Two questions related to elastic motions are raised and addressed. First: in which theoretical framework can the equations of motion be written for an elastic half-space put into uniform rotation? It is seen that nonlinear finite elasticity provides such a framework for incompressible solids. Second: how can finite amplitude exact solutions be generated? It is seen that for some finite amplitude transverse waves in rotating incompressible elastic solids with general shear response, the solutions are obtained by reduction of the equations of motion to a system of ordinary differential equations equivalent to the system governing the central motion problem of classical mechanics. In the special case of circularly-polarized harmonic progressive waves, the dispersion equation is solved in closed form for a variety of shear responses, including nonlinear models for rubberlike and soft biological tissues. A fruitful analogy with the motion of a nonlinear string is pointed out.
Why is nacre strong? II: remaining mechanical weakness for cracks propagating along the sheets
在我们以前的论文（Eur。Phys.J.E4，121（2001）），我们提出了用于珍珠层或硬层和软层的分层结构的粗粒弹性能。然后，我们分析了垂直于层的裂纹，并提出了这种物质韧性增强的一个可能原因。在本文中，我们考虑一个平行于层的裂纹。我们提出了一个新的术语添加到以前的弹性能量，这是与层的弯曲。我们发现，有两个制度的平行断裂解决方案的弹性能量;附近的断裂尖端的变形场是由一个抛物型微分方程，而远离尖端的字段遵循通常的椭圆方程。分析结果表明，断裂尖端是透镜状的，正如一篇关于近晶相液晶的论文（P.G. de Gennes，Europhys. Lett. 13（8），709（1990））。相反，远离尖端，应力和变形分布恢复通常的奇异行为（分别为sqrt（x）和1/sqrt（x），其中x是到尖端的距离）。这表明在平行断裂的情况下韧性没有增强。
