NOVEL HEAD CONTROL ALGORITHM FOR 3D CONTINOUS TOW SHEARING

It has always been challenging to manufacture a composite structure with complex geometry using automated fibre placement (AFP) process. Typically, the tool surface is difficult to be tessellated using fibre tapes with a finite width, without producing gaps and overlaps, and requires fibre steering along non-geodesic fibre paths, which produces defects such as tape buckling and pull-up. In this work, a defect-free fibre-steering process on a complex doubly-curved surface was demonstrated by realising the continuous tow shearing (CTS) process in three dimensions. A new head control algorithm was developed, which defines the head orientations and trajectories based on a pin-jointed strip (PJS) model, to manipulate the fibre tow using both in-plane shear and out-of-plane twisting deformations. Fibre steering process using this new algorithm was tested on a doubly-curved surface, using an industrial robot arm with a CTS prototype head, and its lay-up quality and accuracy were assessed by using a three-dimensional laser scanner. The new control algorithm enables defect-free fibre steering on complex 3D surfaces allowing for simplifying the design and analysis of novel composite structures.