Traditional analyses have generally worked in a single physical domain, however there are many cases in which two or even more physical effects have a critical bearing on the way in which things function. Whilst thermal mechanical situations spring most readily to mind there are many closely coupled systems that must be considered as such if any useful understanding is to be gained from simulation.
Bio systems such as the human heart are excellent examples of a function which exists across several physical domains, and which have been successfully modeled using Abaqus.