Method of manufacturing folded structure with additive features

A method of manufacturing a multi-sided formed engine pylon structure which is a component of an aerospace vehicle, the method comprising:

• constructing a base structure using a first construction technique;
• creating one or more fold lines of reduced cross-sectional thickness in the base structure;
• incorporating one or more additional features into the base structure using an additive manufacturing technique to create an intermediate structure, wherein the one or more additional features include one or more stiffening ribs configured to physically stiffen the multi-sided formed engine pylon structure;
• refining to a tolerance an area of the intermediate structure which will be located within an internal space defined by the multi-sided formed engine pylon structure;
• folding the intermediate structure along the one or more fold lines of reduced cross-sectional thickness to create the multi-sided formed engine pylon structure having two or more sides, wherein at least one of the one or more additional features is located within the internal space defined by the multi-sided formed engine pylon structure;
• welding along the one or more fold lines between the two or more sides of the multi-sided formed engine pylon structure;
• and
• incorporating a closeout element into the multi-sided formed engine pylon structure, wherein the closeout element further defines and closes the internal space.