Development of a generic geometry to test the limits of automated draping and stamp forming processes in composite manufacturing

There are many process parameters that are important in automated composite manufacturing, starting with the handling of fabrics in the preforming process. Characterization of fabrics on their preforming qualities – which will be referred to as drapability in this paper – is necessary to tune the manufacturing process. The location where the fabric is held, the amount and direction of tension applied to the fabric, the order in which it is deformed, all play a major role in how much in-plane shear deformation a fabric can undergo. The inclusion of process parameters in the characterization of fabrics on drapability is therefore important. In this paper a method is developed to determine the critical shear angle of a fabric whilst including process parameters. A family of geometric shapes is derived and a testing procedure to determine the critical shear angle of a fabric using these shapes is proposed. It is discussed how the presented process can be used to tune draping and stamp forming processes in automated composite manufacturing.