Integrated full electric propulsion (IFEP) systems are the subject of much interest at present. Current research is focused on analysing and improving aspects of subsystem and system performance. However, there is a great need to look more widely at the `multi-physics' problem of characterising the dynamic interactions between the electrical and mechanical systems. This paper discusses the changing nature of modelling and simulation to aid research into IFEP systems, outlining the alternative angle taken by the advanced marine electrical propulsion systems (AMEPS) project to characterise and investigate electrical-mechanical system interactions. The paper describes this approach and highlights the unique challenges associated with the problem, discussing the suitable methods that is adopted to address these challenges. Finally, an overview of the present and future research opportunities facilitated via the AMEPS project is presented.