Semisoft elastic response of nematic elastomers to complex deformations.
Semisoft elastic response of nematic elastomers to complex deformations.
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DOI：
10.1103/physreve.78.041704
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发表时间：
2008-10
期刊：
影响因子：
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通讯作者：
J. Biggins;E. Terentjev;M. Warner
中科院分区：
文献类型：
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作者：
J. Biggins;E. Terentjev;M. Warner
我们考虑一种松弛的半软弹性体，其指向矢沿 z 轴取向，首先在 x 方向上受到较大的拉伸，然后受到轻微的 x-z 剪切。我们给出一个一般性的论点，即在任何包括导向器旋转的理论中，在由这些大拉伸引起的导向器旋转的开始和结束时，应力-大应变曲线中都会出现扭结（形成应力-应变平台），并且与施加在拉伸顶部的小剪切相关的 x-z 剪切模量 (C5) 中将出现零。然后，我们找到了特定半软度模型（由成分波动引起）的 C5 应变曲线的分析形式，并表明它与已知的应力-应变曲线一起，为对该理论进行强有力的检验提供了基础。最后，我们考虑其他半软模型的范围，并表明成分涨落模型实际上产生了一种通用形式，即它是最一般的二次自由能，除了指向矢之外，不明确包括最终状态方向。通过引入此类附加方向，可以开发大量替代模型。
We consider a relaxed semisoft elastomer with its director oriented along the z axis that is first subjected to a large stretch in the x direction then to a slight x-z shear. We give a general argument that in any theory including director rotation, at the onset and end of the director rotation induced by these large stretches, there will be kinks in the stress-large strain curve (forming a stress-strain plateau) and zeros in the x-z shear modulus (C5) associated with small shears imposed on top of the stretches. We then find the analytical forms of the C5 -strain curves for a particular model of semisoftness (arising from compositional fluctuations) and show that it, together with the known stress-strain curve, provides the basis for a strong test of this theory. Finally, we consider the scope for other semisoft models and show that the compositional fluctuations model in fact yielded a generic form, that is, it is the most general quadratic free energy that does not explicitly include a final state direction other than the director. By introducing such additional directions, a large range of alternative models could be developed.