Comprehensive approach for informed life cycle-based materials selection

The choice of a particular material, for a certain product, to perform a certain function, is a task that is all too often jumped over, either because the choice looks obvious, or because habits of convergent thinking lead the engineering designer to persist in the most usual material for the application. Done in the early stages of product development, the choice of materials involves complex decision-making processes, balancing intricate functional, technological and economic criteria reflecting the function of the part/product, the manufacturing process and the production volumes and final cost. Development teams rely on some basic methods to decide on materials using engineering properties as benchmarks, but such methods seldom address the whole problem of material-function-shape-process-cost-environmental impacts. This paper starts with an overview of the existing methods for selecting materials and then moves onto propose a new selection procedure (Materials Selection Engine) that overcomes some of the limitations found in the former methods. It uses the materials engineering properties to accommodate their technical fitness, but also considers life cycle cost items and environmental impacts to create a decision space in which the best materials for the application are mapped and classified. According to the importance the design team wants to give to economics and environment issues and to upstream and downstream life phases more informed decisions can then be made. A case study is presented aiming at a better understanding of the procedure proposed.