I am a novice getting my toes wet in continuum mechanics and nonlinear elasticity. I have seen papers that use both approaches in developing constitutive connections to compliment balance equations of various sorts. My question is the energy inequality more general than the virtual work approach? I am tackling a visco-elastic problem where I will need to account for the time dependent relaxation of the material. Can this not be handled by virtual work since energy will be lost rather than conserved?
I ask because virtual work seems a bit more straight forward but I wonder if it is at the expense of applicability. I am looking for the pros and cons of both approaches.
Thanks in advance!