Processing characteristics of out-of-autoclave pre-impregnated discotex™ composites

This paper provides a summary of research performed using DiscoTex" fabric pre-impregnated with Cytec 5320-1. The study was focused on single diaphragm forming and was conducted to gain an understanding of the processing properties of this new material when formed over complex geometries. Advanced diaphragm forming utilizing pre-collimated prepreg laminates is a highly promising process in terms of reducing the manufacturing costs of composite components. A pre-impregnated discontinuous carbon fiber (DCF) reinforcement was formed over a sine-wave spar utilizing a single diaphragm forming process. Sine-wave spars are opposite sign doubly curved geometries that are known to be difficult to form without inducing wrinkling deformations. DiscoTex™ is a five harness satin weave DCF and was pre-impregnated with an out-of-autoclave resin system, Cytec Cycom 5320-1. During forming, varied parameters included: diaphragm stiffness, forming temperature, forming time, laminate thickness, laminate size and lamina fiber orientation. These parameters were investigated to identify the effects on component quality. The component quality is related to the in-plane shear strains generated during the forming process. In-plane shear strains were related to process parameters on a pass or fail criterion basis to determine the forming characteristics of the DCF material. This paper also provides a summary of prior published research in forming technology in order to establish the context within which this experimental study was performed.