立方晶体中超声切变波高次谐波的产生

ON THE GENERATION OF ULTRASONIC SHEAR WAVE HARMONICS IN CUBIC CRYSTALLINE SOLIDS

本文讨论了立方晶体中超声切变波由于晶格非线性而产生的高次谐波特性,结果表明,在立方晶体中某些特殊方向(如晶轴X)上,二次谐波并不出现,而仅产生三次谐波。三次谐波的振幅随传播距离而增加,也与固体本身的高阶弹性常数有关。这样,固体中位错的非线性振荡产生的二次谐波将起主导地位。这给采用超声谐波技术研究固体中位错动力学带来方便。

In this paper we have discussed the properties of ultrasonic shear wave harmonics due to the lattice nonlinearity in cubic crystalline solids. It is shown that no second harmonic wave may appear for the waves propagated in the x crystallographic direcction. On the other hand, third harmonic wave will be generated and its amplitude depends upon both the propagation distance and higher order elastic constants. Therefore the second harmonic from the dislocation nonlinear oscillation may be predominant, which can be used to facili-tate the study of the dislocation dynamics by the ultrasonic harmonic technique.