Composite element and method of manufacturing the same

A method of manufacturing a composite element, wherein the method comprises:

• forming a first skin plate and a second skin plate of composite material both comprising at least one binder material and at least one reinforcing material and said first skin plate and second skin plate being planar elements;
• arranging several local first additional composite structures on an inner surface of the first skin plate, wherein the local first additional composite structures are planar material layers whereby the inner surface comprises integrated additional structures at a distance from each other;
• bulging the first skin plate locally towards an outer surface side at the locations of first additional composite structures for forming protrusions on the side of the outer surface;
• attaching the inner surface of the first skin plate permanently against the second skin plate;
• and
• curing the composed structure;
• wherein
• the method further comprises forming the first skin plate and the second skin plate by laminating technique;
• laminating the first additional composite structures on the inner surface of the first skin plate thereby forming local stiffeners;
• and
• bulging, after forming the local stiffeners, the composite structure of the first skin plate and the first additional composite structures attached on an inner surface of the first skin plate together at the protrusions, wherein the protrusions are formed by simultaneous deformation of both the composite structure of the first skin plate and the laminated first additional composite structures.