The general use of textiles began twenty-seven thousand years ago. However, today, textiles are used, not only in the production of clothing but are also found in numerous applications in medicine, the military, transport, construction sectors and in many industrial applications. Normally textiles are passive, however active textiles have been developed that exhibit the capability of adapting their functionality according to changes in their surroundings, i.e. environment. Such textiles are known as Smart and Interactive Textiles (SMIT) and are capable of sensing and being active. The integration of semiconductor devices into textiles has enormous potential in the creation of SMIT. Such SMIT structures will pave the way for the creation of truly-wearable electronic systems in the near future. The aim of this research is the development of a core technology for embedding functional semiconductor devices within the fibres of a yarn, in order to create electronically-active yarns (e-yarn). Such electronically-active yarns will be the building blocks of the next generation of wearable electronics. Moreover, this will facilitate the creation of innovative solutions able to overcome current problems and difficulties which the manufacturers of wearable textiles are experiencing and open the doors for designers to develop the next generation of truly-wearable computers which are comfortable to wear, flexible and washable. The e-yarns could be used in medical applications such as monitoring of ECG, respiratory patterns, blood pressure and skin temperature. They could be adopted by industries such as automotive, retail, manufacturing, military, the internet of soft things, consumer products, sports, fashion and entertainment. The development of the core technology required raw materials analysis in terms of physical, mechanical and electrical properties; creation of interconnections of electronic semi-conductor chips with copper filaments; encapsulation of the interconnections to improve washability and provide extra mechanical strength to the core filaments prior to making the final yarn. The final step was the process of manufacturing yarns using the knit braiding technique. A number of prototypes of e-textiles were produced including illuminated yarns, thermistor yarns, RFID yarns, magnetic yarns, vibration sensor yarns, illuminated garment, illuminated car seat, RFID-intergraded garments, a temperature-monitoring fabric mat and temperature-monitoring socks in order to investigate the manufacturing viability, identify practical issues, and to promote the technology to attract further funds and potential commercial partners.

Liquid Composite Moulding (LCM) processes are identified as one of the most potentially advantageous manufacturing routes. The challenge currently is to increase their reliability and expand their applicability. To that end, it was perceived that there was a lack of an advanced integrated simulation tool for the manufacture of three-dimensional, multi-layer textile composites. The tools for the analyses of fabric forming and subsequent flow during LCM processes were simple and immature, with the latter suitable to describe flow in thin structures only. Another noted deficiency was that the simulations provided a single answer to any given problem. Industrial experience has shown that during mould filling, due to the nature of statistical variation in the material properties, the filling patterns and arising cycle times are rarely the same between a given set of identical mouldings. This thesis focuses on permeability prediction of textile reinforcements for LCM processes. The issue of textile variability was also explored through the use of the permeability models' predictive capability. Two novel and efficient numerical approaches were developed to predict textile permeability based on the fabric architecture. The objective was to reduce the complexity of the flow domain and hence provide a faster method to fully characterise the permeability of a textile. Within a wider context, these models were implemented within an integrated modelling framework encompassing draping, compaction and impregnation, based on the TexGen textile schema. TexGen is a generic geometric textile modeller that can be used to create a wide range of textile models. Several validation studies were performed using a range of reinforcements including woven and non-crimp fabrics. A stochastic analysis technique was developed to account for the effect of material variability on permeability. The study based on this technique provided important insights into permeability variations. It was shown that the permeability distribution is a strong function of the textile architecture. The permeability models developed from this work can be used to account for the effects of fabric shear/compaction and statistical variations on permeability. These predicted permeability data can complement experimental data in order to enhance flow simulations at the component scale.