Fracture toughness of soft materials with rate-independent hysteresis
Fracture toughness of soft materials with rate-independent hysteresis
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DOI：
10.1016/j.jmps.2018.05.020
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发表时间：
2018-09-01
影响因子：
5.3
通讯作者：
Long, Rong
中科院分区：
文献类型：
--
作者：
Qi, Yuan;Caillard, Julien;Long, Rong
软弹性体或凝胶的断裂韧性可以通过将各种能量耗散机制引入到块体材料中来显著增强。表现在加载-卸载循环的滞后中的体积耗散使得能够在裂纹尖端周围形成耗散区，该耗散区消耗由外部加载提供的大部分能量以驱动裂纹扩展，从而有效地增加断裂韧性。为了预测具有明显滞后的软材料中的裂纹扩展，需要深入了解体耗散对断裂韧性的影响。然而，由于软材料断裂涉及复杂的非线性力学，目前的认识仅限于定性或经验水平。本文提出了一个理论框架，计算与裂纹扩展相关的能量耗散。为了证明它的实用性，我们专注于稳态裂纹扩展，并考虑一个模型材料系统与率无关的滞后：一个新的Hookean固体与Mullins效应。我们确定的断裂韧性和参数之间的解析关系管理体积滞后，并定量预测由于预拉伸断裂韧性的减少。两者与有限元结果吻合良好。本文提出的框架可以应用于更广泛的耗散软材料，从而为指导高韧性软材料的工程设计提供了理论工具。(C)2018爱思唯尔有限公司版权所有
The fracture toughness of soft elastomers or gels can be substantially enhanced by introducing various energy dissipation mechanisms into the bulk material. Bulk dissipation, manifested in the hysteresis of loading-unloading cycles, enables the formation of a dissipation zone around the crack tip that consumes most of the energy provided by the external loading to drive crack propagation, effectively increasing the fracture toughness. An in-depth understanding on how bulk dissipation contributes to fracture toughness is required to predict crack propagation in soft materials with significant hysteresis. However, the current understanding is limited to the qualitative or empirical level due to the complex nonlinear mechanics involved in soft material fracture. This paper presents a theoretical framework for calculating the energy dissipation associated with crack propagation. To demonstrate its utility, we focus on steady state crack propagation and consider a model material system with rate-independent hysteresis: a neo-Hookean solid with Mullins effect. We determine analytical relations between fracture toughness and the parameters governing bulk hysteresis, and quantitatively predict the reduction in fracture toughness due to pre-stretch. Both agree well with finite element results. The framework presented here can be applied to a broader range of dissipative soft materials, thus providing a theoretical tool to guide the engineering of soft materials with high toughness. (C) 2018 Elsevier Ltd. All rights reserved.