Computational analysis of the mechanical behavior of carbon nanotubes in a rail-wheel system

Abstract

Currently, railway systems have presented many problems associated with friction and wear due to movement between the interface of the wheel-rail system, a situation that has been demanding large investments and railway costs in transport companies due to the frequent change of pieces of the system. As a possible solution, the addition of carbon nanotubes (CNTs) has been underway in some modified lubricants to increase the antifriction properties. In this investigation, computational simulations were developed to analyze the behavior of the CNTs as a reducing component of the friction of the material. A constitutive model was considered by Hooke’s law for the wheel-rail system and the CNTs. Numerical lattices were designed to develop the computational simulations. The constitutive equations were solved by the Finite Differences Method (F.D.M.). The computational models were subjected to transverse loads emulating the movement of the system. Simulations were performed for one wheel-rail model with insert of 0.01 percent of CNTs. The results identified in the report of the insertions of the CNTs in the wheel-rail system show a dissipative-absorbent behavior of the deformation energy is detected, combined with rotation effects of the CNTs, a condition that may allow a reduction in friction and wear CNTs can contribute to improve the tribological properties of lubricants in affected railway systems and a longer service life of mechanical elements. The computational developments carried out in this research can facilitate the analysis of behaviors of nanostructured materials under conditions of extreme functionality where the experimental processes are complex.