Patent ID: 7946468

Claim:
A method for manufacturing a friction welded, expanded structural assembly, the method comprising: positioning at least two structural members in a stacked relationship; disposing at least one elongate member between the structural members, each elongate member extending along a path of a corresponding cell of the structural assembly and defining a passage therealong; friction stir welding and thereby joining the structural members in a predetermined pattern to form a preform defining at least one cell therebetween; and inflating the cell with a pressurized fluid to expand the preform to a desired configuration of the structural assembly, wherein inflating the cell comprises inflating at least that portion of the cell that surrounds and is proximate to the respective elongate member to a size larger than the respective elongate member while the elongate member remains within the corresponding cell such that the elongate member maintains contact with only one of the structural members with the contact being along a single line of contact, said friction stir welding step comprising forming a plurality of multiple-pass friction stir weld joints having at least two adjacent friction stir weld joints between adjacent cells of the preform such that the adjacent friction stir weld joints of each multiple-pass friction stir weld joint have a combined width greater than a width of each of the adjacent friction stir weld joints taken individually, said step of forming the plurality of multiple-pass friction stir weld joints comprising forming each of a plurality of the adjacent friction stir weld joints of a multiple-pass friction stir weld joint so as to at least partially penetrate at least two of the structural members such that the adjacent friction stir weld joints join at least two of the structural members.