Abstract
In this study, we derived theoretical equations on the dynamic modulus of elasticity when step-strain amplitude is loaded, and when parts of broken physical bonds are restored returning to an equilibrium in a free state after repeated loading and unloading of strain amplitude along the principal axis of sloped eight-layered nylon fiber FRR, having a matrix of carbon black particle reinforced NR. At the same time, we experimentally confirmed the validity of the equations.