Erofeev V.I., Kazhaev V.V., Pavlov I.S. «Inelastic interaction and splitting of strain solitons propagating in a granular medium» Вычислительная механика сплошных сред, 6, № 2, с. 140-150 (2013)

A one-dimensional model of the granular medium is considered that represents a chain consisting of elastically interacting particles, which possess translational and rotational degrees of freedom. In the long-wavelength approximation, the nonlinear differential equations have been derived that describe propagation of longitudinal, transverse and rotational waves in such a medium. Analytical dependences of the velocities of elastic waves and the nonlinearity coefficients on the sizes of particles and the parameters of interactions between them have been found. In the field of low frequencies, when the rotational degree of freedom of particles can be neglected, the obtained three-mode system reduces to a two-mode one. Numerical investigations of contradirectional and passing interactions of strongly nonlinear soliton-like subsonic and supersonic waves have been performed within the scope of the latest model. In particular, effects of splitting of supersonic solitary waves are demonstrated.