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Novel textile-like linked structures, realised using a rapid manufacturing (RM) process, have been proposed and developed recently. Various potential applications exist, and in most cases the mechanical performance must be evaluated. The present paper outlines a method to solve this problem by employing finite-element (FE) techniques at two scales, using the results of analysis at the meso-scale (the scale of the repeating unit) to provide equivalent non-linear spring behaviour for each textile link at the macro-scale. Validation with experimental test data from each scale was performed and these results are presented. Initial results overestimated mechanical performance. Microscopy suggested that this may be due to edge porosity in the specimens, and the dimensions of the FE models were adjusted accordingly as an initial approach to account for this. Predictions incorporating this modification exhibited excellent agreement with experimental measurements. The current work demonstrates both a technique, which could be automated for use in the design environment, and the potential value of developing an integrated process simulation to provide local material property data for the FE model. [ABSTRACT FROM AUTHOR]

The use of moulds produced by stereolithography (SL) for injection moulding provides a quick route to manufacturing a low volume of parts without expensive hard tooling. However, these parts have been shown to exhibit different material property characteristics than those produced from metal tooling. The aim of the present work is to research methods that would allow SL moulds to produce parts of similar material property characteristics to those from conventional metal tools. This work has identified that the different part characteristics are due to differing levels of crystallinity developed in the parts from the comparative mould varieties (SL and metal). These crystallinity differences have been associated with the cooling rates imparted owing to the thermal properties of the mould material. The latter part of this work concerns controlling and manipulating this degree of crystallinity. After a discussion of possible methods, two approaches are taken to modifying the crystalline content of parts produced by SL moulds. One of the approaches is material based, the other concerns the injection moulding process. Differential scanning calorimetry (DSC) is used to quantify the resulting levels of crystallinity in the parts. The results show that by process modification it is possible to produce parts by SL moulding that possess a similar crystalline content to those moulded from metal tooling. The use of modified materials allows parts created in SL and metal tools to be of a consistent crystalline content. The work concludes that not only are SL moulds capable of producing parts that are more like those from metal moulds but also present some unique opportunities that have been demonstrated to be unachievable in metal moulds. [ABSTRACT FROM AUTHOR]