Investigation on impact behavior with viscous damping and tensile force inspired by Kelvin-Voigt model in granular system

Abstract

This investigation proposes a continuous contact model with different viscous damping factors by employing the physical properties of the Kelvin-Voigt model. The viscous damping coefficient is treated as a function of the loss factor and frequency. The loss factor in the elastoplastic or plastic phase is obtained by solving the linear equation of motion, because the elastoplastic contact stiffness can be assumed to be approximately linear. The loss factor in the elastic phase is derived according to the energy conservation during impact. Two loss factors in the frequency-dependent damping coefficients govern the energy dissipation in the entire contact behavior. More importantly, the proposed contact model inherits the deficiency of the Kelvin-Voigt model, which exhibits a tensile force at the end of the recovery phase. The underlying reason for this phenomenon is revealed. Simultaneously, it is also explained why the tensile force does not affect the solitary wave propagation in the granular system. Performed simulations show that the proposed contact model not only sidesteps the numerical issues corresponding to most contact force models with hysteresis damping factors, but also compensates for the accuracy loss of the EDEM contact model when evaluating the elastoplastic contact behavior in the granular system.