Impact Dynamics of a Dragonfly Wing

The lift force was reported not to be high enough to support the dragonfly’s weight during flight in some conventional investigations,and higher lift force is required for its takeoff.In this study,by employing a thin plate model,impact effect is investigated for the wing deformation in dragonfly flapping during takeoff.The static displacement is formulated to compare with the dynamical displacement caused by impact.The governing equation of motion for the impact dynamics of a dragonfly wing is derived based on Newton’s second law.Separation of variables technique and assumed modes method are introduced to solve the resulting equations.Further,lift force is presented for the cases of considering and without considering the impact on the wing flapping which indicates that the impact has prominent effects for the dragonfly’s aerodynamic performance.Numerical simulations demonstrate that considering the impact effect on the wing flapping can increase the wing deformation,which results in the rise of the lift force.The enhanced lift force is of critical importance for the dragonfly’s takeoff.