Multi-criteria decision-making determination of material gradient for functionally graded material objects fabrication

In contemporary discrete product design, to fulfil some of the design requirements (such as mechanical, thermal, etc.), the material properties (such as material composition) of a design should be graded so that a functionally graded material (FGM) object is produced. With the advent of solid freeform fabrication (SFF) or layer manufacturing (LM) technologies, FGM objects are now possible and there different modelling schemes are proposed for modelling and representing an FGM object. However, determining the proper material composition of an object is an issue to be considered and methodology must be investigated. In the current paper, a methodology is proposed and used to determine the material composition of the model based on the computer-aided engineering (CAE) analysis results. The issue of material composition selection is formulated as a multi-criteria decision-making (MCDM) problem and one of the MCDM methods - ELECTRE III - is employed in the proposed methodology for identifying the optimal material composition alternative for different regions of the model. Applying the methodology, an FGM object will be produced and a reinforced FGM prototype can be fabricated by an appropriate LM process. Apart from the FGM object, the application of the proposed methodology in rapid tooling (RT) will also be discussed.