孤立波在一维复合颗粒链中传播特性的模拟研究*

摘要

采用分子动力学方法模拟研究了孤立波在重轻颗粒相间排列的一维复合颗粒链中的传播特性。结果发现，在轻重颗粒的质量比较大或较小时，散射作用较弱，颗粒的速度和孤立波的速度衰减较慢。在轻重颗粒的质量比为中等时，散射作用较强，颗粒的速度和孤立波的速度衰减较快。孤立波在通过重-轻颗粒界面时，存在有增速效应，可以提高孤立波的传播速度。并且，轻重颗粒的质量比越小增速效应越强。在散射作用和增速效应的共同作用下，改变轻重颗粒的质量比可以调控孤立波在重-轻颗粒链中的传播时间。%The propagation of solitary wave in a one-dimensional composite granular chain with heavy and light particles by turns is investigated by using molecular dynamics simulation. Under the condition of larger or smaller mass ratio of light to heavy particles, scattering effect is weaker and both particle velocity and solitary wave velocity decay slowly. In the intermediate range of mass ratio, the scattering effect becomes stronger, resulting in a faster decay of particle velocity and solitary wave velocity. Moreover, effect of increasing velocity happens when teh solitary wave travels across the heavy-light interface, indicating that the solitary wave velocity is increased. Effect of increasing velocity is enhanced when the mass ratio of light to heavy particles decreases. Due to the combined action of scattering effect and the effect of increasing velocity, the traveling time of solitary waves can be modulated by altering the mass ratio of light to heavy particle.