Updation of Structural Dynamic Response Simulation Using Measured Data for a Typical Naval Aircraft Arrested Landing

Field-measured data form a reliable and accurate means to validate and update simulation. In the present study, vibratory responses in the form of acceleration time data measured during the arrested landing of a typical naval fighter have been used to validate and update dynamic response computations. Naval aircraft operate from an aircraft carrier deck wherein landing recovery is done by the engagement of an aircraft arrestor hook by cables running across the deck. The aircraft usually approaches at a high rate of descent and forward speed and is brought to rest in a short duration and distance. This causes the airframe and equipment mounted inside to experience an initial shock followed by a transient vibration. In order to ensure that the landing shock does not result in unduly high responses of the airframe and installation of critical equipment mounted inside, it is necessary to predict the likely shock response levels experienced by the Airframe. The methodology adopted is to carry out dynamic response computations on a global aircraft FE model. The Shock Response Spectra (SRS) of computed acceleration responses are then compared with measured accelerometer data during arrested landing and the analysis model is updated based on this. This was implemented for a naval fighter application. For reasons of confidentiality, this methodology is illustrated here using a simplified 2D FEM of a naval fighter. These studies have helped to improve simulations and give greater confidence in the predictions. The updated simulations are used to predict responses for test points yet to be evaluated and also for conditions where actual flight tests may be risky or impractical.