A method for fabricating a composite panel comprising stitching a plurality of first continuous reinforcing fibers in N first zones and M second zones of a backing substrate of a preform. The N first zones are arranged near C corners of the composite panel, where C is an integer. The plurality of first continuous reinforcing fibers in the N first zones is arranged radially relative to the C corners. At least one of a fiber density of the plurality of first continuous reinforcing fibers in the N first zones that is less than a fiber density of the plurality of first continuous reinforcing fibers in the M second zones, and a stitch density of the plurality of first continuous reinforcing fibers in the N first zones that is less than a stitch density of the plurality of first continuous reinforcing fibers in the M second zones.