| dc.description.abstract | Product models are being proposed as information models to drive the entire product lifecycle. CAD models that drive the product development cycle presently are primarily a repository of shape information and, therefore, are not capable of allowing any reasoning about or access to other product design-related information, such as material, behaviour, and function.
Towards addressing this gap between CAD model and product model, this thesis proposes a model to represent behaviour. All the definitions and representations of behaviour proposed in the literature are semantic in nature in that they describe (mostly using natural language) the characteristics constituting the representation of behaviour. In the context of the present problem of representing behaviour in a product model, the characteristics and attributes should be representable in a computer program so that further reasoning or manipulation is possible. The syntactic aspect of representing behaviour has not received much attention.
A definition of behaviour based on interaction between artefacts that constitute the product is used to develop a model of behaviour. While the definition is based on interaction between artefacts, allowing for interaction between more than two at a time, the model represents the interaction pair-wise. This allows the behaviour due to the interaction of multiple artefacts to be modelled as a combination of multiple behaviours due to each pairwise interaction. By breaking down complex behaviours into simpler pairwise interactions, this model provides a structured approach to representing and analysing the behaviour of mechanical systems. The artefacts can be extrinsic to the product, such as agents or the environment. The model captures the characteristics of the interaction as attributes, parameters and constraints. The model includes specific features of the artefacts that are interacting. This allows integrating behaviour with geometry. The model is illustrated with three examples. As a proof of concept, the model is shown in a CAD environment using CADQuery.
An ontology for behaviour is constructed based on the pairwise representation of behaviour for over a hundred mechanical artefacts. The ontology is structured around classes representing artefacts, their behaviours, and the relationships between them. The ontology created would serve as the basis for building a consistent and interoperable representation of behaviour in a product model. Several use cases of querying and reasoning about behaviour in a product design and development context are identified. The specific use case of querying behaviour from a product model has been implemented to validate the use of the representation and ontology of behaviour proposed in this thesis.
The thesis establishes that the behaviour can be effectively captured and represented within a product model by focusing on interactions between artefacts/environment. The behaviour ontology created serves as a knowledge base for storing and querying behaviour information. Future work can use the behaviour model and the ontology developed for other use cases, such as design verification, adaptive design and synthesis, and explore its application to artefacts from other domains | en_US |
