Author ORCID Identifier

Year of Publication


Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation




Mechanical Engineering

First Advisor

Dr. I. S. Jawahir


Sustainable manufacturing and the circular economy concepts promote efficient and effective resource use to minimize the adverse economic, environmental, and social impacts of alarmingly increasing consumption rates. Product design is the key to implement these transformations in manufacturing. However, the currently available sustainable and circular design methods are not comprehensive and inadequate—especially for multi-generational products. Therefore, designing sustainable products optimized for circular and closed-loop production systems is a challenging task. The 6Rs concept introduced ‘Redesign’ to modify a product’s engineering specifications and allow sustainable utilization of the end-of-use resources from previous generations, thus closing the production loop. Therefore, the objective of this dissertation is to develop a quantitative methodology for ‘Redesign’—which identifies the optimally sustainable product design configurations in a multi-generational closed-loop manufacturing system.

First, a metrics-based evaluation framework was developed to measure the product sustainability performance (PSP) over a product’s life cycle. It introduced explicit consideration of metrics involving all primary stakeholders (manufacturer, customers, and society-at-large) to ensure comprehensive value creation at the product design stage. Next, using the evaluation framework, a closed-loop simulation approach was developed to forecast the PSP through the demand-cycle. This approach demonstrates that the PSP substantially varies with the demand-cycle profile. Thus, the novel concept of PSP as a dynamic measure over the temporal dimension was introduced for an improved evaluation. To implement ‘Redesign’ and enable closed-loops in multi-generational product systems, a new design methodology that maximizes the PSP by identifying optimal inter-generational component commonality was developed and established. The application of this methodology to a case study demonstrated significant gains in the sustainability objectives. Finally, the designer preferences were quantified to sequester the best design configuration posteriori from Pareto optimal solutions.

The dynamic PSP evaluation introduced in this dissertation integrates production factors with sustainability impacts for informed life cycle planning at the design stage. The fundamental concepts of this dissertation will be even more significant for advancing the circular economy through closed-loops as product-generation upgrades become frequent.

Digital Object Identifier (DOI)

Available for download on Sunday, August 13, 2023

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