Department of Mechanical Engineering

Mr. Shivraj Karthik Ranganathan

Degree Candidacy: Master of Science in Mechanical Engineering
Date: Wednesday, December 4, 2013
Time: 2:00 PM
Location: 108 EIB

Advisor: Dr. Gregory Mocko
Committee Members: Dr. Lonny Thompson and Dr. Georges Fadel

Title: Effects of Iteration on Concept Development

ABSTRACT

Iteration in the conceptual design stage is defined as repetition of design tasks to incorporate new information. A more concise definition of iteration relevant to this research would be the progression of design through different abstraction levels or design stages, defining and refining design solutions while progressing from initial concepts to a more detailed design. Although it is believed that iteration has a positive effect on the quality of ideas in the design process, this experimental study presents an opportunity to determine the effects of iteration on quality of concepts and the factors that lead to increased quality of concepts. The research presented in this thesis details two user studies that were conducted to determine and understand if iteration in the conceptual design stages promotes quality of design concepts. The first user study conducted in this paper involved twelve mechanical engineering graduate students where the participants were provided with a design problem and were asked to generate solutions for the design problem. In order to study iteration of design tasks in the conceptual design stages the participants were divided into three user groups with the first user group participating in a continuous ideation session and the second and the third user groups engaged in a iterative ideation session involving one and two iterations respectively. The user groups that engaged in an iterative ideation session followed the Gallery method of idea generation. The concepts generated by these students were evaluated in terms of quality and quantity metrics by two raters. Results from this study indicate that the quantity of ideas generated decreases with an increase in the number of iterations. A second user study was conducted to study effect of iteration of quality and quantity of concepts by using incubation as an ideation component. This study involved nine graduate level mechanical engineering students generating design solutions to a problem provided to them. The participants were divided into three user groups with the first user group participating in a continuous ideation session and the second and the third user groups engaged in an ideation session involving one and two design iterations respectively. The purpose of this study was to observe, record and analyze the design performance of the participants when iteration is explicitly performed in an unsupervised setting. The concepts generated by the participants were then evaluated from the perspective of ‘best’ quality in addition to average quality of ideas from the session. The results from this user study indicated that the ‘best’ quality of ideas at the participant level increases with an increase in the number of iterations. Consequently the number or the quantity of ideas decreases with an increase in the number of iterations resulting in a strain of convergent high quality design solutions. Our proposed model of creativity based on an iterative idea generation process suggests that as the number of iterations increases the pool of ‘high’ quality ideas decreases ultimately resulting in a significant decrease in the number of high quality ideas under consideration for the next stage of the design process. An analysis of the results of the studies is presented in this document.