Clemson University TigerPrints All Theses Theses 8-2012 Investigation of Prototype Roles in Conceptual Design using Case Study and Protocol Study Methods Timothy Hess Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_theses Part of the Engineering Commons Recommended Citation Hess, Timothy, "Investigation of Prototype Roles in Conceptual Design using Case Study and Protocol Study Methods" (2012). All Theses. 1418. https://tigerprints.clemson.edu/all_theses/1418 This Thesis is brought to you for free and open access by the Theses at TigerPrints. It has been accepted for inclusion in All Theses by an authorized administrator of TigerPrints. For more information, please contact [email protected]. INVESTIGATION OF PROTOTYPE ROLES IN CONCEPTUAL DESIGN USING CASE STUDY AND PROTOCOL STUDY METHODS A Thesis Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Master of Science Mechanical Engineering by Timothy A. Hess August 2012 Accepted by: Dr. Joshua Summers, Committee Chair Dr. Gregory Mocko Dr. Georges Fadel Abstract Prototypes play an important role in the engineering design process. Engineer- ing design textbooks often discourage the use of prototypes early in the design process, citing past research on prototypes in engineering design has focused describing and classifying the prototypes themselves. The gap in this research is the investigation of prototyping processes. While researchers have studied the characteristics of different prototypes and in some cases have tried to tie characteristics to the outcomes of the design process, the actual prototyping activities and the process of building and using the prototypes has not been studied in detail. The work presented in this thesis is an initial attempt to explore the the prototyping process in engineering design. Two research studies are presented that have been conducted to explore the roles proto- types fulfill in the early stages of the engineering design process and to study how designers interact with physical objects and prototyping materials. A case study was conducted to investigate the roles that prototypes fulfill in two different industrial settings. To complement this, a protocol study was developed to see how individual designers interact with physical media during a conceptual de- sign activity. The results from these studies were analyzed and it was found that along with the commonly described prototype roles: learning, integration, commu- nication, and demonstration, prototypes can also be classified in terms of divergent or convergent activities; helping designers to either explore a design space or narrow ii down options and make decisions. Divergent and convergent prototyping activities are presented along with a discussion on how prototypes can be used effectively in conceptual design. iii Dedication I would like to dedicate this thesis to my wife, Roslyn, who has supported me through long hours and late nights. I could not have done this without her love and support. iv Acknowledgments I would like to thank Dr. Summers for his guidance and the members of CEDAR for their help throughout the years along with their friendship. Additionally, I would like to thank Aaron Arvia, Paul Kelly, and Andrew Brown of Electrolux and Scott Morgan, Joe Brown, and Jeff Warford of Michelin for going out to their way to help me with my research. v Table of Contents Title Page ................................... i Abstract .................................... ii Dedication................................... iv Acknowledgments............................... v List of Tables ................................. viii List of Figures................................. x 1 Motivation................................. 1 1.1 Definitions of Prototypes......................... 2 1.2 Prototype Roles.............................. 3 1.3 Prototype Use Throughout the Design Process............. 6 1.4 Prototyping In Conceptual Design.................... 10 1.5 Prototype Taxonomies.......................... 11 1.6 Goals of This Research.......................... 12 2 Industry Case Study ........................... 16 2.1 Michelin Interview Analysis ....................... 19 2.2 Electrolux Interview Analysis ...................... 28 2.3 Case Study Findings ........................... 36 3 Protocol Study Development...................... 38 3.1 Environment and Experimental Setup.................. 39 3.2 Execution Observations.......................... 50 3.3 Coding Scheme and Procedure...................... 51 3.4 Action Sequence Pattern Definitions .................. 60 4 Protocol Validation............................ 64 4.1 Inter-Rater Agreement.......................... 65 5 Protocol Study Results.......................... 70 vi 5.1 Analysis Process ............................. 70 5.2 Action Sequence Comparison ...................... 72 5.3 Time Distribution Figure Description.................. 74 5.4 Pattern Searching............................. 78 5.5 Entity Use................................. 88 5.6 Document Analysis............................ 90 5.7 Protocol Study Results.......................... 93 6 Research Contributions ......................... 95 6.1 Addressing the Research Questions ................... 96 6.2 Additional Contributions......................... 102 7 Future Work................................ 104 7.1 Physical Interactions Protocol Refinement . 104 7.2 Design for Behavior in Experiment Design . 106 7.3 Exapanding Prototyping Research.................... 107 Appendices................................... 109 A Case Study: Interview Transcripts.................... 110 B Protocol Coding Procedure........................ 220 C Pattern Searching Procedure....................... 223 References................................... 224 vii List of Tables 1.1 Summary of engineering design text discussions of prototyping..... 9 2.1 Coded Data from Interview with Scott Morgan from Michelin. 22 2.2 Coded Data from Interview with Joe Brown from Michelin. 24 2.3 Coded Data from Interview with Jeff Warfford from Michelin. 25 2.4 Summary of prototypes discussed at Michelin.............. 26 2.5 Coded Data from Interview with Aaron Arvia from Electrolux. 31 2.6 Coded Data from Interview with Andrew Brown from Electrolux. 32 2.7 Coded Data from Interview with Paul Kelly from Electrolux. 33 2.8 Summary of prototypes discussed at Electrolux............. 34 3.1 Complete list of materials provided to study participants. 45 3.2 Definitions of actions related to fabricating and building a prototype.................................. 53 3.3 Definitions of actions related to the handling of physical objects. 54 3.4 Definitions of other actions captured with the coding scheme. 55 3.5 Definitions of entity types captured with the coding scheme. 56 3.6 Grammar to strictly define the relationship between the action and entity definitions.............................. 57 3.7 Learning Patterns............................. 61 3.8 Integration Patterns............................ 61 3.9 Starting Point Patterns. ......................... 62 3.10 Generic Patterns.............................. 62 4.1 Calculated joint probability of agreement for three video segments. ................................. 67 4.2 Total number of seconds of difference for each action coded. 68 5.1 Total number of instances and total time spent on each action type, arranged by participant. ......................... 72 5.2 This table includes the number of instances of each pattern found in the action sequences along with the total amount of time spent on each pattern. .................................. 80 5.3 Comparison of entities used and solution mechanisms for AP. 91 5.4 Comparison of entities used and solution mechanisms for BM. 92 viii 5.5 Comparison of entities used and solution mechanisms for EN. 93 ix List of Figures 1.1 Schematic of divergent and convergent stages of engineering design.................................... 7 1.2 Schematic of the overall prototyping process............... 13 3.1 The script used to describe the design problem and activity instructions to participants. .............................. 41 3.2 Picture of the space available for working on the design problem. 46 3.3 Schematic of design observatory used to collect video data. 48 3.4 Picture of the four-tiled video feed recorded for each participant. 49 3.5 Example entity encoding worksheet.................... 59 3.6 Example action encoding worksheet. .................. 60 4.1 Time distribution excerpt of Holding, Sketching, Writing, and Pause actions. .................................. 69 5.1 The recorded video was analyzed to study the actions of each partici- pant as well as patterns in the behavior of each participant. 71 5.2 Number of instances of each action type observed............ 73 5.3 Total time of each action type observed. ................ 73 5.4 Time distribution plot showing the occurance of Holding and Manip- ulating actions............................... 75 5.5 Time distribution plot of building actions. ............... 76 5.6 Time distribution plot of handling actions................ 77 5.7 Time distribution plot of other actions.................. 78 5.8 Time distribution plot of the robust search results (dashed green lines) overlaying the normal definition search results (solid blue lines). 79 5.9 Time distribution plot of the pattern search results for each participant. ................................ 81 5.10 Time distribution