Complex wing spar design in carbon fiber reinforced composite for a light aerobatic aircraft

The challenge concerns the realization of the lightest composite wing for E-FAN prototype 1.0 aircraft. This wing must be dismantled and must support critical loads for aerobatics. The bonding conception between the composites parts must transfer the high loads. This article presents a methodology to design a multi-materials structure with a complex geometry of varying thickness. So, the mechanical behavior must be known for the structure, as well as their weaknesses which can involve the rupture. For that, numerical simulations are elaborated in taken into account the constraints inherent in the manufacturing processes and DGAC's requirements (Direction Generale de l'Aviation Civile, French Authorities for Civil Aviation). The predictive character of these models is realized by numerical and experimental results correlations in order to optimize the numerical model accuracy. Indeed, the complete spar's sizing is validated by static rupture tests. This last point requires the building of a special testing equipment which is able to generate a load compared to the one applied in flight. Moreover, the testing metrology is used to quantify the accuracy level of models. Wing spar, central spar and central/wing bonding are qualified by DGAC for flight.