Euler-Lagrangian dynamics to the physical interpretation with granular   constraints for MD simulations
  In this article, Euler-Lagrangian dynamics explain that the two particle interaction has non-conservative forces about the frame of the center of mass. This interpretation clarifies the underlying interaction and the system descriptions become advantages for MD simulations. 
Kyoung O. Lee and Robin P. Gardner
cond-mat.soft physics.flu-dyn