Nonlinear responses of a cantilever wing with an external store

Nonlinear responses of a cantilever wing with an external store have been studied. The system has three possible nonlinearities, including structural, aerodynamic, and store-induced nonlinearities. Structural nonlinearities are expressed by nonlinear beam theory with cubic nonlinearity present and aerodynamic nonlinearities are introduced by a quasi-steady, incompressible flow, stall model. The store-induced nonlinearities are related to the retention of the nonlinear kinematical terms present in the formulation of the governing equations of motion. To systematically investigate the response characteristics, bifurcation and phase plane analyses are performed. LCO responses can be easily detected by phase portraits, and additional characteristics could be identified by Poincaré maps. The effects of the velocity change are depicted in the bifurcation diagrams. For various cases, limit cycle oscillations are found for velocities less than the flutter velocity as predicted by linearized formulations. Some cases having different store parameters, such as chordwise position, store mass and store inertia, are examined. Depending upon the choice of store parameters, the results show regions of subcritical bifurcation characteristics in which the onset of limit cycle behavior or subsidence to zero depends upon the initial conditions. Other response characteristics of interest are also found.

Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference

Nonlinear responses of a cantilever wing with an external store Conference Paper