P. Lequeu, ALCAN Pechiney Rhenalu, Issoire, France; A. Danielou, Alcan, Voreppe, France; B. Commet, D. Dumont, ALCAN CRV, Voreppe, France
Aircraft manufacturers are challenging material suppliers for solutions to increase performance of their airframe structures. Advanced alloys are one straightforward way to decrease weight and thus increase structural performance. This can be done through higher strength and/or improved toughness and fatigue, with additional benefits coming from the reduced density and higher stiffness of the recently introduced third generation of Al-Li alloys.
Another way of optimising the structures is to select alternative joining techniques: for example, fusion or friction stir welding could lead to weight savings provided that the alloy(s) and associated processing are appropriately selected and that the loss in the heat-affected zone is more than compensated by the gain due to decreased number of detrimental-to-DT holes in the structure.
A third way of generating weight benefits is to use new concepts. In the past few years, Alcan has introduced to the aerospace community two such ideas, e.g. pre-machined plates and crenulated structures. In the first case, pre-machining of a plate before quenching was shown to lead to an improvement in the thinner quenched part properties, allowing a better use of unitized structures. In the second case, adding longitudinal crenulations while maintaining a constant stringer bay section was demonstrated to lead to a very impressive CGR improvement of the corresponding structure.
The presentation will describe additional new concepts which were successfully tested by Alcan over the past couple of years. It will be shown how a detailed understanding of the wing design allowed to invent ways to improve the performance of a wing structure. Results of full-scale industrial trials will be presented.
Summary: Aircraft manufacturers are challenging material suppliers for solutions to increase performance of their airframe structures. Advanced alloys are one straightforward way to decrease weight and thus increase structural performance. This can be done through higher strength and/or improved toughness and fatigue, with additional benefits coming from the reduced density and higher stiffness of the recently introduced third generation of Al-Li alloys.
Another way of optimising the structures is to select alternative joining techniques: for example, fusion or friction stir welding could lead to weight savings provided that the alloy(s) and associated processing are appropriately selected and that the loss in the heat-affected zone is more than compensated by the gain due to decreased number of detrimental-to-DT holes in the structure.
A third way of generating weight benefits is to use new concepts. In the past few years, Alcan has introduced to the aerospace community two such ideas, e.g. pre-machined plates and crenulated structures. In the first case, pre-machining of a plate before quenching was shown to lead to an improvement in the thinner quenched part properties, allowing a better use of unitized structures. In the second case, adding longitudinal crenulations while maintaining a constant stringer bay section was demonstrated to lead to a very impressive CGR improvement of the corresponding structure.
The presentation will describe additional new concepts which were successfully tested by Alcan over the past couple of years. It will be shown how a detailed understanding of the wing design allowed to invent ways to improve the performance of a wing structure. Results of full-scale industrial trials will be presented.
