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Abstract
Reuse of components as opposed to material recovery, recycling or disposal
has been identified as one of the most efficient EOL strategies for products. The
concept behind reuse is that some components and subassemblies have a
design life that exceeds the life of the product itself. In order for reuse to be
successfully implemented as an EOL strategy, a designer needs to incorporate
into a product a philosophy of Design for Reuse (DfRe) at the early design
stage. Reliable methods to assess the remaining life of used components based
on a products usage life are also required. Furthermore, current industry
practices and literature advocate that there is no methodology to decide which
parameters need to be redesigned so as to change the life of a selected
component to a desired level.
The objective of this research is to develop a methodology to assess the reuse
potential of product groups based on component failure mechanisms and their
associated critical lifetime prediction design parameters. Utilising these
clustered groups mathematical models were then developed to establish the
useful life of the components for each clustered group. Finally, a means of
equating useful life to design life was established and the relationship between,
the failure mechanisms, critical lifetime prediction design parameters and
design life were represented in graphical format.
In order to achieve the proposed objective, Cluster analysis, in particular Group
Technology (GT) and Hierarchical clustering were employed to group
components with similar failure mechanisms. Following this, multiple linear
regression was used to establish mathematical models based on condition
monitoring data for each of the clustered groups and their related critical lifetime
prediction design parameters. A sensitivity analysis was conducted using the
mathematical models, in order to produce graphical relations between the
useful life and design parameters of a product.
The validity of the suggested methodology was tested on electric motors and a
gearbox as both these components have demonstrated great reuse potential.
The results demonstrate that the methodology can assist designers in
estimating the design life and associated design parameters with great
accuracy, and subsequently aiding in a stratagem for reuse.