Tow placement studies for liquid composite moulding

This thesis describes the work undertaken developing techniques for the design and manufacture of continuous fibre preforms for liquid composite moulding. A prototype tow placement facility based on the roller placement of up to 5 tows onto a flat bed was developed. This was used to prepare preforms for 4 industrially based demonstrator components which were subsequently successfully moulded. In tests vibrational performance of parts so manufactured showed slight improvements in mechanical performance compared with those manufactured from conventional reinforcement. The facility was also used to lay down preforms, the fibre structure of which had been generated by undraping a 3 dimensional model of the finished component. In this manner the performance of the composite, of both mechanical strength and permeability during injection could be optimised. The lay down machine was also used to generate performs with a well defined built in waviness to the fibre structure. This material was used to generate information regarding the degradation in performance when waviness is introduced and also the effect on permeability during the injection phase