Abstract
Many modern and innovative design problems require multi-modal, reconfigurable solutions. Function modeling is a common tool used to explore solutions in early stages of mechanical engineering design. Currently, function structure representations do not support the modeling of formally-defined reconfigurable function models. There is a well-established need in function modeling to dynamically capture the effects of state change of a flow property on the operating mode of the system. This paper presents a formal representation to capture the duality of specific functions, and illustrates it through three verbs that shift from one mode of operation to its logical and topological opposite, based on the existence of, or the value of a signal from, an input flow. Additionally, an approach to extend these functions to function features, in order to support physics-based reasoning on the interactions between flows is also presented. Through the example of a system-level model of a geothermal heat pump operating in its heating mode, the representation demonstrates the ability to support causal reasoning on functional modes of systems, provides quantitative reasoning on the efficiency of those modes, and illustrates the modeling efficacy of the extended representation.
