间软化阶段，降低最大应力但提高断裂应变，明确了弱界面的双重作用。
AI 中文摘要
颗粒-基体弱界面在颗粒填充聚合物复合材料的拉伸断裂中发挥关键作用，但它们如何控制渐进脱粘、断裂定位以及由此产生的宏观力学性能变化仍未得到充分理解。本研究采用内聚力区相场模型，该模型包含超弹性聚合物基体和弥散界面，用于研究颗粒填充聚合物复合材料中界面脱粘与基体断裂的耦合演化。该模型经颗粒填充聚氨酯复合材料的单轴拉伸响应校准并与其对比，随后用于研究界面强度、界面断裂能和基体断裂性能如何影响宏观应力-应变响应与损伤演化。结果表明，弱界面可在应力-应变响应中诱导中间软化阶段，其特征为有效切线刚度降低，且与分布式界面损伤相关。界面强度主要控制脱粘的起始，而界面断裂能影响脱粘是以分布式方式渐进发展还是快速定域为主导裂纹带。与结合良好的参考体系的对比进一步表明，弱界面通过促进颗粒周围的分布式脱粘并延迟主导裂纹带的形成，可降低最大应力但提高断裂应变。这些发现阐明了弱界面的双重作用，并为颗粒填充聚合物复合材料中界面控制的拉伸断裂提供了机理解释。
英文摘要
Weak particle-matrix interfaces play a critical role in the tensile fracture of particle-filled polymer composites, but how they govern progressive debonding, fracture localization, and the resulting changes in macroscopic mechanical properties remains insufficiently understood. In this study, a cohesive-zone phase-field model incorporating a hyperelastic polymer matrix and a smeared interface is employed to investigate the coupled evolution of interfacial debonding and matrix fracture in particle-filled polymer composites. The model is calibrated against and compared with uniaxial tensile responses of particle-filled polyurethane composites and then used to study how interfacial strength, interfacial fracture energy, and matrix fracture properties affect the macroscopic stress-strain response and damage evolution. The results show that weak interfaces can induce an intermediate softening regime in the stress-strain response, characterized by a reduced effective tangent stiffness and associated with distributed interfacial damage. Interfacial strength mainly controls the initiation of debonding, whereas interfacial fracture energy affects whether debonding can develop progressively in a distributed manner or rapidly localizes into a dominant crack band. Comparisons with well-bonded reference systems further demonstrate that weak interfaces may reduce the maximum stress but increase the strain at break by promoting distributed debonding around particles and delaying the formation of a dominant crack band. These findings clarify the dual role of weak interfaces and provide a mechanistic understanding of interface-controlled tensile failure in particle-filled polymer composites.
Comments49 pages, 16 figures
