Initiation and growth of transverse and longitudinal cracks in composite cross-ply laminates

Fibre steering of composite tows within lamina is being investigated as a means of producing composite components with increased strength or stiffness when compared to the commonly adopted unidirectional and fabric laminates used in industry. The concept of fibre steering and application to a tensile plate with an open hole and a pin-loaded hole is reviewed. The design and manufacture of fibre steering along trajectories for a cantilevered C-section beam representative of an aerospace control surface spar is then described. The results of experimental testing and finite element analysis of the beam are presented. The results indicate that a significant reduction in deflection is possible over an equivalent flange-stiffened design.