Crack-induced changes in divergence and flutter of cantilevered composite panels

The aeroelastic characteristics of a cantilevered composite panel of large aspect ratio and with an edge crack are investigated. The panel consists of several fiber-reinforced composite plies, and is modeled with a one-dimensional beam vibrating in coupled bending and torsion. The fundamental mode shapes of the cracked cantilever are used to study the interaction between a crack and aerodynamic characteristics by employing Galerkin's method. Variation of the divergence/flutter speed with respect to the crack ratio, its location as well as the fiber angle is investigated. The divergence/flutter speed is more sensitive to the bending-torsion coupling parameter than to the presence of the crack. The crack may or may not reduce the divergence/flutter speed, depending on the fiber orientation. The qualitative analysis may help the development of an online prognosis tool for an aircraft with large aspect-ratio unswept composite wings.