New resin Film infusion process for manufacture of large composite structures

A new process developed for the manufacture of large composite structures was presented. The basic idea is the use of a porous media (sponge) that is impregnated before placing it upon the dry preform with the aim of generating impregnating flow perpendicular to the reinforcement layers only. The major advantage of this process is the drastic reduction of the resin flow path that corresponds to shorter infusion time compared to the classic infusion methods. In the present work, the process (principle) criteria, the influence of the staking sequence and the sponge type were studied with the aim of understanding the process features. The typical defects were analysed by means of microscopy and the mechanical properties were measure in three-point bending tests and compared with those of specimen obtained by hand lay up and other infusion processes. The performed test indicate that the new process is able to produce high quality composites if the flow dynamics were well taken into account, however this do not appear as a problem. The fibre volume fraction, the modulus and the strength measured were sensibly influenced by the stacking sequence, remaining about the same when the plies number was increased maintaining the same sponge thickness. finally it was found that the developed process is a valid alternative to hand lay up and other infusion processes in terms of mechanical properties, with the advantage of a drastic reduction of the impregnation time.