Function structures are used during conceptual engineering design to
transform the customer requirements into specific functional tasks.
Although they are usually constructed from a well-understood black-box
description of an artifact, there is no clear approach or formal set of
rules that guide the creation of function structures. To remedy the
unclear formation of such structures and to provide the potential for
automated reasoning of such structures, a graph grammar is developed and
implemented. The grammar can be used by a designer to explore various
solutions to a conceptual design problem. Furthermore, the grammar aids in
disseminating engineering functional information and in teaching the
function structure concept to untrained engineers. Thirty products are
examined as a basis for developing the grammar rules, and the rules are
implemented in an interactive user environment. Experiments with student
engineers and with the automated creation of function structures validate
the effectiveness of the grammar rules.