Development of design methodology for product life cycle engineering

Abstract

Life cycle engineering of a product which facilitates product life cycle need to be considered at earlier design stage, i.e., at conceptual design stage. However, it is necessary to develop procedures convenient to the designers in the design and development of products, while taking into consideration various aspects of product life cycle, at conceptual design stage. This thesis deals with the development of design methodology for product life cycle engineering. The methodology is based on graph theory and matrix approach. The life cycle engineering aspects included in this thesis are; LCD modelling and evaluation ; life cycle assessment modelling and evaluation; life cycle cost modelling and evaluation, and sustainability modelling and evaluation of products using graph theory and matrix approach. Product design features such as, design for performance, design for manufacture, design for marketing, design for safety, design for maintainability, design for environment, and design for disposal/recycle which influence the product throughout its life cycle have been identified, in general, and are called LCD attributes. The relationship among these attributes is modelled in terms of a digraph called life cycle attributes digraph. A one-to-one matrix for the digraph is defined to obtain a matrix function and the index of these. A higher value of the index implies better design alternative of product from LCD point of view. This helps the designer to select the best design alternative from life cycle engineering point of view based on product life cycle. Life cycle assessment modelling and evaluation of product on the basis of tribological applications is obtained using graph theory and matrix approach. Tribological applications which influence the life cycle assessment of a product have been fully identified in a logicaland systematic manner and are called life cycle assessment attributes.