Developing insect-like flapping-wing drones from scratch is an ambitious and arduous task for designers due to a lack of well-established know-how. To speed up the development of such vehicles through the preliminary design stage, a framework modeling the aeroelastic phenomena encountered in insect flight is an asset and is the subject of this thesis. Its kernel is a FEM based structural solver coupled in a blade-element approach to a quasi-steady aerodynamic model of insect flight accounting for the wing flexibility, both in the spanwise and in the chordwise direction, and for its large displacement. The complete framework is devised so as to maintain the computation load low while being modular enough for a wide range of applications. To validate the overall aeroelastic framework, a two-steps process has been undertaken with in one hand numerical studies and in the other hand experimental ones acquired on a dedicated test bench. The framework computation agrees satisfactorily, capturing the damping due to the aerodynamic force, and thus paves the way for preliminary design applications of a flapping-wing vehicle. To exhibit the capabilities of the framework as a preliminary design tool, two applications on a resonant nano air vehicle are performed: the definition of an efficient actuation strategy and the search of an aerodynamic potentially interesting wing geometry by plugging the framework to a genetic algorithm. The results are coherent with the ones found in nature and are under implementation on the nano air vehicle.