Design for Inspectability: Investigating the effect of Inspectability Constraints on Designs and Design Strategies
Open Access
- Author:
- Mahan, Tobias
- Graduate Program:
- Mechanical Engineering (PHD)
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 10, 2021
- Committee Members:
- Nicholas Meisel, Major Field Member
Chris McComb, Major Field Member
Hui Yang, Outside Unit & Field Member
Andrea Arguelles, Outside Field Member
Jessica Menold, Chair & Dissertation Advisor
Daniel Connell Haworth, Program Head/Chair - Keywords:
- Additive Manufacturing
Inspection
Inspectability
Design for X - Abstract:
- Components manufactured with Additive Manufacturing (AM) can feature high levels of geometric, material, and functional complexity. Designers can use AM technologies to create components with more complexity than was possible with traditional manufacturing methods. However, highly complex components can be difficult to inspect using existing Non-Destructive Evaluation (NDE) methods. Professional organizations like the Additive Manufacturing Standardization Collaboration (AMSC) have suggested that designers should keep quality in mind during the early stages of design. The Design for Inspectability (DFI) Framework is proposed in this work to help designers consider quality early in design. Based on recommendations from AMSC, ultrasonic testing was selected as the first modality of NDE for which DfI considerations were developed. Through open and axial coding of literature, a set of DfI heuristics was developed for ultrasonic testing. These heuristics were organized into a design tool, the DfI worksheet, to facilitate design studies. First a controlled study with 12 designers from The Pennsylvania State University suggested that introducing DfI considerations may indeed help designers to increase the inspectability of designs. A second study with 20 designers was performed to determine what effect DfI considerations have on design outcomes. Quantitative methods, including static structural analysis of generated designs and simulation of ultrasonic wave propagation, were used to compare the design outcomes of designers introduced to DfI considerations to those in the control group. Results of this test suggest that design outcomes, including inspectability, may not be significantly impacted. Tools including the NASA Task Load Index (NASA-TLX), Linguistic Inquiry and Word Count (LIWC), and Hidden Markov Modelling were used to determine what effect introduction of DfI considerations would have on designers and the design process. Cognitive and design processes are impacted by the introduction of DfI considerations, with a decrease in cognitive processes likely contributing to changes in designer strategies. Continued development of the DfI framework is recommended to ensure designers can create components inspectable using existing NDE technologies.