Forming and consolidation of textile composites
Textile composite materials are of increasing interest not only in the automotive and aerospace industries, but also in other fields such as in the sporting and the marine sectors. However, textile composite materials are not always easy to form and consolidate, and defects such as voids, fibre displacements or wrinkling can inhibit the mechanical performance of the final component. Current tendencies in the textile composite industry focus on predicting such problems through the use of software packages for composite forming, such as PAM-FORM (ESI Software) and PATRAN Laminate Modeler (MSC. Software Ltd.). However, these packages are in their infancy, and so further work is needed to validate their results. This thesis is concerned with the manufacturing of components from textile composites, and addresses the effect that process parameters and deformation have on the consolidation of the component. A simple vacuum forming process is chosen because process parameters are easily controllable and complicated components can be produced at a reasonable cost. A consolidation model is proposed, which predicts the level of void content of a component as a function of the processing parameters, based on experimental data. The validity of the model is assessed by comparison between predictions and measurements, which were correlated with mechanical property' measurements to illustrate the effects of processing on subsequent performance. A combination of theoretical models is proposed to predict the effects of void content and in-plane deformation on mechanical properties. Finally, an automated strain analysis system used in the metal forming industry is adapted to analyse components formed from composite materials and parameters such as fibre angle, extension ratios along the fibre direction and change in thickness on demonstrator components are measured. These measurements are used to validate deformation simulations based on draping algorithms.