Redesign of an aircraft cargo door by using a cad-mbd-fem integration method

This paper focuses on the redesign of the ATR 42/72 cargo door. The redesign process has been carried out by using in an integrated manner CAD (Computer Aided Design), MBD (Multibody Dynamics), and FEM (Finite Element Method) codes. Basically, the CAD-MBD-FEM integration was carried out by employing a method based on the linear theory of elastodynamics. Immediately after the geometric assembling, the complete geometric model was conveniently simplified for creating a multibody model. In particular, the multibody modeling of the opening mechanism was carried out by defining the mass properties, the kinematic constraints, and the force fields. Subsequently, the possible interventions aimed at optimizing and electrifying the system under examination were identified. This led to the redefinition of the geometric shape of the latches and to the design of a connection shaft for their electrical movement. After performing an inverse dynamic analysis of the new latching mechanism, it was possible to determine the functional requirements for the electric motors. In virtue of this redesign, the overall weight is reduced of approximately 8% and the energy required for the latches opening maneuver is reduced of the order of 25%, thereby demonstrating the effectiveness of the approach adopted.