The next generation of light alloys for aerospace applications is being engineered using computer simulations. An understanding of material requirements is gained through analysis of post-buckling, fatigue crack growth and residual strength. If the airframer’s computer models cannot be used by the materials producer, Alcan Aerospace uses its own tool called PAnel. It launches the meshing and analysis of a user defined stiffened panel configuration on a commercial finite element package of proven reliability. PAnel is applicable to both wing and fuselage configurations, with curvature, pressurization and bi-directional stiffening included. It can generate models with rivets as well as monolithic structure. Although shell elements are used, growth of cracks up into integral stiffeners can be simulated through a user defined ratio of crack growth rate in skin / crack growth rate up into the stiffener, an approach that compares well with test data. The large deformation capability of the finite element solver used (MSC MARC) yields accurate analysis of post-buckling designs, in those situations where analytical-empirical approaches are less applicable. Welded structure is an important example.

Once the target properties have thus been defined, physics-based metallurgical computer models are applied to reduce testing matrices and generate quantitative predictions of key properties. Significant reductions in alloy development lead times can be achieved if all experimental alloys are already optimized with respect to their position in the phase diagram, i.e. contain as much total solute as needed or possible whilst remaining solutionizable. Based on the knowledge of the phase diagram of Al-based alloys, a PC-based software package designated Prophase has been developed to calculate such optimum compositions. For 7xxx-alloys, a special tool has been developed to predict yield strength, fracture toughness, conductivity and microstructure for a given composition and processing route: Computer Aided Metallurgy (CAM) 7000.