This paper presents a finite element analysis of steady-state crack propagation in viscoelastic soft solids exhibiting Mullins softening. A cohesive-zone model is employed to simulate the localized processes at the tip of a Mode I crack in materials governed by viscoelastic behavior and damage-induced Mullins effects. The study numerically evaluates the intrinsic dissipation characteristics of typical rubber-like materials, focusing on the influence of key factors such as Mullins damage, relaxation modulus, and relaxation time. The impact of these factors on material toughening is examined, with particular emphasis on their role in crack propagation. The results reveal that crack propagation velocity is highly sensitive to the interplay between energy dissipation mechanisms. Specifically, Mullins damage parameters are shown to increase fracture toughness by raising the local energy release rate threshold at the crack tip. Additionally, the relaxation modulus enhances viscous dissipation, further elevating this threshold and subsequently reducing crack propagation velocity. Interestingly, an inverse relationship between relaxation time and crack propagation velocity is observed. The study provides a detailed analysis of the dissipation mechanisms at the crack tip, offering valuable insights for improving material toughness.

中文翻译：

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Mullins 软化对粘弹性固体中 I 型裂纹扩展影响的数值研究


本文对表现出 Mullins 软化的粘弹性软固体中的稳态裂纹扩展进行了有限元分析。采用内聚区模型来模拟材料中 I 型裂纹尖端的局部过程，这些过程受粘弹性行为和损伤诱导的 Mullins 效应控制。该研究对典型类橡胶材料的内禀耗散特性进行了数值评估，重点关注 Mullins 损伤、弛豫模量和弛豫时间等关键因素的影响。研究了这些因素对材料增韧的影响，特别强调了它们在裂纹扩展中的作用。结果表明，裂纹扩展速度对能量耗散机制之间的相互作用高度敏感。具体来说，Mullins 损伤参数通过提高裂纹尖端的局部能量释放速率阈值来增加断裂韧性。此外，松弛模量增强了粘性耗散，进一步提高了该阈值，从而降低了裂纹扩展速度。有趣的是，观察到弛豫时间和裂纹扩展速度之间存在反比关系。该研究详细分析了裂纹尖端的耗散机制，为提高材料韧性提供了有价值的见解。