COMPACTION OF TEXTILE REINFORCEMENTS FOR COMPOSITES MANUFACTURING - I- REVIEW OF EXPERIMENTAL RESULTS

As new developments are brought to the group of manufacturing processe s for composite parts known as liquid composites molding (LCM), the co mpaction behavior of the textile reinforcements is increasingly seen a s an important parameter of the definition of these processes. The evo lution of the permeability tensor of the reinforcements with time, the general kinetics of the manufacturing operations, and the modelizatio n of these processes depend on a large extent on the compaction behavi or of the reinforcements used, especially in flexible-wall RTM and aut oclave molding. Also, more research efforts are devoted toward the dev elopment of a complete analytical model of the properties of heterogen eous textile reinforcements. In this paper the published experimental data related to the compaction and relaxation of random mats and woven reinforcements are gathered. Observed parameters are defined, which a llow numerical comparisons of the experimental curves to be made, as w ell as the identification of general trends seen with most tested rein forcements. The effects of various processing parameters are identifie d, and relations to published analytical models of the mechanical prop erties of fibrous assemblies are discussed.