Daraio C, Nesterenko V F, Herbold E B, Jin S
Materials Science and Engineering Program, University of California at San Diego, La Jolla, California 92093-0411, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2005 Jul;72(1 Pt 2):016603. doi: 10.1103/PhysRevE.72.016603. Epub 2005 Jul 6.
One-dimensional "sonic vacuum" type phononic crystals were assembled from a chain of polytetrafluoroethylene (PTFE,Teflon) spheres with different diameters in a Teflon holder. It was demonstrated that this polymer-based sonic vacuum, with exceptionally low elastic modulus of particles, supports propagation of strongly nonlinear solitary waves with a very low speed. These solitary waves can be described using the classical nonlinear Hertz law despite the viscoelastic nature of the polymer and high strain rate deformation of the contact area. The experimentally measured speeds of solitary waves at high amplitudes are close to the theoretically estimated values with a Young's modulus of 1.46 GPa obtained from shock wave experiments. This is significantly higher than the Young's modulus of PTFE from ultrasonic measurements. Trains of strongly nonlinear solitary waves excited by an impact were investigated experimentally and were found to be in reasonable agreement with numerical calculations based on Hertz interaction law though exhibiting a significant dissipation.
一维“声真空”型声子晶体由不同直径的聚四氟乙烯（PTFE，特氟龙）球体链在特氟龙支架中组装而成。结果表明，这种基于聚合物的声真空，其颗粒具有极低的弹性模量，能够支持低速强非线性孤立波的传播。尽管聚合物具有粘弹性且接触区域存在高应变率变形，但这些孤立波仍可使用经典的非线性赫兹定律进行描述。在高振幅下实验测量的孤立波速度接近理论估计值，该理论估计值是基于从冲击波实验获得的1.46 GPa的杨氏模量。这明显高于超声测量得到的PTFE的杨氏模量。对由冲击激发的强非线性孤立波序列进行了实验研究，发现尽管存在显著的耗散，但与基于赫兹相互作用定律的数值计算结果合理相符。
