Proposal of Decision Support Method for Life Cycle Strategy by Estimating Value and Physical Lifetimes - Case Study

This paper proposes a decision support method for life cycle strategy based on estimation of product lifetime. In order to design the sustainable product life cycles, "life cycle strategy," especially best mixture of life cycle options, should be determined at the early stages of life cycle design. Lifetime is one of the most critical properties for determining the life cycle strategies and lifetime of a product can be decomposed into two kinds, physical lifetime and value lifetime. While the physical lifetime can be estimated by using the reliability theory, there were no techniques to estimate the value lifetime. The method proposed here enables estimation of both of physical lifetime and value lifetime by collecting users' disposal reasons and supports a designer to select appropriate life cycle options based on this estimation. This paper also illustrates practical case studies of cellular phone, vacuum cleaner, automobile, and secondhand automobile. The result revealed obvious differences in disposal patterns of these products. In other words, this methodology enables a designer to quantitatively classify disposal patterns of products and select life cycle options.