Function Model Based Generation of CAD Model Variants

Abstract

A product is an artefact which fulfils a specific function. However, most design automation (DA) approaches wich are used to generate multiple alternative design concepts focus on the generation of CAD models. These neglect to represent the functional aspects of the product, and are furthermore deemed too rigid for the introductino of novel solutions. Pure function modellingappraoches on the other hand provides methods such as design rationale representation, introduction of novel solutions or instantiation of combinatorial alternative concepts, but the resulting models are insufficient for analysis. To alleviate this, a design space exploration (DSE) approach which couples function modelling and CAD is presented. The approachlinks the product’s design rationale modelled in enhanced functionmeans (EF-M) to a DA approach via the here introduced object model for function and geometry (OMFG). The resulting method is able to automatically generate CAD models of alternative concepts based on combinations of alternative design solutions defined in the function model. The approach is presented through a case study of an aircraft engine component. Sixteen different concepts are generated based on four functions with alternative solutions. In an initial computation of the effort to generate all alternative concepts, the DA aspect of the approach’s effort pays off as soon as five functions have two or more alternative solutions. Beyond the benefit of efficient instantiation of CAD models of alternative product concepts, the approach promises to provide the design rationale behind each concept, and thereby a more systematic way of exploring and evaluating alternative design concepts.