Manual 2-dimensional Fabric Steering, for the Manufacture of Variable Stiffness Panels

Abstract

In recent years, Automated Fibre Placement has been applied in manufacturing variable stiffness panels containing continuously changing fibre paths. The aim is to achieve superior mechanical properties, compared to straight-fibre laminates [1,2]. This paper proposes a novel low-cost manufacturing technique, referred to here as ‘manual 2D fabric steering’. The process is able to manufacture similar variable stiffness panels to those produced using Automated Fibre Placement. By manipulating biaxial fabrics, curvilinear fibre paths can be created. The technique involves very low equipment costs and can be used to steer multiple-layers of fabrics simultaneously (in contrast to the tow-by-tow and layer-by-layer fibre deposition method in Automated Fibre Placement), leading to faster production rates and lower costs, at least for smaller production runs. A computer aided engineering tool, SteerFab [3], is used to guide the design and manufacture process by predicting: (a) the optimum 2D fibre paths, (b) the subsequent mechanical behaviour of the resulting variable stiffness panel (including improvements in buckling resistance) and (c), the step-by-step instructions for the actual manufacturing process. In this paper, manual 2D fabric steering is described and the effect of the manipulation sequence on the final steered fabric preform is investigated. The repeatability of the process is also examined.