Dynamic characteristics of multiscale longitudinal stress and particle rotation in ballast track under vertical cyclic loads

Loads transfer in ballast track through contacts among randomly distributed ballast particles and have strong heterogeneity. Since the size ratio between ballast track and ballast particles is generally small, using averaged stress to describe the internal mechanical state in ballast track faces practical difficulties. For example, particle movements and high local concentration stress tend to be ignored. The inter-particle contact stress is …