Maney Publishing (on behalf of the Institute of Materials, Minerals and Mining)
ASHCROFT, I.A. ... at al, 2012. Environmental ageing of epoxy-based stereolithography parts. Part 2: effect of absorbed moisture on mechanical properties. Plastics, Rubber and Composites: Macromolecular Engineering, 41 (3), pp. 129-136.
The first part of this paper demonstrated how the quasi-Fickian moisture uptake exhibited by
stereolithography resins could be modelled. This part outlines the effect of moisture
absorption on the mechanical properties of one of the materials. Fickian and dual-Fickian
diffusion models, using both analytical and FEA techniques were used to model the moisture
uptake in aged samples. Uniaxial tensile testing of dog-bone samples revealed a decrease in
elastic modulus and yield stress and an increase in strain to failure with increased moisture
content. A model has been developed to predict the change in stiffness of aged samples over
time. The results produced from this model show a good correlation to the experimental data
and FEA predictions. It is proposed that FEA based coupled stress-diffusion analysis methods
can be used to predict the effect of moisture on the mechanical performance of parts made by
SL when used in service.