Mapping the nonlinear crack tip deformation field in soft elastomer with a particle tracking method
Mapping the nonlinear crack tip deformation field in soft elastomer with a particle tracking method
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DOI：
10.1016/j.jmps.2018.12.018
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发表时间：
2019-04-01
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;Zou, Zhanan;Long, Rong
在广泛的现有和新兴应用中，高度期望可拉伸和耐磨损的弹性体或凝胶。软材料的断裂，特别是韧性显著增强的材料，通常涉及裂纹尖端附近的严重变形。然而，由于其高度不均匀和非线性的性质，在软材料中的裂纹尖端变形场的实验表征一直具有挑战性。这是一个重要的限制，对一个完整的理解复杂的力学涉及软材料断裂。在本文中，我们提出的非线性，多轴裂纹尖端变形场的跟踪随机分布的示踪粒子的实验数据。具体而言，我们测量了软硅橡胶中的模式I裂纹尖端周围的位移和变形梯度场。我们实验观察到，为第一次，一个区域的有效性的渐近解的裂纹尖端变形场在超弹性固体与强应变硬化。此外，所测量的裂纹尖端变形场使得能够通过J积分局部评估能量释放率，这可以去除特定实验几何形状的要求，例如纯剪切断裂测试，以测量断裂韧性。它还能够确定参考配置中定义的真实裂纹延伸长度。基于这两个能力，我们能够测量裂纹扩展阻力行为和断裂韧性的速率依赖性的软材料与高度钝化裂纹。(C)2018爱思唯尔有限公司版权所有
Stretchable and fracture-resistant elastomers or gels are highly desirable in a wide range of existing and emerging applications. Fracture of soft materials, especially the ones with significantly enhanced toughness, typically involves severe deformation near the crack tip. However, experimental characterization of the crack tip deformation field in soft materials has been challenging due to its highly non-uniform and nonlinear nature. This is an important limitation towards a complete understanding of the intricate mechanics involved in soft material fracture. In this paper we present experimental data of the nonlinear, multiaxial crack tip deformation field obtained by tracking randomly distributed tracer particles. Specifically, we measured the fields of displacement and deformation gradient around the tip of a Mode-I crack in a soft silicone elastomer. We experimentally observed, for the first time, a region of validity for the asymptotic solution of crack tip deformation field in hyperelastic solids with strong strain stiffening. Furthermore, the measured crack tip deformation field enables local evaluation of energy release rate through the J-integral, which can remove the requirement of specific experimental geometries, such as the pure shear fracture test, to measure the fracture toughness. It also enables determination of the true crack extension length defined in the reference configuration. Based on these two capabilities, we were able to measure the crack growth resistance behavior and the rate dependence of fracture toughness for soft materials with highly blunted cracks. (C) 2018 Elsevier Ltd. All rights reserved.