Patent ID: 7753312

Claim:
A lightweight structure comprising an outer sheet metal material skin, a reinforcing frame including ribs and stringers, said ribs and stringers having skin facing surfaces having a width within the range of 10 to 80 mm, said outer sheet metal material skin comprising a sheet metal material wherein cracks can occur, wherein said sheet metal material is selected from the group consisting of aluminum alloy, magnesium alloy, titanium alloy and fiber metal laminates, and at least one fiber reinforced crack propagation retarding strip interposed between said outer sheet metal material skin and said skin facing surfaces of any one of said ribs and stringers forming said reinforcing frame, said at least one fiber reinforced crack propagation retarding strip having a strip width within said range of 10 to 80 mm of said skin facing surfaces, and an adhesive bond between said at least one fiber reinforced crack propagation retarding strip and said outer sheet metal material skin and a further adhesive bond between a respective skin facing surface of any one of said ribs and stringers forming said reinforcing frame and said at least one fiber reinforced crack propagation retarding strip.