Aeroelastic Divergence of a Randomly Cracked Thin-Walled Beam

Abstract

Aeroelastic divergence, which strongly depends on the torsional stiffness of the aircraft wings, is of concern in the design of aircraft. This paper examines the effect of a discrete damage, such as a crack, on the divergence dynamic pressure of a wing. The wing is represented by a simple model of a thin-walled beam with a crack with random characteristics. Two approaches are used to calculate the divergence dynamic pressure: an iterative approach when the mathematical model is difficult to analyze, and the direct approach, which can only be used if the response for the model can be expressed in closed form. For the assumed simple model of a thin-walled beam with a longitudinal crack, both approaches could be applied. The effects of the location and the size of the crack on the divergence dynamic pressure are examined. The effect of the uncertainties in the crack location and size on the divergence dynamic pressure is examined probabilistically.