High Fidelity Crash Analysis of Ngctr-TD Composite Wing

Abstract

The T-WING project is a research project aimed at designing, manufacturing, qualifying and testing the new wing of Leonardo Next Generation Civil Tilt-Rotor technical demonstrator (NGCTR-TD), as part of Clean Aviation Fast Rotorcraft activities. The methodology proposed in this paper encompasses the development of high-fidelity modelling and simulation procedures in support to virtual certification methods for crashworthiness requirements of tiltrotors. Finite Element Analysis (FEA) of an aircraft drop test is a complex and detailed process that aims to simulate the structural behaviour during an impact or drop event. This type of analysis is critical for assessing the safety of an aircraft in emergency landing situations. Wing crashworthiness requirement is specific for tilt rotors: during a survivable crash event, the wing design must ensure a pre-defined rupture with the purpose of alleviating the inertial load acting on the fuselage to preserve the occupants from injuries and fire, guaranteeing the escape paths. Thus, the highly integrated T-WING wing box concept has been designed with the specific feature of frangible sections near the wing-fuselage intersection. The activation of fracture of the external semi-wings in correspondence of frangible section is triggered by the achievement of a well-defined crash vertical load factor. The objective of the methodology is to simulate the crash effects on the whole wing, using explicit non-linear and time-dependent FE analysis, to verify the wing spanwise placement of the frangible sections, the failure mode, the loads acting at the fuselage links, and the acceleration transmitted to the structure. This work is focused on a standalone analysis of the wing plus a lumped scheme of the fuselage, and it is part of a wider activity which will comprise, in the crash simulation, the most relevant vehicle systems (e.g. fuselage model). Moreover, this numerical activity has been compared with experimental results obtained on a different but similar structure, in terms of global acceleration at wing centre of gravity. Good agreement in terms of acceleration has been found between numerical model and experimental relevant test.