  Using molecular dynamics(MD) simulations, we study thermal transport in
graphene nanoribbons (GNR) subjected to uniform uniaxial and nonuniform strain
fields. We predict significant thermal rectification (over 70%) in a
rectangular armchair GNR by applying a transverse force asymmetrically. The
heat flux is larger from the less stressed region to the more stressed region.
Furthermore, we develop a theoretical framework based on the non-equilibrium
thermodynamics to discuss when thermal rectification under a stress gradient
can occur. We conclude with a discussion of details relevant to experiment.
