Patent ID: 8864074

Claim:
A stringer for use in an aerospace structure, wherein the stringer is made from composite material comprising a multiplicity of layers, the stringer has a foot and a web extending from an edge of the foot so that the stringer has a generally L-shaped cross-section along its length, the stringer defines a first surface on the foot being shaped to abut a structure to be stiffened, wherein the structure to be stiffened has a varying thickness or height along its length, a second surface on the foot being opposite the first surface, a third surface on or in the web being at the same layer in the composite material as the first surface, and a fourth surface on the web being on the same side of the stringer as the second surface, the geometry of the stringer varies along at least part of its length so that with increasing distance in a given direction along the length of the stringer, as the thickness or height of the structure to be stiffened varies along its length, the first surface is displaced in a direction towards the second surface as the fourth surface is displaced in a direction towards the third surface, whereby the risk of causing, during fabrication of the stringer, undesirable creasing, stressing or stretching of composite material layers in a region in which the geometry of the stringer varies with increasing distance along its length is reduced.