Phase shift of solitary wave in a one-dimensional granular chain

In this paper, both the fifth-order Runge–Kutta numerical scheme and binary collision approximation are used to study the phase shift. Both numerical and theoretical results are shown that the solitary wave after head-on collision propagates along the chain behind the reference wave in both even and odd numbers of grain chains. It is the well-known feature of the appearance of the phase shift. Those results are in agreement with the experimental results. Furthermore, it is found that the phase shift is not only related to the collision position of the waves, but also to the position where the time is measured. The value of phase shift increases nonmonotonously with increasing the velocity of the opposite propagation of the wave. Binary collision approximation is applied to analyze the phase shift, and it is found that theoretical results agree well with numerical results, especially in the case of phase shift in odd chain.

Quick calculation of damage for ion irradiation: implementation in Iradina and comparisons to SRIM

Binary collision approximation (BCA) calculation allows for two types of damage calculation: full cascade and quick calculations. Full cascade mode describes fully the cascades while in quick calculations, only the trajectory of the ion is followed and effective formulas give an estimation of the damage resulting from each collision of the ion. We implement quick calculation of damage in the Iradina code both for elemental and multi-component solids. Good agreement is obtained with SRIM. We show that quick calculations are unphysical in multi-component systems. The choice between full cascade and quick calculations is discussed. We advise to favour full cascade over quick calculation because it is more grounded physically and applicable to all materials. Quick calculations remain a good option for pure solids in the case of actual quantitative comparisons with neutron irradiations simulations in which damage levels are estimated with the NRT (Norgett-Robinson and Torrens) formulas.

Pulse propagation in granular chains: The binary collision approximation

The binary collision approximation has been successfully applied to the study of pulse propagation in several types of granular chains. Here we present the theory in a generalized and comprehensive way and discuss and review a number of results found in the literature.