A Modular Design Approach to Improve Product Life Cycle Performance Based on Optimized Closed-loop Supply Chains

Open Access
Chung, Wu-Hsun
Graduate Program:
Industrial Engineering
Doctor of Philosophy
Document Type:
Date of Defense:
May 01, 2012
Committee Members:
  • Gul Kremer, Dissertation Advisor
  • Richard Allen Wysk, Dissertation Advisor
  • Gul Kremer, Committee Chair
  • Richard Allen Wysk, Committee Chair
  • Andris Freivalds, Committee Member
  • Dr David Riley, Committee Member
  • Design for Life Cycle
  • Modular Design
  • Closed-loop Supply Chain
  • Sustainable Supply Chain
Ever-increasing concerns about the environment are causing product designers to seek more sophisticated design elements, incorporating life cycle factors. Modularity has long been a technique used to incorporate life cycle considerations into product architecture design. Most modular design methods rely on predefined modularity measures to evaluate product architectures but lack the ability to assess life cycle consequences of these modules in a supply chain. This research proposes a new methodology—the Architecture & Supply Chain Evaluation Method (ASCEM)—to find an optimal modular architecture during the design stage which has both minimal life cycle costs (LCC) and the lowest environmental impact (EI). Unlike traditional methods, ASCEM expands the assessment scope from the product itself to its supply chain network. The life cycle performance (LCC and EI) of a modular product in a closed-loop supply chain is adopted as the modularity measure to identify the best modular structure from a holistic life-cycle view. In this work, a product is first mapped into a functional model represented by a component-and-interaction connectivity graph. Each component has unique attributes, and their interactions are functional existence, joining, and disjoining. The estimation of a product’s LCC and EI is based on both the component attributes and the interactions between them. A model of existing processing facilities as a supply chain optimization model is created, and the model’s parameters are adapted to various modular structures. This optimization model is used to evaluate the test product’s minimal LCC and EI in the supply chain. To determine the optimal modular structure using this model, a heuristic is created to generate modular structures for evaluation. Using the ASCEM, a designer is then able to identify not only the most beneficial modular structure during the configuration design but also an optimal supply chain allocation for the identified modular structure. Two existing products covered by the Waste of Electric and Electronic Equipment (WEEE) Directive (refrigerator and coffee maker) are used to demonstrate ASCEM. For methodology validation, ASCEM is compared with a common modular design method (the Decomposition Approach) and subjected to an applicability test for product variety. The results demonstrate that ASCEM can effectively and efficiently find a near-optimal modular structure with low LCC and EI for the tested products. Additionally, a preliminary sensitivity analysis of capacity levels in a closed-loop supply chain (investigating whether a product’s reverse supply chain conditions significantly affect design decision making) reveals that reverse supply chain conditions ought to be considered in the modular design process.