A systematic approach to bio-inspired conceptual design

In Conceptual Design, the designer is tasked with searching for new and innovative design solutions. This search process, referred to as the designer's design space, has been shown to dictate the quality and effectiveness of the final design solution [1]. According to the theory of bounded rationality, this design space is bounded by the limited cognitive abilities of the designer [2], amongst other factors. To overcome the limitations imposed by bounded rationality, designers often employ several techniques to aid in idea generation, including building upon analogous solutions in the current domain of application. However, designers commonly fail to take to advantage of solutions and practices of other sciences and technologies and/or fail to even recognize the similarities between their technical problems and solutions to similar problems from otherwise alien domains [3]. To address this problem, the following research question is proposed, "How can we aid the designer in more effective ideation in Conceptual Design?" In this research, biological strategies are used to aid the designer in Conceptual Design. Through millions of years of research and development, nature has developed efficient and economical solutions to the problems it faces. It is believed that harnessing design strategies from nature will lead to more effective solutions to the engineering problems currently faced by designers. Specifically, the primary hypothesis of this research is as follows: "Building upon a rich behavioral model of biological systems and a strategy repository, the proposed approaches to Bio-inspired Conceptual Design can be used to aid the designer in (1) identifying relevant biological systems, and (2) using biological strategies in Conceptual Design to produce (2a) a larger variety of design ideas, (2b) design ideas of greater novelty, and (2c) higher quality design ideas". The fundamental claims of this hypothesis include that of biological system representation, behavioral decomposition, efficient retrieval, and assessing the impact of biological strategies on Conceptual Design.;In this research, it is believed that representations play a key role in bridging the gap between the biological and engineering domains. In the first part of this research, a rich, causal behavioral model was developed for representing the behavior of biological systems. For this purpose, the hierarchical Petri net representation was developed. This representation has the advantage of representing both behavioral refinement and abstraction. The purpose of this behavioral model is to aid the designer in systematically extracting design strategies from biological systems. To ensure consistency in the behavioral model, a systematic method for decomposing and representing the behavior of biological systems, the Method for Reverse Engineering Biological Systems, was developed. This method was found to preserve the fundamental properties of the behavioral systems across hierarchical levels of the representation. The identification of relevant biological strategies in Conceptual Design is also a key issue in bio-inspired design. Although current approaches are useful in storing and providing access to biological information, the current retrieval strategies often result in either providing too many and/or irrelevant results. In this research, an engineering ontology was developed based on concepts from the hierarchical Petri net representation. This ontology was then encoded into a strategy repository using Description Logic (DL), knowledge representation formalism used for representing domain knowledge and reasoning about it. Subsumption, an inference algorithm in DL for determining if one concept is a member of another concept, was shown to enable both consistent and precise retrieval of biological strategies. When compared to current approaches to representing and retrieving biological strategies, subsumption-based retrieval was found to be more effective. Next, the constructs of the Method for Reverse Engineering Biological Systems and the strategy repository were synthesized into two distinct approaches to Bio-inspired Conceptual Design: problem-based and solution-driven. In the problem-based approach, the design begins with an engineering system and searches for solutions through engineering design. In this approach, the strategy repository is used to identify relevant biological strategies and stimulate idea generation. To validate the problem-based approach to Conceptual Design, cognitive studies of Mechanical Engineering students and a comprehensive example of the design of hybrid, bullet resistant armor were used.;In this approach, biological strategies were found to increase the novelty of design ideas generated, while also preserving the variety of design ideas generated. In the solution-driven approach to Bio-Inspired Conceptual Design, the designer begins with a biological solution and attempts to mimic the behavior of this system in the engineering domain. In this approach, the Method for Reverse Engineering Biological Systems is used to systematically decompose the behavior of biological systems and extract behavioral strategies. These strategies are then used as the foundation for the generation of new ideas. To validate the solution-driven approach, historical case studies of bio-inspired systems and a comprehensive example of the development of a novel, renal replacement therapy system were used. In this approach, bio-inspired systems possessing a deeper level of behavioral similarity to their analogous systems were found to perform better than those with less similarity.