A Constitutive Model for Soft Materials Incorporating Viscoelasticity and Mullins Effect
A Constitutive Model for Soft Materials Incorporating Viscoelasticity and Mullins Effect
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结合粘弹性和马林斯效应的软材料本构模型
DOI：
10.1115/1.4035180
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发表时间：
2017-02-01
影响因子：
2.6
通讯作者：
Wang, T. J.
中科院分区：
文献类型：
--
作者：
Lu, Tongqing;Wang, Jikun;Wang, T. J.
包括弹性体和凝胶在内的软材料广泛应用于能量吸收、软机器人、生物工程和医疗器械等领域。对于许多经历加载和卸载循环的软材料，重新加载时所需的应力通常小于初始加载时所需的应力，这就是所谓的穆林斯效应。同时，软材料通常表现出与速率相关的粘性行为。这两种作用都是最近报道的一种新型合成韧性凝胶，具有大变形、高强度和极高的韧性。在这项工作中，我们发展了一个粘弹性和Mullins效应的耦合模型来描述韧性凝胶的变形行为。我们将Zener模型中的一个弹性分量修改为可损伤弹簧，以考虑Mullins效应，并将粘性效应模拟为牛顿流体。我们合成了文献(Sun等人，《自然》2012)中描述的韧性凝胶，并进行了单轴拉伸测试和应力松弛测试。我们还研究了这两种影响对其他三种软质材料，聚丙烯酸酯弹性体、丁腈橡胶和聚氨酯的影响。我们发现，我们提出的模型是如此稳健，它可以描述所有四种材料，模数从几十千帕卡到兆帕卡。所有被测材料的理论和实验符合得很好。
Soft materials including elastomers and gels are widely used in applications of energy absorption, soft robotics, bioengineering, and medical instruments. For many soft materials subject to loading and unloading cycles, the stress required on reloading is often less than that on the initial loading, known as Mullins effect. Meanwhile, soft materials usually exhibit rate-dependent viscous behavior. Both effects were recently reported on a new kind of synthesized tough gel, with capability of large deformation, high strength, and extremely high toughness. In this work, we develop a coupled viscoelastic and Mullins-effect model to characterize the deformation behavior of the tough gel. We modify one of the elastic components in Zener model to be a damageable spring to incorporate the Mullins effect and model the viscous effect to behave as a Newtonian fluid. We synthesized the tough gel described in the literature (Sun et al., Nature 2012) and conducted uniaxial tensile tests and stress relaxation tests. We also investigated the two effects on three other soft materials, polyacrylate elastomer, Nitrile-Butadiene Rubber, and polyurethane. We find that our presented model is so robust that it can characterize all the four materials, with modulus ranging from a few tens of kilopascal to megapascal. The theory and experiment for all tested materials agree very well.