  This article delves into the micro-macro modeling of polymeric fluids,
considering various microscopic potential energies, including the classical
Hookean potential, as well as newly proposed modified Morse and Elastic-plastic
potentials. These proposed potentials encompass microscopic-scale bond-breaking
processes. The development of a thermodynamically consistent micro-macro model
is revisited, employing the energy variational method. To validate the model's
predictions, we conduct numerical simulations utilizing a deterministic
particle-FEM method. Our numerical findings shed light on the distinct
behaviors exhibited by polymer chains at the micro-scale in comparison to the
macro-scale velocity and induced shear stresses of fluids under shear flow.
Notably, we observe that polymer elongation, rotation, and bond breaking
contribute to the zero polymer-induced stress in the micro-macro model when
employing Morse and Elastic-plastic potentials. Furthermore, at high shear
rates, polymer rotation is found to induce shear-thinning behavior in the model
employing the classical Hookean potential.
