Compaction of textile reinforcements for composites manufacturing. III. Reorganization of the fiber network

The objectives of this series of papers are to describe the mechanical beha vior of textile reinforcements under normal load and to quantify the effect s of diverse processing parameters on that behavior. In the first and secon d papers of the series, experimental compaction and relaxation results were reported; general trends were identified and the effects of changes in the processing parameters were analyzed. In this paper, the results of sequenc es of successive compaction cycles applied to dry textiles and to textiles saturated in distilled H2O and silicone oil are presented. The reinforcemen ts investigated are produced by assembling tows or rovings following differ ent patterns; it is shown that the resulting heterogeneity, or regular vari ation of the local fiber volume fraction, can be associated to some particu lar elements of the mechanical behavior of the reinforcements. The reorgani zation of the fiber network and the effect of friction at the fiber contact s are demonstrated. Different stages in the reorganization process are iden tified; each stage is controlled by different parameters and corresponds to a precise behavior. Successive compaction cycles applied to a preform can reduce the void content of the final part.