Tailoring for Strength of Steered-Fiber Composite Panels with Cutouts

The traditional approach to the problem of stress concentrations around cutouts in composite structures is to locally increase the laminate thickness in order to smooth out the stress peak. Often, this practice attracts more loads to the cutout region besides increasing part weight. A more effective solution is to avoid the stress concentrations altogether by using fibre-steered laminates. The production of composites in this format is practical nowadays due to capabilities of advanced fibre-placement technology. This paper shows that it is possible to design and manufacture composite panels whose failure responses is insensitive to the existence of a central hole. This cutout insensitivity does not involve an increase in structural mass, but only the steering of the fibres in the plane of the laminate, in order to promote the redistribution of the loading towards the supported edge sections of the panel