Analysis of three-dimensional textile preforms for multidirectional reinforcement of composites

• Published in: Journal of materials science 1991-07, Vol.26 (13), p.3438-3448
• Main Authors: GUANG-WU DU, TSU-WEI CHOU, POPPER, P
• Format: Article
• Language: English
• Subjects: Applied sciences; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Technology of polymers
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/BF00557129

A mathematical model has been developed to describe the structural geometry of three-dimensional textile preforms made by the two-step braiding process. These structures consist of parallel yarns, interconnected with braiding yarns that lie in complex spatial orientations. The model predicts structural features such as fibre orientation, fibre volume fraction, and interyarn voids from the key process variables of braiding pattern, advance rate, and yarn geometry. The limiting geometry was computed by establishing the point at which yarns jam against each other. Using this factor makes it possible to identify the complete range of allowable geometric arrangements for this type of preform. Experiments of several bare and impregnated samples such as Kevlar 49/epoxy confirmed the theoretical predictions and demonstrated that very high fibre loadings ( > 75% fibre volume fraction) could be achieved. The modelling technique used a "unit cell" approach, which can be applied to many other types of preform for advanced composites. Graphs. 11 ref.--AA