A Sustainable Modular Product Design Approach with Key Components and Uncertain End-of-life Options Consideration

Open Access
Ma, Junfeng
Graduate Program:
Industrial Engineering
Doctor of Philosophy
Document Type:
Date of Defense:
February 29, 2016
Committee Members:
  • Gul Kremer, Dissertation Advisor
  • M Jeya Chandra, Committee Member
  • Charles David Ray Sr., Committee Member
  • Conrad S Tucker, Committee Member
  • Modular Product Design
  • Sustainability
  • End-of-Life
  • Optimization
  • Key Components
An expanding awareness of manufacturing’s short-term and long-term environmental impacts continues to drive manufacturers to reconsider the product design process with a view toward sustainability. An emphasis on sustainability is imperative for the competitive success of modern design and manufacturing enterprises, and incorporating sustainability into the product design process continues to warrant the increasing attention. Sustainability includes three dimensions: economic, environmental, and social. To the best of our knowledge, no existing product design method yet involves these three dimensions of sustainability, partly because social sustainability is difficult to evaluate and measure. This research gap motivates this study. Product life cycle management, especially the end-of-life (EOL) stage management, with its benefits of cost savings and increased environmental awareness performance, has emerged as a critical component of the product design process. However, determining EOL options during the product design stage can present a complex challenge because of vagueness in the design en-vironment—for example, an imprecise factor such as product maintenance. Therefore, developing a comprehensive framework to help understand uncertain EOL options is also a foundational motivation of this study. In today’s challenging marketplace, key components play a significantly important role in product competitiveness. These components may represent a core technology and affect the product’s functional performance, such as the turbocharger in an automobile engine; or they may be expensive or complicated to assemble and consequently influence the product’s market performance, such as the cabinet of a refrigerator. However, based on existing literature, scant research discusses key components in the product design process. Therefore, involving a focus on key components in the design process also stimulates this study. Modular product design (MPD)—splitting a product into several components and then analyzing each separately—has proven to be a widely accepted design tool due to its advantages across the entire product life cycle, evincing benefits to manufacturing, to assembly, and to the product supply chain itself. In this study, a new MPD approach is presented that considers uncertain EOL options and key component specifications to improve three dimensions of sustainability. Three indicators—cost, environmental impact, and labor time—are employed to measure economic, environmental and social sustainability as individual elements. The environmental impact assessment is adopted using an open source software, Eco-99, which measures environmental sustainability in a comprehensive manner. Fuzzy logic is used to estimate the probability of each EOL option and to determine the expected EOL sustainability values (cost, environmental impact and labor time) for each component. Three clustering algorithms, with respect to the three sustainability aspects, are developed for specific key components; component modules are then grouped based on the identified key components and their sustainability optimization at all three stages of the total life cycle (manufacturing, maintenance, and EOL). The tri-criteria model builds toward optimizing sustainability in order to derive the compromised module structure. Based on this investigation into three-dimension sustainability, the economic, environmental, and social aspects are first quantified and measured simultaneously from the view of the product life cycle, and then improved through a product module generation process. Key components are also emphasized in the design stage, and key-component-based clustering algorithms are introduced to generate product modules. Moreover, uncertain EOL options are taken into ac-count in the module forming process. This new MPD approach has proven to generate better performance than previously existing methods (e.g., decomposition approach) in terms of sustainability. Two case studies are used to demonstrate the implementation of the proposed methodology, based on the perspective of product scale. A coffee maker is used to illustrate the analysis of a small and simple product, and a refrigerator is used to illustrate the analysis of a large and complex product. Given pre-determined sustainability indicator weights, both the coffee maker and the refrigerator are decomposed into several modules, as such modular architectures can benefit product life cycle full-dimension sustainability performance assessment.