Skip to main content

Advanced Concepts for Primary Metallic Aircraft Structures

Exploitable results

The aeronautical industry needs new validated concepts for reliable and cost effective airframe structure in order to compete on the global market. Much improvement in large scale structure is achievable by integrated concepts in which design, material and manufacturing routes are optimised towards structural performance requirements, weight and cost. The objectives of the ADPRIMAS program have been to demonstrate the feasibility of advanced design concepts. These design concepts are focused on applications in fuselage panels and suitable for a range of aircraft, including regional, medium to long haul types, and future very large aircraft. -Experimental stress analysis techniques, new developments are made possible by advancements in the areas of physics and computational process power. Stereolithography is currently used in a fairly limited sense for the visualisation of small CAD generated components. This project will enable the stress freezing and tomographic techniques. The low stress optical sensitivities of Stereolithography has been investigated using new automatic polariscopes that are one order more sensitive. Micro Moire, the introduction of very fine grids 3000-4000 lines per mm has enabled to measure strain to microscopically detailed components. Macro Moire new methods has been investigated for non-linear run-away structural behaviour. -The welded panel approach for aerospace application is highly innovative. An in house program was done in Deutsche Airbus, but this concerns stringers onto skin with integral stringer. The manufacturing concept in the present project proposal, has seen major advancements concerning extrusions welding and creep-forming simulation. -Current large extrusions do not reach the very close dimensional tolerances required for fuselage panels and these panels are not welded. In this research extruded welded panels have been manufactured and tested for both narrow and wide body aircraft. The creep-forming technology numerical simulation was applied to predict the radius of curvature of a creep-formed panel. -Glare panels for stiffened panels with longitudinal joints were being tested for damage tolerance. The innovation has been the technical complexity in the design, window cut-out shear-tie and longitudinal joints. Currently such designs are only state of the art for conventional materials, in this research the new concepts are applied for GLARE and other mechanical environment. -Helicopter fuselage structures have been investigated for main design methodology (Damage Tolerance approach) applied to the main topics certification (JAR 29-Joint Aviation Requirement Part 29), welded structures and GLARE materials. Currently such topics are better investigated for the aircraft fuselage (Fix Wing) applications. -In the field of mechanical joint, although as old as aircraft design itself, still continue to have unexpected and currently unexplained problems. For riveted joint fatigue initiation has recently been observed at unexplained location near the upset head of rivets instead of the location of highest stress concentration. In this research squeeze effect using numerical and experimental tests has been investigated and finalised for fatigue life prediction under squeeze load control.