Integrally stiffened extruded panels (ISPs) are aerospace structural components which are composed of both the skin and stiffeners in a continuous part made from the same piece of raw stock and are an effective way of obtaining high strength, lightweight structures.  Renewed focus on the use of extruded ISPs for the wings and wing box of larger commercial planes has been growing over the past few years due to improved extrusion techniques, advances in joining technology and the benefits of new aluminum alloys. 

Extruded ISPs offer cost saving opportunities for original equipment manufacturers (OEMs) as they can provide improved buy-to-fly ratios and can significantly reduce the number of fasteners required compared to a built-up structure, which reduces the time and cost of manufacturing.  The overall result of using ISPs is a reduction in cost and lower part count. 

This presentation summarizes the recent developments in extruded aluminum ISPs including the high performance new aluminum-lithium alloys, results of fatigue crack growth retardation design concepts and the outcome of joining evaluations, all of which provide beneficial options when tailoring an ISP to the customer’s application.