عنوان مقاله [English]
Aircraft flexibility causes problems and difficulties which this problems even might endanger health and safety of the aircraft. This phenomena changes dynamic response of the aircraft to surface control and gust inputs with respect to the rigid models. Also, it has diverse effect on flight quality and handling characteristics. As a result, considering flexibility effects on dynamics response of aircraft is significant which requires that coupled dynamic and vibrational equations of aircraft. The present paper, introduce the dynamics of a large aircraft has been developed on base of a six degree of freedom model, which includes two rigid and four flexible degrees. Quasi steady aerodynamics has been used to describe interaction between solid and fluid dynamics. The essence of this model, enhance perdition of dynamic response to gust and other external disturbances, because of its effects of elastic modes. The characteristics of this external disturbances and elastic model, causes more flexible modes to be exited and strain energy ratio in general dynamics of the aircraft, increases. The effects of different parameters, like stiffness, gust length and profile, has been studied in numerical simulation.